eq | I : By . CHARLES E. SANDO. Se ane ae TION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRE- For THE Degree or Doctor oF PHILOSOPHY IN THE Maryann Stats CoLLece OF AGRICULTURE. : abe Contribution from the Bureau of Plant Industry WM. A. TAYLOR, Chief Washington, D. C. Vv September 7, 1920 THE PROCESS OF RIPENING IN THE TOMATO, CON- SIDERED ESPECIALLY FROM THE COMMERCIAL STANDPOINT: bs : y CHARLES E. SANDo, formerly Junior Chemist, Horticultural and Pomological Investigations. CONTENTS. Page. Page. Shipments of early tomatoes to northern Comparison of the composition of commer- MPA TRUS a eet cnc late tse cos Oabeiaeie sci ee 1 cially picked tomatoes with turning and Growing and handling tomatoes in the field - - 3 yane-ripened Mat 2e as ero c tor Seem coca -e ee 21 Packing and shipping operations. -.-....-.-.- 4 | Effect of lack of ventilation on ripening-..... 24 Previous chemical investigations of the Summary and conclusions. -.-...-.- 5 leer 30 HOWE Co.6 See secret oC ade sccneeas S42 se8cbes (el ellteratine CluCU eminence = mo han ele 32 Mxperimentalmaterialls. -o2o.---cse~-- 225s 13 | Appendix.—Comparison of the composition Mothodsiofianalysise oie ene nee treceo= 15 of ‘puffy’? and normal Livingston Globe Analytical data concerning progressive POMUALOCS as casetee ee aoe saarcee me nsneee aces 37 changes in composition during ripening. - 17 SHIPMENTS OF EARLY TOMATOES TO NORTHERN MARKETS. The shipping of tomatoes grown in Florida to northern markets during the winter and spring months is an exceedingly important industry. In Table I are presented statistics prepared by the Bureau of Crop Estimates and the Bureau of Markets of the United States Department of Agriculture, showing the production and car-lot shipments of the seven States where the early-tomato crop is chiefly grown. From the figures shown in Table I it can be seen that Florida ships annually more than half of the total quantity of early tomatoes forwarded from the seven States specified. Statistics show that 1 This bulletin gives the results of a portion of the work carried on under the project ‘Factors affecting the storage life of vegetables”. The paper was completed after the writer was transferred to the Office of Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Investigations of the Bureau of Plant Industry. ; The writer wishes to express his special indebtedness to Mr. Thomas J. Peters, of Miami, Fla., for pro” viding facilities for the field work and for cooperating in other ways. He desires also to express his thanks and appreciation to Mr. H. H. Bartlett, of the botanical department of the University of Michigan, for counsel and suggestions during the progress of the work. . 175085°—20—Bull. 859——1 2 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. the industry in Florida is very largely concentrated in Dade and Broward Counties, at the southern tip of the State. TaBLE I.—Production of early tomatoes in the principal producing States of the United States, showing also car-lot shipments, for the 5-year period from 1915 to 1919, in- clusive. Crop production (tons). Car-lot shipments.a State. 1919 1918 1917 1916 1915 1919 1918 1917 1916 | 1915 California.» -.4-2 4-26 17, 380 | 11,880 | 17,390 | 20,170 | 18,750 139 | 1,513 518 | 1,169 871 WIOKIGa sat Sse ee oe 58,520 | 46,800 | 77,480 |101,170 | 91,390 | 4,478 | 3,695 | 4,493 6,184) 4,692 ISOMISIA Geet ese ee alae ae 600 | 1,810 A 2, 524 2 10 5 58 Mississippi...-...-.--- 18, 400 | 21,150 | 15,680 | 25,250 | 20,100 | 61,388 | 61,379 |.61,063 | 61,663 | 61,690 Tennessee.-~-: -.. 2. < 6,000 | 10,500 | 13,020 | 29,320 | 24,010 366 654 947 590 529 (QRS soe tent wees oe 17,700 | 16,000 | 16,430 | 10,770 | 11,260} 1,198} 1,123] 1,276] 1,153 | 1,318 Wargintig see ece os ceck |cosceans 69,108 | 75,540 | 85,285 | 62,212 |.......- 97 173 192 121 Topalec ote eee pus; 000 [176,038 |217,350 |274,174 |230,246 | 7,571} 8,471 | 8,484 | 11,009 | 9,279 a Estimated at 13 tons per car except in Mississippi, where the average is 10} tons per car. b Carloads of 104 tons. In spite of the fact that thousands of cars of Florida tomatoes are shipped to the North each year, the quality of a large percentage that reaches the consumer is admittedly inferior in many respects to vine-ripened or greenhouse tomatoes. Tracy (52) 1 makes the following statements in regard to the inferiority of shipped fruit: The tomato never acquires its full and most perfect flavor except when ripened on the vine and in full sunlight. Vine and sun ripened tomatoes, like tree-ripened peaches, are vastly better flavored than those artificially ripened. This is the chief reason Why tomatoes grown in hothouses in the vicinity are so much superior to those shipped in from farther south. It is the custom to pick the fruit when grass green and allow it to ripen and color in ripening rooms before shipment, while in transit, and after arrival at the market. Numerous complaints have been made by commission men and others that a large pro- portion of the tomato crop from the east coast of Florida is picked and shipped too green. When this is done, the fruit ripens very slowly, has a tendency to wrinkle, colors abnormally, and has a bad taste and flavor. Moreover, for quite different reasons, the growers prefer, when shipping their tomatoes, to have the fruit arrive in a slightly colored condition. The arrival of green fruit at the terminal often has the effect of glutting the market. The buyer is compelled to hold the fruit while ripening and consequently assumes a risk of losing a portion, whereas if the shipment is colored when it arrives he is able to dispose of it immediately. Since the difficulties just enumerated bear a close relationship to field practice and to packing and shipping operations, the writer was stationed at Miami during the growing seasons from 1917 to 1919 in order to gain first-hand knowledge of the industry and to 1 The serial numbers in parentheses refer to “Literature cited” at the end of this bulletin. PROCESS OF RIPENING IN THE TOMATO. 3 conduct experimental work with material grown under the con- ditions peculiar to Florida. The quality of a tomato is largely determined by the amount and kind of sugars, plant acids, and vitamins which are present. It was obvious, therefore, that the method of approaching the problem would beachemical one. If the chemical composition of vine-ripened toma- toes were known for a number of stages in the process of ripening, the data would afford a criterion for judging commercially ripened fruit. GROWING AND HANDLING TOMATOES IN THE FIELD. In the region about Miami, Fla., the seed beds are prepared as early as the middle of September and are planted at intervals until the early part of February in order to insure a steady supply of seed- lings. In transplanting seedlings they are placed full length in the furrow, the roots are covered with a handful of moist well-rotted stable manure, and finally the whole stem, but not the leaves, is cov- ered with loose soil. Commercial fertilizer is often used with the manure. The soil upon which tomatoes are grown. is essentially of an ever- glade type and is.covered with water during a portion of the summer. For the past few years the moist soil and the danger of frost have been serious handicaps to very early planting. To insure a crop of tomatoes in case of frost many growers plant a portion of their fields in hills. The seeds are planted over stable manure and com- mercial fertilizer. After the seedlings appear the hills are thinned to one plant, which is allowed to grow to 6 inches or more in height and then bent down and covered with soil. The plants are 2 to 3 feet apart in rows 6 feet apart. Commercial fertilizers are applied throughout the growing season up to picking time. Where only one side of the row is cultivated and the other allowed to grow in weeds, upon which the plants later lean, the fertilizer 1s applied in furrows on the side which is cultivated. About a week or 10 days after the plants are set out a small handful of the fertilizer is placed on one side of each plant. Sometimes it is covered with soil, but generally it is left uncovered. Ten days or two weeks after the first application, more fertilizer is applied be- tween the plants in the original planting furrow. A shallow furrow is then turned to cover this fertilizer and also to support the plants better. The third application is placed in the furrow made when the second application was covered. The quantity is generally larger than the first and second applications and is covered by a new furrow. The fourth and final application is made in the same way. Where the fertilizer is applied at one side only, two rows are planted close together and between them weeds are allowed to grow. Where fertilizer is applied to both sides of the plants the * 4 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. rows are 6 feet apart. The procedure is the same. The usual practice is to fertilize at the rate of 1 to 14 tons per acre, the last application being made several weeks before picking. The interval between applications varies with weather conditions and the growth of the plants. The custom is to locate the position of the rootlets along the side of the furrow made at the preceding application and to keep a quantity of fertilizer just ahead of these rootlets, so that a constant supply is available for the plant. The time of picking the tomatoes of course depends upon the age and condition of the fruit. Many growers believe that it is an easy matter to determine the maturity by the character of the darkened area around the stem end. Toward the last stages of maturation the chlorophyll gradually disappears, especially around the stem end, Fic, 1.—A tomato field in Florida. where a whitened area is left. Fields are gone over once a week by the pickers, who collect the fruit in baskets or tin buckets. (Fig. 1.) In general the pickers (Nassau negroes) do not pay much attention to the color of the tomatoes, but gather those that appear large enough to ship. The tomatoes are dumped into field boxes at the ends of the rows and carried by wagon to the ripening house or pack- ing house. The fruit is generally handled carefully, but often it is dropped from the gathering bucket to the field crate without the picker even bending over. PACKING AND SHIPPING OPERATIONS. Until recently the fruit was sorted, packed, and shipped imme- diately upon its arrival at the packing house, but the loss through disease and bruising was so great that it became necessary to adopt PROCESS OF. RIPENING IN THE TOMATO. 5 the ripening house as a means of culling out undesirable fruit be- fore shipping. In the ripening house the fruit is stored at a tem- perature of 75° to 85° F. for a variable period, depending upon the uniformity and maturity of the tomatoes at the time of picking. When most of them show a very slight red coloration they are re- moved and carefully sorted; all diseased fruits are discarded and the colored.ones are graded, wrapped, and packed for shipment. Green fruit goes back to the ripening room. Improper conditions of ven- tilation, humidity, and temperature in the ripening room often increase the amount of disease, since such conditions favor the ger- mination of fungous spores and the spread of infections brought from the field. Nevertheless, this method of allowing diseases to develop and then culling the fruit before shipping saves paying transportation charges on spoiled fruit, as well as additional’ loss in transit through the spreading of infection to healthy fruit. The use of the ripening room is restricted to the early months of shipping, when the weather conditions are such as to allow the fruit to be shipped in a colored condition. The temperature is generally low enough to prevent too rapid ripening, and when the fruit reaches the North the temperature is still colder, thus allowing the fruit to be kept for a considerable length of time before it becomes too ripe. La- ter in the season, however, it is inadvisable with the present methods of handling to ship colored fruit. The tomatoes are kept in the ripening room for two or three days, to allow infections to develop, and are then sorted and shipped. In general, after warmer weather sets in the green fruit goes directly to the packing house from the field and is graded and shipped at once. Sometimes it ripens in transit, but more often it arrives green and has to be ripened at the terminal. Frequently the fruit is packed in such an immature state ‘that it never attains its normal color. In such instances the grower loses both in reputation and in financial return. When the tomatoes arrive at the packing shed they are dumped into bins, which usually are large enough to hold several crates. From these bins the grader culls all undesirable fruit and throws the good fruit into other bins, assorting according to size. Packers stand- ing directly in front of the bins wrap the fruits individually in special tomato paper and pack them in 4-quart baskets. Each basket re- quires smaller fruit at the bottom layer than at the top, where the basket is wider, but in every basket the fruit is packed very tightly; in some cases quite a little squeezing is necessary. Six baskets are placed in each crate. The top is considerably bulged, owing to the close packing of the baskets. Crates in various stages of packing are shown in figure 2. The method of packing crates for shipment just described is un- fortunately the one generally used at the present time, but there is 6 BULLETIN 859, U. S. DEPARTMENT. OF AGRICULTURE. - another method that deserves careful consideration, in which the fruit after it is picked is washed and handled by means of a machine. The field crates used in connection with the machine, and also by many growers who do not use a machine, are made of hardwood mill edgings that have been carefully planed and smoothed, especially where the tomato is likely to come in contact with them. The crate is open, so that all sand and dirt fall through and do not injure the tomatoes during hauling. When the tomatoes arrive at the packing shed they are dumped into a large tank at the end of the machine, which contains a special washing solution kept at as high a temperature as the fruit will stand. Fig. 2.—Scene in a Florida tomato packing house, Were the solution with which the tomatoes are washed nothing more than hot water, it can hardly be doubted that the thorough removal of adhering sand, dirt, and fungous spores would be beneficial. The tomatoes remain in this supposedly disinfectant solution for about half a minute, constantly revolving, and are pushed toward an end- Jess chain which carries them up an incline, where a spray of cold water rinses off the washing mixture. Drying is accomplished by passing the fruit between two layers of sponges. As it passes over the rollers, cullers are able to pick out the undesirable fruit without handling the remainder. It then passes over a special sizer, from which the several grades drop on tightly spread duck inclined planes PROCESS OF RIPENING IN THE TOMATO. 7 and roll down into pockets. The tomatoes are not jarred or bruised in any way in traveling from the tank to the packer. Careful handling is essential in the successful production and ship- ping of tomatoes, and machine handling in the packing house is therefore to be highly recommended. Any device which will prevent bruising and cutting will reduce the opportunities for fungous infec- tion and subsequent loss. Refrigerator cars without ice are preferred by the growers for ship- ping, since these cars are fitted with ventilators which can be opened and closed as weather conditions require. Ventilated cars are used also when there is a shortage of refrigerator cars, but owing to their poor construction there is likelihood in the colder regions of the fruit freezing. When the cars first leave the South the custom is to have the ventilators open, but as they move farther north these are closed to prevent frost injury. When the cars are billed through to Canada some shippers close the ventilators as soon as the cars are filled. Each car contains an average of 500 crates, or approximately 13 tons of fruit. With so large a volume of respiring fruit in a confined space it is obvious that a condition of oxygen deficiency may easily come about. PREVIOUS CHEMICAL INVESTIGATIONS OF THE TOMATO. The earliest important chemical investigations of the tomato seem to have been those of J. F. John and C. Bertagnini, cited by Peckolt (37, p. 197). .The latter author states that John probably made the first analysis of the tomato in 1814. Bertagnini, according to Pal- meri (34), isolated citric acid from this fruit in 1850 and identified it by means of its silver salt. In 1873, Kennedy (27) first isolated the alkaloid solanin from the tomato. His method was to macerate with dilute sulphuric acid for 48 hours. The expressed liquid was then treated with aqueous ammonia (sp. gr., 0.96) in excess. The precipitate which separated was filtered and dried at 120° F., after which it was extracted with hot alcohol. On cooling, the alcoholic solution deposited solanin as small feathery crystals. The first quantitative analysis of the whole tomato fruit was that of Dahlen (16), who reported the amounts of water, protein, fat, glucose, crude fiber, ash, nitrogen, and phosphoric acid. Since the work of Dahlen, various chemists have published analyses of the tomato. Palmeri (34) in 1885 reported on the constituents of various portions of the fruit and also included an ash analysis. Various later attempts were made to show the amounts of nitrogen, phosphoric acid, and potash which the tomato removed from the soil and also the effect of different fertilizer treatments on the com- position of the fruit. The most important work along this line was 8 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. performed by Patterson (36), Bishop and Patterson (12), Voorhees (55), Alwood (3), Alwood and Bowman (4), Bailey and Lodeman (8), Bailey (7), and Jenkins and Britton (26). There has been no little difference of opinion toncerning the kind of acid occurring in the tomato. As before stated, Bertagnini (37) isolated and identified the acid as citric, while McElhenie (80) be- lieved that oxalic, citric, and malic acids were present. Patterson (36) makes the following statement: On following the schemes for the detection of organic acids as given in Fresenius’s Qualitative Analysis, paragraph 193, page 342, and Prescott’s Organic Analysis, page 336, the following acids were found to be present in the concentrated juice of the tomato, viz, malic, tartaric, benzoic, and formic. Malic acid predominated and the others appeared to be present in very small quantities, and as there has been no time for a further investigation as to the relative amounts of these, the whole of the free acids has been calculated as malic acid. Passerini (35) claims that the acidity is due chiefly to citric acid and makes the statement: ' Il sapore dolce é dovuto a glucosi, i quali hanno azione resultante levogira sulla luce polarizzata; l'acidita per la massima parte ad acido citrico, come dimostrammo in altra nota. Briosi and Gigli (13) also confirm the presence of citric acid: ” Queste esperienze provano nel liquido giallo la presenza dell’acido citrico; esiccome isaggi con l’acqua di calce e col cloruro di calcio, ed altri che per brevité non rife- riamo, escludono l’acido tartarico, possimao credere che l’acidita stessa sia, almeno per la massima parte dovuta a esso acido citrico, gid riconosciuto nel pomodoro per la prima volta.da Bertagnini. . Alwood and Bowman (4) make the following statement: A qualitative examination showed the presence of citric, malic, tartaric, formic, and succinic acids. Of these the citric acid was by far the most abundant, so that in the quantitative determinations the whole acid was calculated as citric acid. Stiiber (50) reports that apparently all the acid present was citric, and in no case was tartaric, malic, or succinic acid found. Formenti and Scipiotti (19) claim that salicylic acid occurs naturally in the tomato to the extent of 15 to 25 milligrams per kilo- gram of fresh fruit juice. Albahary (1) gives the following acids as occurring in the tomato: Malic, 0.48 per cent; citric, 0.09 per cent; oxalic, 0.001 per cent; tartaric and succinic, traces. He also reports the presence of an amino acid (2). Bacon and Dunbar (6) state that— the acid of tomatoes has been called by various authors malic, citric, tartaric, and oxalic. The acid is actually citric, asshown. * * * 1 Translated as follows: The swect taste is due to glucose, which has a resulting levorotatory action upon polarized light; the greatest part of the acidity is due to citric acid, as we have shown in a previous note. 2 Translated as follows: These experiments prove the presence of citric acid in the yellow liquid: experi- ments with lime water and calcium chlorid and others which we do not mention for the sake of brevity exclude tartaric acid. We may believe that this same acidity is due, at least for the most part, to that citric acid already recognized in the tomato for the first time by Bertagnini. PROCESS OF RIPENING IN THE TOMATO. 9 Congdon (15) differs from Bacon and Dunbar (6) and claims that the acids are oxalic, citric, and a very slight amount of malic. Oxalic acid is supposed to predominate. The preponderance of opinion seems to be that the chief acid in the tomato is citric. With regard to the kind of sugar occurring in the tomato there is more uniformity of opinion. Patterson (36) says: A few samples of tomatoes were examined for both classes of sugars, the glucose being determined in solutions made up without application of heat; and then a por- tion of this solution was made up in the usual manner for the cane-sugar determina- tions. The amount of increase indicating cane sugar was so small that it was thought to be probably due to substances of a gummy or pectose nature, which are well under- stood to form sugars which act on Fehling’s solution when treated with mineral acids. And from the amount of free acid in the tomato, cane sugar would not be likely to exist to any extent. Briosi and Gigli (13) believe that levulose is the sugar to which the sweetness of the yellow juice is chiefly due. Alwood and Bowman (4) say that ‘“‘it is very probable that no other sugars than those of the glucose kind exist in tomatoes.”’ Snyder (46), however, reports the presence of reducing and non- reducing sugars. Sttiber (50) finds no change in the sugar content of sugar samples before and after inversion. Albahary (2) presents data showing the presence of cane sugar. Bacon and Dunbar (6) make the following statement: A number of experiments have shown that the sugar of tomatoes is usually invert sugar, with at times a slight excess of levulose. Thompson and Whittier (51) were unable to find sucrose in either green or ripe fruits, but reported approximately equal quantities of levulose and dextrose, concluding that in the classification of fruits according to the kind of sugar present the tomato falls in the invert- sugar group. One of the more recent investigators, Bigelow (11), shows that sucrose is probably absent. He states: It is probable that the sugar in tomatoes is all invert sugar. This was indicated by some samples which were examined, in which the determination of sugar before and after inversion gave the same results. The work herein reported supports the contention of most scientific workers that little or no cane sugar is present in the tomato. It is very probable that where small amounts of sucrose are indicated by the increased reduction of Fehling’s solution after acid hydrolysis that the increased reduction is due to other substances than invert sugar. . Since the data of the present investigation concern the percentage composition of the entire fruit, the comparable results of previous analyses of the whole tomato have been assembled in Table II. 175085°—20—Bull. 8592 BULLETIN 859, U. S. 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.45| 9.45) 7 45)- 55] 585) 2295) 1s0a| ie s0 aes Age l5days....}.-.do....| 1.60) 1.60} 1.60) 1.70) 1.75} 2.80) 2.85) 2.90} 3.10} 3.25) 2.31 Age 21 days....|.-.do...-| 4.50! 4.55] 4.60) 4.60) 4.65] 4.85) 5.65] 5.80/ 6.00} 6..60) 5.18 Age 28 days....|-..do...-.| 4.50) 5.00} 5.00} 5.05) 5.20) 5.50} 5.50) 5.80) 6.20] 7.00) 5.47 Age 35 days....|--.do.:..| 4.45) 4.70) 4.75) 5.15] 5.45) 5.45} 5.60) 6.05) 6.15) 7.00) 5.47 Age 42 days....|-..do....| .5.00) 5.45} 5.50) 5.60) 5.75) 6.25) 7.25) 7.25) 7.25) 7.35) 6.37 Age 56days ....| Turning | 5.25) 5.65} 5.70) 5.80) 5.90) 6.40] 6.60] 6. 4 6.85} 8.85) 6.38 to red. ; Plates I and IL show in color four stages in ripening, which are referred to later in this bulletin as green, i.e., with no red present (A); turning, i.e., mostly green, with a trace of color at the style end (B); pink, i. e., slightly colored over most of the fruit, with little or no green except at the stem end, but not yet a good full red (C); and red ripe,i.e., completely mature as far as color change isconcerned (D). Material for analysis was obtained by tagging blossoms (other than those of the ‘‘crown hand”’)® soon after opening and then collecting tomatoes at the different stages in numbers large enough for sampling. An attempt was made to pick all the tagged fruit from an entire row in order to eliminate the error that possibly otherwise might have occurred of unconsciously selecting large or small fruit. Samples were taken at the end of the second, third, fourth, fifth, and sixth weeks, and after the tomatoes had barely started to color (designated as turning), and finally when fully colored or ripe. At the time of carrying on the work the weather conditions were such that eight weeks were required to bring the tomato to maturity (red ripeness). 3 Growers are accustomed to refer to all the fruit developing from a single inflorescence as a “hand.” The ‘“‘crown hand”’ is the lowest inflorescence on the stem. It frequently fails to set fruit. : a) Bul. 859, U. S. Dept. of Agriculture ~ A.C. STEADMAN. del COLOR STAGES IN THE RIPENING OF TH Green, A: turning, B. Tom ATO PL A Bul. 859, U.S. Dept. of Agriculture PLATE II E . f vey : R.C. STEADMAN, del staan ee a 5-20-18 ; CoLor STAGES IN THE RIPENING OF THE TOMATO. a Pink, C: red ripe, D. ¥ if PROCESS OF RIPENING IN THE TOMATO. £5 METHODS OF ANALYSIS. Sampling and preservation.—In order to obtain representative samples at each stage of ripening and to avoid the necessity of analyzing a large number of individual fruits to determine existing variations, composite samples were resorted to. These composite sam- ples were taken from approximately 20 tomatoes. To eliminate error due to possible correlations between size and chemical composition, * tomatoes were chosen so thateach composite sample was obtained from fruits of all sizes, with the exception of abnormally large or small fruit which were discarded. ‘The method of collecting the samples was uniform throughout. Where the fruits were small (e. g., those 14 days old) a 200-gram lot was made by using entire tomatoes, but with larger fruit samples of 200 grams were made up by removing a cylinder from each tomato with a half-inch cork borer. The cylinders were taken through the equator perpendicularly to the axis. A fairly representative sample was obtained in this manner, for the portion removed from each tomato was roughly proportional to the size of the whole fruit. The method of preserving samples for analysis was similar to that used by Hasselbring and Hawkins (21) in their studies of sweet potatoes and identical with the procedure of Kraus and Kraybill (28) with tomatoes. The material was heated with 80 per cent alcohol for 1 hour at 70° to 75° C., with the addition of cal- cium carbonate (CaCO,) to insure the neutralization of acids. : Two- quart glass-top jars were used, and approximately 1,065 c. c. of 95 per cent alcohol and 0.5 gram of precipitated CaCO, were added, after which the heating was carried out on a boiling water bath. Moisture and ash samples were merely covered with 95 per cent alcohol without subsequent heating. In preparing the samples-for analysis (with the exception of certain moisture, dry-weight, and ash samples) the alcohol was removed from the insoluble residue by filtering into a 2-liter volumetric flask. The residue was thoroughly extracted with warm 80 per cent alcohol, which was cooled, filtered, and added to the original filtrate. The volume of the flask was then made up to mark at 20° C. (referred to later as the original extract) and one-tenth and three-twentieths aliquots pipetted off and placed in separate Florence flasks, which were stoppered, labeled, and set aside. The residue was dried at 80° C. in an air oven for a few days and then allowed to come to air-dry weight, after which it was weighed and finely ground in a drug mill (referred to later as the original residue). One-tenth and three-twentieths portions were weighed and stored in small stop- pered vials. Moisture, dry weight, and ash.—An entire 200-gram sample covered with 95 per cent alcohol was placed in a large beaker and evaporated nearly to dryness on a steam bath. It was then transferred to a 16 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 250 cubic-centimeter tared beaker and dried at 60° to 70° C. to apparent dryness, after which it was dried in vacuo at 80° C. until the loss between two successive weighings was negligible. For ash the residue was ground in a mortar, then placed in the vacuum oven over night and approximately one-half of the total sample used for the crude-ash determination. _ Acidity.—All acid determinations were made with fresh material. Two hundred grams of tomatoes were pulped and placed im a liter ° volumetric flask, made up to volume with cold distilled water, and toluol was added to prevent the growth of organisms. After stand- ing three days, 50 c. c. aliquots were titrated against approximately a tenth normal sodium-hydroxid solution (N/10 NaOH), using phenolphthalein as the indicator. No trouble was experienced in determining the end pomt. Separate determinations were made untilthe duplicateschecked. Inorderto determine the effect of enzyms on acid content, a sample treated with boiling water was titrated three days later and the results compared with one using cold water. For the former, 200 grams of material required 14.28 ec. e. N/10 NaOH, and for the same quantity of material employing cold water, 14.18 c. c. N/10 NaOH were required for neutralization. Freereducing substances.—One-tenth of the original alcoholic extract was evaporated nearly to dryness while the same part of the residue was being extracted on a filter paper with warm water (35° C.). Very little reducing substance remained after extracting the original residue with alcohol, as described under ‘‘Sampling and preserva- tion,” but the warm-water extraction was performed to insure the removal of final traces. The aqueous extract was combined with thé residue from the alcoholic portion and filtered into a 250 ec. c. volu- metric flask, after which the filter paper was thoroughly washed. One cubic centimeter of lead-acetate solution (a saturated solution of the normal salt) was added and the solution made up to volume at 20° C. The whole was filtered immediately and the excess of lead removed by adding approximately 0.5 gram of sodium oxalate. After standing a short time the mixture was filtered through dry filter paper and 10 c.c. of the clear solution used for the sugar deter- mination. The method used for determining reducing sugars was a combination of that of Bertrand (10), and that of Munson and Walker (33, 56). In this method the cuprous oxid is determined by titration, as in the Bertrand method, Fehling’s solution and the time of heating are as specified by Munson and Walker. The Munson and Walker tables were used for the sugar equivalents. Total sugars.—Fifty cubic centimeters of the solution used. for free reducing sugars were transferred to a 100 ¢. c. volumetric flask and 5 c. ¢. of HCl (sp. gr., 1.19) added. The mixture was set aside over night and the flask made to volume at 20° C. the folowing morn- PROCESS OF RIPENING IN THE TOMATO. 17 ing. The solution was then neutralized and filtered and 20 c¢. c. used for reduction. Starch.—The residue from the water extraction of the sample used for reducing substances was placed in an Erlenmeyer flask and heated immersed in a boiling water bath for 24 hours with 150 c. ec. of water and 15 c. c. of HCl (sp. gr., 1.125). After cooling and neutralizing to phenolphthalein with NaOH, the mixture was made to 250 c. c. volume at 20° C. and filtered through a dry filter paper; 20 and 50 c. ¢. aliquots of this solution were used for reduction. Pentosans.—A quantity of the original alcoholic extract represent- ing one-tenth of the total extract was evaporated nearly to dryness in an Erlenmeyer flask and one-tenth of the original residue added to this. Pentosans were determined by the furfural-phloroglucid precipitate method. The usual procedure is to distill over 360 c. c. and then to make up to 400 c. c. with a phloroglucin solution. It required 480 c. c. of distillate to obtain all of the furfural present, and 40 ¢. ec. of phloroglucin solution were added to this. No correc- tion was made for the additional 120 c. c. distilled over. Kréber’s formule were used in calculating the pentosan equivalents, as given in the Official and Provisional Methods of Analysis (57). Total nitrogen.—Two hundred cubic centimeters of the original alcoholic extract, representing one-tenth of the sample, were intro- duced into a Kjeldahl flask and evaported to dryness on the steam bath, and to this residue one-tenth of the original residue from the original sample was added. The total nitrogen in the aliquot was determined by the Kjeldahl method.* Crude fiber—A quantity of the residue representing three-twen- tieths of the sample was used for crude-fiber determination, which was made in the usual manner. ANALYTICAL DATA CONCERNING PROGRESSIVE CHANGES IN COMPO- SITION DURING RIPENING. The data showing progressive changes in composition during the process of ripening are assembled in Table IV. In section A of this table the percentages are referred to the weight of the entire fruit; in section B they are reduced to a basis of dry weight. Each entry in this tableis a mean of two determinations, except as indicated by an asterisk (*), which shows that duplicate determinations were not made. Although the method of sampling has been described, it may not be amiss to emphasize the fact that each sample was a composite of fruits of the same maturity but of greatly varying sizes. The data with regard to average size and average weight at the various ages are found in Table III. 1 A]] determinations of nitrogen reported in this investigation were carried out by the Nitrogen L aboratory, Bureau of Chemistry, United States eepergr of Agriculture. 175085°—20—Bull. 859 18 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE.. TaBLE IV.—Progressive changes in the composition of Livingston Giobe tomatoes during the process of ripening. [The asterisk (*) indicates that the given result is based upon a single determination; results not thus marked are the mean of two determinations. ] Age and color of fruit. Constituents. 14 days, | 21 days, | 28 days, |35 days, | 42 days, | 56 days,|56 days, green. | green. | green. | green. | green. | turning.| red. SEC. A.—Percentage of entire fruit: 3 Moisture. Batata en ee aia mere eee *93.250 | *94.140 (*94.140 |*94.540 | *94. 240 /*94. 450 #94. 40) POtAUSOUOS! 22.0 ere: ee *6. 750 *5. 860 | *5. 860 *5. 560 *5. 760 | *5. 550 *5. 510 Suparirea sods ses) ee fee 5.006 | 3.824] 3.753 3. 416 3.385 | 2.994 2. 847 NSH ACEITM OSs, 42 Som sas seetee a= cence *, 634 *,562 | *. 533 *, 509 *,497 | *, 484 *, 504 Acidity (as citric acid)......2....... | ;320 . 585 SS, . 883 - 640 397 - 420 Rota itoren sa .ds ese sane Ie ae . 150 . 1365 . 1305 . 140 . 1225 - 116 PT Germ (NOD) tne eee 1, 24 . 938 . 853 . 8156 . 875 . 766 Tes Total sugar (asinvert)............-. | 1.748 2.006 | 2.106 | 2.143 2.375 | 2.556 2. 667 (Carle Scans oo ean Fe a aE pe O18 040" 20 018 070 018 . 024 Reducing sugar (asinvert)......._- | 1.724 1.962} 2.112 2.125 2.300 | 2.537 2. 637 SGaT Che Soe eres oe ee eee 1. 068 . 80 . 616 544 555 . 222 - 146 PENEOSATIS (34 dos te oh eee ee . 332 . 276 . 247 oaike . 264 . 228 . 28 Crude heres ot en. See eee *, 503 *, 464 | *, 447 * 484 *, 433 | *, 423 | 304 RaMoSugaric=i4Cid )\....4-4. oe5- oe 5. 450° 3.420} 5.980 2. 430 3.710 | 6.430 6.340 Carbohydrates— Oba < Se B-! re te he | 3.647 3.576 | 3.415 3. 443 3.628 | 3.429 3. 441 Dolupleeeas tae coe san cee ee | 1.743 2.006 | 2.106 | 2.143 2.375 | 2.556 2. 667 ABONEDIA etn. Be se See |. 1. 903 1.570 1.309 1.300 1. 253 . 873 774 Determined constituents........... 99. 100 99. 801 | 99.294 /|100.192 99.870 | 99.526 99, 580 Szc. B.—Percentage of dry matter: Sugariree solids. 2 =e ha: 74. 120 65. 250 | 64.050 | 61.440 58. 760 | 53.940 51.670 Ashseride-..otk unas scare ees ee | *9, 390 *9,590 | *9.090 | *9.150 *8. 620 | *8.720 #9. 140 Acidity: (as'crtricacid)<- 2821-22 se | 4,740 9.986 | 6.000 | 15. 880 11.110] 7.150 7. 620 Motalmitrorens Me Sy cece e | 2.960 2. 560 2. 330 2.340 2. 440 2. 200 2.100 IPTOLGTEN — Ny Osean) sean teens | 18. 500 16. 000 | 14.550 14. 660 15. 250 | 13.780 13. 130 Total sugar (as invert).............- 25. 830 34. 240 | 35.930 | 38.550 42. 230 | 46. 030 48. 320 Ganeisugar=. | 7faaeeeec so. ees . 264 .708 | 0 iit B23 1.215 324 . 435 Reducing sugar (as invert).........- | 25. 560 33. 490 | 36.040. | 38. 200 39.930 | 45.710 47. 850 SUAnChserche ce: emesis 15. 840 14.220 | 10.500 | 9.77 9. 630 4. 000 2. 650 IPentOSAns2 52 te oaeeee pee eco A020 4.700 | 4.210 | 4.890 4.580 | 4.120 4,320 Cride ders. esc seen eee 7. 450 *7.920 | *7.630 | *8.710 ¥*7.510. | *7.620 *7.150 Ratro (Sugar = aed). ease ee 5. 450 3. 420 5. 980 2. 430 3.710 6. 430 6.340 Carbohydrates— ; |. | otal: so: eee LR 2 Seen 54. 030 61.030 | 58. 270 61. 920 63.970 | 61.720 62. 450 Soltibles. “tacos. See eee | 25. 830 34. 240 | 35.930 | 38.550 42.230 | 46.030 48.320 Insel bl Gscen ones see ace ee 28. 200 26.790 | 22.340 23.370 | 21.740 15. 690 14. 130 From Table IV it may be seen that the tomato contains a com- paratively small amount of solid matter and that a considerable portion of this consists of acids and sugars, especially in the ripe fruit. In fruit 14 days old there are relatively small percentages of acids and sugars, but as the tomato matures these increase per- ceptibly in the case of acids and markedly in the case of sugars. In general, throughout the ripening period there is an increase in moisture, acids, and sugars and a decrease in solids, total nitrogen, starch, pentosans, crude fiber, and ash. Some of these losses are probably not absolute, but attributable to changes in the proportion of the constituents. Tracing the figures for moisture content from the first column, concerning tomatoes 14 days old, across to the last ‘column for ripe fruit, it will be seen that there is a gradual and progressive increase in total moisture. The only irregularity is that noticed in the fourth column (for 35 days). The moisture content here is greater than it should be if the change followed a regular curve of increasing water, being greater than in fruit when fully ripe. PROCESS OF RIPENING IN THE TOMATO. 19 ~ Itseems that a clue to the reason for this irregularity is afforded by Table V, showing weather conditions for the period previous to pick- ing the samples. Just before picking this particular sample there was a rainfall of 9.10 inches within 36 hours. ‘This precipitation was as unusual for the locality as it was injurious. Not only was the actual rainfall excessive, but the overflow from the Everglades still further complicated the situation. In some places a total loss resulted, and everywhere some damage was reported. At Peters, Fla., where the fruit for this investigation was grown, the loss was comparatively small, but the ground was saturated for more than a week. In view of the fact that the only anomalous moisture content was found in the 35-day fruit, it seems justifiable to correlate it with the excessive rainfall. It would hardly be warranted, however, to conclude from this one instance that the moisture content is higher after a heavy rain than normally. The coincidence is merely pointed out and should be of some interest in view of the widespread opinion in the canning industry that a heavy rainfall increases the amount of water in tomatoes. Bigelow (11) was recently unable to draw any definite conclusions with regard to this matter. Tanitp V.—Weight and equatorial diameter of tomatocs at dates when samples were taken, together with mean temperature and total precipitation for the period (usually seven days) preceding sampling. Meteorological data. Average Average Time of sampling. Color of fruit. weight diameter Precipita- (grams). (em.). Tempera- ti 7 ture (° F.). (inches). JMEQ 1 EG he ae ee are Greens: dasercces geet 6.74 2.31 66 0.83 PME COI V Sion, <<, 5nicias Stacie oe alee ee (0 50 ea oe ee 63. 65 5.18 73 24 LUDO GST Se ee ee ee Se (i ee at es 5 82.37 5.47 77 -O1 EMBER EM LENUIIOR, cay. Ae Ses acai sates CO. . ae 95.10 5.47 62 9. 42 JVENCHDG Cas ae OS 5 ee ea ea One eae no aoe cae 147.91 6.37 68 arf ( JN(E) FS) (0 SR ea Turning to red........ 162. 81 6.38 76 09 IVs ratte eso ct sone Se noi =f ain ns x ae Nr I no ermine te Sees OM erences. = Rppdleeer sek a: os [aS eohSt [mone e eee e ee e eeee eeeee e ee eee ee eee 10. 85 Inversely with moisture, total solids show a gradual decrease as the tomato matures. Turning to section B of Table IV, which gives the same data as those of section A of the same table, but reduced to a dry-weight basis, the sugar-free solids are seen to decrease con- siderably, while soluble carbohydrates increase and insoluble carbo- hydrates decrease regularly. Total carbohydrates vary somewhat, but in general seem to show an increase. Regarding the changes in acidity, there is considerable fluctuation, but when we consider the changes in a general way there is an increase In quantity from the second week to the fifth and then a gradual decrease during the last three weeks of ripening. The total quantity of acid found in the red-ripe fruit is, however, still greater than in 20 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. the first stage analyzed. The possibility should be borne in mind that the ripe tomato may contain relatively more acid salts and less free acid than the green fruit. Since the acid content was deter- mined throughout by titration to neutrality, with phenolphthalein as the indicator, it is obvious that the presence of acid salts might cause the analytical results to show more acid than the taste would indicate. As will be seen later, the change in the ratio of acid to sugar is in the direction to account for the sweetening that takes place during ripening. Nevertheless it is not impossible that the ratio of free-acid salts is likewise of impor- tance. It is believed that rainfall and _ other factors influence the quantity of acid in tomatoes, although there are few ana- lytical data at hand to indicate this. In the fourth column of figures of Table IV (sec. B), concerning the tomatoes that received the highest rainfall, the acidity is 15.88 per cent, and in the fifth column, where the tomato would no doubt be still affected, there Fig. 3.—Diagram showing the progressive changes in the composition js a decrease to 11.11 Se Ce eS oman ete. paneent, mb thinaes fiber; d-d, crude ash: e-e, starch; /-f, protein; g-g, soluble carbohy- ure is higher than the poe ry ag hiocra cs carbohydrates; i-i, total carbo- remainin g ones. In this connection it may be worth while to suggest that a tomato with excessive water content may have the intercellular spaces sufficiently diminished so that gas exchange is impeded. Under such conditions a deficiency of oxygen might result in an accumulation of acid, due to incomplete oxidation of carbohydrates to carbon dioxid. The most striking change during ripening is that undergone by carbohydrates. In the first stage analyzed it was noticed particu- larly that insoluble carbohydrates composed 52.1 per cent of the F . PROCESS OF RIPENING IN THE TOMATO. 21 total carbohydrates present, while in the last stage, that of ripe fruit, soluble carbohydrates were in excess, amounting to 77.3 per cent of the total. Nearly all of the total sugar in the tomato fruit is appar- ently invert sugar, and this increases from 25.56 per cent in the case of 14-day-old fruit to 48.32 per cent in ripe fruit, an increase of nearly 89 per cent. Starch decreases during maturation from 15.84 to 2.65 per cent. The most marked decrease, as would be expected, is no- ticed during the period of transition from green to red. The progres- sive decrease in starch during ripening is in striking contrast to the increase in starch noticed by Albahary (2). Pentosans decrease during ripening, but only to a comparatively shght extent. Total nitrogen decreases gradually during ripening and this fact is rather interesting and important in the light of some recent investi- gations of Kraus and Kraybill (28). They make the following statements: On account of the wide differences in composition of different parts of any plant grown under a given set of conditions, only similar portions are compared. With but few exceptions, increased amounts of total nitrogen are associated with decreased amounts of total carbohydrates. This condition holds fairly uniformly throughout _ the plant with the exception of the lower leaves. Examination of Table IV (sec. B) shows that increased total nitro- gen in the tomato fruit under the conditions used for the material in this investigation is associated with decreased total carbohydrates. The above investigators analyzed leaves and stems of the tomato plant, while the data presented in the present paper furnish ana- _Tytical figures for the fruit, thus yielding complete analyses of the entire plant. The correlation between total nitrogen and_ total carbohydrates holds with respect to the fruit as well as.to the other parts of the plant (excluding the lower leaves). All of the changes during ripening are represented in the diagram shown as figure 3. ; COMPARISON OF THE COMPOSITION OF COMMERCIALLY PICKED TOMATOES WITH TURNING AND VINE-RIPENED FRUIT. It is conceded by many commission men and by some of the growers themselves that the tomatoes shipped to the North differ very noticeably in flavor and palatability from normal fruit. The chemical composition of Florida-grown tomatoes compares favorably with the various analyses reported of such fruit grown in other locali- ties, so the inferiority of the former can not be attributed to the kind of soil or climatic conditions prevailing in Florida. Elimination of these possibilities led the writer to look for other causes of the trouble. It will be seen from the analytical data which follow that tomatoes picked green and allowed to ripen exposed to air and light differ 22 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. slightly in composition from vine-ripened fruit. They contain more sugar-free solids, slightly more acid, and less total sugar than vine- ripened tomatoes, but these differences hardly explain the great difference in taste. In tracing the trouble to lack of ventilation it is believed that a proper explanation is presented. The analytical _ data upon which these conclusions are based are presented in Tables VI and VII. TaBLE VI.—Composition of artificially ripened and vine-ripened Livingston Globe tomatoes. [The asterisk (*) indicates that the given result is based upon a single determination: results not thus. marked are the mean of two determinations.] Commercially s . picked; green. Turning froit. / Nines ripene Constituents. Ripened Ripened | fruit; red AS at room AS at room ripe. picked. | tempera-| picked. | tempera- ture. ture. Src. A.—Percentage of entire fruit: IMOISGUTO. 2 eee ote eee Oe ene L eee Sec +*93.800 | *94.310 | *94.450 | *94.540 #94, 490 Meapal SOMUGS ook fey We Seen) Ses ary eee ot Ee *6§.200 | *5.690 *5. 550 *5. 460 *5.510 USAT LECCE: SOUASE seemee ema acetates Pee eee 8.975 3.059 2.994 2.916 2.847 AGidity(as' CILEI@ACIC) Eee tee = rc ictee oatee oes 508 475 .397 2375 -420 Movalmiirorenie Wee fe to cetoe cece eee .138 1335 . 1225 -1265 116 — Proven (—IN ex O12) = nar tae cette a eee . 831 . 834 - 766 791 .725 POvaANSH Par (ASIN Vet) sok sa ae ee eee 2.225 2.631 2.556 2.543 2.667 Gane suparcs . Passes AA eet Spee ar ee . 060 -012 -018 024 024 HCduGINP SIP ar (ASiMVert) a. esse sgan ees eseee 2.175 2.628 2.537 2.518 2.637 Blanch tr cle nso SEE RENEE UG AE a Cee *, 855 095 . 222 - 101 . 146 IR GNLOSATIS . o~ -ctve cere «ema ar ie Da aries a 258 214 227 251 238 Grude fibers re 8 taste ae aes aes *, 404 *_ 462 *, 423 *, 438 *, 394 Ratio (SUPAT = ACId) os, ee on se een ee one 4.380 5.540 6.430 6.780 6.340 Carbohydrates— TROUSER SSPE oto | oy ple a ae Oe ee, 3.742 3.403 3.429 3.334 3.441 Solubleves fs we cess >. 2 Sia eae Spee ee 2.225 2.631 2.556 2.543 2.667 Ua \STOv TO) (MRE Sas ae LE i ee ee tee 1.517 7712 .873 791 -774 Sec. B.—Percentage of dry matter: Sugar-free solids oan soe ae mee OE 64.110 | 53.770 53.940 53.410 51.670 Acidity as CliniCaciah) +51: ie Eres Seen we pel 8.190 8.340 7.150 6.860 7.620 ROTA TGROR Clie cy Aemeee). n ieee ee es ae ed 2.140 2.340 2.200 2.320 2.100 iProteimi(— Nt G.2p)e le ates eee eee ae 14.370 | 14.630 13.780 14.500 13.130 Lotalisuigar (@SinVert) sce on 5ce se ee 25 Ten 35.880 | 46.230 46.030 46.580 48.320 Cane sugate Ni scae sete se cce sae eee phn TE See . 821 . 210 .324 . 430 - 435 Reducing sugar (asinvert)............-.-----5-- 34.970 | 46.010 45.710 46.120 47.850 ‘SUCCES ae ae eae mee ak ge Racca ee ei *13.790 1.680 4.000 1.850 2.650 IBGNPOSANS = a5 a5 cmos elec cele eee ee 4.170 3.770 4.120 4.600 4.320 Cruden beres. so csc once ee weet ne eet ee nee *6§.520 | *8.120 *7,620 *8. 020 *7,150 Matio(sugant-= Acid). c-soscee eee eee 4.380 5. 540 6.430 6.780 6.340 Carbohydrates— Total. 2 Fe 54s) See eee eS eee eee 60.870 | 59.800 61.720 61.050 62. 450 SOLIDE. . 5 42.55 oc Sac eee a ee 35. 880 46. 230 46. 030 46. 580 48. 320 Tnsolublests 72.625 eae Oe eee 24.990 | 13.670 15.690 14.470 14.130 The percentage composition of samples of commercially picked green fruit (Pl. I, A), of the same after being ripened at room tem- perature, of turning fruit as picked (Pl. I, B) and after being ripened, and of vine-ripened fruit (Pl. II, C) is given in Table VI. All the fruit for the different samples was collected at the same time, in order that a comparison might be made. In the case of commer- cially picked green tomatoes, four crates were taken at random in one of the largest packing houses of the South. The fruit had just been picked and brought into the packing shed. The sample for analysis PROCESS OF RIPENING IN THE TOMATO. 93 was taken from as representative a lot as could be obtained, portions of approximately 20 tomatoes being used. These had been ripened _ by exposure to air and light in the laboratory until they assumed a characteristic ripe appearance, as judged by the color. They were sampled 13 days later. Turning tomatoes were taken to the labora- tory after being picked and one lot sampled; another lot was set aside toripen. Four days later they showed a red color and were therefore sampled. Vine-ripened fruit was, of course, sampled as soon as it was brought into the laboratory. Table VI.summarizes the analyt- ical results obtained. Comparing the analyses of commercially picked green tomatoes with those given in Table IV, it will be seen that green fruits are not mature, for the chemical transformations of ripening have not been completed. The sugar-free solids are com- paratively high, while the sugars are correspondingly low. The total amount of carbohydrates is still low compared with that in mature fruit. Taking composition as a criterion of maturity, one must con- clude that commercially picked green fruits are immature and there- fore inferior. When green fruit is commercially ripened, however, changes take place, which, although corresponding in general trend to those of normal vine ripening, nevertheless fail to bring the fruit to the same degree of ripeness attained normally. The artificially ripened tomato is lower in total sugar than vine-ripened fruit (46.23 per cent of the dry weight in the former, as contrasted with 48.32 per cent in the latter) and higher in acid (8.34 per cent, as contrasted with 7.62 per cent). The ratio of sugar to acid in the former is 5.54, while in the latter it is 6.34. In other words, the artificially ripened fruit is different in taste, due to the lack of one constituent and an excess of the other. In spite of these differences, however, the taste is not as bad as that of fruit which reaches the market. If some way could be devised to place on the market fruit having substantially the same flavor as that found in tomatoes ripened like the samples used, there would be little likelihood of complaint. When the data for turning tomatoes (Table VI) are examined, it is found that they compare more favorably with vine-ripened ma- ture fruit than the commercially picked green fruits. In the interval between the time when green tomatoes are picked in commercial practice and the time of turning red on the plant, sugar-free solids normally decrease considerably, while sugars increase in proportion. Since in turning tomatoes there is very little starch present which can be converted into sugar, it is seen that there is not so marked an in- crease of soluble carbohydrates in further ripening as in the artificial ripening of green-picked fruit. The acid content changed from 7.15 to 6.86 per cent during ripening, but the latter figure is below that of normal fruit. The total amount of sugar is also below normal, but not as much so as in artificially ripened green tomatoes.- The ratio 24 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. in the case of ripened turnings is 6.78, compared with 6.34 in vine- ripened fruit. This signified that the former should be comparatively sweet and less pronouncedly acid, as was indeed true. The facts brought out indicate that there is less chemical difference between turning and vine-ripened fruit than there is between commercially ripened green fruits and the latter. Differences in chemical compo- sition between vine-ripened fruit and commercially picked green to- matoes ripened in the laboratory, exposed to air and light, are not sufficient to account for the marked differences in flavor and palata- bility between commercially ripened fruit and normal fruit. This conclusion was confirmed by taste comparisons. EFFECT OF LACK OF VENTILATION ON RIPENING. Since the differences due to ripening after picking with normal exposure to the air were obviously insufficient to account for the in- feriority of Florida tomatoes after shipment, it seemed to be clearly indicated that the cause of the difficulty might well be lack of venti- lation during commercial ripening. As already stated, the fruits are wrapped before packing for shipment, and it seemed not unlikely that the paper used might appreciably retard gas exchange and thus modify the course of ripening. In order to test the hypothesis that wrapping plays an important part in influencing the composition and flavor of tomatoes, it was deemed necessary to analyze tomatoes which were ripened in a non- ventilated chamber and to compare the results with those obtained with wrapped fruit. Comparisons were made between (1) tomatoes commercially ptcked and ripened without ventilation, (2) commer- cially picked and ripened, wrapped with one paper, (3) commercially picked and wrapped with three papers, (4) commercially picked and ripened unwrapped at room temperature, (5) turnings ripened un- wrapped at room temperature, and (6) vine-ripened fruit. All of the . fruit used for the above comparisons was obtained at the same time. A box for the green fruit ripened with no ventilation was made of composition board about a quarter of an inch thick. The approxi- mate size was a little less than 1 cubic yard. AU corners were sealed with adhesive tape and the door was made by cutting it from the board and hinging it on. The total exclusion of air from the interior of the chamber of course was not secured, but the degree of nonven- tilation obtained was complete enough for the experiment, as shown by the fact that at times the oxygen content of the chamber would not support an alcohol flame. Six baskets of tomatoes (approxi- mately 125 fruits) were allowed to remain in this chamber, which was heated with one electric bulb, until they showed a red color. They were then removed and sampled by taking portions from 15 to 20 fruits. It required 11 days for the color to appear. Other fruits . 4 : ‘ PROCESS OF RIPENING IN THE TOMATO. 25 were wrapped with one and three papers and set aside at room tem- perature until they also attained a red color. These were sampled 11 days later. Summaries of the analyses are given in Table VII. TABLE VII.—Composition of commercially picked green Livingston Globe tomatoes allowed to ripen under different conditions as compared with artificially ripened turnings and vine-ripened red fruits. [The asterisk (*) indicates that the pee result is based upon a single determination; results not thus marked are the mean of two determinations. ] Commercially picked; ripening— Turning fruit; Vine- ripened | ripened One pa- |Three pa-| Atroom | at room | fruit; Constituents. eee per wrap-|per wrap-| tempera- | tempera- | red ripe. z ping. pings. ture, ture. Src. A.—Percentage of entire fruit: BPGISMIRO Soha fei selon cae kite oe ie #*93.930 | *94.500 | *94.430 | *94.310 | *94.540 *94, 490 PRO MUSONOS 2-3 95.28 oo joo edoeetensse~ 52 *6. 070 *5.500 | *5.570. *5. 690 *5. 460 *5, 510 Duparires SOUS. - 2242-26252 the aoe 3.745 3. 037 3.039 3. 059 2.916 2. 847 Acidity. (AS GItliG ACiIG) =.= <2 >... = 1.104 - 850 - 673 -475 -3t0 - 420 Meeeeotar nitrogen. - S528 seh eri Se *,134 mot - 1265 1335 . 1265 116 SemRrOtell (—N-o6120)~ oc = ss tn ae oie *, 838 -818 - 791 - 834 791 . 725 Total sugar (as invert): --..-..6-5.-.-- 2.325 2. 462 2. 531 2.631 2. 543 2. 667 Wane suear-. 5s-- 5. -ie------- S8ouaS- .- 048 - 012 -077 012 - - 024 . 024 Reducing sugar (as invert)...-.-..--.. 2.275 2. 450 2. 450 2. 628 2. 518 2. 637 SG eee - 07 - 084 - 139 - 095 -101 146 PeCMLOSANIS] = 2i25-0 = eile oe see Pee cese ss . 255 eae . 238 . 214 ol . 238 COTS D102) Be Sioa ee a ee ee *, 482 *, 482 *_. 473 *, 462 *, 438 *, 394 ato (surar = acid)... .25-2.22055 2.110 3.010 3. 760 5. 540 6. 780 6.340 Carbohydrates— eRGheabesta.o0 Gas te ok eee ae oo ee 3.140 3. 253 3.381 3. 403 3.334 3.441 DPOUDIOS. A See akties acca ceo ee eee 2.325 2. 463 2. 531 2. 631 2. 543 2. 667 ‘Teale hijo) eae semen? Hae eee 815 - 790 - 850 172 - 791 .774 Src. B.—Percentage of dry matter: Sugar-free solids....---.-..------------ 61. 700 55.050 | 54.550 53. 771 53. 410 51. 670 Acidity (as citric acid)-..-..-.---.-...-- 18.180 15.450 | 12.080 8.340 6. 860 7. 620 Datalinitropen--2t2..- sn .2 ss = 22s eee <= *2. 210 2. 380 2. 270 2.340 2.320 2.100 AOLCHT (=I) Oh? O220) 2. Sa sace = on *13. 810 14.670 | 14.190 14. 630 14. 500 13.130 Total sugar (as invert). ....-.-------.- 38. 290 45.950 | 45.440 46. 230 46. 580 48. 130 CET SUE ae a eee tok - 218 1.382 - 210 - 430 - 435 Reducing sugar (as invert)...........-. 37. 450 44.540 | 43.980 46. 010 46.120 47. 850 SUTIN WC opeok eee ae eee 1.301 1. 620 2. 500 1. 680 1.850 2. 650 LUST PT SO Re ee 4.190 4. 080 4. 270 3.770 4. 600 4.320 OIE Gi 0) gee eerie eee eee *7, 940 *8.760 | *8.490 *8.120 *8. 020 *7.150 Ratio (sugar + acid)......-...-..---- 2.110 3. 010 3. 760 5. 540 6. 780 6.340 Carbohydrates— MAAN os 2 octane aes x eiaceme se 2'5)2 51. 730 60.400 | 60.700 59. 800 61. 050 62. 450 DGUED Osi cceesasis ses tec oeet ose oe 38. 290 45.950 | 45. 440 46. 230 46. 580 48. 320 SONI DIO! sc ctoc essa eraco8 Seins enee She 13. 440 14.450 | 15. 260 13. 670 14. 470 14. 130 There are striking differences in the analyses between the acid and carbohydrate content of tomatoes commercially picked and ripened without ventilation and the same fruit ripened when exposed to the air. Without ventilation the acids are very high and the soluble carbohydrates (sugars) are low. ‘These facts indicate incom- plete oxidation of carbohydrates to carbon dixoid (CO,) with the consequent accumulation of acid. The connection of these changes in composition with the flavor is very obvious. The nonventilated fruit was markedly inferior. Although the reaction was decidedly acid, the general flavor was insipid. While the same effect was not produced to as great an extent in fruit ripened when wrapped with paper, it nevertheless takes place. Fruit wrapped with one paper had a noticeably inferior flavor; it was not as poor as the sample ripened without ventilation, but it was worse than that of green 26 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. fruit ripened without wrapping. The acid content of fruit ripened without ventilation shows an increase of approximately 138 per cent over that of vine-ripened fruit; that of fruit ripened while wrapped with one paper, an increase of approximately 102 per cent; and that of fruit ripened while wrapped with three papers, an increase of about 58 per cent. The soluble carbohydrate content for fruit ripened - without ventilation shows a decrease of nearly 21 per cent compared with normal fruit; that of fruit ripened while wrapped with one paper, a decrease of nearly 5 per cent; and that of fruit ripened while wrapped with three papers, a decrease of nearly 6 per cent. The data presented also bring out the fact that green tomatoes ripened when exposed to air and unwrapped are superior in taste and chemical composition to the same fruit ripened when wrapped with paper. Several experiments were carried out in order to determine what effect lack of ventilation produced on the normal color of the tomato. Since they all yielded the same results, it will suffice to present the figures from one. Two large glass jars were filled with green fruit and cardboard covers placed over each. Unwrapped fruits were ~ placed in baskets as checks. Both lots were held at room tempera- ture and examined at the same time. (Table VIII.) TasLe VIII.—Hffect of lack of ventilation on the normal coloring of tomatoes held at room temperature. 21 fruits in bottles (no ventilation). 31 fruits in baskets (ventilated). Time of examination. Colored cCheeevaey |PAts bye avirey cs | (Ce 0 | Turning.} Pink. Red. Total. Mftor'6 days. 223.242) ves a Pe eae ° 6 10 6 9 25 After? daysr sic oc seee eee Poet eeeeee Bot =. Danan lesocaeeee 5 a26 31 a 14 soft. ’ These results would seem to indicate that lack of ventilation retards ripening and the consequent formation of pigment in the tomato. It was noticed that the tomatoes kept in jars were firmer than those left exposed to the air. Hill (24) records a similar condition in the case of peaches held in an atmosphere of carbon dioxid (CO,). His explanation is that CO, evidently prevents the hydrolysis of the pectin to which peaches owe their hardness. This may also be the case with tomatoes. An attempt was made to duplicate the results presented above by using a larger closed chamber and also by wrapping the fruit in: paper, but no concordant data were obtained. There are hardly sufficient data to justify making any statement as to the effect of wrapping on the color formation, It is often noticed that tomatoes picked green and ripened arti- PROCESS OF RIPENING IN THE TOMATO. 27 ficially acquire a much better color than vine-ripened fruit. The - color is deeper and more even. , Investigation has been made by Duggar (17) of the effect of various conditions on the development of the tomato pigment (called by this author lycopersicin). He studied the effect of light and tempera- _ ture on its development and concluded that high color is independent of any direct effect of light and that fruit will redden perfectly in darkness at a temperature of even 20° to 25°C. He also states that ‘“when half-grown varieties are employed a temperature of 30° C. is sufficient to suppress lycopersicin development to a marked extent. Fruits nearer maturity, that is, those showing a blush of color, permit a stronger lycopersicin development at all temperatures employed.” Duggar (17) also studied the relation of oxygen to pigment produc- tion in the tomato and concluded that lack of oxygen inhibited lycopersicin development. From a consideration of all the data it appears that wrapping is harmful to the tomato and that lack of ventilation is probably the main cause of inferiority in taste and keeping quality. In 1913 Hill (24) reported on the respiration of fruits and growing plant tissues in certain gases with reference to ventilation and fruit storage. He found that apples and peaches ripened poorly when oxygen was withheld from them. It was also pointed out that an accumulation of carbon dioxid within paper wrappers in which peaches are shipped and an insufficient supply of oxygen cause ‘ice scald.” Fischer and Nelson (18) recently came to a similar conclusion with regard to wrapping cantaloupes, maintaining that ‘‘wrapped cantaloupes do not refrigerate so well in transit nor do they reach the consumer in as good condition as do cantaloupes not wrapped.”’ In both of these investigations similar conditions were found to be the result of wrapping, namely, that wrapped fruits were firmor but of poorer quality than those unwrapped. Another serious disadvantage of the present method of picking and shipping green tomatoes lies in the fact that it is practically impossible to determine comparable stages of maturity in picking. In spite of the fact that the fruit of individual baskets is all approximately of the same size, the coloring of the fruit does not occur at the same time. The explanation for this fact has already been given. The maturity of a tomato depends on its age and not on its size; consequently fruits of the same size do not necessarily ripen and turn red simulta- neously. The most obvious disadvantage of the inability to deter- mine comparable stages of maturity is the fact that when the fruit does ripen, either in transit or after reaching the market, it colors up so irregularly that many sortings become necessary before the dealer is able to dispose of it. The more uniform in size and color a package is the more salable it is, so naturally the dealer sorts the fruit to insure 28 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. a quick sale. In consequence of many handlings the fruit becomes soft and injured and is more liable to fungous attacks through the germination of adhering spores. It is clear that, if possible, only fruit of the same age should be packed in a single container. No criterion for determining age exists except at the time of turning from green to pink. If turning tomatoes could be packed instead of green ones, this particular commercial difficulty would be solved. Since it has been shown, moreover, that Florida tomatoes are lacking in certain fundamental qualities as to taste, which would likewise be remedied by picking more mature fruit, the writer turned his attention to determining the feasibility of shipping ‘‘turnings.”” It was found, as would of course be expected, that the riper the tomatoes the shorter the time it is pos- sible to hold them, but the fact was ascertained that “turnings” can be kept in good condition at a temperature approximating that ob- tained in refrigerator cars (50° to 55° F.) long enough to ship them and tosell them to theconsumer. Turning tomatoes held in the refrigerator for 10 days and then kept at a temperature of approximately 75° F. for 5 days longer were found to be in an excellent condition. Other fruits remaining at the lower temperature for 15 days were still. firm enough to be held at room temperature for a few days. At lower temperatures than those used it is possible to hold tomatoes even longer than 15 days. Iced shipments in pony refrigerators sent by express from Miami, Fla., to Washington, D. C., arrived in excellent condition. One commission man who has been shipping fruit under ice for a number of years states that these tomatoes reach the market in excellent condition and bring higher prices than uniced fruit. The above statements are not offered as recommendations for picking and shipping turning tomatoes under ice. There are, however, many good reasons for suggesting that turning fruit may be picked and shipped under an initial icing. One of these reasons has already been men- tioned, namely, that it would be possible to pick fruit at the same stage of maturity which would ripen uniformly and save considerable of the loss which is at present experienced. Furthermore, chemical analysis has shown that turning fruit compares favorably with normal or vine- ripened fruit in composition, taste, and palatability. Other investi- gators, Powell (38), Ramsey (39, 40, 41), Stevens and Wilcox (47, 48), Ridley (42), and others, have shown that fruits are more liable to fungous infection when they are wounded than when uninjured. This is what one would expect in the light of some recent investigations which show a high correlation between susceptibility to infection and the resistance offered by the fruit to mechanical puncture. The investigations of Rosenbaum (43) on the origin and spread of tomato fruit rots in transit have demonstrated that overripeness, bruises, and other injuries favor the appearance of these rots. Since the resistance of the epidermis shows the relative ease with which a fruit may become infected by means of a mechanical entrance of the 4 . a. }- 3 ‘ Pe Rte” PAP late See ee Ae ee PROCESS OF RIPENING IN THE TOMATO. 29 : spore tube, tables are presented showing these data in connection with tomatoes. Table IX (sec. A) shows the pressure necessary to penetrate the epidermis of fruit of different ages. The epidermis of colored fruit is softer than that of green tomatoes 38 days old, yet the difference is too small to justify the conclusion that green fruits are preferable on this account. Table IX (sec. B) also shows the effect of temperature on the resistance of the epidermis to wounding. These results indi- cate that tomatoes are less liable to injury when cooled than when they are warm and consequently are less liable to fungous infection. It-is generally known also that respiration decreases considerably with the lowering of temperature. The products causing the inferior taste and flavor in tomatoes probably result from intramolecular respiration as a result of withholding free oxygen from the tissues. Under the present methods of shipping tomatoes from the South it would be impossible to allow cars to remain open throughout the entire journey. The initial icing of cars at the warm end of the trip would have the effect of preventing the harmful result of lack of ventilation by reducing respiration to a minimum. TABLE 1X.—Fffect of age and temperature upon the resistance to wounding of the epi- dermis of Livingston Globe tomatoes, showing also color conditions.' Sec. B.—Temperature ef- fects. With needle hay- ing a diameter of— Sec. A.—Ageoftomatoes. With needle hay- ing a diameter of 68 microns. Descriptive data. a 7 13 21 30 38 4 5 . 3 7 , 2 ~.. | days;} 68 microns; | 78 microns; days; days; days; | days; | days; turn- turning. red ripe. green. | green. es aa tne? Temperature of penetration | Ai) sa ees Bees Ba ees 30 29 29 | 30 | 33 30.5 | 24 9 25 14 Average of 10 scate readings at | which penetration occurred for individual tomatoes: _ 3 | 23.6 | 14.4 | 32.4 | 33.8 | 23.91 | 15.75 | 32.48 | 30.92 3 27.8 23.2 33.3 31.6 32.81 | 28754 | 30.87 | 31.21 1 32.6 | 21.3 | 28.2 | 29.5 | 21.40 | 16.70} 32.16 | 28.64 3 | 33.9 | 20.4 | 24.8 | 30.7 | 22.97 | 18.66 | 26.36 | 24.65 3 |. 32.1 23.7- | 30.5 | 32.0 | 25.35 | 20.60 | 28.91 | 22.63 3 | 31.5 | 24.8 | 32.6 | 32.6 | 27.38 | 23.54 | 27.95 | 27.84 6 | 29.3 | 24.9 | 25.8 | 32.3 | 25.38 | 23.36 | 31.32 | 29.32 6 34.7 25.6 18.6 26.1 18.47 | 16.27 | 31.86 | 29.42 6 | 31.5 | 25.1 | 32.2 | 37.0 | 24.35 | 20.38 | 23.66 | 23.79 5 | 34.2 | 25.5 | 30.5 | 30.2 | 27.80 | 25.08] 26.61 | 28.46 8°] 32.1 | 27.7 | 27.5: | 32.6 | 29.19 | 25.72 |......- fade 5 EE Gm ies Se (SE eae eS ee eee ier ce Se Wi. Fee RPALS Fie Ue S | Bort ea POG, be 20 2 |S Se) ey ee £ | 31.3 [28-1 SETS Si er Ns Set eee! Se aaa (aa SM ES 8 Eg ae | he FS ee) Ee eee SY CPS) tere ian ES el eee |e be Sl ey Coe 4Y;) 9G 1535) Soaee . TAR oe | RES SS See: Ee ee eae eee ee St Be NE TBS | ee Sa | eS Racdoe 4 Bee AS Ree Somer Pi (ee RAT) | BR eR 09 Sree) Pee eee, Se eee Ereaeees oR |e SC) a CE ae Se 2 SMe ee See RS oe 38.0 31.1 25.35 | 21.33 | 29.32 | 27.6 Pressure necessary to punc- Ji =~ <.————— ean 2.88] 3.77| 6.14] 8.25] 10.80 | 10.24} 10.28] 11.68] 5.08] 5.58 1 For detailed information as to the apparatus and methods used to obtain the data presented in this rere see the following references: Hawkins and Harvey (22); Hawkins and Sando (23); Rosenbaum and 0 (44). 30 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. Against the arguments in favor of picking and shipping turning fruit one must consider the advantages of present practices. The picking of turning fruit would require that the fields be gone over more frequently than at present and that the pickers exercise much more judgment and care. The writer had planned to make com- mercial shipments of tomatoes picked at the turning stage in order to get dependable information which might serve as a basis for rec- ommending to the growers changes in the current practice, but the discontinuance of this work for the present has prevented the carrying out of the plan. It is of very great importance to the growers that these shipments be made. It is felt that the work reported upon in this bulletin supports the chemical explanation offered of the infe- riority of tomatoes shipped from the east coast of Florida during the winter and spring months. It remains to be determined whether the changes in current practice suggested in these pages can be put into effect. If they can be, the result of these investigations will be to insure the consumer a better product in the future than in the past. SUMMARY AND CONCLUSIONS. With the particular object of discovering the chemical basis for the inferiority of commercially picked and ripened Florida tomatoes marketed in the North during the winter and spring, a series of anal- yses has been made of tomatoes of several degrees of maturity and of tomatoes ripened artificially under various conditions of venti- lation. It was found that the only way to secure samples of comparable maturity for analysis was to tag the blossoms and pick the fruit at a definite age. There is a wide range of variation in the size of the tomatoes within the same variety, but ripening proceeds at a uni- form rate regardless of size. Maturity is dependent upon age, not upon size. — iors Using fruit of known age, therefore, analyses were made which indicate that in general throughout the ripening period there is an increase in moisture, acids, and sugars and a decrease in solids, total nitrogen, starch, pentosans, crude fiber, and ash. The most striking change which occurs during ripening is that undergone by carbohydrates. Sugars increase from 25.66 per cent in fruit 14 days old to 48.32 per cent in ripe fruit. Starch decreases in the same interval from 15.84 to 2.65 per cent. The most marked decrease takes place during the period of transition from green to red. The percentage composition of fruit picked green but ripened with free access of air compared with analyses of turning and vine-ripened fruit did not show enough variation to account for the great differ- ee a a ee ee ee oe 4.5 SP PROCESS OF RIPENING IN THE TOMATO. 31 ences in taste found in commercially shipped fruit. Turning toma- toes showed less difference from vine-ripened fruit than did the green fruit and compared favorably with normal tomatoes not only in composition but also in taste. The effect of lack of ventilation on ripening was to increase the acid content approximately 138 per cent over that of vine-ripened fruit. The flavor of tomatoes ripened without ventilation was very inferior. The soluble carbohydrate content showed a decrease of nearly 21 per cent. Commercially ripened green fruit, wrapped with one paper, showed an increase in acid of approximately 102 per cent and a sugar decrease of nearly 5 per cent compared with correspond- ing tests of vine-ripened tomatoes. The results of wrapping with three papers were less marked and are difficult to explain. The data seem to justify the conclusion that wrapping probably modifies the course of ripening to such an extent as to account for marked changes in taste and flavor. The combined results of pick- ing fruit green, of wrapping, and of closing the cars in transit probably account for the total differences existing in quality between com- mercially shipped and vine-ripened tomatoes. LITERATURE CITED. ALBAHARY, J. M. (1) 1907. Analyse compléte du fruit du Lycopersicum esculentum ou tomate. In Compt. Rend. Acad. Sci. [Paris], t. 145, no. 2, p. 131-133. (2) 1908. Etude chimique de la maturation du Lycopersicum esculentum : (tomate). In Compt. Rend. Acad. Sci. [Paris], t. 147, no. 2, p. 146-147. (3) Atwoop, W. B. 1891. Tomatoes. Va. Agr. Exp. Sta. Bul. 9, 18 p. and Bowman, WALKER. 1890. A study of tomatoes. Va. Agr. Exp. Sta. Bul. 4, 18 p. (5) Bascock, S. M. 1883. [Analysis of the] tomato. InN. Y. State Agr. Exp. Sta. Ist Ann. Rpt. 1882, p. 24. (6) Bacon, R. F., and DunBar, P. B. 1911. Changes taking place during the spoilage of tomatoes, with methods for detecting spoilage in tomato products. U.S. Dept. Agr., Bur. Chem. Cir. 78, 15 p. (7) Baruey, L. H. 1892. Do fertilizers affect the quality of tomatoes? In N. Y. Cornell Agr. Exp. Sta. Bul. 49, p. 456-458. and LopEMAN, E. G. 1891. Notes on tomatoes. N. Y. Cornell Agr. Exp. Sta. Bul. 32, p. 143-189. (9) Brrarp, M. 1821. Suite du mémoire sur la. maturation des fruits. Ann. Chim. et Phys., t. 16, p. 225-251. (10) BERTRAND, GABRIEL. 1906. Le dosage des sucres réducteurs. Bul. Soc. Chim. Paris, s. 3, t. 35, p. 1285-1299. (11) BiaEtow, W. D. 1917. Report on canned vegetables. Jn Jour. Assoc. Off. Agr. Chem., v. 3, no. 1, p. 1-21. (12) Bisnor, W. H., and Parrerson, H. J. 1890. Experiments with tomatoes. Md. Agr. Exp. Sta. Bul. 11, p. 47-74. (13) Brios1, GIOVANNI, and GieL1, TORQUATO. : 1890. Su la composizione chimica e la struttura anatomica del frutto del pomodro (Lycopersicum esculentum Mill.).. In Staz. Sper. Agr. Ital., v. 18, fasc. 1, p. 5-34. (14) CALDWELL, G. C. 1892. The determination of sugar in the tomato. N. Y. Cornell Agr. Exp. Sta. Bul. 49, p. 399-400. : (15) Conepon, L. A. 1912. A further study of the tomato with special reference to canned tomatoes. InN. Dak. Agr. Exp. Sta. 23d Ann. Rpt., 1912, pt. Il, p. 216-242. (16) Danten, H. W. 1875. Beitrige zur chemischen Kenntniss der Gemiisepflanzen. In Landw. Jahrb., Bd. 4, p. 613-721, (4) (8) 32 PROCESS OF RIPENING IN THE TOMATO, oo (17) Duaear, B. M. 1913. Lycopersicin, the red piniant of the tomato, and the effect of condi- tions upon its development. In Wash. Univ. Studies, v. 1, pt. 1, no. 1, p. 22-45. Literature, p. 44-45. (18) Fiscner, G. L., and Netson, A. E. 1918. More care is needed in handling western cantaloupes. U.S. Dept. Agr., Bur. Markets Doc. 9, 11 p., 4 fig. (19) FormMEntTI, Carxo, and Screrorti, ARISTIDE. 1905. Zusammensetzung italienscher Tomatensifte. Jn Ztschr. Untersuch. Nahr. u. Genussmtl., Bd. 12, Heft 5, p. 283-295. (20) Gorg, H. C., and Farrcnitp, Davin. 1911. Experiments on the processing of persimmons to rencer them nonas- tringent. U.S. Dept. Agr., Bur. Chem. Bul. 141, 31 p., 5 fig., 3 pl. (21) HasseLBrine, HEmnricH, and Hawkins, L. A. 1915. Pysiological changes in sweet potatoes during storage. In Jour. Agr. ' Research, v. 3, no. 4, p. 331-342. Literature cited, p. 341-342. ' (22) Hawerns, L. A., and Harvey, R. B. 1919. Physiological study of the parasitism of Pythium debaryanum Hesse on the potato tuber. Jn Jour. Agr. Research, v. 18, no. 5, p. 275-297, 2 fig., pl. 35-37. Literature cited, p. 295-297. and Sanpo, C. E. 1920. Effect of temperature on the resistance to wounding of certain small fruits and cherries. U.S. Dept. Agr. Bul. 830, 6 p., 1 fig. (24) Hitz, G. R., jr. 1913. Respiration of fruits and growing plant tissues in certain gases, with reference to ventilation and fruit storage. N. Y. Cornell Agr. Exp. Sta. Bul. 330, p. 377-408. Bibliography, p. 407-408. (25) Huston, H. A., and Bryan, A. H. 1901. The chemical composition of materials. Jn Ind. Agr. Exp. Sta. 13th Ann. Rpt., [1899]/1900, p. 80-88. . (26) Jenxins, E. H., and Brirron, W. E. 1896. On the use of commercial fertilizers for forcing-house crops. Experi- ments with tomatoes. Jn Conn. Agr. Exp. Sta. 19th Ann. Rpt., 1895, p. 75-90. (27) Kennepy, ©. W. 1873. Solania in Solanum lycopersicum. Amer. Jour. Pharm., v. 45 (s. 4, v. 3), p. 8-9. (28) Kraus, E. J., and Kraysi, H. R. 1918. Vegetation and reproduction with special reference to the tomato. Oreg. Agr. Exp. Sta. Bul. 149, 90 p., 22 fig. Literature cited, p. 87-90. (29) Luoyp, F. E. 1911. Carbon dioxide at high pressure and the artificial ripening of persim- mons. Jn Science, n. s., v. 34, no. 887, p. 924-928. Citations, p. 928. (30) McErHeEnts, T. D. 1872. Lycopersicum esculentum.—Tomato. Jn Amer. Jour. Pharm., v. 44, p. 197-200. . (81) Mrtiarpet, A. 1876. Note sur une substance colorante nouvelle (Solanorubine) découverte dans la tomate. Nancy, 1876. (Abstract.) Jn Just’s Bot. Jahres- ber., Jahrg. 4, p. 783-784. 1876. Original not seen. _ (28). 34 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. (32) MonTANARI, CARLO. 1904. Materia colorante rossa del pomodoro. Jn Staz. Sper. Agr. Ital., v. 37, fasc. 10, p. 909-919. (33) Munson, L. 8., and Waker, P. H. 1906. The unification of reducing sugar methods. Jn Jour. Amer. Chem. Soc., v. 28, no. 6, p. 663-686. (34) Patmert, P. 1885. Sul pomodoro. Jn Ann. R. Scuola Sup. Agr. Portici, v. 5, p. 67-83. (35) PassErRint, N. 1890. Sulla composizione chimica del frutto del pomodoro. (Solanum lycopersicum L.) JnStaz. Sper. Agr. Ital., v. 18, fase. 5, p. 545-572. (36) Parrerson, J. sf, 1889. Report of the chemist. Jn Md. Agr. Exp. Sta. 2d Ann. Rpt., 1889, p. 67-93. (37) Pecxotrt, Tu. 1909. Heil- und Nutzpflanzen Brasiliens. In Ber. Deut. Pharm. Gesell., Jahrg. 19, Heft 3, p. 180-207. Cites early analyses of John and Bertagnini. (38) Powe tt, G. H., et al. 1908. The decay of oranges while in transit from California. U. 8. Dept. Agr., Bur. Plant Indus. Bul. 123, 79 p., 26 fig., 9 pl. (2 col.). Ramsey, H. J. (39) 1915. Factors governing the successful shipment of red raspberries from the Puyallup Valley. U.S. Dept. Agr. Bul. 274, 37 p., 26 fig. (40) 1915. Handling and shipping citrus fruits in the Gulf States. U.S. Dept. Agr., Farmers’ Bul. 696, 28 p., 10 fig. (41) 1916. The handling and shipping of fresh cherries and prunes from the Willamette Valley. U.S. Dept. Agr. Bul. 331, 28 p., 11 fig. (42) Ripiey, V. W. 1918. Factors in transportation of strawberries from the Ozark region. U.S. Dept. Agr., Bur. Markets Doc. 8, 10 p., 6 fig. (43) RosENBAUM, JOSEPH. 1918. The origin and spread of tomato fruit rots in transit. Jn Phytopath- ology, v. 8, no. 11, p. 572-580, 1 fig., pl. 4. and Sanpo, C. E. 1920. Correlation between the size of the fruit and the resistance of the tomato skin to puncture and its relation to infection with Macro- sporium tomato Cooke. Jn Amer. Jour. Bot., v. 7, no. 2, p. 78-82. (45) Scounok, C. A. 1903. The xanthophyll group of yellow colouring matters. In Proc. Roy. Soc. London, v. 72, no. 479, p. 165-176, pl. 6-7. (46) SnypErR, Harry. ; 1899. Tomatoes. Composition and food value. Jn Minn. Agr. Exp. Sta. Bul. 63, p. 513-517. Srevens, N. E., and Witcox, R. B. (47) 1917. Rhizopus rot of strawberries in transit. U. 8. Dept. Agr. Bul. 531, 22 p., 1 fig. Literature cited, p. 21-22. (48) 1918. Further studies on the rot of strawberry fruits. U.S. Dept. Agr. Bul. 686, 14 p. (44) PROCESS OF RIPENING IN THE TOMATO. 35 (49) Street, J. P. 1911. Report on vegetables. In U. S. Dept. Agr., Bur. Chem. Bul. 137, p. 122-134. (50) Stiser, W. 1906. Uber die Zusammensetzung der Tomate und des Tomatensaftes. Jn Ztschr. Untersuch. Nahr. u. Genussmtl., Bd. 11, Heft 10, p. 578-581. (51) THompson, Firman, and Waurrtirr, A. C. 1913. Forms of sugar found in common fruits. Proc. Soc. Hort. Sci., 9th Ann. Meeting, 1912, p. 16-22. (52) Tracy, W. W. : 1907. Tomato culture . . . , 150 p., illus. New York. (53) U. S. Department or AGRicutrurE. Office of Experiment Stations. 1893. Composition of vegetables. In U.S. Dept. Agr. Off. Exp. Stas. Bul. 15, p. 401. (54) Van Styxe, L. L., Taytor, O. M., and ANprews, W. H. 1905. Tabulated analyses showing amounts of plant-food constituents in fruits, vegetables, etc. In N.Y. Agr. Exp. Sta. Bul. 265, p. 223-230. (55) VoorHeEs, E. B. ; 1889. Experiments on tomatoes. N.J. Agr. Exp. Sta. Bul. 63, 27 p. (56) WaLxker, P. H. 1907. The unification of reducing sugar methods. Jn Jour. Amer. Chem. Soc., v. 29, no. 4, p. 541-554. (57) Witey, H. W., ed. 1908. Official and provisional methods of analysis, Association of Official Agricultural Chemists. As compiled by the committee on revision of methods. U.S. Dept. Agr., Bur. Chem. Bul. 107 (rev.), 272 p., 13 fig. _Reprinted in 1912. (58) Wrtstétrer, RicHArp, and Escuer, H. H. 1910. Uber den Farbstoffe der Tomate. In Ztschr. Physiol. Chem., Bd. 64, Heft 1, p. 47-61, pl. 2 (col.). Bul. 859, U. S. Dept. of Agriculture. PLATE III. EXTERIOR OF A NORMAL AND OF A “‘PUFFY’’ TOMATO. Bul. 859, U. S. Dept. of Agriculture.- PLATE IV. INTERIOR OF A NORMAL AND OF A “‘PUFFY"’ TOMATO. APPENDIX. COMPARISON OF THE COMPOSITION OF “PUFFY” AND NORMAL LIVINGSTON GLOBE TOMATOES. The abnormality in tomatoes called puffiness is one in which the seed cavities are affected. The fruit sounds hollow when it is patted with the hand and shows external angular irregularities. Plates HI and IV show the angular appearance of the exterior and also the characteristic appearance of the interior of the fruit. In a locality where the trouble was especially pronounced one crate of tomatoes was taken at random from ‘a packing house and the number of hollow and normal fruits estimated. The figures follow: Estimated by the sound before cutting, normal 58, hollow 95; estimated by cutting the fruit in two, normal 32, partly hollow 56, pronouncedly hollow 66. : Counts were made in order to determine whether certain plants produced fruits that were all hollow and other plants produced normal fruit. It appears that a single plant may produce both normal and hollow fruit. There is no stage in the life history of the tomato at which puffiness is a natural occurrence, but it may occur on small as well as large fruit. It does not seem to affect the amount of color or the time of ripening. Table X shows that although there are some differences in chemical composition between normal and “puffy” fruit there are no possible explanations to be gained from this standpoint. Various fertilizer plats were arranged to determine the effect of different amounts of nitrogen, potash, and phosphoric acid upon the production of “puffy” fruit. Seven plats were set out and the fertilizer mixtures were given in four applications at the rate of 1 ton to the acre. The fertilizer ingredients consisted of acid phosphate, sodium nitrate, and potassium sulphate, and the following ratios were used Cie various plats.1 : 0 +3: 4: 10°: 853 :5 23;3°:10::8;3.:6 +0; - hone wand ¢ :10':8. TABLE X.—Composition of normal and ‘‘puffy” Livingston Globe tomatoes. Both samples picked green, but fairly mature. Normal fruit. “Pufly”’ fruit. Constituents. - —_—— ae Wet basis. | Dry basis. | Wet basis. | Dry basis. MOIST OM meinen ower cece cecies See ote ick Sena eee G4. SGN Nett Sep asec oS ya eee SRGLAUSO NG Seer se deci tease See ee eee ee eS tt EGY lll Le eee Daas |e | enero AES UTA SONG Re A SI OR a SR eee 2. 93 51.95 2. 84 50. 00 SRO ATUL NOP CR SENS ao eee meee fase foe 8S . 140 2. 48 139 2. 45 PIPES Ata (ASCOUVONE) eae een eee Soe ec nine oo Dal 48.05 2. 84 50. 00 edie pr suman (ASNNVErD)eoocs. .ccneeeeae es sacs. == 2. 40 42. 55 2.61 45. 95 STGING fs O28 CoS CO SIRES Deen Tene a ose or ne ae eae ane 42 7. 44 38 6.70 Alcohol-soluble pentosans..........-...-...-.--0.+----- . 034 . 602 . 033 - 581 ANOLON BOT LOSADS a. ceca otiaeen Le cain cceicBu csi sha . 190 3. 54 . 197 3. 47 ST ULGy MGT ae tae ieee te met in teen anceaee See. BaD 9.75 54 9.51 Carbohydrates: OPA eee a cicins donee eee ene See eee 5 Se See 3. 904 69. 38 3. 990 70. 26 [SVE (VNG) (2) jae. Si 5 Sie OS Pee SN soe ak kT oe ne amen a PP ik 48. 55 2. 84 50. 00 PAROLE Deseemee ts ek te IO ne oak De 1.19 20.83 1.15 20. 26 oo “I 38 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. Examination of the fruit produced in this experiment showed that both normal and_ hollow fruits were to be found on every plat. Com- plete counts could not be made, owing to the destruction of the vines by a flood before the end of the season, but enough observa- tions were made to show that within the limits used varying quantities of fertilizer elements did not influence the production of hollow fruit. . No positive results were obtained in this study showing the cause of puffiness in tomatoes, but the evidence indicated that the con- dition is not correlated with any considerable differences in the chemical composition of the mature fruit. The phenomenon is probably physiological in its nature, for the same varieties which show it in Florida are said not to do so, or only to a very slight extent, when grown in Michigan. A great difference that immediately occurs to one between conditions in the two places is that in Florida the crop is produced only through heavy annual applications of commercial fertilizers, which are not used in Michigan. Puffiness may therefore be dependent upon an unbalanced soil solution, but, if so, none of the variations in the fertilizers just enumerated sufficed to restore a proper condition. It is, of course, not inconceivable that puffiness is of a genetical nature and due to somatic variation. _ Ef so, it might, in conformity with the observed facts, be much more frequent in some varieties than in others, and the same plant might show both - normal and ‘‘puffy” fruit. The whole subject is one which needs investigation. 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