LIBRARY OF THE University of California. GIFT OF Class £ U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY— BULLETIN No. 87. H. W. WILEY, Chief of Bureau. CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS AND THEIR PRODUCTS. I. A Study of Cuban Fruits. n. The Composition of Fresh an; Canned Pineapples. BY MACKAY CHACE, L. M. TOLMAN, AND L. S. MUNSON, Assistant Chemists, Food Laboratory. WASHINGTON : GOVERNMENT PRINTING OFFICEo 1904. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY— BULLETIN No. 87. H. W. WILEY, Chief of Bureau. CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS AND THEIR PRODUCTS. I. A Study of Cuban Fruits. II. The Composition of Fresh and Canned Pineapples. BY ED. MACKAY CHACE, L. M. TOLMAN, AND L. S. MUNSON, Assistant Chemists, Food Laboratory. LETTER OF TRANSMITTAL. U. S. Department of Agriculture, Bureau of Chemistry, Washington, D. C, August ^'2, 190^. Sir: I beg to transmit for your inspection and approval a manuscript containing the results of certain investigations on the chemical compo- sition of tropical fruits. Aside from the scientific interest of this study the principal object kept in view has been to make such a pre- sentation of the facts of the case as may be of value to the citizens of the possessions of the United States lying within the Tropics. The cooperation of the expert of the Bureau of Plant Industry in charge of tropical agriculture was secured in the identification of the fruits, and the manuscript has received his approval in regard to all points in which the investigation touches upon the strictly pomological phase of the study. I have the honor to recommend that this report be pub- lished as Bulletin No. 87 of the Bureau of Chemistry. Respectfully, H. W. Wiley, Chief. Hon. James Wilson, Secretary of Agriculture, Digitized by the Internet Archive in 2007 with funding from Microsoft Corporation http://www.archive.org/details/chemicalcompositOOchacrich Vof-t^" LETTER OF SUBMITTAL Department of Agriculture, Division of Foods, Bureau of Chemistry, Washington, D. C.^ August ^'2, 190^. Sir: I herewith submit the report of recent work done in the Food Laboratory, now the Division of Foods, with a number of tropical fruits and fruit products, especially f iniits grown and products man- ufactured in the island of Cuba. The recent acquisitions by the United States of tropical territory make further information regarding tropical fruits of great interest. The fruits mentioned in this report are grown either in the Philippine Islands or in Porto Rico, and many of them are grown in both places. In many cases these fruits grow wild and have at present no commercial importance in those localities. At the same time it is apparent that with proper treatment they should have a large degree of commercial importance. All of the prepared fruit products from Cuba could also be made advantageously in Porto Rico, and should be brought to the attention of (consumers in the United States. Pineapples are extensively canned in the Bahamas and the Straits Settlements. The extension of this industry to the insular possessions of the United States would also seem practicable. The presence of Mr. Chace in Havana for a number of months aflforded him exceptional opportunities to study the nature of fruit products manufactured and used in that locality and to secure samples. Respectfully submitted. W. D. BiGELOW, Okie f of Division of Foods. Dr. H. W. Wiley, Chief of Bureau of Chemistry.^ U. S, Departmetit of Ag7'iculture. CONTENTS. Page. 9 I. A study of Cuban fruits r- ^ Introduction ^^ Citrus fruits -.,. Orange (Naranja) ^^ Grapefruit (Toronja) ^^ Lime (Limoncillo) Tamarind (Tamarindo) ^^ Guava (Guayaba) ^^ Banana (Platano) ^^ Mango 22 Anona 22 Sour-sop (Guanabana) Sweet-sop (Anona) Custard apple (Chirimoya) ^^ Sapota (Sapodilla) 25 Mamey Colorado 25 Mamey de Santo Domingo ^g Hicaco ' 28 Cashew (Marafion) 28 Star-apple (Caimito) 29 Analyses of the ash ^ II. The composition of fresh and canned pineapples ^^ Description of samples ^^ Methods of analysis ^2 Analytical data 6391— No. 87—04 2 ^ CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS AND THEIR PRODUCTS. I.— A STUDY OF CUBAN FRUITS. INTRODUCTION. There has been practically no work done on the chemical composi- tion of tropical fruits other than the banana and the orange, and it is only recentl}^ that the pomologist has given them much attention. Even now the majority of these fruits are ignored commercially and it is hoped that this report will aid in calling attention to some of the comparatively unknown fruits of the near-by islands of the West Indies, some of which undoubtedly have economic value. Among the fruits examined are some which at least are commercial possibilities. The mango and sapota are both pleasant to the taste in the fresh state; they mature when picked green, and will stand ship- ping if properly packed. The mamey de Santo Domingo and the sour orange make excellent preserves and with some care and ingenuity in manufacture others might be made marketable. The superiorit}^ of guava pastes and jellies has long been conceded. The fruits were sampled by Mr. E. M. Chace, in Havana, Cuba, in the height of the season of 1902. Both the fresh and preserved samples were purchased in that city and the retail prices are given. The ripe portions of the fresh fruit samples were analyzed by Mr.- Chace, in Havana, the green fruits being sent to Washington, where, after ripening, they were examined by Mr. Tolman and Mr. Munson. In this way complete data were obtained on all the samples except one. When possible samples of the preserved fruit were purchased in order to test the quality and make a comparison with the fresh sample. All the preserves possessed the same objectionable feature — they were too sweet and contained too little acid, a matter easily remedied^ however. As a rule, the preserves were made from good fruit and no glucose was used. 9 10 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. CITRUS FRUITS. Prior to the American occupation of Cuba nothing had been done toward taking advantage of the great opportunities for raising citrus fruits. During that period a considerable quantity of Florida orange stock was imported, and during the past year (1903) some oranges have been exported. The industry is important on account of its pos- sibilities rather than because of its present condition. As the United States would constitute the principal market, the methods of selection, grafting, and curing, and tariff conditions would determine largely whether the Cuban fruit could compete with that of Florida and California. While grape fruit and limes grow in a semicultivated or almost wild condition and find a ready sale in the markets of Cuba, no effort is made to export them or to increase the volume of the output. The lemon {Citrus limon) grows only in a few private gardens, and the native fruit is never offered for sale, although there seems to be no reason why it should not be cultivated to advantage. CITRUS FRUITS. 11 agg OOOOOOOOOOCX)000 <^?JgJg5SSg3§S5?5?^g5 O 00 o o o ?J ?5 s g^ ^ g8 1 1 OS 1 CO 1 1 1 + 1 -17.60 -18.00 -18. 96 - 2.50 ^_ ^ 8 q S_ § 8 S eo (N o ' «o ci (N c4 II 1 7 1 1 1 g s ^ ^ § 8 §_ o g 8 8 § 8 8 8 o g S 8 S 4- + + + + + + 4- + + + + + + + 11! ■s OC 33 J^ § g S3 g §1 ?;; g s § S;^?J S3 s 1 t^ 05 t- CO r u^ ^ 5 2 S -o i> .o g 1> lO lO Ti< (N I> O t- 05 (N lO Oa -^ t^ lO -^ lO »o § i^ 8 =1 S^-C h CO .2^ ^ § S Tj! eo CO 3J S 1/3 lO 00 5 S 5 S lO iQ at \a T-i cs a> -^ CO 00 c^ i-i «5 r-iTj lOeoeOiHi-tr-ieoeo O «0 Tj. t^ 1> o t> OS CO lO t> t^ c4 <0 M CO IN (N -k^O«OrHO»COOS'«*<->*-<»<-*T»<5^THO>t>oo«o heO'»9<-l>COi0050«0 8 8 00 o ?a eo ^u0 ;^. O O 8 8 l> t^ 1> 50 iCi iC (N O 00 OJ 1> 50 5P-2ro5 o o o o O- CO o o o s s 1 '^ g -O oj Ph S !zi P! CI OQ o -=3 S S SooooooaS 00 12 CHEMICAL COMPOSITION OF SOME TEOPICAL FRUITS. ORANGE (n ARAN J a). ( Citrus aurantium. ) The oranges of Cuba as a rule are smaller, more fibrous, and con- tain more seeds than the same varieties grown in this country, but they are very juicy and have a good flavor. These qualities could undoubtedly be improved by modern methods of selection, grafting, and cultivation. The fruit retails at a very low price in the Havana market, sometimes selling for 50 cents a hundred, although the usual price is from 60 cents to $1. Two varieties of orange {Citrits aurantium) were found, one a thin- skinned small fruit known as the "china," and the other a much larger fruit with a thick skin. The former is superior in quality, having less fiber and a better flavor. Table I, on citrus fruits and preserves, giving the composition of these fruits, shows that there is but a slight difference between these varieties in the content of sugar. The " china", however, contains twice as much acid and only one-fourth the amount of insoluble solids as the thick-skinned orange. In this it resembles the American varieties, the analysis of 80 samples of which gave 1.28 per cent of acid and 10.68 per cent of sugars.^ In sample No. 506, Table I, the very exceptional fact is noted that the polarization after inversion was to the right, showing a difterent ratio between the dextrose and levulose thkn that which usually exists in fruits, right-hand readings being very rare. In some pre- vious work on fruits done in this Bureau * an exception of this kind was also' noted in the case of a sample of plums which after inversion gave a reading of +1.3. The bitter orange, "naranja agria" {Citrus higaradia)^ resembles the large, thick-skinned, sweet orange in appearance, having a some- what thicker skin, but being about the same size. It grows in a semi- wild state in many parts of the island, but is little used except for making "dulces" (sweets). Some of the finest Cuban preserves are made from this fruit. The chief difference between this variety and the sweet orange is in the amount of acid present, both containing about the same amount of sugars. Four kinds of orange preserves were examined. ' ' Pasta de naranja " is a thick orange paste sold in wooden boxes lined with paper. This packing is not sufficient to protect the preserves, as a sample kept in the laboratory dried out and became wormy in the course of a year. The paste was probablj^ made by boiling down the pulp and inner skin of the orange. Owing to the small amount of acid present but little of the cane sugar was inverted. « Colby, California Agr. Expt. Sta. Rept., 1892-93, p. 246. &U. S. Dept. of Agr., Bureau of Chemistry, Fruits and Fruit Products: Chemical and Microscopical Examination, Bui. No. 66, p. 49. CITRUS FRUITS. 18 "Mermelade de naranja" is similar to the orange marmalade found on the American market. Analyses of American and European mar- malades given in Fruit and Fruit Products*^ show that these contain less sugar and more acid than the Cuban products. This gives the former a tart flavor, while the latter are somewhat insipid. The sample was put up in glass. The " naranja en almibar," or orange in sirup, consists of pieces of orange preserved in a heavy sirup and put up in glass. The "cascos de naranja," or preserved orange skins, are made by scraping or rasp- ing the skins of oranges to remove the outer yellow part and cooking them in a heavy sugar sirup. These preserves have a pleasant flavor and are the most palatable of the orange preserves examined. This sample was put up in tin cans, a method not generally employed in Cuba. GRAPEFKUIT (tORONJA). ( Citrus decumana. ) This is a popular f iTiit in Cuba. It has a mild, pleasant flavor, and is quite dift'erent from the acid, bitter fruit to which we are accus- tomed. It retails in Havana at about 2i cents apiece. The analyses given in Table 1 show its composition to be like that of the sweet thick-skinned orange. Two analyses of grapefruit made by Colby * show that the California product is a very different fruit, having about four times as much acid as the Cuban grapefruit and only slightly more sugar. No grapefruit preserves were found on the Cuban markets. In California a preserve called grapef ruitate, which is really a marmalade and very similar to orange marmalade in taste and composition, is being made from grapefruit. LIME (lIMONCILLO). {Citrus hystrix adda.) The lime grows wild in all parts of Cuba and replaces the lemon entirely for domestic uses, making beverages, etc., as it is used with- out the curing which the lemon undergoes, and, either in the ripe or green state, it is on the market during all seasons of the year. In composition the Cuban lime closely resembles the California lemon. The average of 22 analyses made by Cplby ^ is 5.26 per cent of acid (calculated as sulphuric) and 2.33 per cent of sugar. The sample of preserved limes resembles closely the " cascos de nar- anja," being made of fruit from which the juice had been expressed, «U. S. Dept. of Agr., Bureau of Chemistry, Bui. No. 66, p. 61. 6 California Agr. Expt. Sta. Kept., 1892-93, p. 256. c California Agr. Expt. Sta. Kept., 1892-93, p. 249. 14 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. as shown b}^ the low acid content of the preserve. No samples of lime juices were found. The sweet limes and lemons analj^zed could not be positively identified. These fruits are little used, being offered for sale chiefly in the larger markets on account of their alleged medicinal qualities. They possess a highl}^ aromatic odor and taste and their composition is not unlike that of the sweet orange, except that they contain a very low percent- age of acid. TAMARIND (TAMARINDO). ( Tamarindus indica. ) The tamarind is the fruit of a leguminous tree. The fruit is a dark brown pod, from 1 to 6 inches long and from f to 1 inch in width. Small indentations on the pod roughly mark the location of the seeds within. The exterior skin is thin and very brittle. Within, there is a thick dark-colored pasty material closety surrounding the tough seed sacks and joined to the stem of the pod by several coarse fibers. This paste constitutes the edible portion of the fruit and is so intensely sour in taste that the 30 per cent of sugar which it contains is entirely masked and can only be detected by a slightly sweet aftertaste. The tamarind of all the fruits examined is remarkable in that it has the highest content both of acids and of sugars. It contains a higher percentage of acid than the lime and more sugar than any of the sweet fruits. As would be expected, in the presence of so large an amount of acid but little cane sugar is found. A study of the process of the ripening of the tamarind would be of great interest on account of this remarkable ratio between the acid and sugar. H. C. P. Geerlings,^ reporting on the sugar content of the tropical fruits from Java, gives that of the tamarind as only 8.32 per cent, working perhaps on the green fruit. The fruit is used in mak- ing refreshing summer beverages and for flavoring soda-water sirups. It has mild purgative properties, and is used in this country in prepar- ing the confection of senna. «Chem. Ztg., 1897, 21: 719. TAMARIND. 15 o o (N (N S2^ ^g5g5£5 5^ TO HftS o o . . ^ g S g p.. . . . . •c > o •- " S ^ si 1 1 1 1 S. ...gss^ S 1 1 + r 1 ^^^gS ^SSSS Su- crose polari- zation. i 0.4 1.0 75.4 72.4 , .« ■* i-H lO 03 A S 2J « G ■g (M si|>§S r 6 ■sSSStg 'S.5 |3 S ?5 S S C3 cii cS er cent 1.36 2.44 .46 .41 2^ Oh^z; a, t3§53^S r^' ' ■ ^ Alka- linity, as po- tassium carbon- ate. S?o < 3 ^•s s§^ o t;^ H Gi -Sii-S "S S oc i^ r -o •s- g ^ g § 1 ^ssgg aj o § ^ 00 ^ 3 «^ G o ^ ^ s Aver- weight of fruit. ii 05 a. Oi oi O c s oj "C 1 c ® Tamar do Tamar Pulpa Lab- ora- tory No. i 5 o O 01 •M r> o o X o o 1 agg "ci ?3 ?) tl ?l ?l ?-, 'c^l ?! ?5 ?^ G .2 '^^H o tf BS ii^SS 8S§ p li- -* -3- ° 1 1 ; ! i 1 i 111 s HI = HH 5 O iC ?>B^k6S S t^ g ° T7 ^^§SS ^^?:i ^^^ SiiBP.^S 53S?g 1 ^ «5 uc ^■gi^i5i$Ei S?gS Eh |3 ill s" ^^SS^ ^S^ ^ S g S^ S S ?5 ^ ^ 2 fr 5>.S ^ 1) O ■^ 1^ ^ !0Xt^rir-05 cot^ao i|.| ^d ^ SSS^g ?5^^ «>. (^ SSltSSS gggj C «5 'I-' II ^?i?i?5^5:; ^^§5 oo ^ t^ ^ gS -^ o o JpggOiC ^gg ;.. o-o g^:^^ eCr-ico?5-T< Mc^jc^ an oX ^^^ £z ^ r; 1 s ^ §d s l£-S ^d '^^ ■< ^" Ch iMil •Si- i^?:;Sg^?5S Si2J§ ^^' ^• ^•--^l-^ ^ 1— ( < 3 111 iigllil III m ^o >-9 H /^ CQ Qi <: 1. H ■s^s? ?;?? SSS £:?§ G-O ^ ^ ^ uC -r 1(5 ^ -3< W iC t^ Si J: •>J -f r- gSoSSgS?^ S?22 X S ■— ' ^ "o t^% ?;?3^52?5eS §§^ t» £. i o o ^^"3 05 , a a c3 G 1 1 a 'u 0 1 llfl g. 1 b' 1 1^ 5c ^ Si) 1 !■ OS C x c) t ■- o ~ o ■£^ • o o 1 IIIIIIIF' -c ^ ■^iit-6 ^5 Ft^2gje:2S S§ 1 JS2^ ^ X «, CC « 3C 0 «0 c ! ! 1 + 1 + + + 4- : 4- + + + "s •s s g ?2 s 8 S r= f5 § •2 g ^ ^§s ^ l-H t^ {» .-H rH Id . t^ Oi lO ^^ 0 , . 2 >>S = t : g • d : a §? S g : ic CO eo t>: : rn- d C4 d bo ■5 rai '^ 2 >»s S ■e 2 S S : g f2 g S . 05 05 • CO ■ r) TT r-1 1-1 0 rH C35 3 «:s en ^- (^ " ^ ^ ^ S be ■c ^ g ^^8S28?gSS S5S b d os" rHXI^-^' "^ s S5 S § g ?5 § ^ «5= G eo (M -^ ec ■*< C* ? •^ i 1 i i i i i MANGO. 19 The oronoco and Colorado are red bananas very much like those offered for sale in our markets, and their flavor is not the best. One of the samples reported in Table IV was purchased in Washington. The indiano is a large, jellow, angular fruit with a salmon-colored pulp and a rather disagreeable, acid flavor. The Johnson is the variety exported to this country from Jamaica and Central America. It has rather an inferior flavor when compared with the smaller fruits, but stands shipping better than other varieties. Two of these samples were bought in Washington. MANGO. {Mangifera indica. ) The mango is the popular tropical fruit of the native Cuban. It grows in all parts of the island, on trees by the roadside and in orchards of highly prized cultivated fruit. The kinds that have been cultivated onh^ slightly appeal but little to the foreigner, being very fibrous and having a strong resinous flavor. Both of these objections are overcome in the well- cultivated varieties, however, a,nd very soon a taste is acquired for all. The fruit is heart-shaped, some being long and narrow, while others are broad and short, or almost round. The skin is like that of an apple, but thicker, and varies in color from green to yellow, alwa3^s shading to red on one side. The pulp is not unlike that of a peach in texture and color and is extremely juicy. The stone or seed is very large compared with the rest of the fruit, and this is especially true of the uncultivated varieties. Long fibers cover the stone and run through the pulp of the fruit. The season in Cuba lasts from May to September. The mango is preferred in the raw state, but is used somewhat in the preparation of jams and jellies, and the green fruit when stewed resembles rhubarb. The " manga" is one of the uncultivated varieties growing in all parts of Cuba. It has the strong resinous flavor characteristic of the com- mon fruit, a large seed, fibrous pulp, and inferior flavor. The amount of sugar present, however, is about the same as that in the cultivated varieties. The manzano, or apple mango, is one of the smaller cultivated varie- ties, nearly round in shape and very highly colored. The seed is large — in one case it was over half the weight of the fruit. This variety is not so sweet as the others, the flavor being rather too acid. The Filipino is the finest mango grown in Cuba. It is the largest of the native varieties, often weighing over half a pound. In flavor it is superior to an}^ other, having none of the resinous flavor of the common fruit. It stands shipment well, which, combined with its other fine qualities causes it to bring the highest prices. When other 20 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. varieties are selling at 5 cents a dozen the price of the Filipino will vary from 30 to 50 cents, and often it reaches a dollar. One tree is known to have produced in one season fruit bringing $75. This variety contains the largest amount of sugar of any of those examined. The French is also one of the better varieties, having fewer of the disagreeable qualities than most of the others. The sample of Porto Rico mango (No. 830, Table V) was obtained from F. D. Gardner, in charge of the Porto Rican Experiment Station at San Juan, and is one of the common varieties growing there. It is very different in flavor from the Cuban fruits, having less acid and sugar, but also less fiber. The composition of some Jamaican mangos analyzed by H. H. Cousins'^ is also given in Table V. This fruit is much more acid than that from Cuba. «Bul. Dept. of Agr., Jamaica, 1903, vol. 1, pt. 11, p. 268. MANGO. 21 o I > iM 0 c «c 0 (C 0 tc c c c Bk2 c5?5?5S?1g5?!§ ^ s ?; ^ .f ^^5 0 .2 — S t^ S g g g5 :;! s s s^^^^ > 0 «5 f: ^' ^ CO 06 d !>' t-: S J= S3 <-i 1 1 1 1 1 1 1 1 1 1 1 I - 1 S t: 8 2 0 GO t>: + + S 8 8 cj -*■ t>: 1 + -+- d t-^ + + d !>: ^ ;^ + + 1 1 "5 ^ § S S 8 ?: ^ 8 2 g & ^ «: s s 1; CO CO a> 00 1- .0 TI- ^ CO oc r o- (N d H (S^ - - '" S ^ C! •^' cc 0 oo -^ 0 OS 8 S g 2>>So t d ^• r&i t^ r- « d 0 CO 6 3 be "S ?i 0 g S ?i S ^ 8 3; .? S i> s s s 'S.5 05 g.. i-o -; ^ o_ ■* ^ ^ 0 oc ■^ Cs (N m = 1 ■ 1 1 : i : i 1^ " ^ : £^ =^ : 33 -i w ^11 ill § 1 il§i i 11 -^s-g. ^ ^ '"' i^-i^l tj ^ 2 S^i ^ ^ ^ 0 CC CS .>«( .ti a-:: i S ^ « rH 50 CO 0 I- -5 5-|s| ^- • < • rH a i § i ■M 0 s g g - i _g ^ ^ ^ g H ^ ^ ' i^ i Si : S : 33 S ?2 s g 0 2 ri ^c. 1 -' : '^ : ^ ^ ^ ^ •0 ^ s s ?5 S ^ 8 f2 S? 8 g? 1^ ?3 Si S3 ^ fe ^^ t^ d eo lO d CI ^ X a> Tt< § s§a^ gj ^ s? § c ^ ^^ ^ (^ - . ^- .g in X rH 0 CO l> iC 00 00 o- c l-H 0 m CSS g^S .-• d 8 8 s t^ 8 S 1 Hi cc 0 0 m 0 '^ !^' g 5 0 0 i 1 0 0 d d cS ^ " i-( 1-1 a 5 b : £, P. : £ : S s :s "-5 1 im t^ S 1 00 i S 5 i 22 CHEMICAL COMPOSITION OF SOME TEOPICAL FRUITS. Two samples of mango preserv^es were examined, both of which were put up in glass. The '^mangos en almibar" are pieces of mango preserved in a thick sugar sirup, while the marmalade of mangos is a thin paste resembling apple sauce in appearance. Neither sample was of good flavor. ANONA. There are three species of anona in Cuba which are edible. First and most important is the sour-sop, next the sweet-sop, and third the chirimoya, which is of but little importance. SOUR-SOP (guanabana). {Anona muricata.) The sour-sop is a green, irregular-shaped, pod-like fruit varying from 3i to 12 inches in length, about two-thirds as broad near the top, and curving to a blunt point at the lower end to one side of the center. The skin is rather thick and covered with numerous small, hooked briers. The pulp, which has the appearance of wet cotton, surrounds the numerous tough seed sacs containing small brown seeds. A fibrous- core runs through the fruit from the stem to the lower point. Sour-sops var}^ greatly in size, weighing from 100 grams (3.5 ounces) to over a kilo (2.2 pounds). The flavor is acid without being sweet. It is highly esteemed for making cooling summer beverages, flavoring soda-water sirups and water ices, and for preserving. The most popular beverage is made by macerating the fruit with sugar, dilut- ing with water, and straining ofi' the pulp. The fruits sell at from 10 to 25 cents apiece in the season, which lasts from May to September. Two samples of the preserved fruit were examined. The "guana- bana en almibar" is composed of the pulp of the fruit preserved in sugar sirup. The "pulpa de guanabana al natural" is the pulp pre- served without sugar, being intended for cafe and soda-water trade when the fruit is out of season. It yqvj closely approximates the composition of the natural fruit, as is shown in Table VI. Both samples were packed in glass. SWEET-SOP (anona). {Anona squamosa. ) The sweet-sop does not attain the size of either the sour-sop or the chirimoya. The samples analyzed (Table VI) averaged 229 grams (7.3 ounces) in weight. The fruit is heart-shaped and deeply creased, the portions between the creases ending in small knobs, which indicate the position of the seeds under the surface of the skin. The seeds are small and brownish black, resembling those of the sour-sop. The pulp is also ver}^ much like that of the sour-sop, but it contains more sugar and, as a rule, a smaller percentage of acids. Sweet-sops are eaten in the fresh state and are also used in making water ices and soda water sirups. It is not so popular as the sour variety, and no preserved fruit was found on the market. ANONA, 23 lis 03 .2 §.^'§.1 ^ 2^^ 'S.s «o o o o <:i 8 S ^ ^ ^ lO Ti! jo -^' I I I I .SSS8 r' id Tj! ic5 irf I I + I w o i> o |j CO- OS 00 e« 0^ rH r-l ■sS ^ to ^ t~ I— I 5- o •3 cc 3 •»i t^ o 01 O to i-t "M (M 1-1 f-H .ii •8 s 8 8 1 05 "^.S w tH S> Sucros reduc tion. •8 1 0 • S5 It Per ct. 10.85 14.50 7.34 12.68 9.37 ci~ ^ Q ^ 00 0 : 558 . •s2 tj CO ■«< S5 to • s 1.^ r ■ " ' i V 1 ni ti??s3|S| 11 .g <^^ ^0- 1 1 Alka- linity as po- tassium carbon- ate. Per ct. 0.328 .350 .320 .373 .310 i§ c i Per ct. 0.384 .665 .500 .555 .560 8R a. g ^-4 an ^8^ ^ : 06 J > ■SS^85S§ gf^ 1 ^!5^?J5l?5 ?5S Eh i % ^ Per ct. 23.60 23.98 27. 60 19.10 29.40 t3§g§gS gas (^iS^g28g l+l «j >=! 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S ^^ a I S s ^ s s lO m c^ S 36 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. 1 g ^ ■^s *sj ^ W ^ ^ .-§ 5J ^ rn OQ ^ ^ ^ 1 ^ ^ H 5j I..3 ^ ^S cc § m •^ H t ^ w. ooooooooo oX illil M Oj ifi s W 2S S S S S S g I I I I I I I I ! 8 CO CO c- ■^mtNiO -^t^^Ot^ g s s C -^ in »o 00 o t^ m •>! SJ ;^ O lO tH 00 c< o i> CO o i-H t^tOQOTj.-(0>-«»r-5l>inOrHi-HO g ^ s ■ -^ lO iH ■<9< ^ -^ 50 CO lO i gs 5; s M ^ S « ttj !M rH C^ IM (N'*OirH(N00->*THt^ ■<*I>t>Tf'<*cCC<05eO §J^S5J28gS^53 ^<©ScoSr-((M.-HOO OOOit^^r-JOTlJcCCO "e "3 iO(NC^04eooooii> IM lO t^ t^ t^ 00 i-H o o o > 5- 11 tH 00 IM t^ 00 O 00 i-H C^ -^ i-t OS lO o g § i s g g g CO o o lO 1> o ^ s s 00 r-5 Tji ■* lO o m «o t^ t>^ O ■ 0> C<1 CO iH § S5 s s s ^ s s O iH '^ «0 GO O CO o ^ ^ o »0-* c4 lO Oi CO eo CT>CC3;iMC<«l> lOt^OOlO'^CqiOrH O lO CO ut) 00 05 fj 00 t^ ■* -<1< ,-1 ^1 t^ OJ tH ■* CO 6l CO -^ Tit 00 g IM CO -0 to 03 05 CO CO CO ic in to to «o ^ ^ !2 to to to w ;3 g < ^ ^ to o§ 38 CHEMICAL COMPOSITION OF SOME TROPICAL FRUITS. Table XIII contains the results of analysis of 43 samples of canned pineapples from Singapore, the Straits Settlements, and the Bahamas. It is apparent from the high content of sugars that practically all of the canned pineapples from Singapore and the Straits Settlements are preserved with addition of cane sugar. On the other hand, the analyses indicate that but few of the samples from the Bahamas have had any addition of cane sugar. A study of the data contained in the foregoing tables fails to bear out the common supposition that the pineapples grown upon or near the equator contain more sugar than those grown at some distance farther north, and, in fact, the normal content of sugar in pineapples grown in Florida differs so little from that of pineapples grown at Singapore that the difference is practically negligible. It may not be out of place to state at this point that these investiga- tions were undertaken in the Bureau of Chemistry at the request of the Secretary of the Treasury for the purpose of establishing a basis of classification for imported pineapples for the guidance of the appraisers. Since the classification of these bodies for dutiable pur- poses depends upon the answer to the question of whether or not sugar has been added during the process of preserving, it was neces- sary first to establish the normal content of sugar in the pineapples. It is evident, from inspection of the analyses, that since the normal pineapples contain a large quantity of cane sugar, the mere presence of this substance would be no evidence whatever of its artificial «tddi- tion. It is further evident that if a sirup containing practically the same quantity of sugar as the natural sirup of the pineapple were added it would be quite impossible, by a mere determination of the sugar present, to detect the addition. The only guide in this case would be to determine the relation of the sugar present to the total insoluble matters of the pineapple. If, on the other hand, a sirup rich in sugar were added in preserving, it would be easily detected by the increase in the percentage of sugar in the contents of the can. In looking over the accessible literature relating to the analysis of pineapples, at the commencement of these investigations, it was sur- prising to find that no paper has been published on this subject except one by Buignet in " Les Sucres," published by Maquenne (Paris, 1900). The average content of sugar found by Buignet, viz, 18.9 per cent as invert sugar, is not materially different from the amount found in these investigations. 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