Historic, archived document

Do not assume content reflects current scientific knowledge, policies, or practices.

Contribution from the Bureau of Chemistry W.G. CAMPBELL, Acting Chief

Washington, D.C. vV October 15, 1921

THE COMPOSITION OF CALIFORNIA LEMONS.

By E. M. Cxacz, Chemist in charge, and C. P. Wimson and C. G. Caurcn, Assistant Chemists, Laboratory of Fruit and Vegetable Chemistry.

CONTENTS.

Page Page The California lemon industry...-...---.---- ial peDISCUSsIon OLresulismete- cee: oe 45222 seeeee =e 12 Purpose of investigation. <.-- 2.22 52--25 2... 2 Differences in varieties.........--------- 12 Investigational work ......--------.-.--= as 2 Seasonal difierences:........22.-------++- 14 Methodtoticamplin cer ae os eerie says o) 2 Color and thickness of peel........-----.-- il7/ Methodsiofianalysisst 65 2 ee eeen sac 3 IDITOE OOCENO Abo osodedessosaodadcsac 17 Results of investigation.......-:-....-.------ a CONCIUSIONS saan ee yee teeta cer ee ota a cee eee 18 Bibliographiys:: ? eo) ere eee ree eles ele’ Ye aa 18

THE CALIFORNIA LEMON INDUSTRY.

Beginning in 1887 with the shipment of 12 cars of fruit, the Cali- fornia lemon industry has increased a thousandfold, the 1919-20 shipment being approximately 12,000 cars. The California growers have generally settled upon the Kureka and Lisbon varieties as the most satisfactory in that State, and, although there are scattered or- chards of other varieties, the new plantings are confined to these two.

According to A. D. Shamel (1),? the Kureka variety originated in 1858 in Los Angeles, through the planting of seeds obtained from Sicilian lemons. These seedlings bore about 12 years later, at which time several were selected as worthy of propagation. Buds from these trees are responsible for the present Hureka variety of lemon. The Lisbon variety was imported directly from Australia in 1874 (2). While some plantings now in existence can be traced to the original shipment, later importations are also responsible for the Lisbon, the most widely planted variety in California to-day. The Villa Franca lemon has been planted to some extent, but has generally been abandoned in favor of the Eureka and Lisbon varieties.

1 The writers are greatly indebted to F. E. Denny for help with the calculations and for criticism of the

manuscript, as well as to C. O. Young and R. H. Keliner for collaboration in the analytical work. 2 Figures in parenthesis refer to Bibliography at end of bulletin.

56403 °—21— Bull. 9931

2 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

At various times attempts have been made to utilize the culls

from the lemon industry. The first effort which was ultimately successful was that of a company, organized in 1898, now manu- facturing essential oils and citrate of hme. Another company, estab- lished early in 1914, at present produces citric acid and essential oil. Several smaller firms are making citric acid, citrate of lime, and bottled lemon juice. As the history of the undertaking has been treated by others (3) (4), it need not be considered further here.

PURPOSE OF INVESTIGATION.

So far as known, there has been no systematic attempt to study the composition of the California lemon. Analyses of scattered samples have been published, but no series of results from carefully selected trees, where sampling was continued throughout the season, has been reported. It is highly desirable that this information be made accessible to the lemon grower, as well as to the lemon by- product manufacturer, who is especially interested in the oil and acid content of the fruit which he purchases.

INVESTIGATIONAL WORK. METHOD OF SAMPLING.

In a territory as extensive as the lemon-growing section of Califor- nia, adequate sampling presents many difficulties. Since the number of samples which can be examined is necessarily limited by the size of the laboratory force and its facilities, care was taken to select typical locations in each well-recognized growing district. In some instances, circumstances prevented sampling, so that a small number of centers are not adequately represented, and in a few cases certain districts are more fully represented than was at first planned. In all, satisfactory samples were taken in about 20 locations in the following centers: Bonita, Chula Vista, Escondido, Whittier, Santa Paula, Carpenteria, San Fernando, Glendora, San Dimas, and Clare- — mont. From other work conducted at the same time it was possible to obtain data on fruit grown at Corona.

The trees selected originally were such as to give an equal number of locations of the Eureka and Lisbon varieties. Because of irregular sampling, the final selections consist of 10 Eureka and 6 Lisbon trees. The judgment of experienced growers was the deciding factor in selecting typical trees. It is possible that some of the trees in- cluded in the final results are not of the best strains, but, as many groves of such trees exist in the State, the effectiveness of the data is not materially impaired.

Again, the number of fruits to each sample was a matter of con- cern. Manifestly, the larger the number the better the chance of satisfactorily representing the composition of the grove or district

COMPOSITION OF CALIFORNIA LEMONS. 3

from which the sample came. After removing the sample for the experimental work, the trees from which they were taken were picked in the usual commercial way. In a few cases an insufficient number of fruits had reached the proper size when time for the next sampling arrived.

Both the Eureka and Lisbon varieties of lemons in California blossom throughout the year, and pickings of fruit are made monthly, except in September or October, when they are usually omitted. Whenever possible samples were taken at monthly intervals in the course of the investigation here reported.

As a rule, from 18 to 24 fruits were forwarded to the laboratory in cardboard cartons furnished for the purpose. Seldom were they more than 24 hours en route. At the laboratory they were kept in the cartons in cool storage (40° to 50° F.) until analysis was begun. Usually not more than three days elapsed between the time of pick- ing and analysis.

METHODS OF ANALYSIS.

Unfortunately, in order to make a satisfactory determination of the essential oil of the fruit, it was necessary to divide the sample. After the specific gravity of the fruit had been determined by weigh- ing in the air and under water, this division was made as evenly as possible, both as to size and color. Half the sample was ground by being passed through a food grinder three times, and the oil was determined in a portion of it by steam distillation, according to the method of Wilson and Young (5). The acidity of the whole fruit was determined on another portion of this sample by titration with alkali solution, using phenolphthalein as indicator.

The remaining lemons were quartered, the thickness of the skin estimated, and the juice expressed by a small hand press.

In estimating the thickness of the peel, the following arbitrary method was used: The cross section of the peel was measured in several places by calipers, and the average taken. When this was found to be less than 3 mm., the peel was designated as thin; 3 to 5 mm., medium; and above 5 mm., thick (fig. 1). Rarely did peel exceed 7 mm. in thickness.

The acidity of the juice was determined by titration against alkali. All acid is calculated as citric with the water of crystallization in- cluded.

RESULTS OF INVESTIGATION.

The data derived from the analyses of Kureka and Lisbon lemons grown in California are shown in Tables 1 and 2. Table 3 gives the results on samples of the Villa Franca variety; Table 4, those on samples of fruit from a Eureka location in central California; and Table 5, those on samples of lemons of an unknown variety from Arizona. It is not thought advisable to attempt to compare the results in Tables 3, 4, and 5 with those in Tables 1 and 2, for the reason that the number of Villa Franca locations was small, al-

4 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE

Fic. 1.—Standards used to determine the thickness of the peel.

COMPOSITION OF CALIFORNIA LEMONS, 5

though not too small to preclude satisfactory results had the varia- bility encountered been less. While the averages of the three sets are taken from a sufficient number of samples to make them worthy of consideration, the monthly averages depend on but three samples, too small a number from which to draw conclusions. Moreover, neither Tulare County nor Arizona is a large lemon-shipping center, and the number of samples analyzed from each of these districts was small. In Tulare County the lemon season begins in September and lasts but a few months, so that comparison with lemons grown in other districts throughout the season is impossible. The data con- tained in Tables 3, 4, and 5, however, are of no little interest to lemon orowers, and it is felt that they should be published here.

TABLE 1.—Composition of Eureka lemons grown in various sections of California.

BONITA (TREE 1).

Thickness of Specific} Oilin | Oil per Acid in Acid Word ar

ple Color.! gravity | fruit,by| ton of : per ton | -.~. No. | Picked peel. of fruit. | weight.| fruit. | @U4t-? | oftruit. | Juice.’ Per cent.| Pownds.|Per cent.| Pounds.|Per cent. 489 | July..---- DD Ga ers ee gra Se eee ES peek 0. 52 10. 4 3.86 Wee Uo 28 564 | Sept. ..---- DGea ate: WMerys thins 2220" 0.9791 -41 8.2 4.27 85. 4 6. 82 5o4ai Otis a5s- Ges 4 Waving eaeih ne Se eas . 9822 34 6.8 4.41 88. 2 6.57 628 | Nov....-- TU YGRA See) Ko) sk Sear 2 . 9853 42 8.4 4.16 83. 2 6.63 673 | Dec..-.--- YG be Medium.......- . 9214 66 13.2 3.73 74.6 We25 Moy RODia. 23-2 GNG Ss. oe et Osean es -9215 45 9.0 3.10 62.0 6.91 B01 | Mare. fo. - 1 fap Se a hicks ashe yao . 9274 44 8.8 3.24 64.8 6.55 aS I EeAGD Toa 2 2 ReYeus x ee Medium. .-.-..-- . 9287 45 9.0 3.62 72.4 6.72 919 | May...... LYNE ee ees FIST C Kees tape ay Ne . 9368 52 10.4 3.48 69.6 6.88 O74: | UuINe:, 2/7. Ieee fa Medium.......-. - 9537 .67 13.4 ay cu 74.2 Teas 10260) July 22-222 ~ JN Graphs teats AM oitise eau meray - 9618 - 56 Hit 3.34 66N8u i ese eee2 1056) | -Alg...2 2- ENS eis Oe |e OfReEE ee . 9769 -51 10.2 | 3.66 (ERO ESR Se SeKe INS SU aM Ee ME eens WTR a 9522 50 9.9 | 3.71 74.3 6.91 SANTA PAULA (TREE 10). 64in | Deese ook: AGS Jee Gre bb ban SR es 0. 9432 0. 53 10.6 3.72 74.4 7.73 SG) | dene Beer Ge e550? TRICK Se tee ee ke - 9220 44 8.8 3.50 70.0 7.30 (PANG) ope ae Yee ee Medium........ . 9238 -42 8.4 3.36 67.2 7.09 788 | Mar......- ly Cee AeA Seale Gos ae Ase . 9162 43 8.6 3. 22 64.4 6. 91 S36) | Apr. ae: - 1D X GIS Op Gaal ne GO es eae .9190 -40 8.0 3.27 65. 4 6.37 891 | May...... Gee cae ae ae (Oo re eae . 9394 39 7.8 3.41 68. 2 6.71 940 | June...-. Dy Ge ae ene |g Sree aa ea . 9520 44 8.8 3. 83 76.6 7.00 984 | July....-- LG—-DG...| Medium-thin. -. 9517 - 50 10.0 3. 87 77.4 Hara ROSOR ARIE. F-2 Gye oe nies 5a ee . 9524 43 8.6 4.10 82.0 lea25 1073 | Sept....-- pares ae Medium........ 9419 Girl 11.4 4.06 81.2 7.74 1084 | Nov...... ERS Lees AS es es - 9627 seit 10. 2 4.00 80. 0 6. 69 TENS GS EN AT) al USA ey cE OC Pe ee rate . 9386 46 9.2 3.67 73.3 7.09 SANTA PAULA (TREE 11). 639 | Dec...... WGpe ee Medium........ 0. 9347 0. 438 8.8 3. 43 68. 6 7.18 680 |} Jan....... TGR 2232 PRNIGRALOR See: 2 - 9238 30 6.0 BYBY/ 67.4 6. 84 724 | Feb...... 1s pk E Medina 22/22 . 9357 45 9.0 3.49 69.8 7.00 789: ) Mars. 52. < Ge se ee QsLeebe 5s . 9241 42 8.4 3.08 70. 6 7.04 84 7¢| Apr sss: Gea <5 ANOS art ee . 9201 39 7.8 5 2 64. 6 6. 53 892 | May...-.. Ti Gee 3 98 Medium........ . 9347 41 8.2 3.50 70.0 6.65 941 | June..... 1 O06 SA Need |e ae Os eae . 9478 48 9.6 3.45 69.0 6.97 985' |) Julyiz.--.- LG-DG...|....- Ode asses . 9498 46 9.2 3.43 68. 6 6.76 1040 | Aug...... LGE = A |Ree.. dos _ Beko) 2: . 9568 45 9.0 shy / 71. 4 CePA 1074 | Sept...... bG-Livnt|..--2 Gg. ee: . 9393 -46 9.2 3.99 79.8 7.30 £086 |; OCt 2 TAGES reece d0em es ones . 9447 -58 113 ea} 3.43 68.6 6. 38 Sob OWE: esol dees retin Ova he .9773 -d1 10.1 3.06 61.2 6. 83 AV ORAEG Ss: 2 ce eee ann met. . 9407 . 44 8.9 3. 46 69.1 6.90

1 DG, dark green; LG, light green; LY, light yellow; FY, full yellow. 2 All acid is caleulated as citric with water of crystallization. 3 Much sunburn.

6 BULLETIN 998, U. 8S. DEPARTMENT OF AGRICULTURE.

TaBLE 1.—Composition of Eureka lemons grown in various sections of California— Continued.

San FERNANDO (TREE 13).

Per cent.| Pounds.| Per cent.| Pounds.| Per cent.

Gil Nov 2.00 Lene Medium.......- 0.9332 0.57| 114] 3.61| 72.2 6.62 678 | Dec... uae die Phin... 0a 9279 60| 120| 3.641 72.8 6.79 biatlate ae Sa ead OG Hae: Mediums. 25. 9124 57 11. 4 3.47 69. 4 6.30 769 | Feb...... BGs tin shee 9262 5a aol 3.501 00 6.53 42 | Mar...... he Ae Medium........ 9234 5A tos 16 Ree lle aa 6.39 3907 | Apr._.... EA |. Nee Goh SF 9312 58\ 11.6| ~ 3.501 70.0 6.41 997 | May...... Teel TTT ee 9617 61 |. 12.2]. 3.95). 79.0 6. 60 973 | June Pesala Median... 9530 53 | 10.6| 2.84] 56.8 6.39 1031 | July...... Desk fea dg. sees 9513 | 5) |. 400. Oi|.¥. 36.164] 4.682 6.65 1055 | Aug.._..- Des Aires adie ae 9508 47 9.4| 3.41] 68.2 6.90 1090 | Oct....... DG_LYS | Sedpteu coil | 19470 62 }~. 12.31 2.31 | 46:28 6.48 1108 | Nov... ees age ges Pe cain 9730)» 264,|, 12 Sie ae 06, |. athe 6.90

AVOPABG 9. 8) te ae 9408 | 56 | 11.3 | 3.33 | 66.6 | 6.58

624 | Nov...... eGe aad Medium......... 0.9392} 0.60| 12.1] 3.30] 66.0 6.31 Beal Ded.) a. TEV 6. Veale doit a | 9488 65). A130) |e 3 41) eg 6.35 705 | Jan.-..... EY oo es gies ee ks | 26391 50| - 10.0|- 3.13] 62.6 6.55 770. | Feb...... LY hee da cate ah 9297 43 8.6) 2.93| 586] 667 eH Maire o\..| WY¥es... |ee0 dota. 2: | 59115 39 78| 3.01{ 60.2 5.95 379 | Apr._.... LY.pG. |e. dot oe 9352 38 7.6| 2.99| 59.8 6.21 928 | May...... LEGER. EH: doe. 283 9593 48 9.6) 3.01] 60.2 6.51 968 | June...... DELL. eS deeb 9624 55! 11.0|. 3.10] 62.0 6.33 1054 | Aug..._.. Gite tin. ©. a 9653 43 3.6| 3.30] 66.0 6. 29 1076 | Sept...... DG-LY...| Medium........- - 9538 -55 11.0 2. 87 57.4 6. 62 1088 | Oct....... Te ee IBS dover... = 9308| :52| 10.3] 2.75| 55.0 6.58 | | Avernsoe. eee eR 9427 50/ 10.0 3.07| 61.4 | 6. 40

WHITTIER (TREE 16).

646 | Dec...--. DE2a | hig eee 0. 9408 0. 48 9.6 3.33 66. 6 6. 76 693; Jan. Ss... TG Bey a Bees dat ee 9164 42 8.4 3.08 61.6 6. 83 Wl | Feb... os: | TG eee bcd do. tae 9 75 .38 7.6 2.92 58.4 6.91 808 | Mar...._- FIGS Sake ates Hele saree . 9270 534 6.2 2.94 58.8 6.65 R633) Apr: oo. EG. ee aes dope 2508 20865) len- coos tees 3.35 67.0 6. 48 909 | May...-.- EG woes! Medium.......- 9453 SALA PORE? 3. 36 67.2 6.72 955 | June.....- TEVR SS Ue Ge dot fh sx 9554 47 9.4 3.56 71.2 7.35 10139) Tuly <2: GPR sete docs8h.. 2.2: 9576 46 9.2 3.34 66.8 7. 04 1044 | Aug.....- Tete Ae dott eee: 9528 50 10. 0 3.74 74.8 7.16 1070 | Sept.....- SD GlbY i) Cthick. 106.7% 9350 43 8.6 3.13 62. 6 7.10 1082"| Qct-£. 22 - DGkE Adee do-ehe 9315 42 8.4 3°92 64. 4 7.00 1098 | Nov.....- | Gaye | cata do. . 9247 44 Sz 2.91 58.2 alt U7"| Dees : LdeGeny a ay dole se 9729 47 9.5 2. 64 52.8 7.21

Averneee -9/ fBGE ol Be Rea ee Ai 9403 | 43 | 8.6 | 3.19 | 63.9 | 6. 95

| { WHITTIER (TREE 18). |

664 | Dec....-. BYE a Mhicks...%s2s°02= 0. 9206 0. 62 12.4 3.41 68. 2 721. 743 | jan... 0... Leen etsl seen dor 32h esas . 8912 .42 8.4 2.98 59.6 6.41 7oie| Feb... -- TY rs Medium........ ANTS ae, SE (BS Rel ae 3. 06 61.2 6.39 849. | Apr.....- LYE 234 hick. bs ib2 2 . 9000 39 7.8 3.14 62.8 6. 23 889 | May...... TPKE on ede Medium......... . 9359 42 8.4 3.04 60. 8 6. 23 S| Jurie:_ it | LYE 2.3 Mhiek. he 2 52 . 9199 44 RiGH.2 3/48 63. 6 5.99 983 | July...... LY=DG./ {| sMediam ons” 23 9415 45 9.0 2. 87 57.4 6. 06 1059 | Aug...... Buty ieee hin: bens. 7 9500 50 10.0 3. 26 65. 2 7.00 1078 | Sept.....- DG2LY -Nephiek fe 28 . 9359 55 11.0 3.12 62.3 7. 00 WAL Oct_-2 2%. Gee 2 Va do-bae 2 9389 52 10.3 3. 02 60. 4 6.58

AVGTAP OL. <;.-ce te ce: 525. USS. Ee ee . 9232 48 9.6 |

wow _ _ oO 9 _ ao on ran

COMPOSITION OF CALIFORNIA LEMONS.

T

TABLE 1.—Comparison of Eureka lemons grown in various sections of California—

Continued.

San DIMAS (TREE 21).

Per cent.| Pounds.|Per cent.| Pownds.| Per cent. G56: | ‘Dect: J 2... BGs 344 Medium........ 0. 9313 0. 66 13. 2 3.47 69. 4 6. 67 Od: | dane e. 2: LG eee ae | Ko) Yaar ie 9187 41 8.2 3. 44 68. 8 6. 31 Hed | Hebtos.,.: TW a2. oe Mic ke ae se 9186 OU 11.4 3. 38 67.6 6. 46 815 | Mar...... ib & Sem Medium......... 9176 53 10. 6 3. 40 68. 0 6. 55 876 | Apr-ce... TEN Bee aaa Gore ae 9260 BY, 10. 4 3.47 69. 4 6. 25 923 hie ee TY RG 8 AR ee Gone easy 9346 . 58 11.6 3. 32 66. 4 6. 25 960 | June....-.- DGSHY.4 2-85. . do Bese he. 9404 . 46 9.2 3. 00 60. 0 6. 16

1029 | July...... DG ate ere SE GOs 9498 41 8.2 2. 84 56. 8 6. 23 105d) Auge... - DGa lee his ee ae: 9407 .30 7.0 2.99 59. 8 6. 36 1079 | Sept...... NEG: So nece Medium......... . 9611 . 46 9.2 3. 86 77.2 6. 53 1087) “Ot. osen. DG-LY Thick voetes sheds 9370 .49 9.7 2. 68 53. 6 6. 44 1102 |- Novi.2.. - LG-Y..... Medium.......--. 9780 . 67 13. 4 Lost. Lost. 7. 14

FAVOLOE Ore sas sortie ssloe ae se sete rene nse 9378 51 10.2 3.26 65.2 6.45

CLAREMONT (TREE 22).

699 | Jan....... 1b ee eee Medium........ 0. 9242 0.47 9.4 3.52 70.4 6. 16 763 | Feb...... 1D) Go See lone GO ieee .9141 - 50 10.0 3. 01 60. 2 6. 62 824 | Mar...... GRY shes en aN GOPRE Rea . 9187 ~ 44 8.8 2.89 57.8 6. 27 Ser PA press << TE GS) A Ae eae a Bp . 9130 - 46 9.2 2. 88 57.6 | 5.95 908 | May.....-.- ILS Greene Medium........ . 9278 47 9.4 3. 64 72.8 5. 88 957 | June...... LY-DG Sie kes xia 8 . 9329 -45 9.0 2.87 aa AM 5. 92

HOLM Sully= Wee & DG ees 25 Medium........ - 9420 39 7.8 2.59 51.8 6. 42 1047 | Aug to... DIG Ae ek Apa CKO sae . 9507 . 50 10. 0 2. 85 57.0 6. 53 1068 | Sept...... DG-LG...|..... (6 Koes ye - 9560 - 03 10. 6 3. 44 68. 8 6.79 HOSS J OCtseh 22... DG 83 LohbO WER s (6 0 ee . 9464 . 52 10. 4 PAN 61.5 6.11 1099 | Nov...... Bye ea 7h Medium........ 9735 . 63 12.5 3. 43 68. 6 6. 79 HAS) | "Deco. e. LG-Y..... feuyetes GORse eet ye .9775 5 fas 10. 7 Bat 62.6 6. 55

PAST GLEE Oe ach ae OE Sa ps MR LH . 9397 49 9.8 3. 07 61.4 6. 33

CARPENTERIA (TREE 24).

GS2n samen aye ee AN ICks ee sal, 0. 8991 0. 49 9.8 2. 64 52.8 6. 58 (OAD Sw kel ¢ ieee TO) ete cl Ss ia at OO Serer eaes be . 9089 45 9.0 2. 66 53. 2 6. 63 moo wl Mare ot AVS eee ee | CO ahs . 8966 “32, 6.4 2. 66 53. 2 5.90 RAO! ADI es - TO i | ne gone COE Sa . 9068 232 6. 4 2. 28 45. 6 5. 39 902 Chea Ae Gee ena | ee BIG Oe ee tae De AS PAS bd i ehatleee BY wal Me cea 2. 54 50. 8 5. 74 eh IMIS. IDC ye ARES ie oie OKO) ets ena - 9504 . 34 6.8 2. 28 45.6 6. 20 998 | July...... 1 Cee Very thick.....- . 9823 . 40 8.0 2.08 44,2 5. 74

1036 | Aug...... LECH eee MNiCks 2% of 5/42 . 9421 .35 7.0 2.13 42.6 5. 90 1067 | Sept.....- IDC SSS HA au see DOS = ee 9377 .39 7.8 2.56 lla 74 6, 27 1080): OG. 2... IDG esa. 3 (KOSH: Serene 9256 -41 8.2 2. 07 41.3 5. 95 1096 | Nov...-.-.- DGS Ssaees 2 OKO eS eee 2 9306 . 44 8.8 1.91 38. 2 5.75

J NV (ES Yeisen aes Renta Wee aonb ame AN 9274 . 39 7.8 2. 36 47.2 6. 00

8 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

TaBLE 2.—Composition of Lisbon lemons grown in various sections of California.

BONITA (TREE 2).

: ; | Sam- = Specific | Oilin | Oil per Bega he ING! ears ple sed. Color. ! aes of | gravity |fruit, by| ton of pee a) per tom | No. Peo of fruit. | weight.| fruit. OR | offen eae ee — | ———————— : Per cent.| Pounds.) Per cent.| Pounds.|Per cent. 490 | July...... LG-FY... Medium Sakae es 0. 8375 0.58 11.6 3.50 70.0 6.93 570 | Sept..---- IDS eee RU. Seen ee - 9252 -59 11.8 3.96 79.1 7.42 50571 Octane = TEP Ges ieee oe DHiCKe ee ae ae - 9186 a5Y/ 11.4 4.05 81.0 6.55 6291) Novece.- = LG-LY Medium........- - 9012 57 11.4 3202 70.4 aa 674 | Dec...--- 1D Gs ee ee IBhins 355 eas eR 52 10.4 3.94 78.8 6.97 119) | Hebe ae. - 1p \ Geral Medium . 8511 44 8.8 Sor 63.4 6.79 S22 IManeeee = - MNOS) SS aes OF ae ee - 9159 41 8.2 2.92 58. 4 6. 23 R890) A preset iby at Bae a Plas do ghee: .9118 44 8.8 3.24 64.8 6.21 920 | May-.---- Gee se Ee TRICKS So Seat - 9074 49 9.8 2.94 58.8 6.49 975) {7JUuNne 25. -2 TBE eu last Medium-—thin ... . 9148 53 10.6 3.50 70.0 7.07 NO2Z7 I Sulye2ee 1h) Gee eee Mediunt:.....2- -9215 48 9.6 3.43 68.6 6. 83 1057 | Aug...... [AY Se sda ay he al 9455 67 13.4 3.62 72.4 6.97 Ayoraweee seks os Mer eee 9046 52 | 10.5| 3.48| 69.6 6. 82 CHULA VISTA (TREE 4). A92°| Jily22-2- LG-LY...| Medium-thick -. | 0. 8485 0. 62 HORS 3.68 | 73.5 7.24 543 | Aug.....- DG] Yen ao Co Mg Abbe an | .9044 .50 10.0 3.57 71.4 6.90 His | NODE. 25. = - Ve ee | Medium......... | . 9318 - 52 10.3 3.59 71.8 6.93 Od Octaass. a DGG: alana (6 (ee: Se hace 9173 -50 10.0 Sh 7 75. 4 7.14 636 | Nov......- IXGSIIN Ge sige eae 0.42 es | .9306 -61 12.2 3. 60 72.0 7.54 662) |) Dece-ss ay oa| eee (tae eee - 9269 - 66 13.2 3.87 77.4 8.05 764 | Feb....-.. 1S Gaeta hicks es Ses ae } .8931 -53 10.6 | 3.08 61.6 6.83 Sil =|SMare sm =. Gees be Very thick....-- | .8990 -43 _ 8.6 | 2.82 56. 4 | 6.32 877 | Apr....-- Gp eas hick (=. 2 Mo: | :9101 SE\ the | S27 Gas 6.34 937 | ART als eseers tel Py) Cae auc Mesa toe GOs ee | - 9081 -55 11.0! 3.00 60. 0 6.58 1O25s| dulyee= 2. 1 Ne ee ee Medium: ....-:- | . 9207 - 54 10.8 3.47 69.4 7.42 1049 | Aug..-.-- AG Grate es See ChO Se Sears - 9405 - 48 9.6 | 3.65 73.0 751 1072 | Sept...... DG=Y.5. 22255. 0 i) es Sree | .9263 .49 9.8 | Sea0 71.1 7.49 AV OT ASC. eee Sie eee ae eae eee | -9121 54 10.8 | 3.45 69.1 7.10 | CHULA VISTA (TREE 5).

OSE dally ae GIG Was Shik ene 0. 9423 0.56 11.2 3.41 68. 2 6.79 §44 | Aug...... DGS Medium......... . 9396 - 50 10.1 3.43 68.6 6. 82 574 | Sept...-.. DG seeraee sleet GOR ee eee - 9487 .59 11.8 3.94 78.8 7.32 59S Oct -- PGI ess |e C022 ee - 9368 -50 9.9 3.88 77.6 6.81 O37) Nove 2. (Si Gee cet he |ae2 G07 ae seer - 9307 -69 13.8 3.50 70.0 7.74 663: |) Dees 2-2 Ni Gees see ise mae G0 sa eee . 9421 - 84 16.8 3.47 69. 4 7.81 465: | Hebe 2a. 2. dN ee ee meee COE Sse -- eee 9084 54 ‘10.8 3.78 75.6 6.83 B52 MaTy S12 iG sae i Phtekiins 1 Osa e . 9152 49 OES) | Sa See ask a] Eee eee 6.27 SUS WAT alae 22 Guess oe Medium . 9268 53 10. 6 See, 64. 4 5.81 936 | June...... DG-LG | Very thick...... . 9314 49 9.8 2.69 53.8 6.55

HOZ3 5 aby pee Hee ae ae borers Omak ae Foe - 9351 49 9.8 2.99 59.8 7.44 10487 Aug...... 1 Ga es ae meni ks ono ie . 9363 54 10.8 2.95 59.0 7.32 1071 | Sept....-.- DG-Y....! Medium........- . 9280 43 8.6 3.31 66. 2 7.14 AWErA Bet ne Gree” cc beet eee eee .9324| 55 11.1 3.38 67.6 6.97

i | ESCONDIDO (TREE 6).

HOS Heilyae esse | DG-FY.. -| Medium-thick..| 0.9437 0.48 | 9.6 Saas 64, 4 6. 02 BSA OA USS. a2. : Goh YSe|> edo: eee | 9369 50 10. 0 3. 22 64. 4 6. 23 568 Sept...... DG Sn elke eee - 9205 . 60 12. 0 2. 87 57.4 6.12 HOVesO Clase ees iD) Gee a ee GO ae eee 9074 58 11.6 2. 82 56. 4 6. 42 626. JNov.-22.< DG@s])22n|eMedium-s:-2--e 9186 63 12.6 2.99 59. 8 6. 37 671 Dec iG ass eae Giese) sees 9240 59 11.8 3. 03 60. 6 6. 51 766 Feb... IDNGee Whickses oes . 8991 42 8.4 2.62 52. 4 6. 20 826 Mar iG a | eee dot as . 9231 ti 9.8 2.76 55. 2 6. 28 885 Apr... LG.. .| Medium........- 2Q210)|. 5 <2w eee 2. 80 56. 0 6. 27 S2oymI MAY <2 55 LGee a ak QR one . 9247 50 10.0 2.95 59. 0 6. 04 S7le hiner... 5 DGSh Ye = laa (OO een eee . 9410 50 10. 0 2.97 59. 4 6. 27 A021 edailiy. = <5 2 iD YG eet Phick 22 eee - 9313 37 7.4 2. 58 51.6 6. 30 10624 Avie: .5-.. Wiel 1 @ Misa eee | re G0) 323 See - 9341 39 7.8 3. 03 60. 6 6. 97 Piversrese ue neh foie eee 9250 .50 10.1/ 2.91} 582{ 6.31

1 DG, dark green; LG, light green; LY, light yellow: FY, full yellow. 2 All acid is calculated as citric with water of crystallization.

COMPOSITION OF CALIFORNIA LEMONS.

Continued.

SANTA PAULA (TREE 12).

9

TABLE 2.—Composition of Lisbon lemons grown in various sections of California—

BONITA (TREE 3).

Per cent.| Pounds.|Per cent.| Pounds.|Per cent. 640 | Dec......| LG-LY Medium......... 0. 9182 0. 50 10. 0 3. 34 66. 8 7. 28 Sie] ewieae sear NYS. AM ael han See as 8955 . 40 8.0 2.99 59.8 6. 97 725 | Feb. TG ee sk! Medium........- 9140 42 8.4 2. 95 59 O 6. 86 790 | Mar. Geek ee GO Mea ae 8973 30 6.0 2. 80 56. 0 6. 76 $48 | Apr. TG GES es Oe COOL eicnaens Be 8908 30 6. 0 3. 10 62.0 6. 44 893 | May....-. DC ets HC ee Cow es 9099 41 8. 2 Sl 64, 2 6. 74 942 | June...... 3 Lol CO ate | Ie a QOS s a 9205 4l 8. 2 3. 39 67.8 6.77 OSGn ln Lyeee == LG-DG.-..|...-- COM 9239 49 9.8 3.47 69. 4 6. 88 1042 | Aug...... FEA STAN a ClO ne Sin 9204 40 8.0 3. 69 73. 8 7.22 LOZoaeSeptss-2- I La eerie P| ligt (a Ko sparc tens 8952 40 8.0 3. 83 76. 7 7, 25 TOBY | INON os dcr BGS ee a GO) anys 9168 42 8.4 2.95 59. 0 7. 28 TAS SD eGeesrae BGs tee ee (aloe NM eu $666 47 9.5 2.98 59.6 7.18 PATE T GS Ge ae itin ate RTE RCE RI (eal 9141 41 8.1 Bree 64.5 6.97 WHITTIER (TREE 15).

6250 |BINOvacEe oe TO A elma MO Kel ice arn at as 0. 9073 0. 70 14.0 3. 02 60. 4 6. 37 667 | Dec LON Gian, Bel era GO esate 9049 70 14.0 3. 06 61.2 6. 88 74D Weak SAAS TEE Rus ea et dos nivel 8867 55 11.0 2.93 58. 6 6. 51 771 | Feb 1G Gos tie Medias seals 9053 47 9. 4 2. 80 56. 0 6. 37 833 | Mar. Ge Neate 8) Coes 9056 37 7.4 2 64 52. 8 6. 31 880 | Apr Yeu ee UM O Me wa 8884 38 7.6 2. 82 56. 4 5. 90 O20) Many e202 5 DS ei fied at oD etrKel cca TU 9067 45 9. 0 2. 96 59. 2 6. 34 969 | June...... AY i ra aa COM as 8945 . 46 9.2 2. 92 59. 4 6. 37 Os en | uLyeee ae CG AN eae ile x an GO eee 9445 48 | 9.6 2. 85 57.0 (Hall LOSS AUS aoe DG RY aes Gores eas 9297 42 8. 4 | SH2 62, 4 6. 65 1077 +| Sept.-...- ie es Mie dil inniaesa eee 9390 49 9.8 Bus?) 66. 4 6. 79 HOSOROcteaenee. DG Yess |i eke ses. 2 usa) 9382 54. 10. 7 | D5, 51. 4 6. 48, EAT OTE Omer ane pele Nitta Chat Feat eH! es ya 9126 50 10.0 2.92 58.4 6. 51

TABLE 3.—Composition of Villa Franca lemons grown in various sections of California.

Sam . - | Specific); Oilin pl x ee Color. picks: of gravity | frukt, by Pp Bee of fruit. | weight. Per cent.

AGT Mullyes ases- DG-LG...| Medium-thick...| 0.9455 0. 62 565 | Sept...... DEG irs ae aa . 9628 47 SIGE Oc. Gael toh Medium......... - 9557 .00 Gan NOVetee. - DiGe east hick eee. see ue - 9319 59 G75) Dect 22: LoS ass Sete Medium........- - 9304 .70 780) | Hep ea 4. 1 Gi had gel ls a a . 8957 54 823) Marz. .... IOP O eee ele Ole oes ee Hee Weta . 54 883 | Apr. Geese Medium-thick...| .8965 .58 921 | May. -=.- Giese Te ea aa ere . 9079 . 62 976 | June...... lO NGS Aaa pee Goes ease - 9095 «(ef 1028 | July...... N Geen ie Medium........- . 9222 aia) 1058 | Aug...... TONGS Sore eee (0 (Oyen es 9631 74 IAVCTAS OME Roo ee eect ee ee ee . 9247 .58

Oil per ton of fruit.

Acid in fruit .2

— SSH Se EE OOH EO c000 S000

-_ = J

1 DG, dark green; LG, light green; LY, light yellow; FY, full yellow. 2 All acid is calculated as citric with water of crystallization.

56403°—21—Bull. 9932

Pounds.) Per cent. 3.40 |

g2 | yb go'ge go go o9 go D0 90 a (oe) or

Acid 52 ¢ per ton | “cid in of fruit. | Jute

{

| Pounds.| Per cent. 68.0 7.07 83. 2 7.28 80. 0 6. 97 74.6 7. 58

17.0 7. 63 64. 0 7.07 63, 2 6. 90 67.0 6. 65 74.0 Coalit 72.6 7. 28 68. 2 7.14 80. 2 7. 56 UPA 7.19

10 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

TaBLE 3.—Composition of Villa Franca lemons grown in various sections of Cali- Jornia—Continued. ;

ESCONDIDO (TREE 7).

2 | i | poe a . |Specific| Oilin | Qilper| , .,. |} Acid ae ple ae | Color. Seyee Of | gravity |fruit, by} ton of ie per ton ; cid in No. | SieKed- | Eee of fruit. | weight. |. fruit. - | offruit.| Juzee- | | | | Fret ; Per cent. Pounds Pes cent.| Pounds.|Per cent. QD 504 | July.....- | LG-LY...| Thin-thick.._..- 0.9388 | ~ 0.48 9.6] 287] 57.4 5,46 535 | Aug._...- | DG-LG...| Medium-thick...| .9427|. .58| 11.6] 3.10] 62.0 5.42 569 | Sept...... Dest 2 | hicke ever s 9198 60| 120| 220] 446 5.74 600 | Oct......- DEM 55S domes 9268 58 |. 1L6| | 268) -sz2 5.92 627 | Nov...._- Hess eee dg ceeeeere 943 50| 10.0] 258] 51.6 6.27 672 | Dec____-- BGS Eas does. = 9115 65 13.0] 219] 438) 5.99 767) Keb. 2. ry Medium... ____- 9210 38 7.6 |. 2:58 5 6. 16 ois Ee Se ee high se. ae g221) 2] 84] 254) 508| 58h 886 | Apr___..- Bes ees Medium... ____- 9330 | 331 - 7.6). - 2365 |- 50 [sass 996 | May___... [ip Ce PSE eh et | <o1s5| <501- y0.0| _ 306 | 62 | 6.2 972 | June...._- LG=LY.._| Phiek fos | 9395 | 544. 10.8] ee |e 50.8 5.64 1022 | July.....- GEG See. dase eg 933 2 8.4 | 2.63} 526) 5.99 1063 | Aug._...., i Seale Medium...._____ 9598 Silo» 10.2)" 284) ° 7568 | eee ALYST ARE. l2 5. ota 4 joe See Or ee oe 9314 50 10.1) 2.64| 52.9) 5.88 i ! 4 WHITTIER (TREE 17). ; 1 | 647 | Dec... Leis [thick 0.9077] 0.62} 124] 3.30 | 66.0 7. 694 | Jan_.___.. TVs Bs | Medium. .._-_-_- 90225] ..50} 10.0| 3.24] 648 6.79 752 | Bebo... BY OCs WE URC aS ee 8917 52 10.4} 3.17 63.4 6. 46 pie} SMare..!| Ye. .20 [edge | 8903 44 8.8) 3.00} 60.0 | 6.70 ; 364 | Apr___-.- EY owe NEA (2, Someta | 9093 44 88! 331] 662 6.67 910 | May__.._. LYS | Medium. .-.-_-_- | .9238 -5l| 10.2] 3.45]. 69.0| Zit 956 | June... BY oe | hips ie sy six . 9309 48 Weal reer Ml Maal ye. | 7.28 1014 | July.._..- mG eet [= Sd eae oee = 9311 56|° 12:9" “Sop sek ay) tees tOA5 S| Ae oe DGs—. 23 Medium 9499 -58 11.6 | 312°) 62. 4 | 6. 69 1069 | Sept__.._- | DG=LY 5 doe ee Ae .59 11.81 3.40! 680] - 6.44 108% | Oct... ..- 1b Grapes. fet Coes Ae 9167 51 19.2 < e 6.55 1097 | Nov.._..- [Gy 7S Ola caret | 19515 .49 9.8} 266] 53.2 eee is>|"Dec =. | Gaye Veber e aee 9435 6] 113) 2.47] 49.4 | 7.28 PAV EE REO sac Ae 5 lo eee eee $225 | 52 10.4 | 3.11; 62.2 | 6. 80 ‘ : TABLE 4.—Composition of Eureka lemons (Tree 9) grown in Lemon Cove, Calif. a

| i | Se ope : Specific] Oilin | Oilper| ,,..:| Acid aes: ple | oath | Color. Thickness Of — Gravity | fruit,by, ton of | sore | per ton ee Nos | tes leet | of fruit. | weight.| fruit. | 74" | offruit.| ! | | | | | ex | Per cent.| Pounds.\Per cent.| Pounds.\ Per cen. G2)|: Oct. - | ae eet Medium........ o.oss1] 0.62) 124) 3.75] 75.0 7.00 23 | Nov.----. | Ae ge ete I NE oe |. 8406 | 62} 123] 3.50| 70.0 6.06 665 | Deat____- Paes oA Sa A ee! dase | 9368} 54) 108) 3.42) 68.4 6.20 703 | Jane=...._- [see vemee ee era| eee does 9166.) 56) Cd, SOS be 6.13 qeedekap..... ipvases hick ....--.--- Bees 7 Nadaey 4 8.2) 2.98) 50.64 eae S19 | Mar... Pewee tk | Medium......... | 8485] 138 7.6| 2.32) 46.4 4.59 SS eee eS veritas 2 stat of ets | glo} 52] 10.4 | 3.18 | 63.5 5.97 | i j

1 DG, dark green; LG, light green; LY, lizht yalow: FY, ful! yellow. 2 Ali acid is calculated as citric with water of crystallization.

ee be od le ie] Or

.—Com position of lemons ( Tree 19), variety unknown, grown at Yuma, Ariz.

| SN ee ee Sam- - rie ates Specific; Qilin | Oil per} ,.. | Acid z le | aes | Color See of | gravity “fruit, by | ton of | nes | per ton eet Men. sero ae of fruit. | weight.| fruit. | “"''" | offruit.| J | | | | | Per cent.| Pounds. Per ceni., Pounds.| Per cent. 620 | Nov-..-.-:- eb Woaresece = Medium... _.-.: | 0.9636; 0.65{ 13.0| 3.99; 79.8 6. 93 SeePeee= 23) Ye a AL iris eee eeees gee PS hs! 268) )-* 33:6 4-29 235950) = 2920 6. 81 657 | Dec... ..- bie eae ie cul! | 19597 S| TU1.4 1 eee ees 6.77 762 | Feb. ---.- on eee | Very thin._..-.. 9325 40 | 8.0 3.88 | 77.6 6.31 Prete a oe SP I Tk RS 9576| .57| 115 | 3.88] 77.7 | 6.70 | DG, dark green; LG, light green; LY, light yellow; FY, full yellow. . :

Ne

All acid is calculated as citrie with water of crystallization. §

COMPOSITION OF CALIFORNIA LEMONS.

im

TABLE 6.—Summary of composition of Eureka, Lisbon, and Villa Franca lemons

( Tables 1 to 3).

Acid per

ton of fruit.

Specific Oil fant Tree No. gravity Bene. of fruit. of fruit. Eureka Pounds. TY tes Ginn Be aa a RI BS eT ET eae ne eno 0. 9522 9.9 TDS EB ce s SIRES Sh Se ERR eee aie te ae an in Sone) Re Cees yet Cae 9386 9.2 TUT ch Se Ee eT i Rd BE SEE ee Ve nN Ne Ne ie 9407 8.9 TBS EB RSE ici CU eS aL Eo eo PORE Es RIN A Se Pate ae Ne hs SE Re 9408 iS Le ete ep eee ee RN Sa OE Sy AB ete eile Make . 9427 10.0 Ieee eee ate ne pm aly Mee Eley Sennen Reg ELEN Wage Uys Ded Be 9403 8.6 TIF oy A ere ek Loe ee TENE CaS PANE AR a Ue en we ats a a ka Cel . 9232 9.6 TAA ci, SO See AS EO res DR Gar dp Nia Me ae Bm mn ERE Yee ge UR gener eee re . 9378 10. 2 OR ef oS HENS SE ARE Ie ed eee Se He a eh Us eR ee A MR A a . 9397 9.8 FON a STS Sees OE RS SS RE Re NL ree eT Rae 9274 7.8 | POE EOE AREY HAG Se SEU Ee oe EAS OE CCE Oe COR Ts Hee eaeser mers . 938 9.5 + .004 + .3 Lisbon: Dee es Be 8, Gh als ia ae gag eal eh a I a #9 A STARS Lr Pu a 9046 10.5 Ae ett a enn EIS Se (ET eng A epee Ohegeanere aPC SRNR LAD stat aay Spun ur G uuieL 9121 10. 8 ais pa fie UNE a Rh AA Cie et ei Sane Pee I ae ee Us Pa at arte . 9324 11.1 Do ee bie SOS SEIS Bess RGR ERE an een By LC AO a Neer al Oe a . 9250 10.1 RR eae eee UE ray oy eete ay oy a ae a toes 8 RS Ae tt le LOS ad Sues 914) 8.1 EE earn ca ats ce we E Co ws eta MeN PN ERIS oa LN Sah SPL) ea BEN Naot 9126 10.0 ISERIES CAEO REO SRT ES SRE Ee SESE RES CSSA TB . 917 10.1 + .064 + .3 Villa Franca: Fes eh A Sic ee Mg RED Nr oN A US ea 9247 ile a Che oe ES SE Rae eee a ned SD SPT Ree ne ge . 9314 10.1 Tf 5 COS Ce ORO ORE IE ORE ree ES er eR Ee ae ean eI . 9225 10. 4 LNCS ENR S EE a ts YE iP Oe, ee pas i an Soi a Ne . 926 10.7 + .004 + .3

cor) fen | GA SIV ECO SO'S weal VNARNE OPRAH &

for Lab SoS EES wal RANQEO

on Non

TasLe 7.—Summary of analyses of different strains of Eureka and Lisbon lemons grown

at Corona, Calif.

Fat | Num- : . | : Insoluble eas P Specific gravity, Oil per ton . ae Sugars Acidity Variety. fe of fruit. of fruit. Rind. eS in juice. | of juice. Pounds. | Per cent. IEG Obit \\ SEAR BAP W IRAP GAs Branekan: e325 52.)3 10 |0.939 (+0. 005) | 9.5 (+0. 4) |36.2(+0.9)] 1.9 (£0.1)] 2.5 (+0. 1) 5.3 NEISDONERS sian go ae 5 | .905 (+0. 004) | 10.8(£0. 4) |38.8(-+0.5)|1.7(40.07)} 1.9 (+60. 1) On, TABLE 8.—Relation between color and thickness of peel. Nittiber Number samples found to be— Color. Sea DISS “ned, |_,Thin. | Medium | Thick * |skinned. | skinned. | skinned. Eureka: LUE COC GLE RS Oe BE ee Aone See a ee MRE ean ee 15 4 8 3 AG SUT ROCCO Les eee eee Oe, Hah eee Ne ee Leah 2 Tales? 36 6 17 13 Dafa ah), WCHL AAG cca SS Se SR ee eee 32 3 21 8 TRU EU OD ies AR SEB OG GE oF CEH GUC A SaerIGEO one e CMe arma 5 0 3 2 Lisbon: ID seat iGheirte lel ee ee eae Slee ee 3 aah ae sb he eee PS ie gest OR So ES rd 6 0 2 4 AAS NoN ofed WeXey oR SS NAR Caeser ent eR A eal eG ei 21 0 14 o LOPE ANESS CULON Gs Sika epee es ei aes estar ies eaty che ae ee eae es en 24 2 13 9 ew SH Oy sraraes ecco ete watever eke Siero oy seaeseiaceistecbcaterl ais 3 1 1 1

|

—e- ©

1 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 9.—Relation of color to composition of fruit.

stares Dark Light Light | Full yel- Determination. green. | green. | yellow. love: Eureka: ; Speeilic sraviby +2 ee oe. Sere eee ees oe eRe lean: 950 0. 939 0. 926 0. 929 OTE PEL AVOMLO flr UG MOUS) Eee Me eee aoe ge eee sem eee peace ele | 9.1 9.2 9.6 11.0 a eed PEE CONTOMENUTG. Cp OW GS) hee ee ee eee | 62.0 66. 0 66. 0 69.0 isbon: Specific sravilly 2.7 1s ae ce ee ne ee See ee eee oe oe sYPAL | . 922 ote - 918 (L Onl pertomofinuTrG| (Own ds) eee see = see ee ene eeu ae ies 4 9.8 10.0 10.5 Aeid-per ton of inait/ (pounds) 2 eeeee sess ae eee 59.0 | 62.0 66. 6 73.0

TaBLe 10.—Correlation between thickness of peel and compositon of fruit.

Composition. Determination. Sea egie Medium le Thick skin. Saal Thin skin.

Eureka: |

Specilic Shawty 35 ="). Skee ae PN ee ere ee eee eee ee 0. 924 0. 936 0. 958

Oil perton offruit (pounds) <3. aoe oss he Ree ee seen 8.4 O29 9.6

ACIG MEE TON OL eu t (DOUNGS) meee ser see eee eee | 59. 0 67.0 72.0 Lisbon: |

SPOCTIG STA WAI yi Ne ee © RP ae eae ee i IE eT TE ee | BOS . 920 920

Oilsper ton obit (poumds) eee ae a ene eee eee ee ee eee 10.3 10.0 11.2

ACI Per tO Of MUItCpOUNGS) cae Sas oes aes See eee eee ea ense | 60. 0 65.0 75.9

TABLE 11.—Comparison of composition of coastal with that of inland Eureka lemons.

Specific . Acid per Location. gravity Oo ee ton of of fruit. x ; fruit. Coastal: | Pounds. Pounds. Oma ee oe oe ha De Se nee ee ne ee reid eR ae 0. 962 9.9 14:3 RATA GUS (2) cena eas etl awe OP RR ey Lhe 2 Ue oa WE YSN RU - 943 10.0 61.4 1 Bo Fone dee I Pees Rl A Aes er are ae eR a a td . 940 8.6 63.9 TD oR ee Sara le are bs Lea oe RD ea ee A Re ea Se aS - 923 9.6 62.1 Walp ententacs so ase e oot ae ee eh Sts ee ne, oar arte eet eS 927 7.8 47.2 PAN CLA LC so Pan eee eee dees Seki Siok DE ew ee erect ie sae . 939 9.2 61.8 Average (excluding Carpenteria data)..........-------.-.-- - 942 9.5 63.3 d Tniand: SantaePaula ta ee. SS ee Ate Mea Ta aeare ay ee nN eyes le . 939 9.2 73.3 D0 hea areiaug en aimee ci, APC Tem Ope We eat Hig ae A UST ok RE Ug ee 941 8.9 69.1 SAH ermat Oe. es Ast ALUN eT a ye Spc ele eee Ree - 941 is 66.6 Sait Dimas, Ss sass As ae ses he ee See eee an cok mee Se ne eee . 938 10. 2 65. 2 OVENS) 0010101 RE es Seema Nags oR ey me ee ee mie Sees Ocean Ce eA pe LE . 940 9.8 61.4 IA VOR ARE He: cere? a artist ae Be Sato ee eile AR Te Te eat . 940 9.7 67.1

DISCUSSION OF RESULTS. DIFFERENCES IN VARIETIES.

The average composition of the Eureka, Lisbon, and Villa Franca varieties is shown in Table 6. The figures below the averages are 4 the probable errors of the. mean. For instance, under specific gravity the figure 0.938 is the average obtained from more than 100 samples. Had the specific gravity of each sample been 0.938, there would be no doubt that that figure represented the true aver- age of the lot. This was not the case, however, and never is, where . |

" F nn ee

COMPOSITION OF CALIFORNIA LEMONS. 13

natural products are under consideration. The samples varied decidedly from this average, some having a higher and some a lower specific gravity. It is necessary, therefore, to use mathematical for- mulas applicable to such cases, with the result that the chances are even that the true mean is not greater than 0.942 or less than 0.934, or, as it is expressed, 0.938+0.004. The same explanation applies to the other figures. The results reveal little difference in the com- position of these varieties of lemons.

By applying other formulas it is possible to ascertain whether the differences Shown are really significant, and, if so, to what extent. For instance, the odds are 78 to 1 that the difference between the specific gravity of Eureka and that of Lisbon lemons shown is sig- nificant. On the other hand, the odds are only even (1 to 1) that there is a significant difference between the specific gravity of Villa Francas and that of the Lisbons, and about 5 to 1 that the difference of 0.012 between the Kureka and the Villa Franca specific gravities is significant. It is probable also that no significant difference exists between the oil content of the Eureka and Lisbon varieties, nor be- tween that of the Lisbon and Villa Franca lemons. The odds, how- ever, are 18 to 1 that the difference between the oil content of the Eureka and that of Villa Franca lemons is significant. No significant difference is shown in the citric acid content of the varieties.

As these averages are obtained from trees located in all parts of the lemon-growing area of California and from samples taken consistently throughout the year, there is little doubt that the data are repre- sentative of the actual composition of these varieties as grown in California.

In this connection, it is interesting to consider some data obtained from analyzing 18 sets of samples of the Eureka and Lisbon varieties of different strains grown in two groves at Corona. These sets are derived from monthly samples taken over a period of two years. In considering them, the fact that all the Eureka trees were in one grove and all the Lisbons in another should be kept in mind, as this makes the data less desirable for comparative purposes than those from the field samples. The fact that these trees were chosen to illustrate differences between strains within their respective varieties rather than those between the two varieties also lessens their value for comparison. Interesting studies of the strains of these varieties have been reported by Shamel and his coworkers (1) (2).

There are certain marked differences, however, that are not ap- parent between strains within the variety, but become apparent when the varieties are compared. To illustrate, the fruit of 10 Kureka trees under observation had an average specific gravity varying from 0.925 to 0.989, the average being that shown in Table 7. The fruit of the three Lisbon trees had specific gravities ranging

14 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

from 0.898 to 0.915, with the average shown in Table 7. Here it is perfectly apparent that the difference is one between the varieties, for the maximum specific gravity of Lisbon strains is lower than the minimum specific gravity of the Eureka strains. This difference corroborates that already found between the regular samples of each variety.

When the averages for oil are considered, the results are less satis- factory. The averages for all the Eureka strains vary between 7.6 and 11.2 pounds per ton; on the other hand, the Lisbon averages vary from 8.6 to 12.9 pounds per ton. The averages in Table 7, with the probable error of the means, show that the odds are 7 to 1 that the difference is significant in the case of these samples. Whether or not this significance would be maintained throughout the entire plantings of the State would depend largely upon the preponderance of the strains having high oil content. At present no data estab- lishing such a preponderance are available.

Likewise, the acidity of the juice of the Corona samples shows some difference between the varieties, but there is a similar differ- ence between the strains within the varieties, so that this is not significant when the varieties are considered as a whole.

The same conditions apply to the averages on percentage of rind shown in Table 7. Apparently nothing significant in the averages of the insoluble solids is shown, although a significant difference is apparent in some of the strains within the variety.*

The averages for sugar show a rather marked difference, which is more significant between the varieties than between the strains within the variety. Only a single Lisbon strain has an average sugar content greater than 2 per cent, while not one Eureka strain has an average below that figure. Therefore, the odds of over 200 to 1 that the difference is significant probably apply to the varieties as a whole.

SEASONAL DIFFERENCES.

The marked differences found in the samples of lemons harvested at different times of the year are interesting. As previously stated, lemons may be harvested during every month of the year, the selec- tion being made according to size and not according to color. As the samples were harvested in the same manner as the commercial fruit, the changes which are discussed in the following pages are due not to the different stages of maturity but to the composition of fruit maturing at different times of the year. All of the samples analyzed were commercially mature.

3 This difference will be discussed in a forthcoming publication.

-

COMPOSITION OF CALIFORNIA LEMONS. 15

Figure 2 * shows the specific gravity of the fruit in both varieties as harvested monthly. The monthly average shown here must not be interpreted too literally, for usually the differences from month to month are small. A general trend is shown, however, and there is little doubt that the changes from season to season are really signifi- cant. For the first four months of the year, the Kurekas change but little, while there is a gradual increase in the specific gravity of the Lisbons. With the advent of spring, the Hurekas begin to increase rapidly, and this increase continues without interruption until mid- summer. During the corresponding period, the Lisbons also increase rapidly, reaching the maximum in August. From midsummer to January there is a marked decline in the specific gravity of both

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Fig. 2.—Monthly averages of specific gravity.

varieties. The data leave no doubt that both varieties have the lowest specific gravity during the winter months and the highest in midsummer.

Figure 3 shows the variation in the oil content of the fruit har- vested each month of the year. Here again indisputable differ- ences occur in both varieties, and the general trend of both is very much the same. The late winter and spring fruit contains a mini- mum amount of oil. The oil content is only slightly increased in the summer fruit, but with the advent of fall it rises rapidly, until December finds the oil content at a maximum in both varieties.

4In determining the monthly averages, where there are several monthly samples from one tree, the average is taken. Where monthly samples are missing, the results are interpolated, the average of the preceding and succeeding months being used.

16 BULLETIN 993, °U. S. DEPARTMENT OF AGRICULTURE.

Figure 4 shows the periodical differences in acid content. Ap- parently the acid content of lemons varies more from month to month than any other constituent, the graphs being very irregular. It would seem that the Kureka variety has a rather well-defined period of low

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5 BoP (EG (| a

Fig. 3.—Monthly averages of pounds of oil per ton of fruit.

acidity in the late winter and spring months. Rising rapidly from that time, the acid is at its maximum in September, after which it again declines. The acidity of the Lisbon samples was much less

ei octu ie ae aS NN rt Pe eee Ae

Fic. 4.—Monthly averages of pounds of acid per ton of fruit.

uniform, the general trend of the curve being broken by several in- explicable irregularities. While the maximum occurs in September, as with the Kurekas, there is no well-defined minimum, low averages being shown in both July and October. During the first six months

COMPOSITION OF CALIFORNIA LEMONS. hak

of the year, the Eureka variety contains the greater amount of acid; during the last six months, the reverse holds true.

COLOR AND THICKNESS OF PEEL.

Apparently little correlation exists between the color and com- position of the fruit. The data were carefully selected so as to omit those from samples containing too great a ace of colors to be accurately estimated.

The better part of both varieties had peel of medium thickness, but the Eurekas had a larger percentage of thin-skinned fruit and a smaller one of thick-skinned than the Lisbons (Table 8).

Few conclusions can be drawn from these data. Where some corre- lation may exist in one of the varieties, it fails to show with the other. For instance, the Eureka seems to decline in specific gravity as the color lightens, but the Lisbons show no such tendency. Likewise, the acid seems to increase with the Lisbons as the color decreases, but this is not apparent in the case of the Kurekas, although the dark ereen and full yellow correlate.

Classifying the samples according to thickness of skin, 26 thick- skinned, 49 medium-skinned, and 13 thin-skinned EKurekas were found, and 21 thick-, 30 medium-, and 3 thin-skinned Lisbons (Table 8). Unfortunately there are too few thin-skinned Lisbon samples to render the results under this particular head of value, and no account is taken of them in discussing the data.

Two correlations seem apparent from these data: (1) The specific eravity increases as the thickness of the peel decreases; and (2) the acidity of the fruit increases as the peel decreases. Both seem in line with what might be supposed would take place. Thick-skinned fruit often has a hollow center and is generally coarser than that with thinner peel. Inasmuch as the peel contains no acid, naturally the fruit having the greatest amount of peel is likely to contain the least amount of acid. As the oil-bearing part of the peel is near its sur- face and does not correspond in any way with the thickness, it would hardly be expected to change.

EFFECT OF LOCATION.

It was thought at first that the data obtained in this investigation might throw some light upon the effect of environment on the com-. position of the fruit. Locations near the coast as well as in the inland valleys were selected, and if any marked difference in composition between lemons from the two sections existed it should have been revealed. The 10 Eureka locations were equally divided as to situ- ation, 5 being on or near the coast and 5 inland or separated from the coast by ranges of hills. What at first appears to be a slight difference in the results (Table 11) is found in the oil content of fruit from the

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18 BULLETIN 993, U. S. DEPARTMENT OF AGRICULTURE.

two sets of locations, and a more pronounced difference in the acid content. If, however, the location at Carpenteria, which is apparentiy abnormal as to the oil and acid content of the fruit, is discarded, the averages are too nearly the same to render any conclusion possible.

These data are offered not as a final statement upon the subject of the difference in composition between coastal and inland lemons, but merely to show that so far no difference has been found.

CONCLUSIONS.

A few well-defined differences between the varieties of lemons examined exist, the most striking of which is in the specific gravity of the fruit. The specific gravity of the EKureka variety is greater than that of the other varieties, and that of the Villa Franca appears to be practically the same as that of the Lisbon variety.

The Villa Francas have more oil than the Eurekas. Otherwise no absolute difference in the oil content is shown, although there is some indication that the Eureka has the lowest oil content.

There is no difference in the acid content of the three varieties.

A marked difference in sugar content between Eureka and Lisbon lemons exists.

The acidity of lemons is highest in the early fall. Lemons have the lowest specific gravity during the winter months and the highest in midsummer. Their oil content is lowest in late winter and spring and highest in the fall.

No absolute correlation between the color of the peel and the com- position of the fruit was found. As the thickness of the peel increases, the specific gravity of the fruit decreases, as does the acid content.

No correlation is shown between color and thickness of the peel.

No difference in composition between lemons grown on the coast and those grown inland is shown.

BIBLIOGRAPHY.

(1) SHamet, A. D., Scorr, L. B., Pomeroy, C. 8., and Dyer, C. L. 1920. Citrus-fruit improvement: A study of bud variation in the Eureka lemon. U.S. Dept. Agr. Bull. 813: 1-88. (2) 1920. Citrus-fruit improvement: A study of bud variation in the Lisbon lemon. U.S. Dept. Agr. Bull. 815: 1-70. (3) Wri, R. T. 1916. Some phases of the citrus by-product industry in California. J. Ind. Eng. Chem., 8: 78-86. (4) Witson, C. P. 1921. The manufacture of citric acid from lemons. Calif., Citrograph, 6: 110. and Young, C. O. 1917. A method for the determination of the volatile oil content of citrus fruits. J. Ind. Eng. Chem., 9: 959-961.

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