2 5 2 5 :: 111112.8 11111 . 1.0 :~ 1111/2.8 11111 . :: Ilj113.2 2.2 I~ Illp·2 I I" ~ ~~l& ~ ~~~ u. u. 1.1 := I~ 1.1 ~ ~~ 1-' 1 111111.25 111111.4 111111.6 111111.25 111111.4 111111.6 MICROCOPY RESOLUTION TEST CHART MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU Of STANDARDS-\953-A NATIONAL BUREAU OF STANDARDS-\963-A P /:;..3 0 U£3-/ /fl7~ Xanthophyll, Carotene, and a-Tocopherol Stability in Alfalfa as Affected by Pilot- and Industrial-Scale Dehydration . REFERENCE DO NOT LOAN f Technical Bulletin No. 1414 ~ j •""'" ~ 0 0) ~ Eo­ ....- )00.( 0 .~ ~1f.l ...-I ~ ~ 0::: ~ "\. ~ -t ~1 ::E ~ t J Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE CONTENTS Page Introdaction___ .. _ _ ___ ___ _ _ _ _ ____________ _ _ _ __ 1 Procedure____________________________________ 2 Dehydrat,on of alfalfa_ .. _____________________ 2 Ohemicol analyses_____ ______________________ 2 Results and discussion__ _ _ __ _ _ __ ___ ____ _ _ _ __ _ __ 3 Stability of xanthophyils and carot,ene during dehydration_ _ _ __ _ __ _ _ _ _ _ __ ____ ____ ___ ___ _ 3 Pilot-scale dehydration.. _ _ _ ______________ 3 Industrial-scale dehydra.tion_ __ __ __ _ _ _ _ __ _ 5 Isolli.:>rization of lutein___________________ 5 Stability of individual xanthophylls during storage__________________________________ 7 Stability of a-tocopherol and related isoprenoids during dehydration and storage_____ .. _______ 10 Summary____________________________________ 13 Literature cited___ ___ _ _ __ _ _ __ _ _ _ _ _ _ __ ____ _ _ _ _ _ 13 Names of companies and trade names are used in tills publication solely to provide specific information. Reference to a company or product name does not imply approval or recommendation of the pr6duct by the U.S. Department of Agriculture to the exclusion of others that may be suitable. Washington, D.C. Issued lVIarch 1970 For sale by the Superintendent of Documents, U.S. Government Priniing Oillco Washington, D.C. 2O.J02 - Price 10 cents $" 'i i. ,Xanthophyll, Caroten~~ and a-Tocopherol Stability in Alfalfa as Affected by Pilot- and Industrial-Scale Dehydration ~ By A. L. LIVINGSTON, R. E. KNOWLES, and G. O. KOHLEn; 1 INTRODUCTION Dehydmted alfalfa meal is a val­ hydrated alfalfa is an effective' uable sourCe of vitamins and nutri­ source of pigment for broiler skin ents for addition to poultry and and eggs (7), it is important to livestock mixed feeds. Three of Imow the dehydration conditions these nutrients, xanthophyll, caro­ that will retain a high proportion of tene, and C(-tocopherol are suscepti­ xanthophyll in the dehydrated bk to o~1dation (4,5,12,16,120,21) 2 meal. Moreover, the conditions that and iSOlnerization (1,93,4,19) losses serve to prodnce high-xanthophyll during drying and storage of the meal will produce a meal high in plant material. Recent studies at carotene (provitamin A), C(-to­ this laboratory haye indicated that copherol (vitamin E), and other up to 70 percent of the total xantho­ nutrients. phyll of fresh alfalfa may be lost Lutein, vi01a-xanthin, and neo­ during dehydration (9, 10). The xanthin make up about 90 percent ease of isomedzation and oxidation of the total xanthophylIs of fresh of the xtUlthophyJl is due principal­ alfalfa (1,10). In addition to these ly to the large number of conju­ three, cryptoxanthin and zeaxan­ gated double bonds in the m01ecule thin make up 6 to 8 percent, while (932). Since the xanthophyll of de­ minor components such as zeino­ xanthin make up the remaining 2 to 1 Research Chemist, Chemist, and Chi(>f, respectively, of the 'Western Util­ 4: percent (11). Lutein, which com­ ization Research and Development Divi­ prises 60 to 70 percent of the total sion Field Crops Laboratory, Agricul­ xanthophyll, is an effective pig­ tural Research Service, U.S. Department menter, while violaxanthin and of .Agriculture, Albany, CaUf. 94710. • Italic numbers in parentheses refer lleoxant11jn have little if any pig­ to literature cited, p. 13. menting activity for broiler skin 2 TEOHNICAL BULLETIN NO. 1414, U.S. DEPT. OF AGRICULTURE (8). 'l'herefore, retention of lutein falfa produced only 5 major xan­ during dehydration is of utmost thophyll bands during chromato­ ~ importance in the production of graphy, dehydrated meal produced high-qt:':tlity poultry feeds. In addi­ at, least 40 xanthophyll bands (1). tion to oxidative and enzym~tic The present study wa~ carried out losses, isomerization of xanthophyll to ascertain the retention of xan­ and carotene readily takes place thophyll, carotene, and a-tocopherol during heating (9, 19, 9393). Thus, during pilot- and industrial-scale a pre\'iotls study at this laboratol'J alfalfa dehydration and subse­ demonstrated that while fresh al­ quent meal storage. PROCEDURE Dehydration of Alfalfa paint to the fresh plant material as it moved up the elevator, and ascer­ Initial studies used a pilot Arnold taining the time required for th~ dryer (model 5D45-12) with a paint-treated alfalfa to appear rated capacity of 1,000 pounds of among the dehydrated chops. water per hour. The flame to the burner was l'egulated manually, Chemical Analyses controlling both the input and out­ Total xanthophyll and carotene put temperature. In a second study, were determined by the improved It fan was incorporated into the sys­ (TX) procedure of Kohler and tepl to provide a negative air pres­ others (6). The individual xantho­ sure and l'egulate the throughput phylls were determined by the thin­ time of the alfalfa chops. The flame layer chromatographic (TLC) pro­ to the burner was automatically reg­ cedure of Nelson and Livingston .. ulated by the output temperature (14). a-Tocopherol and related iso­ of the dryer. prenoid compounds were deter" Following initial evaluation on a mined by the method of Livingston pilot scale, studies were extend~d to and others (1~). include an industria,l-scale Arnold Meal moisture determinations dryer at Dixon, Calif., and a were made by drying the samples ' Steams-Roger dryer at Clarksburg, for 24 hours at 105 0 C. in a forced­ Calif. The industrial dryers ''7f~l'e in draft oven. The fresh plantmaterial sufficiently close proximity that was prepared for analysis by rapid fresh alfalfa chops from the same freezing between layers of dry ice, field could be dehydrated in poth followed by drying in a Virtis ..dryers simultaneously. freeze dryer. Both the freeze-dried The throughput time of the [t1£al­ material and the dehydrated chops ia chops was determined by the ad­ were ground so as to pass through a dition of heat-resistant aluminum 40-mes11 screen before analysis. XANTHOPHYLL; CAROTENE, II-TOCOPHEROL STABILITY IN ALFALFA 3 RESULTS AND DISCUSSION Stability of Xanihophylls and obtained as presented iIi. table 1. At t~l.e three high leveli3 of meal mois­ Carotene During Dehydration ture, 90 percent or more of the xan­ Pilot.scale dehydration. thophy11 was retained; but xautho­ Study l.-The first study em­ phy11 losses were very large at the ployed the pilot Arnold dehydrator. three lowest moisture le'Ve1s. The The input tetnpe!.'&ture was regu­ carotene, however, was relatively 1ated manually by controlling the stable during dehydration. flame to the bnrper. The feed rate of Although xanthophyll was the the fresh chops entering the de­ inost stable in the higher moisture hydrator, -as well as the input tem­ meals during dehydration, tlia.t in pei'a.ture, determined the outlet or the 3 to 4: percent moisture meals rear-end temperature. The average was more stable during stor9,ge. Ac­ retention time of the alfalfa chops cordingly, during dehydration plus in the drum was 15 minutes in this storage the total xanthophyll and initiuJ study. carotene retention of the medium­ A direct correlation of xantho­ moisture meals was greater th~n phyll retention, dehydrated meal that of the high-moisture meals. moisture, and, inversely, the outlet This emphasizes the necessity of temperature of the dehydrator, was treating the dehydrated meal with 'rABL"E I.-Stability oj xanthophyll and carotene during pilot alfalfa dehydration and storage 1 XimthophyU Carotene Dryer tom perature Initial Retained In meal Initial RetaIned In meal Moisture content -.------- content At At oCmenl In Cresh ACter de- After dehy- In fresh ACter de- ACter de­ Inlet outlet alfalfa hydration dratloll and alfalfa hydration hydration storage aud stor­ age OF. of. Pet. Mg./kg. Pet. Pet. Mg./kg. Pet. Pet. 1,600 220 11.0 498 93 29 2?­~() 100 28 1,400 220 9. a 573 90 31 267 100 35 1, 200 220 8. 6 456 92 28 205 100 35 1,600 270 4. 0 538 68 34 238 100 49 1,400 270 3. 2 626 57 34 275 100 58 1,200 270 1.6 575 6.5 32 258 100 50 1,600 320 1.2 616 41 26 282 100 52 1,400 320 O. 7 570 50 26 269 100 49 1,200 320 0.3 616 42 24 284 88 43 I Stored 12 weeks at 90· F. 4 TEOHNICAL BULLETIN NO, 1414, U.S. DEPT. OF AGRIOULTURE an antioxidant such as ethoxyquin lationof xanthophyll retention with (17, 18), or storage of the med meal moisture, fan speed and, in­ under an inert atmosphere (3), or versely, with retention time. This :storage in the cold (5) in order to same correlation was present at the preserve the xanthophyll and caro­ 255 0 F. outlet temperature, except . tene of the higher mOIsture meals. at this outlet temperature all of the SMtd!12.-In order to achieve ef­ meals contained less than 3 percent ficient regulation of the flow of moisture.