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INDUSTRIAL AND ENGINEERING CHEMISTRY
many young and raised 80yGas many as those on the control diet. This performance tends t o support the growth data in that the phosphorus of the tricalcium phosphate was less available t h a n t h a t in the Osborne and hlendel salt mixture. At the higher phosphorus level the animals on the 0.2% fluorine phosphate produced 85% as many young as those on the control diet and raised 75% as many. T h e 85% value vould give this phosphate material a rating of "very good" i n relation to the Osborne arid hlendel salt mixture when appraised according t o the method of Ellis et a!. @), who rated as very good a phosphate that was SOc/, as effective as bone meal, n-hen gron-th and bone ash were the criteria. At the adequate phosphorus level, the animals on the 0 3Yc fluorine phosphatc dict produced 78% as many young a s those on the control diet and raised 93% as many. .lppnwntly 7,fluoIirie when reproduction is the basis of comparison, the 0 3 fused phosphate is a satisfactory source of phosphoruq t o rats. SUaIhIARY Ah-D CONCLUSIONS
1. Eighty-mesh fused tricalcium phosphate, containing 0.2 to 0.55% fluorine, was fed at a minimal dietary phosphorus level to white rats during the 30-day period of their most rapid growth. This was found to be less assimilable than inorganic phosphate of the standard Osborne and hlendel salt misture. The difference in degree of assimilability was not manifest when the is, phosphorus demand of the growing animal was less-that during the 60- and 90-day periods. The difference was less apparent also mhen the level of total phosphorus rvas raised from 0.2 to 0.47, in the breeding experiments. With such increases in phosphorus content, there were increases of 53 to SOYc in numbers born and raised on the phosphate diets. 2. When sodium fluoride was introduced into the diet to provide a fluorine content equal to t h a t fed as fused tricalcium phosphate, there was no detrimental effect upon gron-th of the rats t o maturity or upon their bodily retention of phosphorus. 3. The 80-mesh fused tricalcium phosphate containing as much as 0.3% fluorine proved as efficacious as the precipitat'ed dicalcium phosphate in the promotion of rat growth to maturity and in phosphorus storage. 4. Eighty-mesh fused tricalcium phosphate of 0.2 or 0.3% fluorine content was fcd at a 1% level, and the phosphorus con-
Vol. 38, No. 6
tent of the dict n a s brought to 0.4yo. The fused material proved t o be 78-857, as effective as the phosphate of an Osborne and Mendel salt mixture when effectiveness was measured by reproduction, and 75-93y0 when effectiveness Tvas measured by lactation. 5. The data obtained indicate that fused tricalcium phosphate of 80-mesh, containing not more than 0.370 fluorine was virtually as effective as the control phosphate of the Oshorne and Mendel salt mixture, when evaluated by rat growth and body storngc of phosphorus during a 90-day period. When judged by reproduction and lactation, the fused phosphate proved from 75 t o 93T0 as good as the salt mixture. The results also indicate that nutritional ineffectiveness of a phosphatic product should not be attributed to its fluorine content until the factor of low phosphate availability has been taken into account. LITERATURE CITED
(1) Bnrrentine. B. F., Maynard, L. A., and Loosli, J. K., J . Sufrilion, 27, 3 5 4 2
(1944).
( 2 ) Ellis, N. R., Cabell, C. A, Elrnslie, 'A7. P., Fraps, G. S.,Phillips, P. H., arid Williams, D. E., J . Assoc. Oflcinl Agr. Chem., 28,
12932 (1945). (3) Fraser. 13. F., Hoppe, T. C., Sullivan, J. H., and Smith, E. R., ISD.E K G . C H E M . , 35, 1087-90 (1943). (4) Goulden, C. H., "SIethods of Statistical Analysis", pp 42, 2 e i , New York, John Wiley &Sons, 1939. (5) Jacob, K. D., Feedstuffs, 16, 1s-32 (1940. (6) J . r i s s n c . Oficial Agr. Chem., 28,38 (1915). (7) hladntire, 11'. H., Winterberg, S. H.. Hatcher, B. W., a n d Palmer, George, Soil Sei., 57, 42542 (1944). ( S ) XIitchell, H. H., Natl. Resoarch Council, Reprint Circ. Series 113 (1942). (9) Oshorne, T. B., and Mendel, L. B., J . B i d . Chem., 37, 557-601 (1919). (10) Phillips. P.I I . , Bohsteclt, G., Faryo, J. h l . . Hart, E. B., and Haloin. J. G.. Wis. Aar. ExDt. Sta.. Bull. 428.9-12 11934). (11) Phillips, P. H., Hart, E. B.,'and Bohstedt, G., Ibid., Research Bull. 123 (1934). (12) Tolle, Chester, and Maynard, L. A , , Cornel1 Univ. Agr. Expt. Sta., Bull. 530 (1931). PRESEXTED on t h e program of the Division of Agricultural and Food Chemistry of the 1943 Meeting-in-Print, AhrERIcax CHEVICAL 8OCIETY. This study was conducted in cooperation with t h e Tennessee Valley Authority.
VITAMIN CONTENT OF' PEAS Effect of Freezing, Canning, and Dehydration C. H. IIIAHONEY, E. P. WALLS, H. A. HUXTER,ANDL.E. SCOTT M a r y l a n d Agricultural Experiment S t a t i o n , College P a r k , M d .
T
IIE objective of this investigation was to determine, a t the time of serving, some of the nutritive levels of peas. Direct comparisons n-ere made on identical lots a t the same stage of maturity, preserved by canning, freezing, and dehydrni ion. Eight varieties of sweet peas R-ere gro\vn a t the LIaryland station during 1944. The plots rrere large enough so that they could be harvested with commercial equipment and threshed in a standard viner. The shelled peas n-ere thoroughly mixed a t the viner and then separated into the various sieve sizes. I n all cases the prevailing sieve size typical for the variety was used for processing and for vitamin determinations. , The peas were thoroughly m-ashed, cooled, and processed rrithin 2 hours. The variety Dark Podded Thomas Laxton was used i n comparative studies of the three methods of preservation. Large samples of No. 4 sieve peas of this variety mere taken from the same lot for freezing, canning, and dehydrating.
I3laiicliing htudies conducted several years ago at this station indicated t h a t a better quality of frozen peas was obtained by blanching a t 190 O F. than in boiling v-ater, and this temperature was selected for the 1944 studies. Twenty-five to thirty pounds of peas were blanched in a R ire basket in 30 gallons of water in a steam-jacketed kettle where the temperature could be accurately controlled. The peas were agitated during blanching and were then cooled immediately in cold running water. Some lots of peas were blanched with steam. A special steam blanching box with a water seal made i t possible to obtain a temperature of 214" F. in the center of 30 pounds of peas in a n ire basket n ithin 30 seconds. All steam blanching treatments were made at 214' F. Samples for freezing viere separated into floaters and sinkers in a 13y0brine after blanching in water at 190" F. for various times. The peas were washed and packed in one-pound, mois-
June, 1946
INDUSTRIAL A N D E N G I N E E R I N G C H E M I S T R Y
Comparable lots of eight iarieties of peas were canned, frozen, and dehydrated, and ascorbic acid was determined o n the product after 6-111onth storage, before and after cooking. There w a s considerable Fariation in ascoTbic acid levels among *arieties, and an interaction between blanching time and variety. Canned peas (considering both peas and liquor) had a higher ascorbic acid content than frozen or dehydrated peas after 6- or 9-month storage. Dehydrated peas contained asout one third as much ascorbic acid as frozen or canned peas; when stored under carbon dioxide, they had a higher level than those stored
655
under air or in vacuum. Ascorbic acid retention (dry weight basis) of the stored products (after cooking), compared with the original content, was 38yo for the canned material, 53y0 for the frozen, and 197, for the dehydrated. The carotene content of the frozen peas was higher than that of the canned or dehjdraled lots. The frozen and canned peas retained about two thirds and the dehydrated peas about one half of the original thiamine rontent. Prolongation of the storage period from 6 to 9 months resulted in further appreciable loss of ascorbic acid from the frozen and canned peas.
ture- and vaporproof containers and v,ere frozen a t -25 F. with a n air blast of 1000 feet of air per minute. The samples w r e stored a t this temperature for oiie month and a t 0" F. for the balance of the storage period. Peas for canning r e r e blanched for 3 minutes in hot water (190" F.), separated in 13% brine, cooled, and filled into S o . 1 cans. .The peas in the can n-ere covered with boiling sugar-salt solution (25 pounds of sugar and 15 pounds of qalt in 100 gallons
facilitate comparison among various processing and storage treatments. Excess moisture lvas removed from both the freshly n-ashed and the thawed frozen peas with paper ton& before weighing for both moisture and vitamin determination.. lloisture content of all samples was determined in a vacuum oven at 28 inches of vacuum and 70" C. The samplrq w'cre left in the vacuum oven for 14 hours. A\corbic acid was determined b r the titration method of I3cssey and King ( I ) . Iroore'T method of carotene analysis waa 'r.%BLE I. E F F E C T OF B I . , % S r l i I S G (IS .ISCORBI(. .%('ID C O S T E S T OF D A R K - k'(1DDLD nued as modifid by 1Ioore and EIy ( 5 ) . 1 " O M A s 1,.4XTOS PE.\S, R E F O R E FREEZISG . I S D .IFTER 6 X I O S T H B O F FROX ,-.\ECO+~C, ;\emperaturein the primary end of 180' F. and 1200 times a t 190" F. At this blanching temperature after storage linear feet of air per minute, and were finished a t 160" F. in the there was a higher level of ascorbic acid in peas at the 2-minute secondary tunnel. blanch than a t either 1 or 1.5 minutes (Table I). I n fact there was a much higher ascorbic acid level after 6-month storage in METHODS OF ANALYSIS the peas blanched for 3 minutes than in those blanched 1 or 1.5 T h e concensus of the station workers in the northeastern misutes. This was prohahly due either to failure of inactivation region is that, vitamin values should be expressed on the wet of enzymes or possibly t o regeneration. There was a tiecline in basis, and losses in terms of the fresh n-eight of the original fresh sample. If t.he purpose is to discover when and Rhere vitamin Iopqes occur, this method has definite advantages, as emphasized by the work of Clifcorn and Heberlein ( 2 ) . However, the purTABLE11. EFFECT OF BLZSCHING TI\fE O U .4SCORBIC .ICID COXTEXT O F EIGHT 1-ARIETIES O F FROZEN P E A S I N STOR.4GE pose of the present study was to determine the actual vitamin G MONTHS content of frozen, canned, and dehydrated peas n-hen a given Ascorbic Acid (l\Ig./lOO G. W e t Wt.) after Kater amount of each was prepared for serring. Since erery precaution Blanch (190' F.) f a r : had been taken to secure typical samples for all three methods Variety 1 min. 1 . 5 mm. 2 mn. 2 5 min. 3 min of preservation from the same lot of peas, i t v a s believed that the Thomas Laxton ... ... 10.51 ... 11.98 Glacier . . . . . . 1 3 . 9 4 . . . 12.94 actual content of vitamins in 100 grams of peas prepared for Teton 4.11 11.60 ... 8.71 Canner King 13.94 l2:92 10.86 ... 9.88 serving ~ o u l dgive the fairest evaluation of the effect of the Shasta 14.30 13.61 13.72 . . . 13.22 preservation method on the nutritive level. No. 312 13.93 ... 12.09 ... 13.10 Dark Podded The data in thetables are presented on both the wet and dry basis, Thomas Laxton 4.7.5 5.20 12 47 9.38 8.54 Early H a r v e s t and the moisture cont,ent is included for those interested in the Sinkers . . . . . . 11.57 . . . 13.20 loss of soluble solids during processing. The reason for presenting Floaters ... ... 8.07 ... 10.59 the apparent vitamin retention on a dry Iveight hasifi is t o 7
C
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 38, No. 6
certain inlitbrent bioiogical dilTerences aniorig varieitate studies to determine t,hr optimum blanch for each variety. For this reason Fresh a t Harvest Frozen, Not Cooked Canned, N o t Cooked the data on minimuni blanching times are presenteci. JIoisAshloisAsReten- re t isAsRetenHowever, n h e r r rc:tention comparisons are made ture, corbic ture, corhic tion, ture. corhic tion, \ ariPt\ % acida % acida xb FcC ' c acida3d ';b3d (Table I I I ) , only those ascorbic acid value5 from ti13r1t5 21.9 80 3 81 9 13.9 82.8 69 1 15.i 62 U t hc 2-minute blanch are used t o determino averages. Teton 78 3 16.6 78.5 11.0 71,4 79.5 11.6 81.8 Shasta 22.5 80.4 77.3 80 3 61.1 82.2 15.1 13.7 EFFECTOF VARIE.TY. Table I11 shovis varietai Thomas Laxtori 18.6 10.5 55.8 83. I 12.7 81.0 78 1 81 3 differciirt~sin ascorbic acid in frozen and i n canned Canner King 20.7 13 4 78.2 79 49.0 82.i i6.2 10 9 Pride 26.8 82 , 13.1 46.1 17.6 72 3 81.3 84.3 sample: after 6-month storage. The data are prrEarly Harvest 78 5 17.6 55.2 74.2 15.9 91 T 11.6 78.8 Dark Podded on both wet and nioisturc-free bases, anti wnted T h o n i . i s 1,axton 81.0 23.8 83.0 12.3 SS.:i X4 7 14. I i5.l thr total solids may be deterniined from the moisMean retention, < ! 58.4 i!, 0 ture percent>ages. The retention \vas detcrmined on " LIiIligraius per 100 grams wet weight the moisture-free basis of the original asrorhic. firid b Calculated on moisture-free hasis. iwntent of the raw product. C Drained peas. d Pea> and liquor. The retention of ascorbic acid after 6-month frozen storage varied from 46.1% for Pridr t o 71.47, for Tcton, wiih a n average for the eight varieties of 58.497,. The retention in the drained canned pras after the same storage period varied from 41.0% for Pride t,ct Ascorbic Acid Carotene Thiamine, &lois- Mg.,/lOO G . Mg./lOO G. Jlg., 100 G ~53.4% for Teton, with a n average of 47.4. The total retentu1.e. Wet Dry \Vet Dry Wet Dry tion of the canned peas (drained peas plus liquor) varird t'roni L'raatlueut c; wt. wt. nt. \VI. at. at. 72.370 for Pride to 91.770 for Early Harvest,, with a n average or Frehh, unblariched 8 1 . 0 2 3 . 5 123.4 0 317 1 668 Frozen, 6 mo. 8 3 . 0 12 5 7 3 . 2 o 378 i . n x n 1 8 4 I 0x2 79.0. Glarier, cont,aining a high level of ascorbic acid, anti Frozen, cooked (pea* and liquor) 73 6 10 7 64.9 Tetoii, a niedium level variety, had high retention in the frozerl Canned, 6 mo. (peas stat(,. K i t h one exception those varieties which had a high and liquor) 84 ; 1 4 . I 92 8 0 . 3 3 3 I MI II ltik I 09s level in thc: frozen peas likewise, hati a high level in t,he canrie(i Canned, cooked (peas and liquor) RR 6 11 .(i 72 0 product. Ilehydrated, 6 nio EFFLCT08' PHOCESSING METHOD. Ascorbic acid \va\ detrrAir pack . i . 7 20.5 2 2 0 1.582 I 68 0 750 0 , i N COSpack 5.6 25.3 26.8 0 825 0 874 mined iii frozen, canned, and dehydrated samples of Dark Poddrd Vacuum pack . 5 6 23.8 25.2 0 658 0 697 Thomas Laxton after 6 months. Analyses were made oii the Dehydrated, cooked Air pack (total) 68.2 7 0 21.1 processed producks hrfore and after cooking, with the liquor and COz pack (total) 65.9 7.1 20.2 Vacuum pack (total, ti9 1 7 6 23 , llrained peas analyzed separately in each instance. The dehp(hated material included samples packed in air, in carbon dioxide, ,. and under vacuim (Table IV), 1 A B I X V. ISFI.IESCL OF I,ES(;TH OF S m t u ( ; E o x \.-t,oBBii The canned peas before additional heating had a higher a+ .Arm ('OSTI:YT OF FROZE D T).ARK t'oDni.:n THOIT 4. wrbic content (14.1 mg. per 100 grams) when both drained peas and liquor were included than the uncooked frozen peas (12.5 Ascorbic Acid, Llg, per 100 Graiii5 . _ _ _ _ ~ ~ 6-month storage 9-month storage mg. per 100 grams). The canned peas and liquor contained Wet Drv E-~~ _D_ r y_ _ ~ about 75% of the original ascorbic acid content aftcr 6-nionth wt. u-t. Wl, at. storage, expressed on a moisture-free basis. The frozen peas Frozen, uusooked" 12 5 73.2 y 89 .53 78 Frozen, cookedb 10.7 R4.9 , .os1 :33.34 contained about 60% of the original content. Part of the differCanned, uncookedh 14,i 92.8 11.2; 67.80 ence, on the dry weight, basis, ran be ascribed to loss of soluble Canned, cookedb,' 11.9 72.0 9 19 tjI 7ii solids in the canned peas. The ascorbic acid cont,eiit of the (original freqli ~ e a sW ' R E Xw P t #rid I23.4drv basis. The authors wish to point out that the ascorbic acid figures b Drained peas and liquor. presented should not be used by biochemists or nutritionist? as Boiled for 2 minutes. measures of biologically active vitamin C, as dehydroascorbir acid was not determined. Hotwver, previous work indicat,ed the value of using ascorbic acid to measure the influence of certain handling and storage methods on the deterioration of quality. ret'erition wlieii the blanching tinie was ext eiided beyond 2 The dehydrated peas stored under carbon dioxide had a slightly minut,es. The 3-minute steam hlanrh was approxiniat.ely equal higher retention t,lian those stored under vacuum and a signifit O t,he 2.5-minut,ewater blanch. cantly higher retention than those stored in air in tin cans. Ascorbic acid determinations on the frozeii product aft ur 6Ascorbic acid levels in the dehydrated lots amounted to ahout iiionth storage have shown that the effect of blanching time 207, of the original content. varies with pea varicty (Table 11). Thus, the 2-minute blanch Tht: frozen, canned, and dehydrated samples were cooked t o was optimum for Dark Podded Thomas Laxton and Teton; serve by recommended methods in order to compare the final the 1-minute blanch was optimum for Canner King, Shasta, nutrient levels in lots of peas processed by t,he several procedures. and N o . 312. The 3-minute blanch appeared to be optimum for Retention was determined on the dry basis, using thc dry &-eight Thomas Laxton and Early Harvest, although the significance of of the cooked drained product in each case. If the weight's of the these differences in ascorbic acid may be unimportant. T h e fact uncooked product had been used, the results in case of the frozen that the sinkers in a 13'% brine showed more retention of ascorbic peas would have been approximatcly 15% loiver because of difacid after t,he 3-minute blanch subst,ant,iatesthe genrral belief ferences in moisture content. Direct comparison of the cooked that more mature peas require longer blanch. frozen and cooked canned peas shows a slightly higher ascorbir There is a tendency among commercial packers LO shurten acid cont,ent in the canned product on both fresh and moistureblanching times in a n effort to improve quality of frozen vegefree bases. The cooked dehydrated samples contained approxitables. I n some cases overblanching has resulted in products of mately one t,hird as much ascorbic acid as the cooked frozeii or poorer qualit,y, but t,hese data illustrate the fallary of using the canned products. These results are somewhat at variance with riiinimum blanch for products which are to be stored for any length of time. The data on varieties also show that therc, are those of Farrell a n d Fellers ( 4 ) on snap beans. HnwwPr, thry
T ~ H LTII. F , XSCORBIVACID IS EIGHTVARIETIESOF STORAGE
€'EAS AFTER
6-~~OSrl'H
~
'
.
lune,
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INDUSTRIAL AND ENGINEERING CHEMISTRY
1946
l i d riot compare samples prepared from the sanie lot of beans grown under t h e same conditronq and harvestpd at the same rime. EFFECTOF STORAGE PERIOD -4lthough most of the data reported here are for a 6-month storage period, a few samples of 'rozen and canned peas were analyzed for ascorbic acid a t the end of 9 months. Table V shows a continued loss of ascorbic w i d during the additional 3 months of storage in hoth frozen snd canned samples.
and canned samples was about, the same or slightly above 1.0 mg. per 100 grams (moisture-free basis) T h e thiamine level of the dehydrated samples was 0.87 mg. for the carbon dioxide pack, 0.76 mg. for the air pack, and 0.70 mg. for the vacuum pack. The original tliiaminr rontent of tho fresh peas waq 1.67 mg. per 100 grams. LITER4TUHE CITEI) I I)
(2)
CAROTERE 4 \ D T H I A I l I 3 E
l'able IF' sho4s the carotene and thiamine contents of cwtaln or the samples. Unfortunately the original carotene content of *he fresh peas was not obtaincd. Analyses after 6-month storagr ,f the frozen, canned, and dehydrated products gave carotene wntents of 1.98, 1.80, and 1 68 mg. per 100 grams, respectively, )ri a rnolsturp-free basis Thr thiamrnr content of the frozen
13) 14)
(5)
Bessey, 0 . .i.. and King, C. G.. b. B i d . (,'hem.. 103, 687-98 (1933). Clifcorn, L. E., and Heherlein, D. G.. ISD. ENG. CHEM..36, 168 (1944). Conner, I
