INDUSTRIAL A S D EIVGIiYEERILVGCHEMISTRY
648
T’ol. 20, S o . 6
Biological Values of Certain Types of Sea Foods’ 111-Vitamins in Clams D. Breese Jones, E. M. Nelson, and J. C. Murphy, with the cooperation of J. P. Devine BUREAU OB CHEMISTRY A N D SOILS, WASHINGTON, D . C.
ECAUSE of the meager information on the nutritive found devoid of vitamin B. The soft-shell clams, however, value of sea food, particularly that of shell fish, this proved to be a somewhat better source of vitamin A. No laboratory has been engaged in a study of the vitamin detectable difference in the antirachitic properties of the two distribution and nutritive value of the proteins of some of species was observed. the more common types of this class of sea food. I n a preThe clams as fed contained 80 per cent moisture. Five vious publication2 it was shown that oysters are a good grams of the moist clams, the maximum daily quantity fed, source of vitamins A, B, and D, but are deficient in vitamin E. therefore corresponded to 1 gram of dry material. Con The article now presented deals with vitamins in clams. sidered on a dry basis, clams must be regarded a s a good Next to oysters, clams are the most important shell fish source of vitamins A and D, and compare favorably with of the American continent. The similarity in the diet of articles of food that are recognized as good sources of these ovsters and clams would lead one to expect a rather close vitamins. agreement in their vitamin E v i d e n c e has been recontent. The clam, like the cently adduced by several oyster, takes its food mei n v e s t i g a t o r s indicating Feeding experiments with albino rats showed that that vitamin B as formerly chanically from the constant clams are a good source of vitamins A and D. regarded is a complex coninflow of sea water. Minute Two species of clams were used, Venus mercenaria, sisting of two factors.4 One plant and animal organisms, commonly known as “hard-shell clams” or “quais definitely antineuritic and particularly diatoms, conhaugs,” and M y a arenaria, commonly called “softcan be destroyed by heat. stitute their chief article of shellf clams.” Both species contain little, if any, The other, muchmore stable food.3 Although both oysvitamin:B. Soft-shell clams were found to be a someto heat, is not antineuritic ters and clams were found to what better source of vitamin A. No difference was but is essential be good sources of vitamins for growth observediwith respect to vitamin D. and maintenance of body A and D, one striking differFive grams daily of soft-shell clams, equivalent to weights, and is probably the ence between them was dis1 gram of dry material, are sufficient for the cure and same as the factor required covered. Unlike oysters, a prevention of xerophthalmia. Somewhat more of for the prevention and cure good source of vitamin B, hard-shell clams is required. of pellagra. clams were found to be deFive grams of either species given daily to rachitic I n a s m u c h as the work void of this vitamin. Tests rats induced complete calcification in the small bones described in this paper was c o n d u c t e d on samples of in 15 days. The rate of calcification was not appreciwell under way before most clams obtained from differably influenced by the ash constituents of the clam. of the publications on the ent places and at different Compared with oysters, which are rich in vitamin B, multiple nature of vitamin seasons, and also on differclams are practically devoid of this vitamin. As a B had appeared, the term ent species, gave invariably source of vitamin A clams are somewhat inferior to “vitamin B” has been used negative results. Rats that oysters, but they have more vitamin D, and are a better in the old sense to refer t o received daily 5 grams of Source of the factor, or factors, essential for reproduct h e v i t a m i n B complex. fresh clams in addition to tion and rearing of young. The desirability of having the basal diet declined in t h e r e s u l t s of work with weight and died about as clams as c o m p a r a b l e a s soon as a n i m a l s t h a t repossible with those previously obtained with oysters also ceived no vitamin B in their diet. As a source of vitamin A, clams are somewhat inferior to necessitated following the same technic. Although no atoysters. On the other hand, clams have more pronounced tempt was made to differentiate the two factors of the vitaantirachitic properties, and are a better source of the factor, min B complex, the results of the experiments show clearly or factors, essential for reproduction and rearing of young. that clams contain little, or none, of the antineuritic Two species of clams were used--S’enus mercenaria, com- factor. monly known as “hard-shell clams” or “quahaugs,” and Vitamin B M y a arenaria, commonly called “soft-shell clams,” “soft clams,” or ‘[sand clams.,’ South of New York the common HARD-SHELL CLAMSOR QUAHAUGS-In general, the same species is the quahaug, but north of Boston the soft clam is methods were followed that were used in studying the vitathe most common. Between New York and Boston these two mins of oysters.2 For the tests conducted by the curative species are about equally abundant The quahaugs were method, young albino rats from our stock colony, weighing purchased in the Washington market and had been collected about 50 grams, were placed in separate cages having raised from the lower Potomac region. The soft clams were col- screen bottoms. and were fed the vitamin-B-free diet inlected from the Maine coast, and shipped from Pine Point, Me. dicated in Chart I. Osborne and Mendel’s salt mixture No striking difference in vitamin content between the hard- was used. At the end of about 3 weeks, after a decided deshell clams and the soft-shell clams was noted. Both were 4 Salmon, J . Bid. Chem., 73, 485 (1927); Sherman and Axtmayer,
B
Received March 10,1928. Jones, Murphy, and Nelson, IND.ENG.CHBM.,20, 205 (1928). Stafford, Sessional Pafie7 22a (1902), Supplement to 32nd Annual Report of Dept. of Marine and Fisheries, Canada. 1
p
I b i d . , 76, 207 (1927); Chick and Roscoe, Biochem. J., 21, 698 (1927): Goldberger and Associates, U.S. Pub. Health Repts. 41,297,1025 (1926); Hauge and Carrick, J . B i d . Chem , 69, 403 (1926); Smith and Hendrick, U. S . Pub. Health Repts. 41, 201 (1926).
June, 1928
I S D U S T R I A L A S D Eil’GIil’EERISG CHEMISTRY
cline in weight, Tveighed quantities of the clams v-ere fed daily apart from the basal diet. RAW, FROZEN C ~ a ~ s - F o rthe preparation and handling of the material to be tested, the method used in the studies on vitamins in oysters was found so satisfactory that it was used again in the study of clams. The meats of fresh clams were frozen in a low-temperature room, finely ground, and the quantities to be fed daily were weighed in the frozen condition. In this way the material could be kept throughout the period of experimentation without deterioration, and a homogeneous product obtained, uniform samples of which could readily be weighed in the quantities desired for the daily feeding. The first lot of rats used for these tests were given 2 grams daily of the frozen clams, Fed a t this level, the clams showed no indications of the presence of vitamin B. After a short initial growth response the rats rapidly declined in weight, and all died in about 3 weeks with severe polyneuritis. In Chart I, Lots I and 11,are shown the results of increasing the quantity of clams fed t o 5 grams. The rats of this lot were fed the basal vitamin-B-free diet up to the point indicated by the broken lines. I n all cases there was a short growth response a t the start, but this was followed by a rapid decline in weight, terminating in polyneuritis and death within an average of 1z1/*days. Difficulty was encountered in getting the rats to eat all the clam portions given them. Many of the rats on Lots I and I1 ate only one-half to two-thirds of the daily doses. However, the results of the tests were so uniform that there can be no question that the clams fed were practically devoid of vitamin B. Rat 2574, for instance, ate the full quantity of clam given, but fared no better than the others that ate less. The contrast between the vitamin-B content of oysters and clams is clearly demonstrated in the case of rat 2754, Lot 11. Five grams of clams given this rat daily did not prevent a rapid decline in weight or the development of polyneuritis. After 12 days the 5 grams of clams were substituted by 2 grams of oysters. The polyneuritis was promptly cured, the decline in weight arrested, and the animal gained 13 grams in 15 days. The clams fed rats of Lot I were purchased in February, and those used for Lot I1 were obtained in January. Cooked Clanis (Chart I, Lot 111). I n view of the unsatisfactory consuniption of the raw, frozen clams, it was thought that better results might be obtained if the clams were cooked. Accordingly, a quantity of quahaugs in closed jars were heated for 30 minutes in boiling water. The product was then frozen and handled as already described. The consumption of the cooked clams vias not much better than that of the raw, and the results obtained were practically identical with those obtained with rats of Lots I and I1 that had received the raw material. Desiccated Clams (Chart I, Lot IV). As another recourse to obtain the desired daily intake of clams, dry. desiccated quahaugs were mixed with the basal diet in the proportion of 20 to 80 parts, respectively. This proportion was calculated on the basis of the average daily food intake of rats on the basal diet, so that the mixture consumed daily would include a quantity of the desiccated clams equivalent to 5 grams of the raw, frozen material. The actual intake of this mixture was such that the rats received close to an equivalent of 5 grams of fresh clams daily. I n order to avoid any possible deterioration of material during desiccation, ground, frozen clams were allowed to stand over phosphorus pentoxide a t 0” to - 10” C. in an evacuated (14 to 17 mm.) desiccator until thoroughly dry. The product was then ground to a fine meal. At the end of the preliminary period on the basal vitaminB-free diet, the rats were given the mixed diet containing the
649
desiccated clams. Again the results showed no evidence of vitamin B. These results obtained by the curative method were confirmed by prophylactic tests. (Chart 11, Lot 11) The mixture of basal diet and desiccated clams, as above described, was fed from the beginning. With the exception of a better rate of growth during the first 2 weeks, the results obtained were almost identical with those of control tests using the vitamin-B-free basal diet alone. SOFT-SHELLCLAMS(Chart 11, Lot 1)-Prophylactic tests showed that soft-shell clams were also devoid of vitamin B. I n these tests 5 grams of the frozen product were fed daily apart from the basal diet to young rats weighing about 50 grams. The animals all developed polyneuritis about as soon as controls on the vitamin-B-free basal ration. Rats 2968 and 2971 ate all the clams given them, but the other two ate only about two-thirds of their portions. Vitamin A
For estimating vitamin A the efficacy of clams both for preventing and curirg xerophthalmia were studied. In the curative tests albino rats averaging 48 grams in weight and 25 days of age were fed the b a d \itamin-A-free diet until definite indications of xerophthalmia were manifest. The composition of the basal diet is shown in Chart 111. Weighed quantities of frozen clams were then given daily. apart from the basal diet, and the curatire effect was noted. In contrast to the experience in the vitamin B studies, the
H
H
CURATIVE TESTS FOR VITAMIN B IN HARD SHELL CLAMS LOT I 5 GMS RAW C L A M S
60
50 40
30
60
f
50
2 40 w
_-
_In
z
LOTIO
--I
1
LOTE!
5 GMS C O O K E D C L A M S
5 G M 5 RAW D E S I C C A T E D C L A M S
1
50 BASAL
DIET
CASEIN (8-FREE) SALTS BUTTER FAT CORN STARCH
20 5 I5 100
NOTE THE DOTTED LINE ON THE GROWTH CURVES INDICATESTHE END OF THE PRELIMINARY PERIOD ON THE BASAL DIET. AND THE POINT AT WHICH THE CLAMS WERE FIRST FED
I
INDUSTRIAL A N D ENGINEERING CHEMISTRY
650
Table I-Vitamin GAIN
Grams
Grams
Grams
Grams
CLAM WAS GIVEN Days
1 1 1 1
113 105 100 82
110 75 117 127
-3 30
49 7
2 2 2 2
107 170 115 188
131 185 120 155
3.5 3.5 3.5 3.5
120 126 85 101
5 5 5 5
3036 d 3037 67 3038 a’ 3039 9 Lot V I 2891 Q 2892 0 0 The rats A !Ithe animals
Lot I 3040 0 3041 0 3042 P 3043 0 Lot I1 3003 Q 3004 d 3005 Q 3006 d Lot 111 3071 d 3072 a’ 3073 d 3075 3 Lot I V 3068 Q 3069 d 3070 a’ 3074 d
Lot
v
A [Curative T e s t ) =
TIME
CLAM W E I G H T WHEN GIVEN CLAM FINAL DAILY FIRSTGIVEN WEIGHT
RAT
5’01. 20, KO. G
EFFECTON
CURATIVE
XEROPHTHALMIC
RATS
HARD-SHELL CLAMS
-
Xerophthalmia gradually became worse Animal died on 7th day after clam was first fed
17 45
g j 1
24 15 5 33
39 39 39 39
N o improvement in condition of the eyes; respiratory infection developed
154 176 131 134
34 50 46 33
35 35
Nearly cured in 17 days then became gradually worse Improved during first 14 days, then became worse Condition of eyes gradually improved
113 99 138 75
186 237 257 219
73 138 119 144
3.5 3.5 3.5
148 160 144
176 173 174
28 13 30
32 32
3.5
159
166
7
35
-
E: 1 84
Xerophthalmia gradually became worse Xerophthalmia gradually became worse, followed by slight improvement Condition slightly improved: respiratory trouble Left eye became keratinized; decided improvement in condition of right eye: animal died in 39 days
All these animals showed a definite cure a t some stage of experiment, but in all cases there was a slight recurrence of xerophthalmia
SOFT-SHELL CLAMS
35
Eyes practically healed No appreciable improvements in condition of eyes became someXerophthalmia had disappeared by 21st day; subsequently . eyes . what inflamed Left eye healed completely, and condition of right eye was improved ~~
104 160 56 Rapid improvement and complete healing of eyes 150 38 112 were given basal vitamin-A-free diet until well-defined xerophthalmia had developed. Weighed quantities of clams were then given daily. except those of Lot V I were irradiated for 10 minutes weekly. 5
5
2’; ]
HARD-SHELL CLAMS(&UAHAUGS)-In the curative tests the clams were fed at four different levels of intake-namely, 1, 2, 3.5, and 5 grams. The results of these tests are summarized in Table I. One gram of clams daily had no apparent effect on the progress of xerophthalmia. The disease gradually became worse u p to the end of the experiment. The rats of Lot 11, receiving 2 grams of clams, showed some improvement in the condition of their eyes; 3.5 grams of clams produced a marked improvement but in no case effected a cure. The results obtained with Lot IV rats that received 5 grams indicate that this quantity, although sufficient to bring about a temporary cure of xerophthalmia, was not enough to prevent slight recurrences of the disease. This quantity is, however, very near the minimum daily quantity of hard-shell clams required for the complete and permanent cure of xerophthalmia in rats. Chart I11 shows the results of prophylactic tests in which 2 grams of hard-shell clams were fed from the beginning of the experiment. For each of the rats used a litter mate of the same sex was selected as a control. Both the experimental and control animals were irradiated from the start. Two of the controls showed the first definite symptoms of serophthalmia in 28 days, and the other two in 31 days. The four animals receiving 2 grams of clams first showed xerophthalmia in 38, 38, 42, and 45 days, respectively. This quantity of clams given daily was therefore effective in delaying the onset of xerophthalmia for an average of 11days. Inasmuch as all the animals were irradiated, the difference in the rate of growth of the rats receiving clams as compared with the controls can also be used as a criterion to show the quantity of vitamin A present, I n all cases xerophthalmia appeared while the animals were still growing a t a fair rate. SOFT-SHELLCLAMS-Daily curative doses of 3.5 grams of soft-shell clams produced in all cases a rapid improvement in the condition of the eyes of xerophthalmic rats, resulting in some cases in almost complete healing. When fed on a 5-gram level the rats were entirely cured of xerophthalmia. The results are summarized in Table I. The results obtained in these curative tests for vitamin A indicate that soft-shell clams are a somewhat better source of this vitamin than hard-shell clams.
Vitamin D
The antirachitic property of clams, both of the hard-shell and the soft-shell variety, was determined by the so-called line test method.6 The general procedure folIowed was the same as that described in the paper on vitamins in oysters.2 Young rats were brought to a rachitic condition by feeding consisting them for 3 weeks Steenbock’s rachitic ration 29566~~ of yellow corn 76 parts, wheat gluten 20 parts, calcium carbonate 3 parts, and sodium chloride 1part. Five grams of frozen clams were then given daily for definite periods, and the degree of calcification induced in the radii or ulnae of the rachitic animals observed. Examination of the bones of control animals that had received the rachitic diet showed entire absence of calcification in the zone of proliferation. Five grams of hard-shell clams given daily for 10 days induced about half calcification of the rachitic metaphyses. The same quantity in 15 days brought about almost complete calcification. Almost identical results Fere obtained with soft-shell clams. Table 11-Vitamin D i n Clams. Effectiveness of Clams in Inducing Calcification in Bones of Rachitic Rats (5 grams of clams given daily) TIMEGIVEN DZOREEOF CALCIFIC4TION OF CLAMS RACHITICMETAPHYSES RAT
Days 2798 3 2845 0 2846 0 2847 8 2848 d 2853 0 2854 3 2855 Q 2856 d
HARD-SHELL CLAMS
10 10
10
15
15
About 50 per cent Slightly calcified-less About 75 per cent About 90 per cent
than half
Complete SOFT-SHELL CLAMS
2920 Q 2921 d 2922 0 2923 8
Complete 15
About 75 per cent
The results of these tests are given in Table 11. Compared with the results obtained in the same manner with oysters, it apears that clams are superior to oysters as a source of vitamin D. The same degree of calcification was induced 6
McCollum, Simmonds, Shipley, and Park, J . B d . Chem., 51, 41
(1922). 6
7
Steenbock and Black, Ibid., 64, 263 (1925). Nelson and Steenbock, Ibid., 64, 299 (1925).
I S D U S T R I A L A S D ESGI.l%ERI.YG CHEMISTRY
June, 1928
in 10 days by 5-gram daily doses of clams, that required 15 days with the same quantity of oysters. EFFECTOF FEEDIXG ASH OF CLAMSox CALCIFICATIOSInasmuch as clams contain a considerable quantity of phosphorus, the calcifying property of clams as found in these teats might be ascribed, a t least in part, to a possible alteration of the calcium-phosphorus ratio due t o the phosphorus in the PROPHYLACTIC TESTS FOR VITAMIN B IN CLAMS SOFT SHELL CLAMS (P- POLYNEURITIS)
BO 70 60
m I50
5
40
I
1
LOT U HARD SHELL C L A M S
, LOT I CASKIN (B-FREE) SALTS 1p BUTTER FAT CORN STARCH 5 C M I HAW 53FT SHELL CLAM DAILY
I
I
r
,
LOT
i
I
U
PO LOT I DlCT 80 DCSICCATED HARD SHELL C L A M S 100
5 I 5
0 100
C h a r t I1
ingested clams rather than to vitamin D. I n order to throw light on this question, the effect of feeding rachitic rats the ash obtained by incinerating clams was studied. Young rats were brought to a rachitic condition by feeding them the basal rachitic diet for 3 weeks. Their ration was then changed to a mixture consisting of 700 grams of the basal diet and the ash obtained from 500 grams of clams. This proportion of ash to basal diet was calculated so that with a daily food intake of 7 grams each animal 7%-ouldreceive the mineral equh alent of 5 grams of fresh clams. I n fact, the actual food intake of the rats receiving the mixture closely approximated 7 grams daily. The experimental ration was fed over periods of 10, 15, and 20 days. The results given in Table I11 show that the calcifying effect of the ash as fed in these experiments is practically negligible as compared with that noted when 5 grams of frozen clams mere fed. The results obtained with the frozen clams must then be ascribed to vitamin D, and not to the effect of the superimposed phosphorus contained in the clams. T a b l e 111-Effect
TIWE
RAT
GIVES ASH DIET
Days
of F e e d i n g A s h of Clams on Calcification in B o n e s of R a c h i t i c R a t s ASH
AVERAGEEQUIVALENT DAILY IN T E R M S FOOD OF FRESHD E G R E G OF CALCIFICATIOX OF INTAKE CLAYS RACHITICI d E T A P H Y S E S
Grams
651
and immersed in boiling water for about 15 minutes. I t had been found that by first cooking the clams the process of +atisfactorily drying and grinding them was much facilitated. They were then coarsely ground in a meat chopper and dried in a current of air at 70" to 80" C. The dry product was ground to a fine meal and incorporated in the diet. The clam meal contained 59.8 per cent of protein ( N X 6 25). The diet as fed had the following composition: clam meal 30.1 parts, salt mixture 5 parts, Crisco 20 parts. and cornstarch 44.9 parts. Cod-liver oil (4.3 parts) and yeast (5.7 parts) were incorporated in the diet to furnish vitamins A, B, and D. The feeding experiments were carried out through two generations of rats. Normal, healthy, young albino rats from the stock colony, about 4 weeks old and weighing, for the greater part, from 50 to 60 grams, were grouped in two cages. From this time to the termination of the experiments with the second-generation rats the animals received only the experimental clam diet. Each cage contained two males and five females. As soon as the females were observed to be pregnant they were segregated and placed in individual cages. The young were allowed to remain with their mothers until they weighed from 40 to 50 grams and it was certain that they could be reared alone. The mothers were then returned t o the group cages, and handled, together with their successive litters, as just described. Sel-en of the young females and two males were selected from two litters of different mothers for the second-generation experiments. As soon as they were removed from their mothers the males and females were placed in separate cages and allowed to grow on the clam diet until they m-ere 74 days old, when they were all grouped together in one cage. Thenceforth the experimental procedure was the same as that described in the case of the first-generatioq rats. The rate of growth of both first- and second-generation rats was quite satisfactory. The average weight of the four first-generation males a t the end of 192 days on the experimental diet was 326 grams, and that of the secondgeneration males a t the end of 130 days \vas 304 grams.
I 1 '
~
VITAMIN A IN HARD SHELL CLAMS PROPHYLACTIC TESTS 2 GRAMS CLAM GIVEN DAILY
200 I80 160 140
2 120 4
KIOO 80
60 40
Grams
HARD-SHELL CLAMS
3045 3046 3047 3048
10 10 15 15
5.4 6.4 7.7 7 3
3040
20 20
7 5 10.1
3050
::E;} 5.50 5.21
::;:\
No trace of healing in radius T w o small spots Calcification irregular a n d sparse in about one-half of t h e metaphyses No trace of healing in radius
Reproduction and Rearing of Young Hard-shell clams were used to test for the factor or factors that influence reproduction and lactation. Fresh clams were drained to remove most of the liquor
C h a r t 111
The first-generation females in Group I (Table IV) had 12 litters comprising a total of 63 young, 19 of which were reared. Much better results were obtained with the rata in Group 11. Fourteen litters were produced in this group with a total young of 107, 81 of which were reared. Of the total young in both groups that were selected 61 per cent was reared. If we leave out of consideration rat 2939. which did not rear any of her young, the average per cent reared by the other four females of Group I1 is 79. The exact reproduction period in the case of the first-generation rats is not definitely known. because the males and females were grouped together as soon as they mere weaned.
INDUSTRIAL A S D ESGIXEERING CHEMISTRY
652
Table IV-Efficacy of 30 Parts of C l a m Meal in D i e t for Reproduction a n d Rearing of Y o u n g w i t h First-Generation R a t s DURATION OF NUMBER YOUNG INITIALFINAL EXPERI- OF YOUNG SE- YOUNG RAT WEIGHT WEIGHT MENT LITTERSBORNLECTED REARED Grams Grams Days GROUP 1
2930 c 3 2931 3 2932 0 2933 Q 2934 0 2935 0 2936 0
60 62 63 63 59 56 52
288 412 250 269 266 264 234
29373 29383 29390 2940 0 2941 0 2942 P 2943 0
55 46 55 56 52 60 44
338 268 322 232 261 242 216
192 192 192 192 192 210 192
18 1g 19 11
18 1: 19 11
6
3
0 10 0
G R O U P I1
170 170 156 184 195 188 174
vel. 20, KO.6
Table V-Efficacy of 30 Parts of C l a m Meal in t h e Diet for Reproduction a n d Rearing of Young w i t h Second-Generation Rats (Age of rats when mated, 74 days) WEIGHT REPRO-NUMBER WHEN FINAL DUCTION OF YOUNG YOUNGYOUNG RAT M A T E D WEIGHT PERIOD’ LITTERSB O R N SELECTED REARED Grams Grams Daw 3067 3 214 271 3058 3 253 338 3069 Q 164 210 49 17 17 9 .?Ofin Q 152 220 91 19 19 19 5oSi h 148 210 52 6 6 0 3062 Q 165 200 73 14 14 12 3063 0 146 200 66 16 16 16 3064 0 153 84 208 22 17 16 3065 Q 140 15 198 91 17 17 ~.
-
TOTAL
2 3 3 3 3
10
27 29 24 17
-
-
TOTAL26
170
10 26 26 24 17
-
166
-
0 20 25 23 13 100
R‘ith the second-generation rats better results were obtained (Table V). The seven females delivered 14 litters comprising 111 young. Of the young selected 82 per cent were reared. Most of the young were hea!thy, vigorous animals. The experiments were terminated as soon as the young of the second litters were weaned. The reproduction period was therefore somewhat shorter than that of the first-generation rats.
-
-
-
14
111 106 87 a Covering period from time females were first mated up t o time they were segregated before delivery of their last litter.
Although the character of the basal diet in these experiments may be questioned, it is believed that the degree of success in reproduction and rearing of the young is t o be ascribed to the presence in the clams of the dietary factors influencing these functions. This conclusion is supported by the fact that in the previous work with oysters, in which the same basal diet was used, very different results were obtained. With the first-generation females on the oyster diet only 14 per cent of the young were reared. Six eecondgeneration females produced only 2 litters comprising 6 young, none of which was reared.
Tallowiness or Rancidity in Grain Products’ M . S. Fine and A. G. Olsen POSTUM COMPANY, INCORPORATED, BATTLECREEK,MICH.
The development of tallowy odors in grain products or lower moisture contents, lies ANY materials conundoubtedly in the fact that in taining even small can be delayed for long periods of time by appropriate p e r c e n t a g e s of fat control of the moisture content. In samples having ~ ~ $ o , ~ ~ ~~ undergo during storage cermoisture contents of 2 per cent or less, tallowy odors a l d e h y d e stage,while when tain changes which give rise to developed relatively quickly. Moisture contents of moisture is present it proceeds approximately 5 per cent were found to be protective. directly to the acid stage, thus odors described as “tallowy” or “rancid.” Referring to the This protective effect became more pronounced as the confusion which has attended moisture content increased. Samples of 10 to 12 per the other by-products, the use of these terms, Holm cent moisture after about three years’ storage are still and Greenbank2 state: “It free from any apparent tendency toward tallowiness. Anderegg and Nelson4 reSuitable addition of moisture can also exert a “curaported observations on codis generally agreed, however, tive” effect in samples of initially low moisture which liver oil which are in harmony that the term ‘rancid’ should be a p p l i e d t o h y d r o l y t i c have developed tallowiness. Glycerol in concentrawith t h o s e of H o l m a n d tions of 0.25 to 0.5 per cent also was found to postpone G r e e n b a n k . They noted changes only, while the term for long periods the development of tallowiness. that mixtures of cod-liver oil ‘ t a l l o w y ’ s h o u l d be used with such materials as milk where other changes are the cause of the off odor and flavor, excluding fishiness.” I n powder, starch, and dextrin developed pungent odors, which accordance with this viewpoint the odor changes which occur could be avoided by the addition of 95 per cent alcohol, in grain products may be properly described as “tallowy” wheat-embryo oil, and water, these substances being increasingly protective in the order mentioned. It was noted, and this plan is followed in the present paper. I n connection with their studies on the keeping quality for example, that with 10 per cent added water the previof butter fat and milk powders, Holm and Greenbank ob- ously described decomposition of the oil did not occur served that the presence of water retards the development even after several months, although mustiness and disof tallowy odors. They reported, for example, that for the coloration developed. Their studies disclose a relationship keeping quality of drum-dried and spray-dried milk powders between the state of fat preservation and the nutritional moisture contents of 2 and 3 per cent, respectively, were opti- value of an experimental ration containing the fat. Thus mum. This is opposed to the common viewpoint that mois- they observed that the mere addition of water to the ration, ture favors the development of tallowy odors. I n discussing bringing the moisture content to 5 per cent, not only delayed autoxidation and the influence of moisture in this reaction, decompositional changes but also made the ration capable Greenbank and Holm3 state: of supporting reproduction and lactation. In short, the presence or absence of suitable moisture content determined humidities, The explanation for the greater tallowiness at whether or not the ration displayed the characteristics com1 Received January 20, 1928. monly ascribed to a vitamin-E-bearing ration.
M
k iz
~
~
~~~~~
2
8
Proc. Worlds Dairy Congress, 2, 1263 (1923). INU.END.CHEW.,16, 598 (1924).
4
I N D ENG.CHEM.,18, 620 (1926).
