r//>^ 014 338 739 2 9 558 8 C3 py 1 )ME NUTRITIVE PROPERTIES OF NUTS; THEIR PROTEINS AND CONTENT OF WATER- SOLUBLE VITAMINE <> " 3C 1 pTa. cajori (From the Sheffield Laboratory of Physiological Chemistry, Yale University, New Haven) Reprinted from THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. XLIII, No. 2, September, 1920 Reprinted from The Journal of Biological Chemistry, Vol. XLIII, No. 2, 1920 SOME NUTRITIVE PROPERTIES OF NUTS; THEIR PROTEINS AND CONTENT OF WATER- SOLUBLE VITAMINE.* By F. a. CAJORI. {From the Sheffield Laboratory of Physiological Chemistry, Yale University, New Haven.) (Received for publication, June 25, 1920.) The extensive series of metabolism experiments on fruitarians and nutarians in California reported by Jaffa (1901, 1903) indi- cated that nuts used as a substantial component of the diet are quite thoroughly digested and are of a higher nutritive value than is popularly attributed to them. The same conclusion was reached by Cajori (1918) through digestion trials of raw and heated nuts, nut butters, and nut pastes. In his experiments the coefficient of digestibility for nut proteins and carbohydrates fell well within the range of the protein coefficient for a mixed diet. There was no indication that nuts are especially resistant to the digestive functions of the alimentarj^ canal; so that the conclusion seemed justified that nuts are valuable foods and, if eaten properly and used in the diet with due regard to their concentrated make-up, are on a physiological par with common staple articles of the diet. A more detailed investigation of the nutritive properties of nuts has, however, hitherto been wanting. The Nutritive Value of Nut Proteins. It is clearly recognized that individual proteins may vary greatly in the proportions of the various amino-acids which may be obtained from them and that their dietary value depends in * The data in this paper are taken from the dissertation presented by the writer for the degree of Doctor of Philosophy, Yale University, 1920. A part of the expense of the investigation was defrayed by a grant from the Russell H. Chittenden Research Fund for Physiological Chemistry. 583 THE JOURNAL Of B.OLOi;;CAL CHEMISTRY, VOL. XLIII, NO. 2 584 Nutritive Properties of Xuts large part on the character of this amino-acid yield. An appre- ciation of the significance of these nutritive differences is largely due to the extended studies of Osborne and Mendel and others, who have demonstrated in the case of the albino rat that the naturally occurring proteins differ widely in their efficienc}- for maintenance or growth. With reference to the chemical make-up of the proteins of nuts, Osborne and Clapp (1907, 1907-08) have studied the products of acid hydrolysis of amandin and excelsin, the principal proteins of the almond and Brazil nut, respectively. Osborne and Harris (1903, a, c, d) compared the distribution of basic amino-acid nitrogen in the globulins of the almond, Brazil nut, black walnut, English walnut, butternut, and filbert, and have shown that the Hopkins-Cole test for tryptophane is strongly positive with all these proteins. From the investigations of these authors, the black walnut, English walnut, and butternut would seem to contain very similar, if not identical, globulins as their principal proteins. The name juglansin has been given to this globulin of the juglans species of nut. Osborne and Harris (1903, b) found the only essential difference between corylin, the globulin from the filbert or hazel nut, and juglansin to be a higher content of anaide nitrogen in corylin and a difference in the specific rotation of the two proteins. Using Van Slyke's newer method for protein analysis, Nollau (1915) has analyzed the pecan nut, peanut, black walnut, and hick- ory; Johns and his collaborators (1917, 1919, a) applied the same method to a study of the globulins of the peanut and coconut. In all these studies, the relatively high content of basic amino-acids found and the presence of tryptophane suggest that these nuts are likely to be sources of complete protein. Speaking of the. peanut, Johns says: "the relative high percent- age of lysine in the proteins of the peanut indicates that this seed might be used to advantage in supplementing diets deficient in lysine." This conclusion, based on chemical analysis, that nut proteins are of a high biological value, has been verified by the feeding experiments of Johns and coworkers (1919, h) with the coconut, and Daniels and Loughlin (1918) with the peanut. These investigators observed normal growth in young rats on diets in which the coconut and peanut furnished the sole source of protein. Osborne and Mendel (1912) have maintained rats over long periods in which the protein of the dietarj' was derived from excelsin of the Brazil nut. Feeding Experiments with Rats. The experience of numerous investigators in experiments involving growth and maintenance has demonstrated the many advantages in the use of the rat as an experimental animal in nutrition studies. Gift University ^OV ; i 1820 F. A. Cajori 585 Following the general technique of Osborne and Mendel, as recently described by Ferry (1920), we have extended the feeding observations on nuts to include the almond, English walnut, filbert, pecan, and pine nut. Young rats were fed on diets complete in respect to every known dietar}^ essential for growth, provided the proteins were of a character to support growth. Nut proteins made up approximately 18 per cent of the diets. It is well recognized that rats will grow to adult size at a normal rate on this level of protein intake, if the protein is "complete" from a nutritive point of view; i.e., furnishes all the essential amino-acids in suitable amounts. There are not many nuts that contain over 3 per cent of nitro- gen. Therefore in order to prepare a diet containing 18 per cent of protein {e.g. 2,9 per cent N X 6.25) and still insure, in addition to the protein, the presence of adequate quantities of the recog- nized dietary essentials, fat-soluble and water-soluble vitamines and inorganic salts, concentration of the protein of certain of the nuts was necessa^3^ To effect this, the shelled nuts were passed through a meat grinder and then subjected to pressure in a tincture press. This process removed considerable quantities of oil from the nut, and nitrogen determinations of the residual press cake indicated that the protein content had been sufficiently increased to incorporate in the diet at the desired 18 per cent protein level. Charts 1 and 2 show the growth curves of albino rats on diets in which the essential source of protein was derived from nuts. At the time these experiments were inaugurated the presence of water-soluble vitamine in the nuts used had not been demon- strated. Dried brewer's yeast was added to the diets, to the extent of 2 per cent, to make sure that they contained adequate c}uantities of tliis dietary essential. The possibility of the sup- plementary action of the yeast in these diets must be recognized. Osborne and IVIendel (1919, a) found yeast to be adequate for growth when fed as the sole source of protein. However, the amount of protein derived from yeast fed in a concentration of 2 per cent and its supplementing action cannot be large. In Osborne and Mendel's successful experiments the dried yeast furnished 30 and 40 per cent of the total food intake. Neuberg ^lOUV) estimates that 52 per cent of yeast nitrogen is non-protein 586 Nutritive Properties of Nuts TABLE I. Weekly Food Consumption on Nui Diets. Almond. English walnut. Filbert. Pecan. Pine nut. Casein. Week. Average for Rats 10, 11. 12. Aver- age for Rats 13, 14, 15. Average for Rats 16, 17. Rat 30. Rat 31 Rat 32. Rat 33. Rat 7. Rats. gm. gm. gm. gm. gm. gm. gm. gm. gm 1 45 50 40 43 40 39 42 41 41 2 41 40 40 60 40 45 42 44 42 3 33 42 39 48 35 39 38 53 48 4 42 47 44 46 34 35 44 50 52 5 44 51 44 47 41 53 50 54 54 6 50 45 41 47 33 44 37 61 59 7 55 50 54 44 40 48 43 59 57 8 49 50 41 43 41 44 48 61 63 9 51 48 58 44 40 53 57 63 54 10 53 48 45 55 59 57 52 54 47 11 51 48 54 52 50 59 46 61 58 12 51 46 56 52 51 53 55 13 50 47 45 54 47 45 50 14 52 42 38 46 52 15 56 43 53 45 45 16 66 43 53 48 55 17 57 41 50 54 50 18 48 38 41 63 65 62 66 Rat 10. Rat 12 + young. Rat 16 + young. Rat 17. 19 65 68 37 41 20 50 76 69 31 65 55 21 49 60 69 41 60 50 22 49 49 60 40 68 59 23 45 49 65 41 65 53 24 61 61 85 42 63 54 25 54 62 98 77 45 26 84 91 80 27 104 46* 99 28 122 42 29 117 30 45* 31 44 Young removed. F. A. Cajori 587 nitrogen. If this estimation is correct, yeast proteins made up but 4 per cent of the total protein of our diets. Table I gives the weekly food consumption of the rats on the nut diets. The average normal intakes of animals of the same weight on a comparable casein diet are on record (Osborne and Mendel, 1915). The animals, as a rule, ate less of the nut food than did Osborne and Mendel's rats on the casein diet similar in composition to that from which their normal intake was calcu- lated. The nut foods, consisting of a large quantity of a fat-rich press cake probably were of a higher calorific value than the casein diet. This fact would explain these differences, as the quantity of food eaten by rats which limit their intake to their energy requirement is largely determined by the calorific value of the food. Examination of the growth curves shows that growth resulted at a normal rate on all diets except the one in which the pecan supplied the protein. The animals on this diet grew at a rate about two-thirds normal during the 9 weeks that they were on this diet. When casein was introduced into the pecan diet in such a waj^ that one-third of the pecan protein was replaced by casein, a marked rise in the rate of growth was noted. This increased growth may have been due either to a supplementing action of the casein or to an increased food intake resulting from some favorable modification in the taste or character of the pecan diet on addition of casein. More experiments are necessary before final conclusions can be drawn regarding the comparative efficiency of the proteins of the pecan. Growth of the second generation of young rats on the nut diets is shown in Chart 3. With the limited number of observations that we have recorded it is not possible to make numerical comparisons of different nut proteins, nor were our experiments planned to demonstrate the maximum gro\\i:h-promoting power of nut proteins. But, accepting the opinion of Osborne and Mendel (1920, a), ". . . . that if an animal is able to attain adult size upon a diet which furnishes protein from a single source, the nutritive value of this protein is clearly established," we conclude from our experiments that the almond, English walnut, filbert, and pine nut are sources of protein adequate for nutrition. 588 Xutritive Properties of Nuts Nuts as Sou7'ces of Water-Soluhle Vitamine. Numerous feeding experiments, carried out during the last few years, have demonstrated that vitamines are widely distributed among plant products. The cereals, vegetables, and forage crops have been in^'estigated in some detail as to their content of the water-soluble and fat-soluble vitamine. Nuts, as a class, how- ever, have received little attention with respect to the presence in them of these impoi-tant dietary essentials. Halliburton and Drunuiicunl (.1917), studying various naturally occurring fats, failed to obtain normal growth in rats when the butter of their diets was replaced by coconut oil, peanut oil, or walnut butter. Hence the fat- soluble vitamine would seem to be absent in nut oils. Daniels and Loughlin (1918) showed that peanuts are lacking in the fat-soluble factor but that considerable amounts of the water-soluble vitamine are present; and Johns, Finks, and Paul (1919) observed satisfactory growth in young rats on diets in which coconut meal was supplemented by butter and inorganic salts only and therefore represented the sole source of water-soluble A'ita- mine. Mackenzie-Wallis (1918) has reported that a flour made from ground peanuts was antiscorbutic. Grieg (1918) used ground nut meal biscuits with some success as a therapeutic agent in experimental beri-beri. Feeding Experiments with Rats. We have studied many of the more common nuts, that have not previously received attention, as possible sources of water- soluble vitamine and have planned our experiments with a view to being able to obtain an approximate quantitative idea of the comparative distribution of this essential food factor among members of this class of plant products. Two methods are available for such trials. An animal may be placed on a diet deficient in respect to the water-soluble factor. On such a diet, the animal, if it is still small, will cease to grow and in any event will, in a short time, begin to decline rapidly in weight, a condition that terminates in death unless a change is made in the diet. If a product containing sufficient quantities of water-soluble vitamine is added to the diet before the animal is permanently injured by undernourishment, a rapid recovery of weight and nutritive well-being take place. The second method depends on the fact that normal growth can be observed in young rats only when the product to be tested is available in sufficient F. A. Cajori 589 quantities to supplement an otherwise complete diet with an abundance of water-soluble vitamine. In the experiments reported below, both methods were em- ployed. The basal diet used, consisting of casein, butter fat, inorganic salts, starch, and lard, was deficient in water-soluble vitamine as evidenced by the rapid decline of animals when placed on this food mixture exclusively. Control experiments indicated that the casein diet was complete with respect to all other food essentials, as normal growth was observed when small amounts of brewer's yeast, known to be rich in water- soluble vitamine, were added to this diet. In the majority of our trials weighed quantities of the nut to be tested were fed daily apart from and in addition to the basal diet. This method, introduced by Osborne and Mendel (1919, h), insures a constant intake of the product under investigation and enables a comparison to be made of the potency of the foods consumed in like amounts. By varjdng the daily dosage, further evidence in respect to the comparative quantities of the water- soluble vitamine present can be obtained. The nuts were shelled and care was taken to remove all frag- ments of the shell and the coarser parts of the integument. In the case of the almond, the nut was blanched. The chestnuts used in the later trials (Charts 6 and 8) were fed after completely freeing them from the adhering integument. We found that the rats, at least after the first few days, readily ate the nuts and, as a rule, consumed the entire nut allowance as soon as it was placed in the cage. The only failure to eat that we experienced was in the case of the Brazil nut. It was found necessary to incorporate this nut in the basal diet before the animals would consume it in the desired amounts. The outcome of the restorative trials is shown in Charts 4, 5, and 6 and Table II. A daily dosage of 2 gm. of hickory nut, pine nut, and pecan, respectively, or the inclusion of 27 per cent of almond, or filbert, and 19 per cent of English walnut in the food sufficed to enable animals that had declined on the basal diet to recover rapidly their nutritional well-being and resume growth. 1 g-m. of English walnut, black walnut, hickory nut, or pine nut proved to be an equally efficient restorative agent. Partial recovery and slow growth resulted from daily consump- 590 Nutritive Properties of Nuts tion of 1 gm. of almond and 0.5 gm. of chestnut, English walnut, or pecan in addition to the basal diet. These charts show that all the nuts tested are comparatively rich in water-soluble vita- mine. The chestnut, English walnut, and pecan appear to be especially potent, daily doses of 0.5 gm. sufficing to permit slow growth. The animals receiving 1 gm. daily of either TABLE II. Weekly Consumption of Basal Diet and Nuts. Hickory nut. Pine nut. Almond. \^eek. Rat 4. Rat 6. Rat 38. Rat 39. Rat 8. Rat 9. Rat 34. Rat 35. Rat 2. Rat 18. Rat 19. Rat 20. gm. gm. gm. gm. gm. gm. gm. gm. gm. gm. gm. gm. 1 53 80 43 43 58 49 22 46 71 43 47 48 2 52 68 . 32 37 55 45 13 37 63 41 41 26 3 42 65 49 29 56 44 31 53 55 43 39 39 4 59 58 61 36 45 37 74 78 32 45 48 46 5 49 61 62 58 31 29 78 60 65 25 38 29 6 80 101 63 55 46 32 73 55 72 27 27 22 7 62 82 79 58 69 44 42 41 8 62 78 59 58 71 43 49 36 9 58 73 60 63 59 43 51 40 10 68 78 60 58 30 40 40 11 56 42 51 12 54 56 56 13 Eng ish walnut. Pecan nut. Rats. Rat 7. 1 Rat 24. Rat 30. Rat 31. Rat 21. Rat 22. Rat 25. Rat 26- gm. i im. gm. on I. gm. gm. gm. gm. gm. 1 74 61 47 5 2 45 51 38 54 39 2 59 53 52 5 7 53 49 41 70 50 3 46 49 42 5 2 37 42 32 64 50 4 32 42 38 3 6 22 34 24 53 44 5 88 30 35 3 5 28 61 46 32 29 6 71 30 67 5 3 30 *59 42 23 24 7 55 23 68 5 7 31 45 31 47 40 8 55 60 61 5 8 48 58 37 50 49 9 67 57 5 3 57 54 35 54 42 10 77 73 5 9 63 60 35 44 44 11 59 7 3 51 52 62 12 53 5 3 48 59 69 13 60 .60 F. A. Cajori TABLE II— Concluded. 591 Chestnut. Black walnut. Filbert. Week. Rat 27. Rat 28. • Rat 29. Rat 36. Rat 37. Rat 1. gm. gm. am. gm. gm. gm. 1 66 55 62 50 47 84 2 55 56 63 39 34 57 3 32 50 32 31 44 45 4 21 30 27 45 19 36 5 19 19 26 48 35 112 6 43 43 50 52 45 106 7 51 38 47 63 44 80 8 43 34 43 82 9 41 37 44 10 45 39 45 11 55 45 56 12 55 50 59 13 58 65 67 English walnut or pine nut showed as rapid recovery as in any trial where the daily dose of other nuts was 2 gm. A comparison of the growth curves indicates that the almond was not so effi- cient as a source of water-soluble vitamine. 1 gm. of this nut was less effective as a restorative agent than 0.5 gm. of the pecan or chestnut. Osborne and Mendel (1920, b) beheve that animals which have suffered a decline due to a deficiency of water-soluble vitamine may become so badly nourished that failure to effect prompt resumption of growth may sometimes be ascribed to the condi- tion attained by the animal rather than to a lack of the vitamine in the tested product used as a supplement to the deficient diet. The rats used in our experiments were subjected to quite similar degrees of undernutrition and it would seem that the variations in rapidity of recovery can be interpreted, in our experiments, as being due to differences in the quantity of water-soluble vitamine present in different nuts rather than to a radical difference in the nutritive condition of the animals at the time that the nut feed- ing was inaugurated. The weekly food intakes are shown in Table II. The growth curves of animals on diets in which nuts, supplied in different daily doses, furnished the sole source of water-soluble 592 Nutritive Properties of Nuts vitamine aie sliown in Charts 7 and 8. Here again, the richness of nuts in this vitamine is demonstrated. Normal growth was observed when the basal diet was supplemented daily by 2 gm. TABLE III. W'eekli/ Consumption of Basal Diet and Nuts. Almond. En ?lish walnut. Brazil nut. Black walnut. Rat 18. Rat 19. Rat 20. Rat 21. Rat 22. Rat 23. Rat 24. Rat 25. Rat 26. Rat 34. Rat 35. gm. gm. gm. gm. gm. gm. gm. gm. gm. gm. gm. 1 44 43 43 48 47 41 48 50 43 77 55 2 42 43 42 43 42 39 46 47 48 68 67 3 47 43 43 43 39 38 48 31 34 71 55 4 46 43 47 47 44 37 46 45 33 70 60 5 40 41 47 51 38 40 43 38 43 54 55 6 39 37 41 51 35 40 43 38 35 46 64 7 44 61 42 43 58 37 54 8 42 45 35 43 52 40 50 9 51 36 47 54 34 43 10 31 62 11 30 64 Chestnut. Pecan. Y east. Rat 27. Rat 28. Rat 29. Rat 38. Rat 39. Rat 36. Rat 37. Rat 9. gm. gm. gm. gm. gm gm. gm. gm. 1 53 47 50 60 7C 66 73 41 2 51 51 50 57 57 56 55 41 3 51 44 51 54 57 55 54 45 4 52 45 53 47 6S 48 66 47 5 51 52 68 52 61 52 62 43 6 42 45 45 60 61 54 55 39 7 60 53 57 55 5£ 55 57 49 8 56 48 55 55 54 51 59 50 9 66 55 62 47 51 57 46 56 10 51 48 58 47 11 48 55 49 55 of the almond, English walnut, chestnut, Brazil nut, or black walnut. When the daily ration of the nut was 1 gm,, the pecan and chestnut furnished sufficient quantities of this dietarj' factor for normal growth. F. A. Cajori 593 The weekly food intakes are shown in Table III. The char- acteristic deline in food consumption during the period when there was insufficient water-soluble vitamine in the food, and the prompt recovery of appetite and resumption of eating when the vitamine was added to the diet, are to be noted. A^ut Proteins and Milk Production. The present experiments with nut diets have furnished an opportunity to test some of the relations of the dietaiy proteins to milk production, inasmuch as a number of the female rats under observation were bred in the course of the feeding trials. If the mammarj'' gland has at best a limited power, if any, of synthesizing the essential amino-acid precursors of its protein complexes (McCollum and Simmonds, 1918), the importance of furnishing a proper source of amino-acid groups in the ration during lactation is evident. In studying the lactation of dairy cows, Hart and Humphrey (1915, 1916, 1917, 1918), among others have found wide differences in the efficiencies of various protein mixtures as producers of milk. Not only the quantitj^ but also the biological quality of the proteins in the ration affect the char- acter of the mammary secretion. Likewise Hoobler (1917, a, h) has con- cluded from studies of Avet nurses that, as a rule, animal proteins are more efficient than vegetable proteins for the elaboration of human milk. How- ever, nut proteins were an exception to this generalization in that diets containing almonds, English walnuts, pecans, and peanut butter as a source of protein proved to be as suitable for milk production as diets which furnished protein from animal sources. In other words, nuts seemed to furnish the nitrogenous complexes necessary for the elaboration of milk as effectively as any other type of protein. Judging the character of milk production by the ability of the mother to nurse her j^oung successfully, we have observed satisfactory mammarj' function in rats, on diets containing the almond, English walnut, pine nut, and filbert as the essential source of protein in the ration. Some loss of weight of the mother rat occurred during the nursing period in the experiments with the almond, Enghsh walnut, and filbert, but tissue disintegration during the temporary decline could scarcely have furnished enough indispensable nutrient units to account for the newly synthesized milk protein sufficient in quantity to have produced the increments in weight observed in all the young. 594 Nutritive Properties of Nuts SUMMARY AND CONCLUSIONS. Satisfactory growth was observed in young rats on diets in which the almond, English walnut, filbert, and pine nut, respec- tively, furnished the essential source of protein in the ration. Normal growth can be secured when rats are fed upon other- wise adequate diets containing the almond, English walnut, black walnut, Brazil nut, chestnut, or pecan as the sole source of water-soluble vitamine. Animals which have declined on a diet devoid of water-soluble vitamine promptly recover when the almond, English walnut, filbert, hickory, pine nut, chestnut, or pecan is introduced in the diet. These observations indicate that nuts are sources of abundant quantities of water-soluble vitamine. The proteins of the almond, EngKsh walnut, pine nut or filbert furnish the necessary nitrogenous complexes for the elaboration of milk in rats. I desire to express my hearty thanks to Professor Lafayette B. Mendel, Avho suggested this study to me, for his helpful advice and criticism during the course of the investigation. BIBLIOGRAPHY. Cajori, F. A., The utilization of some nuts as food, /. Home Econ., 1918, X, 304. Daniels, A. L., and Loughlin, R., Feeding experiments with peanuts, J . Biol. Chem., 1918, xxxiii, 295. Fern', E. L., J. Lab., and Clin. Med., 1920, in press. Grieg, E. D. W., Anti-beri-beri vitamine in ground nut meal biscuits, Indian J. Med. Research, 1918, vi, 143; abstracted in Chem. Abstr., 1919, xiii, 2067. Halliburton, W. D., and Drummond, J. C, The nutritive value of marga- rines and butter substitutes with reference to their content of the fat-soluble accessory growth substance, J. Physiol., 1917, li, 235. Hart, E. B., and Humphrey, G. C., The relation of the quality of proteins to milk production, J. Biol. Chem., 1915, xxi, 239. Hart, E. B., and Humphrey, G. C., Further studies of the relation of the quality of proteins to milk production, J. Biol. Chem., 1916, xxvi, 457. Hart, E. B., and Humphrey, G. C., The relation of the quality of proteins to milk production. Ill, J. Biol. Chem., 1917, xxxi, 445. Hart, E. B., and Humphrey, G. C., The relation of the quality of proteins to milk production. IV, J. Biol. Chem., 1918, xxxv, 367. F. A. Cajori 595 Hoobler, B. R., Problems connected with the collection and production of human milk, /. Am. Med. Assn., 1917, (a), Ixix, 421. Hoobler, B. R., The effect on human milk production of diets containing various forms and quantities of proteins, Am. J. Dis. Child., 1917 (b), xiv, 105. Jaffa, M. E., Nutritional investigations among fruitarians and Chinese, U. S. Dept. Agric, Off. Exp. Stations, Bull. 107, 1901. Jaffa, M. E., Further investigations among fruitarians, U. S. Dept. of Agric, Off. Exp. Stations, Bull. 132, 1903. Johns, C. O., and Jones, D. B., The proteins of the peanut, Arachis hypogea. II. The distribution of the basic nitrogen in the globulins arachin and conarachin, /. Biol. Chem., 1917, xxx, 33. Johns, C. O., Finks, A. J., and Gersdorff, C. E. F., Globulin of the coconut (Cocos nucifera). I. Preparation of coconut globulin. Distribution of the basic nitrogen in coconut globulin, J. Biol. Chem., 1919 (a), xxxvii, 149. Johns, C. O., Finks, A. J., and Paul, M. S., Studies in nutrition. I. The nutritive value of coconut globulin and coconut press cake, J. Biol. Chem., 1919 (6), xxxvii, 497. Mackenzie-Wallis, R. L., Food value of the ground nut (Arachis), Indian J. Med. Research, 1918, vi, 45; abstracted in Chem. Abstr., 1919, xiii, 2247. McCollum, E. v., and Simmonds, N., The nursing mother as a factor of safety in the nutrition of the young. Am. J. Physiol., 1918, xlvi, 275. Neuberg, C, cited by Funk, C, Lyle, W. G., and McCaskey, D., J. Biol. Chem., 1916, xxvii, 173. NoUau, E. H., The amino-acid content of certain commercial feeding- stuffs and other sources of protein, J. Biol. Chem., 1915, xxi, 611. Osborne, T. B., and Clapp, S. H., Hydrolysis of excelsin. Am. J. Physiol., 1907, xix, 53. Osborne, T. B., and Clapp, S. H., Hydrolysis of amandin from the almond, Am. J. Physiol., 1907-08, xx, 471. Osborne, T. B., and Harris, I. F., Nitrogen in protein bodies, J. Am. Chem. Soc, 1903 (a), xxv, 323. Osborne, T. B., and Harris, I. F., The specific rotation of some vegetable proteins, J. Am. Chem. Soc, 1903 (6), xxv, 842. Osborne, T. B., and Harris, I. F., The globulin of the English walnut, American black walnut and the butternut, J. Am. Chem. Soc, 1903 (c), xxv, 848. Osborne, T. B., and Harris, I. F., The tryptophane reaction of various pro- teins, J . Am. Chem. Soc, 1903 (d), xxv, 853. Osborne, T. B., and Mendel, L. B., Beobachtungen iiber Wachstum bei Fijtterungsversuchen mit isolieten Nahrungssubstanzen, Z. physiol. Chem., 1912, Ixxx, 307. Osborne, T. B., and Mendel, L. B., The comparative nutritive value of certain proteins in growth, and the problem of the protein minimum,. J. Biol. Chem., 1915, xx, 351. 596 Nutritive Properties of Nuts Osborne, T. B., and Mendel, L. B., The nutritive value of yeast protein, J. Biol. Chem., 1919 (a), xxxviii, 223. Osborne, T. B., and Mendel, L. B., Nutritive factors in plant tissues. II. The distribution of water-soluble vitamine. Treliminary report, ./. Biol. Chem., 1919 (6), xxxix, 29. Osborne, T. B., and Mendel, L. B., Nutritive value of the proteins of the barley, oat, rye, and wheat kernels, J. Biol. Chem., 1920 (a), xli, 275. Osborne, T. B., and Mendel, L. B., Nutritive factors in plant tissues. III. Further observations on the distribution of water-soluble vitamine, J. Biol. Chem., 1920 (6), xli, 451. Chart 1. Growth of young rats on diets in which the English walnut, pine nut, and pecan, incorporated in the diet in the form of a press cake, furnished the essential source of protein. A casein diet of similar com- position, except for protein, served as a control experiment. The broken line in the curves of Rats 30 and 31 indicate the period when the pecan diet was replaced by a mixture of one part casein diet and two parts pecan diet. The composition of the casein and nut diets was as follows : Casein Diet. Rat 7. per cent Casein 18 Salt mixture* 4.5 Starch 50.5 Butter fat 9 Lard 18 Brewer's yeast, dried 200 mg. daily. * The salt mixture used in all the diets of the feeding trials is that described by Osborne, T. B., and Mendel, L. B., J. Biol. Chem., 1917, xxxii, 317. English Walnut Diet. Rats 13, H, 15. per cent English walnut press cake, 3.5 per cent N 82 Salt mixture 3 Starch 4 Butter fat 5 Lard 4 Brewer's yeast, dried 2 Pine Nut Diet. Rats Si, SS per cent Pine nut 50 Salt mixture 3 Starch , 36 Butter fat 5 Lard 6 Brewer's yeast, dried 200 mg. daily. F. A. Cajori 597 (6 n o Pecan Diet. Rats so, 31. per cent Pecan press cake, 3.6 per cent N 80 Salt mixture 3 Starch 7 Butter fat 5 Lard 5 Brewer's yeast, dried 200 mg. daily. n Chart 2. Growth of young rats on diets where the almond and filbert^ incorporated in the diet in the form of a press cake, furnished the essential source of protein. The composition of the casein diet was the same as given in the descrip- tion of Chart 1. The composition of the nut diets was as follows: Almond Diet. Rats 10, 11, It. percent Almond press cake, 5.0 per cent N 58 Salt mixture 3 Starch 12 Butter fat 5 Lard 20 Brewer's yeast, dried 2 598 F. A. Cajori 599 Filbert Diet. Rats 16, 17. per cent Filbert press cake, 3.6 per cent N 80 Salt mixture 3 Starch 3 Chart 3. Growth of the second generation of young rats on diets in which almond, English walnut, filbert, and pine nut, incorporated in the diet in the form of a press cake, furnished the essential source of protein. The broken line in the curves of Rats 47 and 48 indicates the period when the almond diet was replaced by the casein diet and 100 mg. of dried yeast daily. The composition of the casein and nut diets was the same as described in Charts 1 and 2. THE JOURNAL OP BIOLOGICAL CHEMISTRY, VOL. XLnl, NO. 2 600 Nutritive Properties of Nuts Chart 4. Recovery of growth of animals which had declined on a diet devoid of water-soluble vitamine, on the addition of the almond, filbert, hickory nut, pine nut, pecan, and English walnut as supplements to the basal diet. The animals receiving the hickory nut, pine nut, and pecan were given 2 gm. of the nut daily. The almond, filbert, and English walnut, respectively, were incorpor- ated in the diet, one part of nut diet and two parts of basal being thor- oughly mixed together. In such a mixture the almond and filbert nut furnished 27 per cent of the diet and the English walnut 19 per cent. The broken line on the curves denotes the period when the animals were on the basal diet. The composition of the diets was as follows: Basal Diet, per cent Casein 18 Salt mixture 4.5 Starch 50.5 Butter fat 9 Lard 18 Almond Nut Diet. Rat t. per cent Almond press cake 58 Salt mixture 3 Starch 14 Butter fat 5 Lard 20 Filbert Diet. Rat 1. per cent Filbert press cake 80 Salt mixture 3 Starch 5 Butter fat 5 Lard 7 English Walnut Diet. Rat S. per cent English walnut press cake 82 Salt mixture 3 Starch 6 Butter fat 5 Lard 4 F. A. Cajori 601 CHART *. aROBTH EXPERIMENTS ON RATS. RECOTCRY OF OROWTK WITH 'IJTS AS SOURCE OF SATER SOLUBLE VITAaiNE 3.0 Oma. Nut daily Chart 4. 602 Nutritive Properties of Nuts Chart 5. Recovery of growth of animals which had declined on a diet devoid of water-soluble vitamine, on the addition of almond, hickory nut, black walnut, pine nut, and English walnut as supplements to the basal diet. The animals were given 1 gm. of nut daily. The broken line of the curves denotes the period that the animals were on the basal diet. The composition of the basal diet was the same as described in Chart 4. F. A. Cajori 603 CHART 6. QROWTH EXFERIilENTS ON RATS. ' RECOVERY OF QROWTH WITH 5UT3 -^^ ISO AS SOURCE OF WATER "SOLUbLE VlTArUNE. 0.5 Oni. Vut daily y / 160 ^ P -'/ / 140 • s X \^ 4f f M r i ___, V 2i Of / / J /' / 120 ->,, \ X V 120 o ^\ / ^ /y o^/*"^^ ^ ^1 t 100 ^' «r ^ \ — y- / / 120 ^ ^ N > ^ / <^ 10 ^ X A Ij^^^ ^ 100 \ =Nu t replaced ty Yeaat. Chart 6. Recovery of growth of animals which had declined on a diet devoid of water-soluble vitamine, on the addition of the English walnut, chestnut, and pecan as supplements to the basal diet. The animals were given 0.5 gm. of nut daily. The chestnut was blanched before feeding. The broken line indicates the period that the animals were on the basal diet alone. The composition of the basal diet was the same as described in Chart 4. Chart 7. Growth of young rats on diets where the almond, English walnut, chestnut, and Brazil nut furnish the sole source of water-soluble vitamine. 2 gm. of the nut were fed daily in addition to the basal diet. The basal diet was found to be inadequate to support growth unless sup- plemented by a source of water-soluble vitamine (see Charts 4, 5, 6). The almond was blanched before feeding. The coarser parts of the integument of the other nuts were removed. 604 Nutritive Properties of Nuts The composition of the basal diet was as follows: Basal Diet. Casein. per cent . 18 Salt mixture 4.5 Starch 50 . 5 Butter fat 9 Lard 18 F. A. Cajori 605 Chart 8. Growth of young rats on a diet in which the black walnut, Brazil nut, pecan, and chestnut furnish the sole source of water-soluble vitamine. 2 gm. of the black walnut and Brazil nut were fed daily in addi- tion to the basal ration. 1 gm. of the pecan and chestnut was fed daily in addition to the basal ration. The chestnut was blanched before feeding. The coarser parts of the integument of the other nuts were removed. 606 Nutritive Properties of Nuts The small vertical lines on the growth curves of Rats 25 and 26 indicate days when the animals failed to eat any of the nut given in addition to the basal ration. The prompt resumption of growth indicates the point where the diet was changed to a ration consisting of one part Brazil nut diet and two parts basal diet. The composition of diets was as follows: Basal Diet. percent Casein 18 Salt mixture 4.5 Starch 50.5 Butter fat 9 Lard 18 Brazil Nul Diet, Rats S5, £6. per cent Brazil nut press cake 80 Salt mixture 3 Starch 7 Butter fat 5 Lard - ,,,,, 5 LIBRARY OF CONGRESS " i"'il' HI I iliiJiJiiilii,il||ii{||jji<| 014 338 739 2 • THE WAVaRLY PRESS BALTIMORE. U. S. A