D. Breese Jones

Proteins of the castor bean—Their preparation, properties, and utilization

This article is a review of technical papers and information that are now available on the proteins of the castor bean. Included among the various aspects of the subject are the following: The chemical composition of castor bean seeds and castor cake; the preparation and properties of their proteins, including the toxic albumin riein, its properties, physiological reactions and amino acid content; the allergenic properties of castor bean protein; the utilization of castor bean cake or pomace for feeding, fertilizer and industrial purposes. An extensive bibliography is appended.

Chemical composition and vitamin content of royal jelly.

Summary The composition and vitamin content of royal jelly, the substance responsible for the differentiation of the two castes of the female honeybee (Apis mellifera L.), has been determined by standard chemical methods and biological assays. Royal jelly has the following chemical composition: moisture, 66.05%; protein, 12.34%; total lipid, 5.46%; total reducing substance, 12.49%; ash, 0.82%; undetermined, 2.84%. Royal jelly protein has an average digestion coefficient of 81% and a biological value of 75% as determined by the Mitchell method. Royal jelly proved to be a good source of vitamin B1, containing from 1.0 to 1.5 international units per gram. It contained no demonstrable amount of vitamin A or vitamin C. It has been previously shown that royal jelly contains little, if any, vitamin E.

The vitamin content of oysters.

A twofold interest is connected with a study of the vitamin content of oysters. They constitute an important and an extensively used item of food. Furthermore, the material upon which they feed consists largely of diatoms and minute organisms, marine forms of life to which have been traced the origin of the fat-soluble vitamins found so abundantly in certain fish liver oils, such as that of the cod. 1 So far as we are aware, no work has been hitherto reported on the vitamin content of oysters with the exception of that published by Randoin 2 on the antiscorbutic factor. They found that oysters contain this vitamin in abundance. By means of feeding tests with rats, we have found that oysters are rich also in vitamins A and B In order to obtain uniform samples, fresh oysters were ground in a frozen condition. Quantities of the frozen product equivalent to 0.5 gm., calculated on a dry basis, caused prompt resumption of growth when fed daily to rats that had declined in weight as a result of the lack of vitamin B in their basal ration. Experiments in progress indicate that smaller quantities are sufficient to meet the requirements of rats for this vitamin. As little as 0.25 gm. of a product obtained by dehydrating fresh oysters at a temperature not exceeding 40° under reduced pressure, enabled rats to make a fair recovery from the results of vitamin A deficiency. It mas found that during the process of dehydrating the oysters a change took place which caused a partial destruction of vitamin B. Whether this process also impaired the vitamin A value of the oysters is being investigated. Work is also in progress to estimate the vitamin content of clams, shrimp and other articles of sea food.

The globulins of rice, oryza sativa☆

Compared with the proteins of other cereals, those of rice haye been but little studied, notwithstanding the fact that rice constitutes one cf the most important sources of food for a large part of the world’s population. One reason for this is doubtless due to the unusual distribution of the classes of protein found in this seed. Unlike the proteins of other cereals, nearly all of the proteins of rice endosperm are insoluble in water, salt solution, and alcohol, and belong to the rather ill defined class of proteins called glutelins. Consequently, most of the data recorded in the literature on rice proteins has been on a mixture of the total alkaliextractable proteins.

The nitrogen distribution and percentages of some amino acids in the muscle of the shrimp, peneus setiferus (L.)

The amino acid composition of muscular tissue from various sources is recorded in chemical literature. The hydrolysis and complete analysis of the muscle proteins of chicken (l), halibut (2), ox (3), and scallop (4) have been made. Percentages of the diamino acids have also been determined by the Van Slyke method in the muscular tissue of rabbit, chicken, ox, horse, sheep, and pig (5). Similar analyses of various tissues from the same, and from different, animals are also recorded (6, 7). With but one exception, all of these citations refer to work done on the muscle of fish and of animals of higher forms of life. So far as we are aware, the amino acid composition of the muscle of a crustacean has never been determined. Having available a quantity of fresh shrimp which was procured for studies in progress on the nutritive value of certain types of sea food, it was considered of interest to determine the distribution of nitrogen and percentages of some of the amino acids in shrimp muscle. Such data would throw light on the nutritive value of the proteins of this muscle, and would afford a means of comparing the proteins with those of the scallop, as well as with those of the muscle of animals of the higher forms of life. The diamino acids were estimated by the Van Slyke method, and tyrosine, tryptophane, and cystine were determined colorimetrically. Aspartic and glutamic acids were isolated and determined gravimetrically. The quantities of the amino acids determined are expressed in percentages of the ashand moisturefree muscle (Table I). There are also inciuded, for comparison,

Proteins of the cotton seed.

By extracting finely ground cottonseed kernels (hull-free) with benzene (C6H6) nearly all of the fatty and resinous substances and much of the coloring material is eliminated. For this purpose benzene is far superior to ether. Such a thorough removal of the above substances from the flour greatly facilitates a satisfactory subsequent extraction of the proteins by different solvents. The high percentage of nitrogen extracted by sodium chloride solution (Table I) is doubtless due to the method of preparation of the flour. We were able to separate from the salt extract two globulins. Of these one can be precipitated directly at 0.4 to 0.5 of saturation with ammonium sulfate. The other flocculates at a saturation of 0.7 to 0.8, but only after it is diluted with water so that the ratio of the final volume to the weight of the original cottonseed flour extracted is as 50:1. A fraction having a relatively low nitrogen content, but containing a constant and very high ash percentage was obtained from the salt extract by coagulation; the composition of this preparation points to a nucleic acid. The examination of this product is under way and the results will be published later. The globulins were prepared by reprecipitation with ammonium sulfate followed by dialysis. The identification of glutelin and a nucleo protein present in the meal, and also the chemical analyses and determination of certain physical constants of the different protein fractions are under way.