From the result of a fundamental dietetical study on albino rats, it was known that a diet in which animal protein (casein or fish meal) and soybean protein were mixed at the rate of 9: 3 was more efficient than a diet composed of.either one of them. One of the reasons for this higher efficiency is attributable to a supplementation effect of essential amino acids, especially of methionine and tryptophan, but it consists in yet unknown factors that the addition of soybean protein is unexpectingly effective.
Observation was made on the growth of albino rats fed on the flour products A, B and C. The products A and B were manufactured from polished rice, and the product C from potato starch. When skim-milk powder was added to the products by 25 per cent, the animals fed on A showed the most rapid growth followed by those f ed on. B. Those fed on C showed a growth rate far below those on A and B. When skimmilk powder was added so as to attain the protein content of 13 per cent, diet with A was superior to B and C.
An addition of methionine or rice-bran to potato starch and skim-milk diet gave little effect on the growth of rats. Nutritive value of these diets was lower than polished rice mixed with skim-milk diet.
Polished rice powder with addition of salt mixture and vitamin mixture was used as the basal diet. Supplement with L-lysine and DL-threonine improved markedly the growth of rats, but further addition of L-tryptophan did not stimulate the growth. Further addition of.DL-methionine with or without L-tryptophan to the diet supplemented with lysine and threonine did not improve the growth rate. The supplement of a small amount of L-lysine (0.025 to 0.4%) to the basal diet was also ineffective.
For many kinds of food products which are roasted during the processing the formation of organic acids from the main constituents of the food, such as sugar, starch, protein, pectin and tannin, was investigated. The following acids were respectively estimated; acetic, formic, citric and lactic acid from wheat starch; acetic, formic, citric, malic, succinic and lactic acid from soybean cake meal; acetic, citric, malic and lactic acid from tannin; propionic and acetic acid from cane suger. Organic acids in peanuts butter and cocoa were also determined. Only acetic acid was found in fresh and roasted peanuts. Deteriorated peanuts butter contained many kinds of acids. Acetic acid, citric acid, and lactic acid were found in fresh cocoa beans and by roasting acetic acid increased while citric acid decreased.
Trimethylamine oxide (TMAO) in commercial sausages was estimated to determine whether they are mixed with fish flesh or not. Determination of TMAO was made by the revised colorimetric method based on Dyer'sone. It was found that reduction temperature influenced on the yield of trimethylamine (TMA) and that the lower the extraction temperature was the lower the yield of TMA. In the author's experments 30°C was adopted both for extraction and reduction TMA and TMAO were determined in Rhinoplagusia japonica, Makaira mazara, whale, pork and beef as freshand after heating at 70°C and at 100°C for 30 min., respectively. Rhinoplagusia japonica and Makaira mazara contained TMAO, the amounts of which were changed by heating. Whale meat contained far less TMAO.Pork and beef contained neither TMAO nor TMA, and also the amounts did not increased by heating. Addition of 5%M. M. azara to pork can be distinctly detected. Commercial vienna sausage of high quality sold at more than 70 yen per 100g contained little TMAO, while various sausages based on fish flesh contained much TMAO. Mostof the so-called sausages of ordinary quality sold at 50-70 yen per 100g on the marketcontained identifiable amounts of TMAO, indicating that they are adulterated withfish flesh.
Anionic surface active agents with long alkyl chain containing SO3 or SO4 group such as sodium lauryl sulfate and sodium dodecyl benzene sulfonate possess high solubilizing power on protein. On the other hand, nonionic surface active agents are less effective than the anionic. Also a study on the inhibiting action of surface active.agents on α-, β-, γ-amylase shows that nonionic agents have no influence or slightly affect the action ofα-, β-amylase. Anionic agents inhibit the action of α-, β-, γ-amylase, and cationic agent has no influence on β-amylase but it inhibits the action of α-, α-, γ-amylase while the ampholytic agent inhibits only the action of α-amylase.