The dependence of the organism on its food supply is well recognized. Protein malnutrition, avitaminoses, effects of fats or carbohydrates, trace metal deficiencies, toxicity of some food additives are all related to the quality of the diet. During the past 20 years it has been recognized that the metabolic activity of the cells of the body is determined not only by the quality of food intake but by its periodicity. The tissues respond quite differently to the same diet depending on whether it is fed continuously throughout a 24 hr day or for only 1 or 2 hours per day, or every other day. In order to adapt successfully to the ingestion of large amounts of food at widely spaced intervals the animal must make a very complicated set of adjustments in 1) the gastrointestinal tract, 2) the secretory activity of glands which are concerned with the disposition of nutrients (for example, insulin) and 3) reorganization of the biochemical machinery of the cells so that they can accommodate periodic flooding with nutrients and store the excess for mobilization during periods of food deprivation.
This lecture will deal with a brief historical review of our current ideas about periodicity of food intake; some of the gastrointestinal adaptation that occur on some “stuffing” regimens; the central role of insulin (and, possibly, insulin antagonists) as signals to the tissues; the functional and biochemical modifications that occur in tissues, particularly liver and adipose tissue, as a result of exaggeration of the usual fast-refeed cycle; some recent ideas about the role of cyclic AMP in enzyme adaptation, especially of lipogenic enzymes; and finally, the potential of “stuff and starve” eating habits to contribute to the pathogenesis of several diseases. The latter include 1) experimental gallstones, 2) experimental atherosclerosis in chickens and 3) lipemia, vascular disease and myocardial infraction in man.

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An experimental study was directed toward to clarify the effect of supplementing amino acids to a basal diet on its protein quality by use of male-weanling rats. An essential amino acid pattern in this experiment was calculated from 537 kinds of lunch menus which are used by the elementary school of 34 cities in Japan, and was consisted of 280mg Ileu, 488mg Leu, 339mg Lys, 202mg Met +Cys, 542mg Phe+Tyr, 229mg Thr, 79mg Try and 331mg Val per g of nitrogen. The basal diet (diet A) contained 9.38% of the amino acid mixture as protein.
In experiment 1, test diets were made as follows: diet B (basal diet+0.15% L-Met), diet C (basal diet+0.30% L-Met), diet D (basal diet+0.05% L-Try), diet E (basal diet+0.25% L-Lys-HCl) and diet F (basal diet+0.5% L-Met+0.05% L-Try). Rats were fed ad libitum on diets of A, B, C, D, E or F for 21 days, and the body weight gain, PER, BV and XOA in liver were measured to evaluate the each diet protein. As the results, the supplemental effect of amino acids was confirmed in diet B and C, esgecially in diet F but the deposition of liver fat was found in the rats on these three diets. In experiment 2, supplementation of amino acids to diet F was attempted to eliminate accumulation of fat in liver. The diets were made as follows: diet G (diet F+0.20% L-Thr), diet H (diet F+ 0.25% L-Lys·HCl) and diet I (diet F+0.20% L-Thr+0.25% L-Lys·HCl). Rats were fed on 5 diets of A, F, G, H and I. As the results, supplementation of threonine was very good for lowering liver fat content to normal range and also diet I showed the best protein quality.

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Retrogradation of cooked rice was investigated by measuring adhesiveness of rice grain during the storage in a room, in a refrigerator and in a freezer. Materials included new and old non-glutinous and glutinous rice. The effects of amounts of water and some additives used at cooking were tested.
In many cases, changes in the adhesiveness tended to coincide with those in the in vitro digestibility and in the X-ray diffraction pattern previously reported. From these three results, it was found that the situation of retrogradation of various cooked rices became more evident.

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1. Fifteen arginyl peptides have been isolated from the L fraction in bovine milk whey, using the techniqes of chromatography and high voltage paper electrophoresis. Among the fifteen peptides, the ten peptides were ninhydrin negative but were only Sakaguchi's reaction positive indicating to have no amino terminal. Four strongly basic peptides, L-1-4-1, L-2-2-1, L-2-4-1, and L-3-5-1, were detected by high voltage paper electrophoresis.
2. Main components of the peptides in the L fraction consist of aspartic and glutamic acids, glycine, alanine, valine and basic amino acids, lysine and/or histidine besides arginine. No sulfur containing amino acids were detected with one exception of cystine in L-2-10-1.

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The mucilage in Satoimo was extracted with water precipitated by making up to 75% ethylalcohol. After the precipitate was dissolved in the water and then dialyzed against the distilled water, it was precipitated with alcohol again and dried in a vacuum desiccator. The chemical properties of resulting browny white powder were studied. The results were as follows:
1. General composition: Moisture was 16%, crude ash was 4%, crude protein was 51% and total sugar was 16% (as glucose).
2. Qualitative reactions for identification of carbohydrates: Molish, Pinoff, Elson-Morgan, Phloroglucinol and Calbazol-sulfulic reactions were affirmative, while Fehling reaction was negative.
3. Carbohydrate composition: The sample was hydrolyzed (conditions of hydrolysis is shown in Fig. 1). Free carbohydrates were then identified by paper chromatography. As the results, 8 kinds of carbohydrates were found.
4. Color reactions for specific amino acid: Biuret, Ninhydrin, Sakaguchi, Hopkins-Cole, Xanthoprotein and Pauly reactions were all affirmative.
5. Amino acid composition: The sample was first hydrolyzed at 110°C for 32 hours in 6N-HCl. The free amino acid were then identified by paper chromatography. Consequently, 16 (or 17) kinds of amino acids were identified.
6. Identification of N-terminal amino acid residue: The sample was first reacted with FDNB. After DNP-peptide was hydrolyzed at 110°C for 16 hours in 6N-HCl, DNP amino acid was separated and then identified by paper chromatography and spectrophotometry. DNP-Gly, DNP-Ser, DNP-Asp were found.
7. Identification of C-terminal amino acid residue: The sample was first reacted with hydrazine at 100°C for 7 hours and then C-terminal amino acid was identified like N-terminal analysis. DNPThr was found.

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An experimental study was conducted to clarify the following question by use of male-weanling rats. When L-lysine·HCl, enriched to a diet containing amino acid mixture which simulated the pattern of Japanese school lunch menus, was taken 5 hours before or after intake of 90% rice diet, it was doubtful whether there was some effect of the lysine diet on nutritional improvement of the rice protein.
Results showed that the effectiveness of the lysine diet on the rice protein was confirmed when this diet was taken 5 hours before the rice intake, and that the diet was ineffective when taken after the rice intake.

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The content of sterol in the unsaponifiable matter of lipids extracted from fruits (28 kinds), fungi (6 kinds), marine algae (10 kinds) and tea, coffee and cocoa (11 kinds) was determined. The sterol content of fruits, tea, coffee and cocoa as well as brown and green marine algae was presented as the quantity equivalent to that of β-sitosterol (β-S) as reported previously in Part 1¹⁾, 2²⁾ and 3³⁾, while that of fungi and of red marine algae was presented as the quantity equivalent to that of ergosterol (Er) and of cholesterol (Ch), respectively. The sterol portion separated from the unsaponifiable matter by thin layer chromatography was analyzed by gas-liquid (GL) chromatography as reported in Part 2²⁾ and 3.³⁾
1) The sterol content of fruits was 0.6-59.9mg in 100g of edible part and 0.06-2.78mg in 1g of dried material. The content of β-S was the highest in all of the samples. In addition to β-S, both of campesterol (C) and stigmasterol (St) were found in some of the samples, while in other samples one or both of them were not detected. A GL chromatographic peak presumable to be of cholesterol (Ch) was noticed in grape-fruit, bitter orange juice and peelings, citrus hassaku, shaddock, lemon and its peelings, banana and coconut milk. A peak not yet identified appeared in musk-melon and princemelon, in common with melons as reported in Part 3³⁾. The content of sterol was much varied in some of the samples, while the composition of sterol was found to be peculiar to the kind of the samples.
2) The sterol content of fungi was 14.7-46.6mg in 100g of edible part and 0.16-4.39mg in 1g of dried material. Ergosterol (Er) was contained most abundantly in all samples of fungi, except in Jew's ear. A peak not yet identified was noticed in fungi besides that of Er.
3) The sterol content of marine algae was 1, 9-80.9mg in 100g of edible part and 0.02-1.38mg in 1g of dried material. The main sterol of 5 kinds of brown algae in the present report was fucosterol (F), and 24-methylene cholesterol (M) was also contained in all of the samples of brown algae. In 3 kinds of red algae in the present report the main sterol was cholesterol (Ch). A kind of green algae (Ulva pertusa) and 2 kinds of green laver contained 28-isofucosterol (If) as the major sterol, while in another sample of Ulva pertuso 28-isofucosterol was not detected and β-S, M and Ch was found to be contained at the ratio of 100: 81: 65.
4) The sterol content in 100g of edible part of tea, coffee and cocoa was high in green tea, especially so in Bancha (1, 140mg), while in other samples of green tea it was 326-411mg. As for coffee it was 80-110mg except that it was 15mg in powdered, so-called “instant” coffee. The sterol content and composition of coffee beans was found to be unchanged by roasting. In coffee and cocoa the content of β-S was the highest, while C and St were also contained, β-S was the almost exclusive sterol in tea, in which neither C nor St was detected, though a peak not yet identified was found.

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The cucumber and sweet pepper plants were cultured on the field at Toride, Ibaragi Prefecture to examine the variation of the quality and chemical components of their fruits during growth and to know the optimal time for marketing conditions. The cucumber fruits were picked up on the 2nd, 5th, 8th and 10th days after blossoming, and were analyzed on the respective day. The sweet pepper fruits were picked up for sample at 3 stages according to the fruit bigness. Quantitative analyses were made for moisture, ash, ascorbic acid and chlorophylls a and b.
The results are summarized as follows:
1) Cucumber flavor was good when the fruits were young, while sweet pepper flavor did not change during the growth of fruits.
2) The moisture content increased, while ash, ascorbic acid and chlorophyll contents decreased as the cucumber became bigger.
3) As the sweet pepper grew, the moisture content increased, ash and chlorophyll contents decreased, and ascorbic acid content increased.
From the above results, it may be concluded that the cucumber was good in quality when it was young, but sweet pepper showed similar quality during growth from the viewpoint of marketability.

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