A study was made on the fluorescence spectra of erythrosine, rose bengal and their protein complexes. In the visible region, the maximal emission of these colors shifted to a longer wavelength with increase of concentration of these colors. The fluorescence intensity decreased following the increase of concentration of these colors on the range of 4-10 X 10^-5M. This is a result of concentration quenching.
The addition of bovine plasma albumin to the buffered solution of erythrosine increased the fluorescence intensity of the buffered solution of erythrosine but decreased that of rose bengal.
In the addition of lower cancentration of bovine plasma albumin to the buffered solution of erythrosine, the fluorescence intensity increased at 508mμ and 549mμ or maximal emission over the pH range 5.2-10.0. However, at pH 12.0, the intensity increased in the addition of protein at 508 and 549mμ. Under the same condition of rose bengal, as the molar ratio of rose bengal to bovine plasma albumin decreased, the fluorescence intensity increased at 508mμ over the pH range 5.2-10.0. At pH 12.0, the intensity increased within tbe range of 5.0 X 10^-4 to 2.0 X 10^-2% but it started to decrease above 5.0 X 10^-2%. In the addition of bovine plasma albumin to the buffered solution of rose bengal, the determination at 570mμ or maximal emission showed that the fluorescence intensity increased in some cases or decreased in other cases over the pH range 5.2-12.0.
In the addition of lower concentration of casein to the buffered solution of erythrosine or rose bengal, the fluorescence intensity increased at 508mμ over the pH range of 5.2 to 10.0 but at pH 12.0 it started to decreased above 5 X 10^-2%. In the addition of casein to the buffered solution of erythrosine or rose bengal, the determination at 547mμ on the erythrosine and 570mμ on the rose bengal showed that the fluorescence intensity increased in some cases or decreased in many other cases.

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The validity of spectrophotometric procedure for the determination of the free energy of interaction between bovine plasma albumin and azo color (ponceau 3R), xanthene color (rose bengal, eosine and erythrosine) or triphenylmethane color (fast green and acid violet) was examined by the comparison with the established method of equilibrium dialysis. The free energies for the binding of these colors with bovine plasma albumin determined by spectrophotometric procedure were in the range of -6, 040 to -7, 460cal/mole at pH 5.2 and 7.0. These energy values by spectrophotometric procedure were somewhat lower than those calculated from dialysis equilibrium. However, the validity of the spectrophotometric method of measuring interaction with protein and food colors was proved.

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The nutritive value of eleven species of fish egg Proteins was investigated by the amino acid analysis and the biological test. Amino acid composition of fish eggs was determined by the use of the amino acid analyzer. Growing male rats had been fed with the diet containing 10% fish egg protein for 10 days, and net protein ratio and net protein utilization were calculated from their growth rate and body nitrogen content.
Results were as follows.
1) In their amino acid composition, tryptophan and sulfer-containing amino acids were insufficient, but other amino acids were contained sufficiently.
2) The nutritive value of fresh matter ranged from 56 to 69 in NPU, from 3.7 to 4.9 in NPR, and they correlated to EAA index respectively.
3) Among the eleven species, the nutritive value of “Sawara”, “Hamo”, “Buri” and “Tara” were higher than others, and that of “Saba”, “Kamasu” and “Karei”, were lower than others.
4) There was no significant differences in the amino acid composition between fresh and salted fish eggs, but significant reduction of nutritive value was observed by salting.

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In order to standardize the cookery methods of rice in a mass feeding, experiments were made using a gas cooker in four different quantities of rice, 5kg, 6kg, 8kg and 10kg. The moisture content of the rice used in the experiments was 14.97%. The conditions in cooking should be compared with the result, that is, the qualitative evaluation of cooked rice.
(1) The rate of water to rice (weight percentage) was found to be 136%. This rate is closely similar to the theoretical rate (136.6%) which was calculated, taking into accounts a moisture content in rice, the amount of water contained in cooked rice and the amount of water evaporated in the cooking process.
(2) The gas rice cooker was kept warm from 130°C to 170°C, even 15 minutes after the turning off of the gas. So the medium heat treatment usually followed by that of the weak heat to finish the rice cooking can be omitted.
(3) Temperature control was very sirnplified. The cooking was started and finished always by the strong heat, only that the regulation of the time of heating was necessary in proportion to the quantity of rice. Namely the heating time was 18 minutes for 5 kg of rice, 19 minutes for 6kg and 23 minutes for 8kg. Each figure of time shows the time necessary for the middle layer of rice of respective amount to reach the temperature of 100°C and to continue the temperature for 2 minutes. After the turning off of the gas it was appropriate in all cases to allow the cooked rice to settle by its own heat for 15 minutes. This temperature control satisfied the conditions of keeping 98°C for 20 minutes which is necessary to gelatinize the rice.

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The frozen shiitake mushroom (Lentinus edodes) darkens remarkably at defrosting and this browning is considered to derive from phenolase. In order to prevent this discoloration effectively, the properties of phenolase in shiitake mushroom should be clarified. As no detail information on shiitake has been obtained so far, the present paper deals with the several properties of this enzyme.
Phenolase was prepared as shown in Fig. 1, and the enzyme activity was measured colorimetrically.
The optimum pH of phenolase was about 4, 8 (Fig. 2), and optimum temperature was 50°C (reaction time 8 min., Fig. 4). As to the substrate specificity, all tested o-diphenols were oxidized and of all, the highest activity was noticed by catechol. It was inactive for p-cresol and hydroquinone (Fig. 3).
Phenolase lost the activity by the following treatments; blanching at 80°C, 1min. or 90°C, 30 sec. (Fig. 7, 8), CO airation (Fig. 10) and addition of sodium bisulfite (Fig. 9).

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According to the study on the shiitake phenolase in a previous paper, a few attempts for the prevention of the browning of defrosting shiitake were carried out.
Sodium hydrosulfite prevented the browning (Fig. 1), but the usage of sulfite for fresh vegetables was prohibited in Japan from Oct. 1969.
Blanching at 90°C, 5min. also prevented the browning (Fig. 2) ; however, the marked deterioration of both texture and flavor was observed.
As shown on Fig. 3, the authors have found that CO gas can successfully be used to prevent browning (2 hrs. 50min.).
Moreover, it was noticed that the extent of browning varied widely with the samples obtained at different places and dates, it seemed to depend chiefly on the content of polyphenols (Fig. 4) ; and the main polyphenols as substrate in shiitake were chlorogenic acid type.

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Hydroxyurea is hypothetically presumed to be one of reaction products from urea by urea dehydrogenase discovered by us. Therefore, some properties of hydroxyurea were investigated in order to obtain a clue to identification.
Hydroxyurea was synthesized and its infrared spectrum was estimated. Incidentally, some qualitative tests were also carried out; it showed a blue-violet color with FeCl₃ solution, a brick-red color with sodium aminoprusside and MgCl₂, a yellowish-green color with p-dimethylaminobenzaldehyde and positive result for Tollen's test while negative one with ninhydrin.
Rf values of hydroxyurea on paper chromatogram were estimated with several solvents. However, distinctive difference could not be determined between hydroxyurea and urea. On the other hand, conditions for ion-exchange chromatography and gel-filtration could settled for separation of hydroxyurea from urea.
Competitive inhibition of urease with hydroxyurea was confirmed as presumed on the basis of resemblance of its structure to that of urea and inhibition constant, Ki, was estimated. Then, effect of hydroxyurea on catalase was investigated in connection with some biological functions of hydroxylamine. While catalase was also inhibited by hydroxyurea, it was confirmed that this was non-competitive one.

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Rats fed on a low casein diet supplemented with sulfur containing amino acid produce fatty livers and the liver fat accumulation is prevented by the further supplementation of threonine. From this fact, metabolic interrelationships between methionine and threonine were studied with special reference to the plasma level of free amino acids. Supplementation of 0.3% of methionine or cystine to a 8% casein diet, reduced slightly the plasma level of most free amino acids of rats, but the decreases in the level of threonine, serine and glycine were remarkable. Similar decreases were observed even when threonine was supplemented to the low casein diet previously to meet the requirement of rats. In the next experiments, dietary level of methionine was variously changed by using an amino acid mixture in the diet. The plasma level of threonine, serine, and glycine showed the inverse relation to the dietary level of methionine.
These results may have relation to the fatty livers due to methionine supplementation and its prevention by threonine.

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Effects of hidden damage on rough rice threshed with a threshing machine were investigated. The results obtained are as follows:
1) Water soluble dry matter content of rice was 8.0% when hackled with hands, and 7.9, 7.6, 6.5% when hackled in 550, 600 and 700r. p. m., respectively with a threshing machine.
2) Total sugar content ranged from 3.88 to 3.74% with an increase of revolutions per minute of a threshing machine.
3) pH-an all-round index of the quality of rice was low in the samples threshed with high revolutions per minute. This was probably because a visible or an invisible injury increased respiratory functions.
4) Electric conductivity of rice showed high figure at high revolutions of a threshing machine.
5) Germination rate of rough rice threshed with a threshing machine was lower than that of rough rice threshed with hands. But the pace of germination of rice kernels threshed with the machine was much rapid than that of rice kernels threshed with hands.
6) These physical, chemical and biological qualities of rice reached detrimental levels without an external sign of damage. The author guessed that the deterioration of rice qualities was due to invisible “distortion” in rice kernels.

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Changes of pH, electric conductivity, total sugar content and water soluble dry matter content of rice during storage of rough rice threshed with various revolutions were studied. The results obtained are as follows:
1) pH values of the rice samples threshed with high revolutions were smaller than those with low revolutions and decreased very much during storage.
2) Electric conductivity of rice threshed with high revolutions was higher than that threshed with hands and low revolutions.
3) Water-soluble dry matter content and total sugar content were lower in the samples threshed with a machine than in the samples threshed with hands. This difference became greater during storage.
4) When rough rice samples were stored at a room temperature (10-16°C) and in 40-50 % of relative humidity, rice quality remained relatively unchanged.
5) Storage at 23°C and in 80% of relative humidity of rough rice samples threshed with a threshingmachine easily resulted in a further decrease in rice quality.
6) In these cases the quality of rice threshed before drying was lower than that threshed after half-drying.

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