Among the browning reaction of various foods, the Maillard reaction has been studied extensively and it is known that the reaction products show strong antioxidative activity, while on the discoloration of autoxidized oil, the detailed reaction mechanism has not been explained.
This paper deals with the antioxigenic effect of the browning products of autoxidized oil and several amino compounds, and the difference of the reactions between the Maillard reaction and the discoloration of autoxidized oil were also discussed.
The acetone-soluble fractions of several model systems (Table 1) were examined, after incubation at 78°C, 10 hours, for antioxigenic effect (Fig. 1), reducing activities, nitrogen contents (Table 2) and IR absorption spectra (Fig. 2-5).
As the result, only the water-soluble fraction of autoxidized oil and the amino acid system (WS-AA) showed remarkable antioxigenic effects and reducing activity out of autoxidized oil systems. In regard to nitrogen content, WS-AA system was higher than the other autoxidized oil systems and nearly equal to that of the Maillard reaction. In another of the autoxidized oil systems, the most important reaction in the discoloration of fisheries products showed no antioxidative activity and a low nitrogen content. These results suggested that in the browning of autoxidized oil, the reaction of the water-soluble fraction with amino acid is similar to the Maillard reaction, but the reaction with ammonia is different from the former.

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Considering that raw oysters may contain the precursor or the same pigments found in canned ones, the physico-chemical property of the green pigments of raw oysters was compared to that of canned ones. By extraction with hydrochloric acid-acetone mixture, followed by the purification method adopted in case of canned ones, the green pigments of raw ones were separated into five components as in case of the former.
From the experimental results obtained by absorption spectral analysis, thin layer chromatography, solubility test, infra-red spectral analysis and micro elemental analysis, it is concluded that the above consideration is correct.

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For the purpose of investigating whether the green pigments of canned oysters are chlorophyll a derivatives or not, the physico-chemical property of the green pigments of Aosa was compared to that of canned oysters by extraction with hydrochloric acid-acetone mixture and addition of copper, followed by the purification method adopted in case of canned oysters.
Judging from the similarity between them with the exception of micro elemental analysis values, it is considered that the green pigments are chlorophyll a derivatives.

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The relations between the browning of potato tubers caused by gamma radiation and the time of irradiation after harvest or maturity of the tubers at harvest were referred. The effects of polyethylene package and low temperature on the browning were also discussed. Potato tubers were irradiated with the doses of 5-40 Krad and stored at room temperature.
The browning induced by radiation was partially observed around the vascular bundle of the tubers and the death of the cells was occurred. It was enhanced from 3 to 7 days after irradiation. The partial browning occurred in the tubers irradiated with the doses of 10-40 Krad one month after harvest. However, when the tubers were irradiated 2 months after harvest, little browning was observed with the doses of 10 and 20 Krad, but at 40 Krad still became brown. The browning may be enhanced more in immature tubers (small tubers) than in mature ones (large ones). The polyethylene packing during irradiation and the following several days may reduce the browning. The treatment of low temperature (5-7°C) after irradiation may also supress the deve-lopment of the browning.

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By means of paper chromatography, polarography and the p-nitrophenyl acetic acid(p-NPA) method, free cystine, cysteine, oxidized glutathione, reduced glutathione and vitamin B₁ were isolated from rice embryo and identified. The reduced glutathione and cysteine which were isolated from rice embryo decomposed p-NPA, but the islated cystine, oxidized glutathione and vitamin B₁ did not decomposed p-NPA. Cystine, oxidized glutathione, reduced glutathione and vitamin B1 which were determined polarographically and by the p-NPA method were 1, 71, 15 and 7mg percent respectively.

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This study was carried out with the purpose to check the quality of "Wasabi" powder by gas chromatography.
(1) Column used for gas chromatography were 10% SE-30/Celite 545; 5% SE-30/Chromosorb W; 2% OV-17/Chromosorb W and 2.5% DEGS/Celite 545. Temperature of column bath was 125°C and flow rate of carrier gas (He) was 12.5ml/min.
(2) The peaks of both allyl and β-phenylethyl isothiocyanate were separated clearly. Ratio of peak area of the latter to that of the former was calcurated by percentage, to be noted as R value.
(3) The R values of horseradish powder were large, whereas those of black mustard powder were small.
(4) The R values of six "Wasabi" powder (c), horseradish powder (a), and black mustard powder (b) were put into next formula.
ax+b(100-x)=100c
where x indicated the rate of horseradish powder in "Wasabi" powder, because (100-x) indicated the rate of black mustard powder. The x values of two samples of six "Wasabi" powders were below fifty percent.
(5) One sample of six "Wasabi" powders showed above ten percent in ash content.

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