It was observed that Penicillium sp. TK-2087 (tentatively identified as P. caseicolum) isolated from Camembert cheese could remarkably produce methyl ketones when cultivated on whole milk (or whole milk powder solution). C₃, C₅, C₇, C₉, C₁₁, C₁₃ methyl ketones were detected in the distillate from the cultured broth. Methyl ketones were also produced when whole milk powder was added after enough growth was achieved on the growth medium. Methyl ketone formation on the whole milk powder solution began to increase after about 50 hours of lag phase, reached to the maximum at about 190 hours and then decreased gradually. During cultivation, titratable acidity continuously increased after about 50 hours of lag phase. Whole milk powder concentration for the most effective methyl ketone production was in the range of about 20-25%. This strain could also produce methyl ketones from the lipolyzed whole milk powder when cultivated on it from the beginning. But methyl ketones were not produced in any significant amount when the lipolyzed whole milk powder was added after enough growth was achieved on the growth medium. These properties of methyl ketone formation by this strain were considerably different from those by fungi from blue cheese.

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The present work was carried out to account for the dual, stimulatory and inhibitory, action of some spices on bacterial growth depending on its concentrations, which was noticed during the study of anti-bacterial effects of spiced. The results obtained on E. coli were as follows: (1) Besides a well-known growth inhibiting effect of garlic, a commercial garlic powder sample and diluted garlic juice promoted the growth of E. coli, due to the presence of scordinine. (2) Thymol in thyme was a growth inhibiting substance, while tannic acid, one of tannic substances in thyme, at low concentrations and ascorbic acid in fresh spices were assumed to be growth promoting factors.

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Rice is usually eaten as easily digestible form by heating with water. On rice cooking, the amount of water added to rice and heating conditions are extremely important factors to obtain palatable cooked rice. These conditions are more critical compared with other starchy foods. The purpose of this study is to find the best cooking conditions of rice in terms of the gelatinization of starch during the heating process and the palatability of the rice. The degree of gelatinization of starch was determined by BAP method, turbity method, X-ray diffraction and differential scanning calorimetry (DSC). Three different heating conditions were examined, quick heating process which took 8 min to boiling, slow heating process which took 25min to boiling, and two steps of cooking process where rice was held for 20min at 60°C, then heated to boiling in 5min. These experiments lead to the following results. The degrees of gelatinization of starches were almost same by either quick heating or slow heating. The results of sensory analysis showed that the former was hard and the latter was soft in texture. On the other hand, cooked rice obtained by two steps of cooking process showed that starch was sufficiently gelatinized, and the palatability of cooked rice was the best among the samples examined. During the first step where rice grains were held for 20min at 60°C, water could be absorbed into rice grain. Then during the second step where quick heating applied for 5min to boiling, rice starch could completely be gelatinized.

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The method using paraffin oil for extraction of essential oil in black pepper powder was developed as follows. Ten grams of ground sample were extracted with mixing for fifteen minutes in paraffin oil (50ml) kept at 30°C in a water bath. After separation of paraffin oil from mixture by centrifugation (3000rpm, 10min), essential oil was obtained from paraffin oil (35ml) by steam distillation. Contents of essential oil were determined by gaschromatography. The proposed method was effective for the estimation of aroma strength, and the coefficient of variation of this method was found to be about 8.6%.

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In order to improve the functional properties of white leaf protein concentrate from white clover (Trifolium repens), the leaf protein concentrate was succinylated to different levels and its functional properties were examined. The succinylation improved all the properties examined here (nitrogen solubility, heat coagulability, water hydration, oil absorption, bulk density, emulsifying activity, emulsion stability, foam expansion and foam stability) and several properties are linearly changed with the degree of lysine modification.

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The major organic acids (tartaric and malic acids) and potassium contents in the grape juices (13° Brix) reconstituted from commercially six frozen concentrated juices were examined. The tartaric acid contents were 0.06-0.01g/100ml; the malic acid. 0.51-0.56g/100ml; the potassium, 18.7-31.6mg/100ml. The concentration of malic acid was higher than that of the tartaric acid in the above mentioned grape juice. These data suggested that the grape juice contained ca. 0.1g/100ml tartaric acid and ca. 30mg/100ml potassium was stable against the tartar precipitaion.

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This study was carried out to clarify the mechanism of chlorophyll degradation by peroxides in leaf vegetables. The changes of chlorophyll contents, TBA value and peroxidase activity in spinach leaves stored at 1°C and 25°C were determined. Chlorophyll content showed a sharp decline with the progress of yellowing of spinach leaves stored at 25°C, but the shift of absorption spectrum was not observed. TBA value increased gradually during storage at 25°C. Peroxidase activity increased for the first 2 days of storage at 25°C and diminished with the progress of yellowing. It is suggested that peroxides, hydrogen peroxide and lipid peroxide, would relate to chlorophyll degradation.

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Effects of low pressure on the growth of fungal colonies were investioated in three fungi, Penicillium digitatum, P. italicum and Botrytis cinerea which grow on both Satsuma mandarin and tomato fruits under different conditions. The growth of colonies and hyphae of the three fungi on the medium and fruit peel was retarded under conditions of 190 torr and 24°C and of 760 torr and 2-5°C, for the pressure and temperature, respectively. The growth of colonies of fungi that caused storage diseases was retarded on account of a low partial pressure of oxygen under low pressure cooditions.

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A simple and reproducible method for the determination of 5'-ribonucleotides (5'-RNT) in flavor seasonigs was investigated by using high-performance liquid chromatography (HLPC) with ion exchange resin. A column (4.6×250mm) was packed with Shim-pack ISA-07 (anion exchange resin) and eluted with stepwise gradient program in phosphate buffer (PH 3.5 and 3.8) at a flow rate of 1.0ml/min. The streigth calibration curves of 5'-RNTS were obtained in range of 0.05-0.3mg/ml of the each 5'-RNT. Under this analytical condition, the reproducible results on the retention time and the coefficient of separation were obtained in the repeated analysis of 5'-RNT in commercial flavor seasoning.

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Gel forming ability was investigated for the mince of round sardine. The mince was ground with its 3% wt of sodium chloride at 4°C for 20min and the resulting sol was heated to gel at 80°C for 30min. The texture of gels resembled that of sausage rather than of japanese style fish flesh flesh ge1, "kamaboko". In the range of 70° to 100°C, the gels were strengthened as heating temperature rose, however, they were weakened by standing the starting sol overnight at 4°C or by preheating the sol at 40°C before heating at 80°C. The gels were strengthened also by the additives, such as wheat flour, soybean flour, milk casein, egg white, whey protein concentrate, corn starch or soybean protein, and this was especially remarkable in the egg white. The gels containing 10% wt of the egg white and the same amount of water were somewhat strengthened by the further addition of more than 1% wt of sodium chloride, but they were not influenced by the addition of sodium pyrophosphate or by the regulation of their pH. Though the fats, such as lard and vegetable oils, weakened the gels, they improved organoleptic values.

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Gas leakage from a portion sealed with string, sublimation rate of dry ice with various grain size, with or without heat insulator and damage of polyethylene bags due to sublimation of dry ice were investigated. (1) Amount of gas leaked (as air) from a sealed portion increased as the film thickened. Amount of air leaked was almost the same when the bag mouth was fixed by winding a string more than 6 turns, while there was considerable difference between 3 and 4 turns. (2) Fifty grams of dry ice sublimated within 1 hour at 23°C. On the other hand, the sublimation time delayed by about 3 hours when the dry ice was wrapped with a foamed sheet of polyethylene-mixed polystyrol and by about 5 hours when the wrapped dry ice was further covered with two sheets of newspaper. (3) There were no significant difference in sublimation rate when the weight of dry ice block was 10-25g, but it was depressed greatly when the block weight was arount 50g. The time required to become one third of the initial weight at 21-23°C was dependent on the block size; 102min for 1-5g, 113min for about 10g, 117min for about 25g and 143min for about 50g of block. (4) A polyethylene bag of 5l in volume containing 30g of dry ice was bound by winding with 6 turns of string and allowed to stand at room temperature (23°C). The bag containing dry ice blocks without heat insulator was damaged even if the film was 0.07mm in thickness, but when the dry ice was wrapped with foamed sheet the bag was damaged only with the film less than 0.05mm. The damage of the bag by the sublimation of dry ice was depressed when persimmon fruits were enclosed in it.

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