The stabilization of isothiocyanates in wasabi (Wasabia japonica Matsum) and horse radish (Cochlearia armoracia L.) using high-pressure treatment was studied. High-pressure treatment of wasabi caused the increase of the activity of myrosinase and the decrease of the activities of peroxidase and lipase. In horse radish the rise of activity of myrosinase was not shown. The high-pressure treatment greatly decreased the amount of palmitic acid, whereas it had little affect to isothiocyanates. The addition of gluten effectively stabilized isothiocyanates in wasabi, but was not effective in horse radish. The effect of addition of albumin was little on them.

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Effect of pressure from 0.1 MPa to 400 MPa on death rate of Bacillus subtilis spores during heating treatment from 298°K to 381°K were investigated. A sample tube made of silicon rubber (I.D.=4mm, L=100mm), containing spore suspension (ca, 1.07 spores/ml, pH 7.0, 1/15M phosphate buffer), was inserted into a pressure vessel (I.D.=8mm, L=180mm), then the vessel was heated in a constant temperature bath under controlled pressure. Even in a moderate temperature range from 298°K to 338°K, pressure influenced the death rate, though the survival curves did not obey the first order rate equation. In this temperature range, the relationships between log (spore survivors) andlog (time) showed a clear linear correlation, indicating that the spores do not die completely under the high pressure conditions only. On the contrary, pressure influenced so much the survivors of the spores, and the death curves obeyed the first order rate equation in a high temperature range from 368°K to 381°K, and a remarkable decrease of spores was measured during come up time of the heating under constant pressure. The death rate constant increased with an increase of the pressure. These results showed that the pressurized heating sterilization process can shorten the heating time or decrease the sterilization temperature for complete spore death.

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The effect of hydrostatic pressure on activation of Bacillus spp. spores was studied in apreparatory stage for synchronous germination. Activation of B. subtilis ATCC 6633 spores in whole milk by hydrostatic pressures as high as 200MPa in temperature from 25 to 60°C was more effective than activatiod by heat at 80°C. The rate of spore activation idcreased with idcreasing temperature and time of compression. But, withregard to pressure stretgth, little difference wasobserved between 50 and 200MPa. Most of the pressure-activated B. subtilis spores germinated within about lh of incubation at 37°C and their heat-resistance was lost. The residual non-germinated spores displayed extreme dormancy and did not germinate even after more than 6h of incubation at 37°C. The growth curve of the B. subtilis spores activated by pressure, including the length of the lag phase, was similar to the growth curve of untreated spores. Hydrostatic pressure also activated B. polymyxa NIAH-474 and B. licheniformis IAM-11054 spores which were difficult to activate by heating at 80°C.

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The changes of extractive components of Katuobushi during smoking process was investigated. Extractive-nitrogen content of the product was almost constant (around 2.8%) throughout the smoking process. Histidine, a principal component of free amino acids and their related components, decreased during the smoking process, but other amino acids almost unchanged. The contents of creatine and creatinine were also found to be high. During the smoking process, creatine gradually decreased, but creatinine gradually increased. Inosinic acid, a prominent nucleotides, almost unchanged during the smoking process. From the analysis of SDS-polyacrylamide gel electrophoresis and peptide analysis, it was detected that extractive protein degraded and peptides formed during smoking process. Buffering capacity of extracts in pH 3.5-9.5 almost unchanged during smoking process.

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Substances from 9 edible seaweeds and 8 medicinal herbs, which have been traditionally prescribed in Japan as medicative materials, were screened for stimulating phagocytes by measuring the carbon clearance activity in mice after intraperitoneal injection. Among the tested seaweeds, the ethanol-insoluble fraction of a hot-water extract from Gracilaria verrucosa augmented the in vivo phagocytic activity. Among the herbs, we also found this effect from the ethanol-insoluble fraction of a hot-water extract from Actinidia polygama, and from both the ethanol-insoluble and ethanol-soluble fractions of a hot-water extract from Polygonatum odoratum.

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Inhibisory effect of the fraction (CT-I) from Cassia mimosoides L. var nomame Makino on lipase activity was investigated. Fracsion CT-I consained 54% of phenols, 95% condensed tannins and small amount of proanthocyanidin. CT-I inhibised the acsivities of porcine pancreas lipase using 4-methyluybelliferyl oleate and triolein as she substrases, which was stronger than epigallocasechin gallate (EGCg), major tannin in green tea and inhibitory acsive component for various enzymes. The inhibition caused by CT-I decreased with addition of casein, however compared with case of EGCg, the amount decreased was less. The inhibitory activisy of CT-I was found sufficiently stable afser heasing for lh at l00°C in the pH range of 3.0 to 5.0

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Extraction of capsaicin from red pepper was carried out with liquid carbon dioxide (L-CO₂) at a pressure of 60-100kg/cmcm² and 20°C, and the effects of ethanol or acetic acid as an entrainer (0.2-1.2%) were investigated. The recovery ratio of capsaicin with L-CO₂ was about 92%. When ethanol (1.0%) or acetic acid (0.5%) was added to L-CO₂, the recovery ratio of capsaicin with L-CO₂ showed the same value as the case of non-addition, but the required amount of CO₂ decreased by approximately one-half. The recovery ratio of capsaicin with L-CO₂ increased in proportion to ethanol or acetic acid concentration. These results indicated that ethanol or acetic acid acted as an entrainer. Acetic acid as an entrainer was more effective than ethanol on the extraction of capsaicin with L-CO₂. By adding acetic acid (1.2%) to L-CO₂, the recovery ratio of capsaicin was about 94%, and the amount of CO₂ used decreased to approximately one-quarter of the case without an entrainer.

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Organic acids, free sugars, free amino acids and oligopeptides of Kochujang seasoning made in Korea were analyzed, and the characteristics ofits taste were discussed. Also, the difference in the palate between Japanese and Korea people was investigated according to the results obtained in our present and previous studies. Two varieties of Kochujang were analyzed in this study, one purchased at food shops in Seoul, Korea (F-Kochujang), and the other made in private homes in various areas of Korea (D-Kochujang). The results were as follows: (1) F-Kochujang was greater in the content of free sugars and smaller in the content of NaC1 than D-Kochujang. (2) Both types of Kochujang were rich in glucose and citric acid. (3) F-Kochujang was especially higher in ratio of free glutamic acid and proline to the total free amino acids, and D-Kochujang was markedly higher in ratio of proline. (4) The content of oligopeptides in both types of Kochujang was almost the same. The oligopeptide content of F-Kochujang was half that of free amino acids, but that of D-Kochujang was similar to the free amino acid content. (5) It is presumed that both types of Kochujang contained glutamic acid-rich oligopeptides, which might contribute to a delicious taste. Kochujang is considered to be a unique seasoning in Korea characterized by a high level of citric acid and proline. The sweet taste of Kochujang might be due not only to sugars, but also to the proline content.

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The thermal gelation properties of milkfish meat paste were investigated. Moisture content and pH of meat pastes could be controlled by washing with NaHCO3 to obtain better conditions for gelation. When pH was adjusted to 6.8, a meat paste with about 79% moisture was obtained. On washing, the gel strength of the meat pastes increased about 2.5 times for both ordinary and dark muscles. The setting index of 12 and disintegration index of 33 for meat paste indicated that the milkfish appertains to adiffcult-setting and diffcult-disintegrating fish species. In the setting, however, a maximum of the gel strength was observed at 50°C, and its minimum was observed at 70°C, suggesting that the gel forming ability was infiuenced by the environmental adaptation of growth.

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