Effects of green tea polyphenols (GTP), which contain (+) -catechin, (-) -epicatechin, (-) -gallocatechin, (-) -epigallocatechin, (-) -gallocatechin gallate, (-) -epicatechin gallate and (-) -epigallocatechin gallate, on rigor indexes of fish body and K values of meats in the cultured fish during round ice storage were investigated. The moist pellets supplemented with different concentrations of GTP (0, 0.02 and 0.2%) were fed to young yellowtails (Seriola quinqueradiata) of 0 (zero) -year fish. These fish were killed on the 2nd week after feeding of the moist pellets. The rigor indexes of fish body were not effected very much by GTP feeding during rigor mortis was perfected and kept up, but the decrease of them after starting of rigor resolution was slower than control group of GTP no feeding. However, the dose of supplemented GTP in the moist pellets did not show significant difference between test groups. On the changes in K values of fish meat during ice storage, there were no differences among three groups. Therefore, it was thought that the enzymatic reactions of ATP metabolism after killing fish might be not affected very much on either inhibition or acceleration by GTP feeding. Thus, it was concluded that GTP feeding would be useful for maintaining freshness of cultured fish during storage or delivery.

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The growth inhibition activity against bacteria, yeasts and mold of the synthetic 31 derivatives of ferulic acid were evaluated and 12 compounds were found to inhibit the growth of Gram positive bacteria, yeasts and mold. Majority of the synthetic ferulic acid derivatives showed higher antimicrobial activity than that of ferulic acid. Butyl ferulate and 2-methyl-1 butyl ferulate showed the significant growth inhibition against B. subtilis, S. aureus and S. cerevisiae. Whereas hexyl ferulate significantly inhibited the growth of B. subtilis and S. aureus, those of the yeasts and the mold were not affected within the examined concentrations. Methyl ferulate and ethyl ferulate showed relatively wide antimicrobial spectrum that inhibited all examined microorganisms excluding Gram negative bacteria. It was observed that growth inhibitory activity of the ferulate esters is increased along with the alkyl chain length, simultaneously with the increase in the cytotoxicity. Methyl ferulate and 2-methyl-1 ethyl ferulate showed higher activities than those of commercial preservatives such as sorbic acid and benzoic acid and did not show severe inhibition against the growth of mice fibroblast cell line Balb/c 3T3 A31-1-1 at 100 μ M. These compounds would be good candidates of noble antimicrobial agent for food.

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An indicator organism, E. coli, and pathogenic bacteria, S. Typhimurium, S. Enteritidis, A. hydrophila, P. aeruginosa and S. aureus, were inoculated into high pressure processed raw hams, and then the changes of the viable counts of these bacteria in the hams stored at 15°C, 10°C and 4°C for 30 days were investigated. During the storage at 15°C, the viable counts of E. coli, S. Typhimurium and S. aureus increased, but those of S. Enteritidis, A. hydrophila, P. aeruginosa did not. The only viable count of S. aureus was on the increase at 10°C. All of the indicator organism and pathogenic bacteria could not grow at least for 30 days during the storage at 4 t. Therefore, it was supposed that the storage of high pressure processed raw hams at 4°C would inhibit the growth of pathogenic bacteria for a long time even if the hams were contaminated by those bacteria after processing.

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The first-order kinetic of a two-component system was applied to investigate the thermal property of tomato juice. The commercial Mathcad program package was used to calculate the necessary parameters from the experimental data for the model. The thermostable and thermolabile enzyme populations in the juice were 2. 0% and 98. 0%, respectively. The Zs and Zl values of thermal destruction curves for the thermostable and thermolabile pectinesterase enzymes were 8. 3°C and 7. 0 °C for the temperature range of 75-90°C, respectively. The calculated Z's value were in good agreement with the literature values for tomato juice. The calculated and experimental nonlinear thermal property curves for tomato juice were in good agreement at a wide range temperature of 75-90°C.

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