In the previous paper we reported the fate of Clostridium botulinum spores inoculated into tea drinks and postulated that the spore-killing effect of these drinks is due topolyphenolic (tannic) components of tea. In the present experiments, minimum inhibitoryconcentration (MIC) of each tea polyphenolic component against spores and vegetative cells of C. botulinum was determined. As tea polyphenols, "crude catechins" and "crude theaflavins" were separated. These crude substances were further purified into each four catechins and theaflavins. Catechins and theaflavins were mixed at graded concentrations with TGC medium to make the test medium. Spores (5×10²) were mixed with above test media anaerobically in pouches. Vegetative cells were preincubated and streaked on the solidified test medium. All these samples were incubated anaerobically at 30°C for 3 days to find out the growth inhibitory concentrations. As a result, several hundred ppm concentrations of crude catechins, gallated catechins and all theaflavin fractions inhibited the growth of both spores and vegetative cells of C. botulinum, duly supporting the validity of the previous paper. The same experiments were done with some other heat-tolerant bacteria with convincing but unpredictable results.

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Spinach leaf blade. (2) The respiration rates of open-field grown spinach were 630 (CO₂mg/kg·h), 280, 123 and 42mg when stored at 0°, 10°, 20°and 30°C in the dark, respectively. The respiration rates of green house grown spinach were 343 (CO₂mg/kg·h), 163, 68 and 26mg, respectively. The respiration rate of open-field grown spinach was 1.6-1.8 times higher than that of green house grown spinach. (3) The sugar content of spinach decreased with increasing storage temperature. Decrease of sugar contents in outer leaves during storage was distinctly faster than that in inner leaves. (4) When spinach leaves were not yellowing, the ratio of measured sugar decrease to estimated sugar decrease from respiration was about 0.9, however, it decreased about 0.4 when spinach leaves were yellowing. (5) Yellowing of spinach leaves started when the sugar contents of the outer leaves dropped to 0.06-0.05 (g/100g f.w.). The yellowing decreased the quality of bundled spinach. (6) The sugar content of open-field grown spinach was higher than that of green house grown spinach. Respiration rate of spinach leaves cultivated at open-field were also higher than that cultivated at the green house. There was little difference in shelf life between open-field grown and green house grown spinach leaves.

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The effects of protease treatment on biscuit processing were investigated and compared with those of sodium hydrosulfite. The enzymes used were bromelain, papain, two kinds of fungal protease (Denazyme and Amano-A) and bacterial protease (Bioprase). In the case of biscuit dough, the addition of the proteases and sodium hydrosulfite resulted in decreases in dough development time and resistance to extention. Sodium hydrosulfite increased the extensibility of the dough more than the proteases. The proteases and sodium hydrosulfite decreased the shrinkage of biscuit dough on baking Process and increased the shortness of biscuit. These effects of bromelain were more remarkable among the five proteases. These results suggest that the use of protease instead of sodium hydrosulfite is available in biscuit processing.

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To know the dependence of tastable quality of soybean seeds on cultivar and prod ucing district, total sugar, free type of total sugar, and free sugar contents were de termined in 105 samples (60 cultivars and 7 lines) of 7 districts cultivated at 23 Agricultural Experiment Stations in 1980. In the all samples, their ranges and mean values on dry matter basis were as follows; total sugar: 21.7 to 35.4% and 28.3%, free type of total sugar: 9.4 to 14.7% and 11.5%, peak A: 0.02 to 0.56% and 0.24%, glucose: 0 to 0.40% and 0.13%, sucrose: 3.67 to 9.64 % and 6.40%, peak B: 0 to 0.65% and 0.26%, peak C: 0 to 0.70% and 0.13%, raffino se: 0.48 to 1.14% and 0.81%, and stachyose: 2.52 to 4.31% and 3.31%. A large variation in cu ltivar and producing district was observed in the levels of peak A, glucose, peak B, and pe ak C. Significant differences were observed in total sugar, free type of total suga r, peak A, sucrose, and stachyose among the cultivars, and also observed in all kinds of su gar among the districts. The correlation between sugar content and chemical component cont ent (previously reported), and also between sugar content pairs was examined on all samples. The total sugar, free type of total sugar, and sucrose contents correlated negat ively with the protein content, and positively with the carbohydrate content. The glucose conte nt correlated negatively with the oil content. As to the sugar content pairs, the total sugar positively with free type of total sugar, glucose, and sucrose, and free type of total sugar correlated positively with glucose, sucrose, and raffinose. Stachyose correlated negatively with the total sugar, glucose, sucrose, and raffinose.

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A method for processing cheese in the absence of emulsifying salt was investigated. Several hard type natural cheeses such as Gouda and Cheddar were used for this experiment. When the above cheeses were cooked and melt at 80°C in the absence of emulsifying salt, their water contents and pHs were found to be strongly responsible for emulsion stability of the melt. Within the critical range of the water content and pH in each cheese type, stable cheese emulsion was obtaind, and the resulting product after cooled at 5°C possessed homogeneous texture. Excessive addition of water to cheese and increasing pH up to more than 6.2 caused water and oil separation. Since the use of either high shear-force during cooking or well-ripened cheese was not a critical factor to obtain stable emulsion, the water and oil obsorption capacities of calcium-para-caseinate in cheese at various pHs were considered to be important factors in formation of the stable emulsion without emulsifying salt. In the absence of emulsifying salt, cheese cooking was attained at 80°C in the same manner as the standard processed cheese making within the limited ranges of water content and pH of cheese.

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Effects of emulsifying salts and holding conditions after cooking on the functional properties of processed cheese were investigated. Emulsifying salts such as sodium citrate, disodium phosphate, sodium pyrophosphate and sodium polyphosphate were added to the three types on natnral cheeses: Emmental, Gouda and Cheddar. The functional properties of the resulting products such as meltability and stringiness were determined and compared with those of the cheeses cooked without these emulsifying salts. The functional properties of each cheese changed with holding temperature and time after cooking. It was indicated that in the of absence of the emulsifying salt, these functional changes were associated with the amount of non-ionic calcium in cheese rather than cheese age, while they were strongly related to the type of emusifying salt when the emulsifying salt was added approximately 2% to cheese.

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The change in the structure of sesame seed during processing was observed by using a scanning electron microscope. Oil droplets were observed both in the raw and parched seeds. Membranous structure connecting oil droplets together shrinked with parching. Cell wall structure around oil droplets expanded by soaking sesame seeds in water for 3h, resulting in distortion of the cell. By parching this soaked sesame seeds, cell wall was destroyed and oil droplets almost disappeared.

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Minimum inhibitory concentration (MIC)of polyphenolic components of tea againstwell known 16 strains of foodbornepathogenic bacteria was determined. As teapolyphenols, "crude catechins"from greentea extract and its four components, and "crude theaflavins" from black tea extractand its four components were used. Theresults showed tha these tea polyphenolshad antibacterial activities against Vibrioparahaemolyticus, V. fluvialis, V. metschnikovii, Staphylococcus aureus, Clostridiumperfringens, Baeillus cereus, Plesiomonasshigelloides, and Aeromonas sobria. Butthey hardly had the activities against A.hydrophila subsp. hydrophila, Salmonellaenteritidis, S. typimurium, enteropathogenic Escherichia coli, enteroinvasive E. coli, Yersinia entergeelitica, Campylobacter coli, and C. jejuni.

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Effects of cooking temperature and pH on emulsion stability of melted cheese in the absence of emulsfying salt were investigated. Five types of cheese whose pH ranged from 5.1 to 5.7 were cooked at 60, 65 and 70°C, respectively. Maximum water content levels of these cooked cheeses were then determined. It was found that the maximum level of each cheese decreased with increa sing cooking temperature, and was also dependent on initial pH of each cheese rather than on finally adjusted pH of it. The cheese whose initial pH was nearly 5.5 showed the highest water content level among the five.

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Effects of protease treatment on textural properties of wheat flour dough were investigated. The enzymes used were bromelain, papain, two kinds of fungal protease (Denazyme and Amano-A) and bacterial protease (Bioprase). The maximum amylograph viscositiy of wheat flour, for both of hard type and medium type flour, decreased with an increase in the concentration of protease added. For the farinogram properties of wheat flour, these proteases decreased the dough development time and stability, and increased the weakness. The effects of bromelain were the most remarkable among the five proteases. On the extensography, an increase in extensibility and a decrease in resistance to extension were observed with increasing concentration of the protease. Bromelain was effective to dough of both types of flour, but papain and Denazyme were only effective to dough of medium type flour. Other proteases were less effective to dough of any type.

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A basic study on the operational conditions of Kamaboko steamer linked with a microcomputer was carried out. The box temperature was controlled at 40°C (corresponded to Suwari temperature) or 90°C (Mushi) by steaming directly or by circulating hot water through the heat exchange pipe. The distribution of the box temperature was reduced by decreasing the time interval of sampling of signal and by increasing the fuel gas flow rate. However, the flow rate had little effect on the distribution when the temperature was set at 40°C. The circulation of hot water was less effective than steaming. The energy efficiency of the steamer under model operation was improved by increasing the fuel gas flow rate during the transitional period from Suwari to Mushi. The time schedule of heating process could be established by applying the numerical equations obtained.

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