In order to study the food preservative effect of ozone, microbicidal effect of ozone in aqueous solution were investigated employing Aspergillus spores, Penicillium spores, yeasts, yeast spores, lactic acid bacteria and Bacillus spores. The condition to evaluate the microbicidal effect on various microbial suspensions of 106-9/ml was: ozone gas concentration, 0.3-0.5mg/l, time 5S-4h, flow rate 1455ml/min, and temperature 5°C and 20°C. Result were as follows: 1) Microbicidal time of the microbial suspensions were: Aspergillus spores, 90-180min; Penicillium spores, 45-60min; yeasts, 5-10min; yeast spores, 8-10min; lactic acid bacteria, 15-120S; Bacillus spores, 180-240min; and Candida paracreus, 60min. 2) Lower pH value and lower temperature resulted in greater microbicidal effect. 3) Microbicidal effect of ozone against all the tested microorganisms was elevated by the addition of 1-5% sodium chloride and lowered by the addition of 1-10% saccharose. Furthermore, the effect against yeasts and Bacillus spores was lowered by the addition of wheat flour, whereas that against molds was elevated by the addition of wheat flour at a concentration of 0.2-1.0%. Accelerating effect of garlic powder was seen only against Bacillus spores at a concentration of 0.2-1.0%.

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The enzymic browing of extracts from cocoa, coffee and tea was examined using the polyphenol oxidase from Alternaria tenuis strain A-2 and applications of the enzyme were developed. Fermented cocoa was more easily oxidized than unfermented or roasted ones. All cocoa extracts became deeper brown as a result of the enzymic oxidation. Raw cocoa beans which corresponded to fermented cocoa beans were prepared by treating unfermented ones with the enzyme. Coffee extracts were also oxidized by the enzyme. Green coffee turned brown, and roasted one became deeper brown on account of the enzymic oxidation. Darker colored coffee beverage was prepared by the enzymic treatment of instant coffee. Green tea was readily oxidized by the enzyme and turned brown. Instant tea was prepared by converting green tea to black tea using the polyphenol oxidase.

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The purpose of this paper is to obtain basic data to calculate the amount of ice required for an ice bunker in forced convection type precooling and cold storage facilities. The melting phenomena of an ice sphere placed in forced air convection was investigated experimentally. The results are as follows: 1) The total heat transfer rate to an ice sphere can be obtained as the algebraic sum of free convection, radiation and condensation heat transfer rates. 2) An ice sphere melted in an almost spherical shape on the front hemisphere, while it changed to an anomalous shape on the rear hemisphere. There was a stagnant point on each hemisphere. 3) Separation point moved backward with melting. 4) Local Nusselt and Sherwood numbers were larger near the both stagnant points and smaller at the separation point than any other points. The dependence of these values on Reynolds number was minimum near the front stagnant point and maximum near the rear stagnant point. 5) When Reynolds number was constant, there was a tendency that local Nusselt and local Sherwood numbers increased with turbulent intensity. 6) Average Nusselt and Sherwood numbers were given by the following equations: Nu_Q=2+0.46 Re^0.51 Pr^1/3, Sh_Q=2+0.46 Re^0.51 Sc^1/3. Average Nusselt and Sherwood numbers were smaller than those in the heat transfer without fusion, presumably due to the resistance of melted water film to heat transfer.

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Flavonoid pigments were prepared from peanut skin or cocoa shell by treatment with microbial polyphenol oxidase. The extracts from peanut skin or cocoa shell turned brown with the polyphenol oxidase from Alternaria tenuis strain A-2. Impurities in the brown pigment solutions thus obtained were removed by the addition of ethanol followed by centrifugation, and then the brown pigments were precipitated by adjusting the solutions to pH 12 with sodium hydroxide. The precipitated pigments were dissolved in a small quantity of water, and the pigment solutions were powdered by freeze-drying after adjusting them to pH 6.5 with hydrochloric acid. The yield of peanut pigment or cocoa pigment was 15 0 or 16.5%, respectively. The flavonoid pigments thus obtained were water soluble and the color of them changed to orange-yellow with decreasing pH. These flavonoid pigments were stable against heat and light. Metal ions other than ferrous ion did not affect their color. While the peanut pigment was stable against chemical reagents, the cocoa pigment faded slightly with ascorbic acid or isoascorbic acid. The flavonoid pigments were good dyestuffs in acidic solutions and had a great affinity for wheat gluten. These pigments were applicable to drops, cookies or soft adzuki-bean jelly.

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The previous methods for recovery of yeast proteins and reduction of the nucleic acid content resulted in low yields of the protein and impairment of the desirable functional characteristics. In this paper, emulsifying properties of yeast protein isolates prepared with three different methods (yeast protein isolate I, II and III) were studied in comparison with those of a soy protein and a caseinate at various pH's, ionic strengths and lecithin contents (%). The emulsifying capasity of the yeast protein isolate I prepared by the method of authors were far superior to those of the soy protein and caseinate, especially in acidic and alkaline region. However, yeast protein isolate II and III prepared by the previous method gave low emulsifying capacity, which was similar to those of the soy protein or caseinate. From these results, it was suggested that emulsifying properties of the yeast protein isolate was largely influenced by the preparation methods of the protein.

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Changes in quality of green Kabosu fruit (Citrus shaerocarpa Hort ex Tanaka) were investigated during cold storage and controlled atmosphere storage (CO₂:O₂:N₂=1:9:90 and 3:7:90) at 5°C. (1) The color change of the rind from green to yellow was retarded in CA storage. The storage life of Kabosu was prolonged markedly by controlled atmosphere of 3% CO₂ and 10% O₂. (2) The amounts of sucrose, titratable acid (in juice sac) and chlorophyll (in rind) in the fruit decreased gradually under all storage conditions. The decreasing rate of titratable acid and chlorophyll was less in the fruit stored in CA condition of 3% CO₂ and 10% O₂. (3) The result of organoleptic test showed that the fruit stored in CA condition kept strongly characteristic aroma and flavour of Kabosu during storage. (4) Pretreatment of curing before storage was effective to keep fruit quality during CA storage. Cured fruit continued to remain a high percentage of titratable acid and juice volume.

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Air borne microbes in a confectionery factory were surveyed by means of the pin hole sampler method over a year from January to December, 1980. Average contents of fungi and bacteria were 0.45 and 0.31 per 1 of air throughout the experimental period. Microbial contents showed a tendency to increase to some extent in the fall, although differences were not significant among the air samples in every season. The bacterial flora consisted largely of gram positive spore forming rods and gram positive cocci, and the main fungi were Penicillium, Aspergillus and Cladosporium. Particularly, Penicillium spp. were the most commonly and predominantly identified throughout the year. Penicillium spp. were the most common mold on the surface of ceiling, walls and so on.

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The effects of preparing conditions on the rheological properties of soybean milk were investigated. The flow curves of soybean milk containing 4.0 to 6.4% protein exhibited non-Newtonian behavior and were approximated by the power law flow expressed as τ=K(D)n. The value of flow behavior index, n, of "soybean milk" before heating was 0.50 to 0.55. In protein concentrations below 4.9%, the flow behavior index did not changed remarkably and the apparent viscosity increased slightly by heating at 100°C. The rheological properties of soybean milk containing 5.9% protein, the optimum concentration for making kinugoshi-tofu, changed remarkably by the heating. Namely, heating caused a considerable increase in the apparent viscosity and a decrease in the flow behavior index. In this case, therefore, the analysis of rheological properties should be useful for rational operation and control of the process for making soybean milk.

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Thirty five samples of sardine frozen surimi commercially prepared from November 1979 to May 1980 were examined for quality characteristics such as Chemical composition, kamaboko forming capability etc. The results were as follows. (1) Wide seasonal variations in chemical composition of sardine frozen surimi were found; moisture content 70.0-76.8%, crude lipid content 2.0-8.3%, crude protein content 13.3-17.6%, extractive nitrogen content 55-149mg-N/100g and pH 6.89-7.12. (2) The quality factors of kamaboko cooked at 85°C varied also widely with the season of year; jelly strength 63-617g·cm, folding test C-AA, Hunter's whiteness 16.8-29.2 and lightness 48.9-64.6. The kamaboko forming capability was the best in January and the worst in March-May. The whiteness of kamaboko was the maximum in November and the minimum in March. (3) Little change in kamaboko forming capability was found during cold storage at -30°C of sardine frozen surimi from 3 to 6 months.

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