Investigation of heat transfer in the food heated by far-infrared radiation is important for development of efficient heating process, since far-infrared radiation has recently been used in the process of food industry. To predict temperature profiles in the food, two mathematical models were studied. One is the model that some of the irradiated energy penetrates into the food. Another is the model that all of the irradiated energy are absorbed at the food surface. There was no significant difference in calculated results between these two models, and it was found that the penetration of far-infrared radiation energy did not affect the temperature distribution in the food. Therefore, the latter model was used to examine the influence of the temperature of a far infrared radiation heater and convective heat transfer coefficient on heat transfer in the food. To check the mathematical models, far-infrared heating experiments were carried out. Calculated temperature distribution in the food was in good agreement with experimental data.

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The present study was designed to examine the effects of high pressure on the survival of microorganisms in Surimi (fish paste) and the leakage of materials from bacterial cells treated with high pressurization. The number of survivors in Surimi decreased rapidly after the high pressurization. The most of microorganisms in Surimi was killed by the treatment of high pressure between 300 and 400MPa, and fungi, Gram negatives and Gram positives were sensitive to high pressure in this order. Several pressure-resistant strains were isolated from Surimi and were identified as Moraxella sp. (viable at 200MPa), as Acinetobacter sp. (viable at 300MPa), as Streptococcus faecalis (viable at 400MPa) and as Corynebacterium sp. (viable at 600MPa). It was consequently found that the sensitivities of bacteria in Surimi to high pressurization were different considerably. Examination of the growth curve of each strain treated with high pressurization showed that the starting point of growth curve was retarded more than non-tr ated specimen. Especially the growth of S. faecalis treated with high pressure of 400MPa was retarded abut 20 hours more than non-treated specimen. The release of metal ions from bacterial cells was detected after pressurization. Fe and Mg ions were released particularly. From the leakage of 260nm absorbing substances, orcinol reaction positive materials like RNA and carbohydrates from bacterial cells after treatment of high pressure, it was suggested that the damage of the cell membrane and degradation of ribonucleic acid took place the high pressure treated cells.

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Polygalacturonase (PG) was isolated from satsuma mandarin fruits (Citrus unshiu Marc.) stored in cold (5°C) for five months and the properties of the enzyme were investigated. From the slight lowering of viscosity and raising of the liberation of reducing sugar from pectate, this PG was found to be exo-polygalacturonase. The activity of the PG was 137.3units/g fresh weight of satsuma mandarin fruits peel. The pH optima for the PG was 4.5. The temperature optima was 40°C. The activity of the PG was decreased to 50% when the mixture was heated at 60°C for 15min. When the substrate (MW: 6000 -100000) was acted by exo-PG, the rate of reaction with the low molecular weight substrate was higher than the high molecular weight substrate.

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In order to clarify the mechanism of gelatinization of starches inside cells, a separation method of cotyledon cells of Adzuki bean (Vigna angularis) without gelatinizing starches has been developed. Gelatinization of starches inside cells and of isolated starches have been examined. Cotyledon cells were obtained by passing cotyledons, which were previously treated with acid and alkali successively, through a 83-mesh screen by reasonable force. The proportion of intact cells was estimated to be 90.7%, which indicated that the cells separated were well suited for studies on gelatinization of starches inside cells. When cells and isolated starches were heated in water at temperatures above 70°C, the solubility and swelling power of starches inside cells were extremely low, compared with those of isolated starches. The loss of birefringence of starches inside cells was also low at 70 to 80°C. When cells and isolated starches previously heated in water were homogenized, the solubility, swelling power and loss of birefringence of starches taken out from cells by homogenization were lower than those of isolated starches. These results showed that the gelatinization of starches inside cells was suppressed, compared with that of isolated starches.

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Sediment formation of rice vinegar was studied to maintain vinegar quality for a longer period. The main component in the sediment was protein. The browning component of the sediment was extracted with a chloroform-methanol solvent and was mainly attributed to the hydrolysates of rice, koji and enzymes used in the fermentation process. Perfect prevention of the sediment formation in rice vinegar was attained by ultra-filtration with a membrane cutting off at molecular size up to 13000. The sediment preventive activity of many substances (polysaccharides, synthetic high molecular compounds, adsorbents and coagulants) were tested, and it was found that an addition of xanthan gum, carboxy methyl cellulose (CMC) and sodium polyacrylate to vinegar was useful. An addition of bentonite was also effective at 80°C. Xanthan gum, CMC and sodium polyacrylate. dissolved in vinegar may act as stabilizer for the prevention of the secondary sediment. Ultra-filtration and bentonite-treatment could only remove the sediments from rice vinegar and it was presumed that no artificial materials were remained in rice vinegar obtained from ultra-filtration and bentonite-treatment. From the above results, the ultra-filtration process and bentonite treatment at 80°C were found to be favorable in maintaining rice vinegar quality against the secondary sedimentation.

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Partially processed carrots were prepared as two styles, lengthwise cut sectionsdivided into eight equal parts (1/8 LCS) and crosswise cut sections with 1cm thickness (1 CCS). These sections and whole carrots were exposed to continuous flow of atmosphere with or without 100ppm ethylene in air at 20°C. In 1/8 LCS and 1 CCS the occurrence of bitterness and astringency, the appearance of brown pitting injury in cut surface, the formation of isocoumarin responsible for bitterness, and rapid increase of phenols were induced by ethylene during 5days storage, whereas, these changes were not noted in whole carrots exposed to ethylene, 1/8 LCS and 1 CCS exposed to air. Partially processed carrots of 1/4 LCS were sealed in low density polyethylene (0.05mm thickness) or polypropylene (0.025mm thickness) bags into which 100ppm ethylene was injected and stored at 20°C. Ethylene did not induce bitterness of carrot in both bags during 10days storage.It is possible that the decrease of O₂ concentration and the increase of CO₂concentration in bags were responsible for the inhibition of producing bitter compounds by ethylene.

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Iron binding capacity of plasma proteins from slaughtered pig were investigated with a view to using them as iron binding materials in food processing. Iron content of samples (SI) and unsaturated iron binding capacity (UIBC) were measured according to Nitroso-PSAP method. Total iron binding capacity (TIBC) and saturation percentage (S%) were calculated from following equations; TIBC (μg ·Fe/g)=UIBC+SI, S%=(SI/TIBC)*100. TIBC of plasma proteins was higher than that of whey powder, but lower than that of egg white powder. Iron saturation percentage of plasma proteins was about 50%, which was higher than that of whey or egg white powder. It was possible to obtain a fraction having high iron binding capacity from plasma proteins by ion-exchange chromatography. Iron binding capacity was stable in neutral or alkaline pH region during storage of plasma protein solution at 4°C. On the other hand, iron binding capacity was stable in acidic pH region during heat treatment of plasma protein solution at 80°C. Iron bindingcapacity decreased remarkably with peptic hydrolysis of plasma proteins. We concluded that it is possible to develop food materials having iron binding capacity from plasma proteins.

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A pre-fermentation moromi mash, made from a soy sauce koji autolyzate and sodium chloride, was subjected to fermentation processes in 44kl tanks for soy sauce manufacturing by inoculating salt-tolerant lactic acid bacteria (Pediococcus halophilus) and yeasts (Zygosaccharomyces rouxii and Candida versatilis). Fermentation method used was a modified 1 tank-2 steps method in which the pre-fermentation moromi mash containing about 13% (w/v) of sodium chloride was inoculated by P. halophilus and C. versatilis simultaneously to start the first step fermentation (mainly lactic acid fermentation), and incubated at 30°C for 14 days. The moromi mash was, then, divided into two equal portions and each portion was mixed by an equal volume of freshly prepared pre-fermentation moromi mash. Sodium chloride was dissolved to a concentration of about 15-16% (w/v) in the mixed moromi mash, and the mash was inoculated by Z. rouxii to induce the second step fermentation (mainly alcohol fermentation) and was kept at 28°C for 45 days. After the second step fermentation, incubation was allowed to continue at 25°C for additional 30 days for maturation. In the moromi mashes, production of lactic acid proceeded smoothly and that of ethanol ceased before excess consumption of reducing sugars. Matured-flavor compounds such as 4-ethylguaiacol, 4-ethylphenol and 2-phenylethanol were detected in the filtrate of the mash obtained after the second step fermentation, and well-balanced kiage (non-heated soy sauce) was produced within three months. Composition of the kiage thus prepared was very close to that of the kiage made by the conventional method and the former was not distinguished from the latter by a sensory test.

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Inhibitory effects of 142 kinds of plant extracts on the growth of food-borne bacteria, yeast and molds were investigated. Extraction was carried out with 70% ethyl alcohol. To detect the inhibitory effects of plant extracts, 10 kinds of microorganisms were used with the cup assay technique. The following 17 samples showed the antimicrobial action to one or almost all kinds of microorganisms tested. Some of them were effective to suppress the growth of food poisoning bacteria, Lactobacillaceae and my cotoxigenic molds.
Alpinia katsumadai, Alpinia officinarum, Artemisia capillaris Thunb, Cassia obtusifolia L., Dendrobium moniliforme L., Epimedium grandiflorum Moore, Glycyrrhiza glabra L., Lithospermum erythrorhizon Sieb. et Zucc., Magnolia obovata Thunb, Morus bonbycis, Natopterygii incisium, Polygonum multiflorum Thunb., Prunus mume Sieb. et Zucc., Rheum palmatum L., Ricinus communis L., Sophora flavescens Ait., Swertia japonica Mak.

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The effects of pH metal ions and ascorbic acid on the formation of yellow pigments from 1-(2'-pyrrolidinethion-3'-y1)-1, 2, 3, 4tetrahydro- β-carboline-3-carboxylic acid (PTCC) were investigated by using UV spectrometry and HPLC analyses. The formation of yellow pigments was enhanced with increasing pH of the reaction mixture. The presence of Fe (II) and Cu (II) (50μM) increased the formation of yellow pigments a little, but the addition of ascorbic acid (5mM) decreased it. When a methanol solu- tion of the yellow pigments was subjected to Sephadex LH-20 column chromatography, their discolorlation was observed. As a result, a paper chromatography showed that the yellow pigments were consisted of three fluorescent components. From the UV spectral and the fluorescent characteristics, it was presumed that these compounds have β-carboline as a common structural moiety.

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This study was conducted to investigate the flow behaviors of Chinese yam pulp and its serum with a concentric cylinder visco-meter.
Both pulp and serum showed a power law fluid behavior at shear rates ranging from 0.1-20 s^-1. Activation energy of the serum was 1182cal/mol. In addition, serum showed a time dependency, and marked shear decay was observed at shear rates of more than 1.02 s^-1.

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