Recently, oligosaccharides have been acknowledged to have physiological activity and many of them have been used for food. These oligosaccharides are generally produced from various food materials using bioreactors are separation systems. We studied the separation properties of nanofiltration membranes for model oligosaccharide solutions, and applied them to purify oligosaccharides extracted from Jerusalem artichoke (Helianthus tuberosus L.) to develop an oligosaccharide purification system with nanofiltration processes. The observed rejections (R_obs) and the permeate fluxes (J_v) of four membranes, G 5, G 10, G 20 and G 50, for oligosaccharides having smaller pore sizes in the order in G 5<G 10<G 20<G 50, were evaluated by the batch filtration at various pressures. In all of the membranes, J_v increased linearly with pressure. The R_obs increased with the molecular weight of oligosaccharide. The R_obs for each oligosaccharide became low in sequence from G 5, G 10, G 20 and G 50. It appeared that G 5, G 10 and G 20 had effective pore sizes to separate the oligosaccharides, and G 50 could remove high molecular weight molecules over 10, 000 Daltons. The extract of Jerusalem artichoke contained fructo-oligosaccharides linking from 2 to 10 sugar units. In the extract filtrations, membranes rejected oligosaccharides almost in the same level as the model filtration, however, the fluxes decreased with increase in the concentration of saccharide and/or high molecules in the extract.

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'Ume-zuke', a salted ume-processed product which is manufactured from ume fruit (Japanese Apricot, Prunus mume Sieb. et Zucc. var. microcarpa Makino) by salting with sodium chloride, is one of the traditional food produced in Japan. There is a serious problem about deterioration of 'Ume-zuke' by film-forming yeast in recent trend of reducing salt concentration in food products. In present study, to clarify the mechanism in evolution of contamination with film-forming yeast in 'Ume-zuke', isolation, identification, and characterization of yeast, the surveying on the time course of changes in yeast flora, and some constituents in the decomposed 'Ume-zuke' sample during salting process were performed. All isolates were identified on the basis of standard biochemical and morphological tests as Kloeckera apiculata (17 isolates), Pichia anomala (37 isolates), Candida guilliermondii (14 isolates), Debwyomyces hansenii (29 isolates) and other un-identified Candida sp. (8 isolates). As a result of surveying of changes in yeast flora, K. apiculata from ume fruit was the dominant species at initial stage, but decreased progressively. On the other hand, with the salting period progress, strains of P. anomala, C. guilliermondii and D. hansenii increased subsequently. At the last stage of salting period, strains of D. hansenii were only detected after the rise of the pH of 'Ume-zuke'. And, successive decrease of organic acid content and the pH rise in 'Ume-zuke' caused by assimilation of P. anomala was observed. In conclusion, these results support the following mechanism. P. anomala which showed rapid growth and strong assimilation ability of organic acids in 'Ume-zuke' was the main film-forming yeast species together with C. guilliermondii promoting yeast contamination by pH rise in 'Ume-zuke'. And, D. hansenii and other yeasts increased because of pH rise, and its growth spread the yeast contamination.

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A procedure was developed for an on-line control system to achieve the correct heat sterilization for conduction-heated food considering the come-up delay in heating the retort. The procedure collects a series of time/temperature data via a sensing probe during the early stage of the heating sterilization process, and analyzes the collected data for parameters of conduction heating. Using these parameters it predicts the temperature history for the remainder of heating phase and during cooling, integrates the lethal rate, and determines an appropriate time to start cooling to achieve a designed lethality. The experiment using acrylic resin as the model food, achieved the designed lethality within 5.7% for an infinite slab and 6.8% for an infinite cylinder. This validated that the inversion method of this study was applicable to the cases where the report temperature has a come-up delay.

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We have already reported the aluminium binding ability associated with organic acids, polyphenol compounds and dietary fiber³⁾. Aluminium ions were easily bound to citric acid, oxalic acid and tannic acid. Organic acids and polyphenol compounds are commonly co-existing in foods. Absorption amount of aluminium may be influenced to co-existing ligands. Binding property of aluminium ion with citric acid or oxalic acid was investigated in the presence of polyphenol compounds. Consequently, the binding ability of aluminium ions was increased by oxalic acid in the presence of polyphenol compounds.

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The influences of sugar alcohols on hardening and water mobility of wheat starch gels stored at 2°C were investigated by kinetic treatment on rheological parameters (creep compliance) and by ¹⁷O-NMR technique. In general, the hardening process of sugar alcohols-supplemented gels could be separated into the four regions similar to that of saccharides-supplemented gels in the previous report. The initial creep compliance (J_0I) of all the sugar alcohols-supplemented gels became smaller than that of control gels, indicating that the gels became harder. Sugar alcohols-supplemented gels also appeared to be harder than the saccharides-supplemented gels in the most cases. Commercial hydrogenated malto-oligosaccharides and hydrogenated isomalto-oligosaccharides reduced the hardening rate constant, but meso-erythritol, D-xylitol, D-arabitol, D-ribitol and D-sorbitol increased the constant compared with the control gels. Apparent transverse relaxation time T₂ was reduced by addition of meso-erythritol, maltitol, D-sorbitol and D-arabitol compared with the control gels, and the values gradually decreased during the storage period. But no remarkable differences were observed among the effects of sugar alcohols on T₂ during storage, gel hardening rate and water mobility in the gel could not be related clearly.

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To efficiently produce a fermented flavored liquid for improving the taste of bread, we studied repeated batch fermentation in a bioreactor with the use of immobilized yeast cells. By using the bioreactor, a fermented flavored liquid containing about 5% (w/v) ethanol could be constantly produced. However, the bacterial count in the fermented flavored liquid gradually increased as the batch fermentation was repeated and reached 10⁷ CFU/ml on the day 12. The growth of the bacteria separated from the fermented flavored liquid could be stopped at a lactic acid concentration of 0.25% (w/v). Lactic acid at this level did not affect the growth of the test yeast. When 0.4% (w/v) of lactic acid was added at the initiation of the culture in the repeated batch fermentation, the bacterial count in the fermented flavored liquid rapidly decreased and reached almost 0. An increase in the bacterial count could be inhibited by subsequently adding 0.2% (w/v) of lactic acid. When the addition of lactic acid was ceased, there was observed a tendency toward an increase in the bacterial count. After storing at 10°C for 16 days, the immobilized yeast cells enabled the production of the fermented flavored liquid similar to the one before storing. Regarding the major flavoring components in the fermented flavored liquid, the concentrations of ethyl acetete, isoamyl alcohol and isobutyl alcohol remained relatively constant, while organic acid concentrations considerably varied.

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Effects of the conditions of processing and a kind of fish on the physical properties of Kamaboko gels were investigated and following results were obtained. (1). Seventeen kinds of commercial Kamaboko showed different and characteristic physical (textural) properties depending on fish species (walleye pollack, sharp-toothed eel, croaker). (2). The laboratory-prepared Kamaboko that were indistinguishable each other as to their physical properties in terms of the jelly strength were distinguishable by the technique used in the present study. The present technique correlate well with sensory method in evaluating textural properties. (3) With increasing the added water, the values of mechanical parameters corresponding to fracturability of the laboratory-prepared Kamaboko increased, but those to elasticity and hardness decreased. With increasing the added starch, the values of mechanical parameters corresponding to fracturability tended to decrease but those to hardness tended to increase. The higher the heating temperature, the larger the values of mechanical parameters corresponding to fracturability, elasticity and hardness. The values of mechanical parameters corresponding to fracturability decreased with storage time.

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Katsuobushi was extracted with electrolyzed water which was obtained by electrolyzation from city water. The maximum amount of IMP was obtained by the extraction with basic water of pH10.0. The highest concentration of glu-tamic acid was obtained with the water of pH 10.0. By sensory evaluation, the extracts with the basic water of pH9.0 had the highest umami. Moreover it was found electrolyzed water in-fluenced the strength of sourness and smell of the extracts.

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Antioxidative activity of alcoholic extracts of polyphenols from barley bran (polyphenol ex-tracts) was studied. The extracts were prepared by following procedures. After removal of lipid by n-hexane from barley bran, it was extracted with 75% ethanol. The crude extracted solu-tion was washed and purified by a Sepabeads SP -850 resin. This polyphenol fraction was eluted from the resin with 75% ethanol and evaporated under 30°C, and then freeze-dried. The poly-phenol content of the extracts was 28.7% as (+)-catechin. Antioxidative activity of the poly-phenol extracts to linoleic acid was found to be the same or less than that of BHA and BHT, but higher than that of dl-a-tocopherol and ascorbic acid by using the TBA and ferric thiocyanate methods. The polyphenol extracts showed more effective super oxide scavenging ability than that of dl-a-tocopherol, BHA and BHT.

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"Hanpen"-like whipped sausages with powdered yam as a foaming material were produced and evaluated by an organoleptic test and texture analysis. As the results of using a continuous whipping machine, cohesiveness of the product decreased only about 20%, but hardness, adhesiveness and gumminess decreased 67-75%. Ten% fat content was most desirable in an organoleptic test. In the experiment, the organoleptically most desirable fat and powdered yam content were 10% and 1%, respectively. Varying the specific gravity by the amount of flowing air of a continuous whipping machine, the specific gravity of the organoleptically most desirable product was 0.6±0.05. Xanthan gum and/or monoglyceride were added to improve the form stability and emulsification of products. Each evaluations of the added products was higher than a product with no addition.

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