Extensive screening for β-glucanase-producing fungi for mugi miso-koji (barley-koji) was done. Seventeen strains of Aspergillus oryzae and 6 strains of Aspergillus soyae assayed for their β-glucanase and glucose forming activities after barley solid cultivation. There was a roughly proportional relationships between β-glucanase and glucose forming activities (the liner correlation coefficient, R, 0.4596). As the most potent fungus having the highest β-glucanase and glucose forming activity, A. oryzae IFO 7410 was selected. β-Glucanase endohydrolase was purified from barley solid culture filtrate of A. oryzae IFO 7410 by chromatographies on gel filtration (TOYOPEARL HW-55) and ionexchange (SP-TOYOPEARL 550). The purified preparation showed a single protein band on SDSPAGE. The molecular weight of purified enzyme by SDS-PAGE was 34, 000. The purified enzyme had optimum β-glucanase activity at pH 4.5 and 40°C, and was stable in the range of pH from 4.0 to 7.0 and up to 50°C. The specific activity of the enzyme purified 77-fold of the crude extract enzyme. The analysis of substrate specificity suggested that the enzyme is likely to be 1, 3; 1, 4-β-glucan 4-glucanohydrolase. It considered that the β-glucanase of barley-koji contribute to increase sugar contents in mugi miso making (barley-koji miso).

View full abstract

As a part of effective utilization of Okara (by-product of Tofu processing), some baking characteristics, palatability of the product and oxidation stability of lipids contained were studied. The POV data showed that cookies contained Okara from 0 to 10%, 20% and from 30 to 50% were kept bellow 30meq/kg for 430 days, 330 days and 200 days respectively. The tendency of decreasing anti-oxidant activity by increasing amount of Okara to cookies was due to excess burning phenomenon by heat. Fracture test of cookies contained Okara by compression showed lack of shortness. On the other hand, pound cake contained Okare showed sufficient swelling and softness. Both of cookies and pound cake contained from 10 to 20% of Okara were evaluated high palatability by sensory test of young women panel.

View full abstract

The quality characteristics of four potato cultivars for chips (Toyoshiro, Hokkaikogane, North Chip and Line P982) during storage at 2°C and 6°C were examined. Chemical composition and physical properties of potato tubers and the appearance of the chips obtained from the potato tubers were evaluated every 30 days for 180 days. Reducing sugar content and chips appearance as well as sprout growth differed depending on the cultivar and storage temperature. The reducing sugar content increased after the first month of storage in all treatments. Sprout growth was completely inhibited in all of the tubers stored at 2°C, while it was delayed in the tubers stored at 6°C. Chips obtained from the low temperature resistant cultivars of potato tubers (North Chip and Line P982) stored at 6°C for 6 months showed an acceptable color for commercial purposes.

View full abstract

For the purpose of cultivating high-quality mitsuba (Japanese honewort, Cryptotaenia japonica Hassk, cv. 'Osaka-Shiroguki Mitsuba') without reducing its yield, the differences in physiological and chemical properties with varied durations of concentrated solution culture in mitsuba were determined in this study. The following four test lots were established for the solution culture of mitsuba : Control lot (cont.) -cultivated with 0.5 unit culture solution for 30days from planting to harvest, 10-day lot (10d) -cultivated with 0.5 unit for 20 days from planting and with 1.5 unit for the remaining 10 days, 20-day lot (20d) -cultivated with 0.5 unit for 10 days from planting and with 1.5 unit for the remaining 20 days, and 30-day lot (30d) -cultivated with 1.5 unit for the duration of cultivation. The yield was highest in cont., and the longer duration of 1.5 unit solution culture resulted in the shorter plant length during cultivation and the lower yield. The shorter duration of 1.5 unit solution culture caused the lighter green leaf colors and higher lightness. In the sensory evaluation, the flavor of cont. lot was weaker than that of 30d. But there were no significant differences in flavor among 10d, 20d and 30d. Freshly harvested mitsuba was divided into leaf blades and stalks to determine the contents of chemical components (chlorophyll, phenols, free amino acid) for each portion of the plant. The contents of these components were higher in the leaf blades than in the stalks. Also, the contents of these components were lowest in cont. for both portions and increased in proportion to the duration of 1.5 unit solution culture. The respiration rate was higher with the leaf blades than with the stalks and lowest in cont. for both portions, and rose in proportion to the duration of 1.5 unit solution culture.

View full abstract

Chemiluminescence (CL) analysis was attempted to evaluate the quality of buckwheat under the various storages. Buckwheat was stored at 30°C for 60 days with or without vacuum packaging. After every 30 days storage, buckwheat hull and flour from buckwheat were determined the acid value (AV), peroxide value (POV), content of total polyphenol and rutin. CL intensity was measured at 30°C for 17.5 min at 30 (s) gate times. AV of buckwheat hull and flour were increased with storage periods. POV of buckwheat flour increased with storage period, however, POV of buckwheat hull increased at 30 days storage and then decreased at 60 days storage. Changes of AV and POV correlated closely with the quality deterioration progressed with storage period. Content of total polyphenol and rutin in buckwheat hull and flour decreased with storage period, and vacuum packaging inhibited decrease of polyphenol and rutin. CL intensity of buckwheat and buckwheat hull shows no correlation with index of lipid deterioration. But CL intensity of buckwheat flour increased with storage period; therefore it was considered that CL analysis was correlation with quality deterioration of buckwheat flour.

View full abstract

Changes in the activity and some characteristics of NADP-dependent isocitrate dehydrogenase (NADP-IDH, EC 1. 1. 1. 42) of banana [Musa spp (AAA group, Cavendish subgroup)] fruit during postharvest ripening were investigated. The activity was about 2.7-fold higher in yellow (ripe) fruit than in mature green fruit. These activities were NADP-dependent in both stages of fruit, but the degree of Mg²⁺ dependency was slightly higher in mature green fruit than in yellow fruit. The Km values of the enzyme for DL-isocitrate in mature green and yellow fruit were 48. 4μM and 59.5μM, respectively. While the value for NADP⁺ in mature green fruit was 6.14μM, that was 11.56μM in yellow one. The elution pattern of gel filtration showed that yellow fruit have different peaks for these activities from mature green fruit. From these results, NADP-IDH in banana fruit may change their isozymes which have different Km values during postharvest ripening.

View full abstract