In recent years, the production of bread using the frozen dough method has rapidly spread in the baking industry. However, there are some limitations of the frozen dough method, which are not completely resolved. Therefore, in this study, we focused on the characteristics of wheat flour used for the frozen dough method. In other words, we evaluated the suitability of various blended flours made from two types of domestic flours (extra-strong flour "Yumechikara flour" and strong flour "Haruyokoi flour") using the no-time frozen dough method. The characteristics of doughs and breads made from domestic flours were compared to those of doughs and breads made from commercial flours. The doughs made from the domestic flours blended in an appropriate ratio showed high gas-retention ability during storage under frozen conditions; also, the breads made from these doughs showed high specific loaf volume, good appearance, and preferable crumb grain during storage. In addition, the breads obtained from the frozen doughs with blended flours stored for 14 days showed significant improvement in physical (staling and rupture characteristics) and sensory properties compared to the breads obtained from commercial strong flour. The main reason behind the preferable frozen dough properties of blended flours was the improvement of dough freezing tolerance accompanied by the high protein content and tough gluten network of the extra-strong flour ("Yumechikara flour"), which was related to the reinforcement of the dough's physical properties.

　The Japanese chestnut (Castanea crenata Sieb. et Zucc.) "Porotan" has excellent peelability, but its quality deteriorates during storage and heat-processing. We investigated the effects of storage temperature and peeling timing on chestnut quality after steam treatment of "Porotan". The chestnuts were subjected to five processing strategies with different storage conditions, and their peelability, color tone, fruit cracking, and physical properties after storage were evaluated. First, regarding peelability, no clear differences were observed among the five processing strategies. Second, on measurement of color tone by using a color reader (L^＊, a^＊, and b^＊ values) after steam treatment, discoloration was noted especially after refrigeration storage (R) along with the occurrence, but it hardly occurred under freezing conditions (F), after refrigeration and under freezing conditions (RF), after refrigeration for 1 month followed by peeling and further storage under freezing conditions (RPF). Furthermore, occurrence of mold was observed after R. Third, fruit cracks were observed in all chestnuts at the start of storage (S) and after storage under F, whereas the number of fruit cracks decreased after R and RPF. Finally, with respect to physical properties, chestnuts under RPF tended to soften after steam treatment compared to those under R. Together, these results indicate that RPF is the most suitable storage method.

　In this study, we screened several fungi for the production of α-ethyl glucoside (α-EG) and successfully identified Aspergillus kawachii N-3 that exhibited high activity for both α-glucosidase and amylase. High-yield production of α-EG from maltose or soluble starch was achieved at pH6 and 30℃ in the presence of 30% ethanol. Moreover, continuous α-EG production from a commercial syrup (Sun-Oligo: Sanmatsu Co., Ltd.) using A. kawachii N-3 immobilized on a non-woven polyester fabric was successfully accomplished for a period of ＞90 days.

　We screened optical isomer-preferential lactic acid assimilating microorganisms (LAAMs) for their ability to generate lactic acid with high optical purity from dl-lactic acid by isomer-specific assimilation. Fifty-seven strains of LAAMs were isolated from soils samples and plants. Five strains of LAAMs demonstrated preferential assimilation of l-lactic acid, and 10 strains of LAAMs demonstrated preferential assimilation of d-lactic acid. One such strain, LAAM001 produced a high ratio of d-lactic acid (94.0%) and had a high d-lactic acid yield (67.9%) ; this isolate may be suitable for preparation of lactic acid with high optical purity. LAAM001 was identified as Pichia manshurica by morphological observation, physiological analysis, and sequence analysis of the 26S rDNA-D1/D2 region. Other strains of P. manshurica also demonstrated preferential assimilation of l-lactic acid, although the optical purity of the resulting d-lactic acid was the highest with LAAM001. The optimal culture conditions for LAAM001 were investigated. Optimal temperature was 30℃ or 35℃, and optimal initial pH of the medium was 3.8. The use of LAAM001 for preparation of d-lactic acid with high optical purity by isomer-preferential assimilation from biosynthesized d-lactic acid with low optical purity was investigated. After 48 hours, l-lactic acid was not detected in the culture broth by HPLC, and 9.72 g/ℓ of d-lactic acid with high optical purity was obtained.

　Grated yam (tororo) is characterized by its viscosity and formability, which make it useful for improving the physical properties of confectioneries, fishery products, and noodles. However, the viscosity of grated Nagaimo yam is lower than that of Tsukuneimo and Ichoimo yams, which are prepared in Honshu Island in Japan. We elucidated the quality characteristics of 'Kitanebari,' which shows intermediate viscosity between the two types of yam mentioned above. The viscosity of yam showed a high positive correlation (p＝1.3306×10^－34, R²＝0.87429) with its solids content (＝100%－water content). Specific viscosity was defined as viscosity per unit of solids content, and the degree of viscosity was compared. The results showed that the specific viscosity of 'Kitanebari' was close to that of Ichoimo yam and that of 'Nebari Star' was close to that of Nagaimo yam. There was no significant difference in the polyphenol content in any of the yams tested. However, 'Kitanebari' and Ichoimo debu type, which are liable to browning immediately after grating, had a significantly higher polyphenol oxidase activity than Nagaimo and Ichoimo Nakakubi type, which are resistant to browning (p＜0.01). In particular, we found that 'Kitanebari' browns easier than any of the yams tested. However, browning was remarkably suppressed by adding sodium ascorbate, and the resulting color tone was equivalent to that of Nagaimo yam, which is resistant to browning. When processing into frozen grated yam, browning can be suppressed by adding sodium ascorbate.