In this study, to improve the reliability of identifying natto bacteria strains isolated from natto all over Japan, the effectiveness of a pretreatment, using an ethanol-formic acid treatment, in identifying and distinguishing the natto bacteria strains using MALDI-TOF MS was investigated. Samples pretreated with the direct coating-matrix treatment, which is the manufacturer's recommended pretreatment method, were subjected to MALDI-TOF MS and identified using an existing database. As a result, it was difficult to accurately identify the strains of the B. subtilis groups including the isolates from natto. Therefore, it was necessary to construct an original database to improve the reliability of identifying natto bacteria strains isolated from natto. To improve the accuracy of their analysis, the MALDI-TOF MS analysis was performed with the ethanol-formic acid treatment as the pretreatment. In a dendrogram that was constructed based on the mass spectral data obtained, strains isolated from natto formed independent clusters distinct from other species of the B. subtilis group. Furthermore, the mass spectra obtained for the strains isolated from natto were characteristic of "B. subtilis subsp. natto", which is different from those obtained for other B. subtilis groups.

　The aim of the present study is to clarify the influence of the difference in acidity of the fruits and the storage temperature on the citrus fruit 'Shiranuhi'. Sugar content, acidity and organic acid contents decreased significantly during storage, and the fruits stored at lower temperature had a tendency to keep higher levels than the fruits stored at higher temperature. On the other hand, the fruits with high acidity kept higher levels than the fruits with moderate acidity. Sucrose content increased slightly during storage, while glucose and fructose content decreased. The fruits stored at lower temperature had a tendency to keep higher contents than the fruits stored at higher temperature in a similar manner as above. Little change in content of l-ascorbic acid was observed during storage although there was a decrease in dehydroascorbic acid. Although most of the scores from sensory evaluation of the fruits decreased during storage, the fruits with high acidity (ca. 1.1%) stored at 7℃ kept the highest sensory properties. As conclusion, it was revealed that the fruits with high acidity (ca. 1.1%) stored at 7℃were kept their quality for 4 to 5 months.

　卵白タンパク質の加熱ゲル物性は乾熱処理により向上する。乾熱処理乾燥卵白（DEW）製品は種々の食品の物性改良を目的に利用される。DEW製品は主に中性およびアルカリ性で製造されるが，それぞれ異なるゲル物性を示すため，目的とする物性を創出するために使い分けられている。したがって，タンパク質の性状は両者で異なると推察される。本研究では，同等の表面疎水性を示す中性DEW（NDEW）およびアルカリ性DEW（ADEW）製品のタンパク質可溶性凝集体の性状について調査し，ゲル物性への影響について検討した。ゲルろ過―高速液体クロマトグラフィー（HPLC）により，NDEWはADEWと比較して可溶性凝集体の量およびその分子量が大きいと示された。ポリアクリルアミドゲル電気泳動および分子間架橋の定量結果より，可溶性凝集体の形成にはリジノアラニンおよびランチオニン結合が寄与し，両結合量はNDEWと比較してADEWの方が有意に多いことが明らかになった。陰イオン交換HPLCおよびその分画物を用いた電気泳動により，NDEWと比較してADEWの方がタンパク質可溶性凝集体の表面負電荷が強いと認められた。NDEWゲルは繊維状の構造が，ADEWゲルは小さい凝集体が均質に分散した構造が観察され，ADEWゲルは圧縮荷重が有意に小さかった。以上の結果より，NDEWと比較して，ADEWの可溶性凝集体の分子量は小さいが，そのリジノアラニン架橋密度および表面負電荷が大きいことが明らかになり，これら可溶性凝集体の性状がゲル構造および物性発現に寄与するものと推察された。