う蝕原性Streptococcus mutansおよびStreptococcus sobrinusはスクロースを基質として非水溶性グルカンを産生し，歯面表面上に強固なバイオフィルムを形成する。本研究ではセリンプロテアーゼに属するナットウキナーゼの抗バイオフィルム効果について検討を行った。S. mutansとS. sobrinusのバイオフィルムはナットウキナーゼ1mg/mℓ濃度において約80％程度阻害された。このとき，非水溶性グルカン量の著しい低下が確認された。以上の結果からナットウキナーゼは非水溶性グルカン合成酵素に影響しているものと推察された。セリンプロテーゼに属するトリプシン，プロテイナーゼK，サブチリシンはナットウキナーゼと同程度のバイオフィルム抑制効果を有した。一方，パパインやブロメラインなどのシステインプロテアーゼのバイオフィルム抑制効果はセリンプロテアーゼと比較して著しく低下した。

　This study was performed to measure the changes in pericarp color and cumulative ethylene production of mature green tomato fruits (cv. Momotaro) during postharvest ripening at different storage temperatures (15, 20, and 25oC). The changes in hardness and quality (Brix value, l-ascorbic acid content, and lycopene content) of tomato fruits when the pericarp color (a^＊/b^＊ value) reached －0.5, 0, 0.5, and 1.5 were also investigated. The results showed that the relationship between the a^＊/b^＊and a^＊ values of pericarp color were not affected by storage temperature; however, there was an influence of storage temperature on the relationship between pericarp color (a^＊/b^＊ value) and cumulative ethylene production. Furthermore, whereas fruit hardness decreased with increasing pericarp color (a^＊/b^＊ value), the Brix value, l-ascorbic acid content, and the lycopene content all increased. No significant differences (P＜0.05) were noted in the relationship between pericarp color and hardness or quality among storage temperatures. On the basis of these results, it can be suggested that pericarp color (a^＊/b^＊ value) has potential value as an index for evaluating the a^＊ value, hardness, and quality of tomato fruits without the necessity to take into account the storage temperature during postharvest ripening.

　We constructed a gramineous plant-specific primer set-matK 792F1GC and matK 979R1, targeting the maturase K (matK) gene, for detection of gramineous raw materials in processed food. For this, we used polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The primer set was evaluated using agarose gel electrophoresis and DGGE. Our results confirmed that the primer set was specific for gramineous plants. From our analysis, we confirmed that up to 6 types of gramineous plants can be simultaneously detected using PCR-DGGE. Results of a model test showed that by using this method, it was possible to detect wheat from a sample, if present more than 0.1% (w/w). Thus, our method of PCR-DGGE with matK 792F1GC and matK 979R1 can be used to detect the presence of gramineous raw materials in processed food.