中国の金華火腿より分離した糸状菌の同定,酵素活性の測定を行った. (1) 火腿から分離された糸状菌は比較的低い水分活性でも生育するPenicillium, Aspergillus属で構成されていた. (2) Penicillium属ではP. aurantiogriseum, P. solitum, P. implicatum, P. viridicatum, P. fellutanum,他4種類の菌が,Aspergillus属ではA. ochraceus, E. repens, A. sydowii, E. amstelodami他4種類が同定された.以上より火腿にはPenicillium属9種,Aspergillus属8種,計17種の糸状菌が分布していた. (3) プロテアーゼ活性は酸性側でPenicillium属,中性～アルカリ側でAspergillus属が強力であった。pH 6.0でのプロテアーゼ活性の強い菌種はA. ochraceusであり,原料の分解に関与すると考えられた. (4) リパーゼはPenicillium属での活性が高く,火腿製造時における脂質の分解はPenicillium属が主体と推察した.Penicillium属の中では特にP. fellutanum, P. canescensが強い活性を有していた. (5) 分離糸状菌のαーアミラーゼは全体に活性は低く,火腿の品質へ与える影響は少ないものと推察した. (6) 分離糸状菌のホスファターゼ活性の強い菌株は存在しておらず,そのため5'-イノシン酸が高く維持されているものと推察した. 以上より火腿に生育する糸状菌は,その低水分活性のため,Penicillium属,Aspergillus属が選択的に生育し,蛋白質分解はAspergillus属が,脂質の分解はPenicillium属が主体となっているものと思われた.
Twelve kinds of food proteins were hydrolyzed by Bacillus licheniformis alkaline proteases to form peptides of average chain length, 2.26-4.02. The hydrolyzates from shrimp, crab and sardine contained many di- and tri-residues whose angiotensin I converting enzyme (ACE) inhibitory activities were stronger than that of the hydrolyzates from soy bean, hair tail, oyster, beef, chicken, pork, chicken egg yolk, chicken egg white and casein. The IC50 was 0.072, 0.075 and 0.076mg protein/ml, respectively. Hydrophobic amino acid residues situated in the interior of protein molecules were exposed by fragmentation with proteases, and the peptides containing hydrophobic amino acid residues were found in aqueous solution. The peptide from casein showed the highest hydrophobicity and whose taste was the most bitter.
The substance inhibiting the growth of lactic acid bacteria in samac fruit, which is added to the sugarcane wine-"basi" in the Philippines, was isolated, and its structure was investigated. When the polyphenol components in the aqueous extract of samac fruit (AESF) were combined with gelatin and removed, the growth inhibition of lactic acid bacteria by AESF disappeared. Consequently, it was confirmed that the substance inhibiting the growth of lactic acid bacteria in AESF was the polyphenol component combined with gelatin. Furthermore, the three fractions separated from AESF by ultrafiltration were individually measured to determine the growth inhibition of lactic acid bacteria, and the fraction of M.W. below 1×104, which contained 80% of the polyphenol components in AESF, was perceived to be the cause of the growth inhibition of lactic acid bacteria. Therefore, it was found that the substance inhibiting the growth of lactic acid bacteria was the low molecular weight polyphenol component. The substance inhibiting the growth of lactic acid bacteria in AESF was isolated using thin-layer chromatography, and it produced gallic acid, glucose and xylose by hydrolysis with HCl. Consequently, it was assumed that the substance inhibiting the growth of lactic acid bacteria in AESF was gallotannin.