Functional Properties of Peptides Produced by Bacterial Enzymes from Traditional Fermented Foods

几千年来，人们通过传统和自然的发酵来制作食物。自然产生的微生物，如细菌、酵母和霉菌，会产生用于制作食品的蛋白水解酶。芽孢杆菌的变种。已经参与了传统的发酵谷类和豆类食品。本研究的目的是收集发酵食品中的微生物，并对细菌酶的蛋白分解能力和功能性质进行表征。由于与泰国、越南、中国和柬埔寨签署了以《生物多样性公约》为基础的合作谅解备忘录，因此这项研究的数据可以公开分发。对分离的细菌进行16S rDNA鉴定，并进行系统发育树分析。纯化酶的相对分子质量为33 kDa，N端氨基酸序列为AQSVPYGISQIKAPA。然而，这是从传统发酵面粉食品中分离到的第一个报告。纯化的蛋白水解酶将酸性酪蛋白消化成C端含有亲水和疏水氨基酸的片段，特别是Arg、Glu、Val和Ile。枯草杆菌DB和SR的浓缩粗酶通过对免疫印迹检测到的醇溶蛋白片段的水解，降低了醇溶蛋白(小麦过敏原)的致敏性。此外，枯草杆菌的浓缩粗酶还能在1h内将β-乳球蛋白(牛奶变应原)消化成小片段，培养3h后这些片段消失。对这些片段进行N-末端氨基酸序列分析，发现该酶能在谷氨酰胺-Lt；35&gt；-Ser^&lt；36&gt；位对β-乳球蛋白的主要变应原表位进行水解。因此，这些酶可用于生产低过敏性小麦面粉或奶制品。

For many thousands of years, people have prepared foods by traditional and natural fermentation. Naturally occurring microorganisms such as bacteria, yeast and moulds produce the proteolytic enzymes for making foods. A variety of Bacillus sp. have been involved in traditional fermented cereal and legume foods. This study aimed to collect microorganisms from fermented foods and characterize proteolytic potentials and functional properties of bacterial enzymes. Memorandum of Understanding (MOU) of collaboratory based on the Convention on Biological Diversity was decided with Thailand, Vietnam, China and Cambodia, the data from this research could therefore be publicly distributed. The isolated bacteria were identified by 16S rDNA and phylogenetic-tree analysis was also performed. The molecular mass and N-terminal amino acid sequence of purified enzyme were 33 kDa and AQSVPYGISQIKAPA, respectively. However, this was the first report in which it was isolated from traditional fermented wheat flour food. The purified protease digested acid casein into fragments with hydrophilic and hydrophobic amino acids at C-terminal, in particular Arg, Glu, Val and Ile.The concentrated crude enzyme of B. subtilis DB and SR could reduce allergenicity of gliadin (wheat allergen) by hydrolyzing the allergenic gliadin fragments detected by immunoblotting. Furthermore, the concentrated crude enzyme of B. subtilis DB could also digest β-lactoglobulin (milk allergen) into small fragments within 1 h and these fragments were disappeared after 3-h incubation. The fragments were then analyzed for N-terminal amino acid sequence ; it was found that this enzyme could hydrolyze the major allergenic epitope of β-lactoglobulin at Gln^<35>-Ser^<36> position. Therefore these enzymes can be applied for the production of hypoallergenic wheat flour or milk food products.