School of Food Science and Engineering, South China University of Technology, Guangzhou, China.
Guangdong Food Green Processing & Nutrition Regulation Technology, Guangzhou, China.
J Sci Food Agric. 2023 Jan 30;103(2):606-615. doi: 10.1002/jsfa.12172. Epub 2022 Aug 25.
Soybeans and defatted soybeans, commonly used as protein ingredients, have different flavors of their fermented soy sauce. Clarifying the differences between the two soy sauces, as well as the formation mechanism, is an important prerequisite for improving the flavor of defatted soybean soy sauce. To this goal, the aroma characteristics of two soy sauces and their volatile profiles were compared by sensory evaluation and gas chromatography-mass spectrometry, and eight enzyme activities and volatile profiles of matured koji were determined.
Sensory results showed that the acids, fruity and cooked potato-like attributes were higher in whole soybean fermented soy sauce, whereas defatted soybean soy sauce exhibited higher smoky and malty attributes, closely related to the contents of aroma-active compounds in soy sauce, such as isobutyl acetate, 2/3-methylbutanal, acetic acid and 2/3-methylbutanoic acid. The content of most volatiles in the matured kojis showed a consistent trend with that of soy sauce: alcohols, acids, furan(one)s and ketones. Interestingly, acid protease and cellulase activities were 3.3 and 1.6 times higher in the whole soybean koji than in defatted soybean koji, respectively, whereas neutral protease, aminopeptidase, glucoamylase and β-glucosidase were approximately 2.0 times higher in defatted soybean koji.
In summary, the flavor differences between soybean and defatted soybean fermented soy sauce were not only caused by the differences in the content of flavor precursors in the materials, but also closely related to the differences in the enzymatic profiles accumulated during the koji-making process. © 2022 Society of Chemical Industry.
大豆和脱脂大豆作为常用的蛋白质原料，其发酵酱油的风味也有所不同。阐明两种酱油之间的差异及其形成机制，是提高脱脂大豆酱油风味的重要前提。为此，通过感官评价和气相色谱-质谱联用技术比较了两种酱油的香气特征及其挥发性成分，并测定了成熟曲的八种酶活性和挥发性成分。
感官结果表明，全豆发酵酱油的酸、果香和煮熟的土豆味较高，而脱脂大豆酱油则表现出较高的烟熏和麦芽味，这与酱油中香气活性化合物的含量密切相关，如乙酸异丁酯、2/3-甲基丁醛、乙酸和 2/3-甲基丁酸。成熟曲中大多数挥发性成分的含量与酱油的含量趋势一致：醇类、酸类、呋喃（一）和酮类。有趣的是，全豆曲中的酸性蛋白酶和纤维素酶活性分别比脱脂大豆曲高 3.3 倍和 1.6 倍，而中性蛋白酶、氨肽酶、糖化酶和β-葡萄糖苷酶在脱脂大豆曲中的含量约为 2.0 倍。
总之，大豆和脱脂大豆发酵酱油的风味差异不仅是由于原料中风味前体物质含量的不同所致，而且还与制曲过程中积累的酶谱差异密切相关。© 2022 化学工业协会。
