- 期刊
應用伽瑪輻射誘變改良少孢根黴優化天貝之糖苷配基異黃酮含量
Improving the Aglycone Isoflavone Contents of Tempeh with Rhizopus oligosporus Mutated by Gamma-irradiation
摘要
天貝（tempeh）是起源於印尼的一種大豆醱酵食品，為印尼人民蛋白質主要來源之一，含有豐富的異黃酮與多胜肽，有改善高血壓、增強免疫、延緩衰老及神經保護等良好生理功效。製造天貝的真菌為根黴屬（Rhizopus），常用菌種為少孢根黴菌（Rhizopus oligosporus），其高活性的脂肪酶及蛋白酶以生物轉換方式將大豆大分子成分轉變成易於被人體吸收利用的分子，同時透過其葡萄糖苷酶水解人體不易吸收的各式寡糖、糖苷以及受矚目的異黃酮成分。本研究首先以伽瑪輻射誘變少孢根黴菌，再藉由酵素活性分析篩選出具有高脂肪酶及蛋白酶活性之候選菌株，發現部分候選菌株具有高活性大分子分解能力。將其中SW02與SW08候選株利用於發酵PDB培養液或製成大豆天貝後發現香氣出現變化，隨後將之實際應用於大豆製成天貝並分析其中異黃酮成分與含量，發現SW08候選菌株發酵之天貝具有較高大豆異黃酮苷素（daidzein）與金雀異黃酮苷素（genistein），酵素活性分析證實SW08菌株之β-葡萄糖苷酶活性遠高於原始親株。本研究證實伽瑪輻射誘變可篩選出具有高蛋白酶、高脂質酶以及β-葡萄糖苷酶活性之少孢根黴菌，並可提升天貝中大豆成分的功能性與利用率。
並列摘要
Tempeh, a fermented soybean food originated in Indonesia, is one of the main protein sources for the people. It is rich in flavonoids and polypeptides, and has many health effects, including high blood pressure improvement, immunity enhancement, aging slowing, as well as neuroprotection. The fungus used for making tempeh is Rhizopus, and the commonly used species is R. oligosporus, of which the highly active lipase and protease bio-convert the soybean macromolecules into the good nutrient for human. Moreover, its glucosidase hydrolyzes oligosaccharides, glycosides, and isoflavones that are not easily utilized or absorbed by the human body. In this study, the analysis of enzyme activity was conducted to screen gamma-irradiated R. oligosporus for high lipase and protease activity and some candidate strains were found. The aroma of PDB ferments or soybean tempeh cakes made with SW02 and SW08 mutant strains diff ered from that one using wild type starter. The isoflavone components and content of the lyophilized tempeh cakes fermented with wild type, SW02 and SW08 were separately analyzed, and that SW08-tempeh showed higher daidzein and genistein, isoflavone glycosides, than others. Conceivably, higher β-glucosidase activity was demonstrated in the SW08 mutant strain than wild type strain. This study confirms that gamma-radiation mutagenesis generates a large variety of heritable mutations in R. oligosporus, in which the candidates harboring high protease, high lipase, and β-glucosidase activities can be selected, and these mutant strains are able to enhance biological function and bioavailability of the soy nutrients.