| Summary: | 碩士 === 國立虎尾科技大學 === 生物科技研究所 === 101 === The sesame beer was made from defatted black sesame (Sesamum indicumL.) meals, hops, maltose and sucrose by local commercial yeast (Saccharomyces cererisiae) powder. The effects of two-step fermentation time (0~7 days for the 1st step and 0~28 days for the 2nd step after the 1st step) on the properties (alcohol, saccharides, organic acids, amino acids, antioxidative activity and flavor compounds) of sesame beer were investigated in this study. The alcohol content of sesame beer increased with increasing fermentation time and it was up to 4.35% at 14 days of fermentation in the 2nd step, and then decreased thereafter. The contents of glucose and fructose in sesame beer first increased with increasing the fermentation time in the 1st step. The sucrose content was kept at the very low value and not significantly affected by fermentation time. Moreover, the contents of acetic acid and malic acid were increased with increasing fermentation time at first 6 and 7 days in the 1st and 2nd steps, respectively, and then decreased. Total 16 amino acids of the sesame beer were identified; only 6 amino acids were tyrosine, phenylalanine, valine, alanine, aspartic, glutamic identified in the 1st step. Among glutamic acid and alanine were increased with increasing at first 6 days fermentation and the highest values were obtained at 6 days of fermentation in the 1st step. In the 2nd step, 16 amino acids were little increased with increasing fermentation time at first 21 days, and then they much increased as the increase of fermentation time, except the contents of glycine, glutamic acid and cysteine were little decreased after 21 days. Both DPPH radical scavenging activity and reducing power of sesame beer were increased with increasing the fermentation time at first 2 days, and then they decreased at last 5 days in the 1st step. Subsequently, they increased at first 7 days in the 2nd step, and then decreased. Moreover, the total phenolic contents increased with increasing the fermentation time at first 4 days in 1st step. There were 10 flavor compounds found in sesame beer were identified in this study. Fermentation time is the major factor to affect some properties of sesame beer. If the sesame beer is expected to become the excellent health beer in the future, the fermentation time have to be concerned.
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