培養溫度與時間影響Aspergillus awamori製備豆麴之抗氧化活性與總酚含量   全文下載

Cultivation Temperature and Length Affect the Antioxidant Activity and Total Phenolic Content of Soybean Koji Prepared with Aspergillus awamori

本研究利用常作為清酒菌?之Aspergillus awamori於25、30或35°C下發酵黃豆1~5天製備豆麴，並就各豆麴中菌絲之增殖及其甲醇萃出物之總酚含量與抗氧化活性包括清除dPPH自由基與亞鐵離子螯合能力加以比較。結果顯示發酵3天之豆麴中，在30°C製備豆麴萃出物所呈現dPPH自由基清除之能力最高，為25或35°C下製備者之2.5~3.5倍。而30°C豆麴萃出物對亞鐵離子螯合能力則為在其他溫度下製備者之3.6~3.8倍。培養時間從3天提高或減少，均降低製備所得豆麴萃出物之抗氧化活性。培養溫度與時間亦被發現會影響菌絲之增殖及豆麴萃出物中之總酚含量。A. awamori在30°C下培養3天後菌絲之增殖可達最高。30°C下製備豆麴萃出物含有最高量之總酚類化合物與其所呈現之最高抗氧化活性有密切之關連性。

In this study, soybean koji was first fermented with Aspergillus awamori, a starter organism commonly used for the fermentation of sake, at 25, 30 or 35°C for a period of 1~5 days. Antioxidant activity, including DPPH radical-scavenging effect and Fe2+-chelating ability, and total phenolic content of the methanol extract of these fermented soybean koji as well as mycelial propagation of starter organism were compared. Results revealed that fermented for a same period of 3 days, the DPPH radical-scavenging effect exerted by the 30°C-koji extract was the highest showing 2.5~3.5 folds of that fermented at 25 or 35°C. The Fe2+-chelating ability exerted by the 30°C-koji extract was also found to be 3.6~3.8 times higher than those fermented at other temperatures. Furthermore, it was also noted that increasing or decreasing cultivation time from 3 days resulted in a decreased antioxidant activity of the koji extract. Cultivation temperature and length were also observed to affect the mycelial propagation and the total phenolic content of the koji extract. Maximum mycelial propagation of A. awamori was achieved after cultivation at 30°C for 3 days. Finally, the highest phenolic content noted in 30°C-koji extract was closely correlated to the highest antioxidant activity observed.