不同米基質釀造甜酒釀之抗氧化性研究

Abstract

本試驗利用黴菌Rhizopus sp. No. 2與酵母菌Saccharomyces cerevisiae HP01進行純菌接種至黑糯米、紅糯米、圓糯米、蓬萊米與小米等不同米基質發酵製造甜酒釀，分析其甲醇萃取物與水萃物之抗氧化活性，並探討甜酒釀之花青素與總酚含量對抗氧化性之影響。此外進一步探討黑糯米甜酒釀於發酵前後及經加熱處理後對其抗氧化活性之影響。 實驗結果顯示，以黑糯米為米基質發酵製成之甜酒釀甲醇萃取物或水萃物，呈現較強之DPPH自由基清除能力、亞鐵離子螯合能力、超氧陰離子清除力及還原能力。其次則為紅糯米甜酒釀，亦表現較佳之抗氧化活性。在花青素與總酚類化合物含量方面，以各種米基質釀製之甜酒釀中，黑糯米甜酒釀具有最高之花青素與總酚類化合物含量，顯示黑糯米甜酒釀具有之高抗氧化活性與其高含量之花青素與總酚類物質相關。而在發酵前後及加熱處理對抗氧化性之影響方面，發酵0小時之黑糯米甲醇萃取物和水萃物具有最高之DPPH自由基清除效力與還原力，表現出較佳之抗氧化活性。黑糯米經微生物發酵72小時後，其抗氧化活性較未發酵者降低，並且與經72小時發酵及加熱處理後（100℃、20 min）之黑糯米甜酒釀所表現之抗氧化活性相似。

In this study, lao-chao was made from black rice, red rice, glutinous rice, white rice(Oryza sativa L. japonica)and millet cultured with Rhizopus sp. No.2 and Saccharomyces cerevisiae HP01. Then the antioxidative activity of methanolic and water extract of lao-chao was analyzed. This sduty also compared the content of anthocyanins and total phenolic compounds of lao-chao. In addition, we investigated the effect of fermentation and heating on the antioxidative activity of lao-chao made from black rice. The results indicated that the methanolic and water extract of lao-chao made from black rice had the greatest scavenging activity on DPPH radicals and superoxide anion, ferrous ion-chelating ability, and reducing power among lao-chaos. The lao-chao made from black rice also showed the highest content of anthocyanins and total phenolic compounds among lao-chaos, and this related to its strong antioxidative activity. In the other hand, the methanolic and water extract of lao-chao made from black rice before fermentation had better DPPH-scavenging activity and reducing power than that after 72-hours fermentation and that by heating(100℃,20 min). This result showed that the antioxidant substances such as anthocyanins and total phenolic compounds in lao-chao made from black rice may be decreased with microbial growth on rices and heatin.