利用非釀造清酒酵母菌共培養製備清酒之品質分析

Abstract

清酒是日本國酒，其以稻米為原料，經由米麴菌與酵母菌並行複式發酵製成。微生物發酵過程中會產生多種二級代謝物，進而影響酒類品質與消費者購買意願。非釀酒酵母菌存在於天然環境中，由於其容易造成發酵的停滯，因此多被視為腐敗菌，近期許多研究顯示非釀酒酵母菌可以有效提升紅酒香氣複雜度，而較少有應用於清酒發酵的研究。本實驗目的為使用多種酵母菌共發酵以提升清酒風味與品質。實驗透過分析米麴酶活性與小分子產量評估不同米種與麴菌菌株之影響，後續選擇臺南十一號與吉野一號為清酒原料；從水果純化、鑑定與篩選野生酵母菌，選用 Saccharomyces cerevisiae NTUAFM-Y018和 Hanseniaspora uvarum NTUAFM-G001進行共培養，並以順序接種優化清酒發酵製程；清酒成品使用氣相層析分析揮發性香氣圖譜，並以 CATA 與9分喜好性品評進行感官分析。米麴分析結果顯示，實驗室菌株 Aspergillus oryzae NTUAFM-M001具有較高的 b-葡萄糖苷酶活性，吉野一號組別高出60 %，臺南十一號組別高出63 %，而益全香米組別高出32%。酵母菌共培養實驗結果顯示順序式接種進行清酒發酵可以延長 H. uvarum 存活時間並延後發酵天數。相較於單一培養，共培養方式顯著了提升酯類與高級醇含量，吉野一號與臺南十一號組別的酯類總量分別增加15% 和12%；高級醇總量分別增加14% 和8%，並在感官品評中的香氣、風味與整體喜好度獲得較高評分。本研究以 H. uvarum 與 S. cerevisiae 進行清酒的共發酵，可以有助於提升清酒的風味。

Sake is a Japanese traditional alcoholic beverage. The brewing process include multiple parallel fermentation which is performed by Aspergillus oryzae and Saccharomyces cerevisiae, respectively. Non-Saccharomyces yeasts is naturally present on the environment. Many studies showed their capacity for modulating wine aroma recently, however, the effect of non-Saccharomyces yeast in co-fermentation on sake flavor remains unclear. The study aims to evaluate the influence on sake flavor with mixed fermentation. Tainan-11 and Yoshino-1 were selected to make koji by enzyme activity analysis. Wild yeasts were screened from fruits and identified by 5.8S ribosome DNA sequencing. S. cerevisiae NTUAFM-Y018 and Hanseniaspora uvarum NTUAFM-G001 were selected to carry out co-fermentation by sequential inoculation. Gas chromatography (GC) analysis would be used to analyze aroma compounds. Finally, we performed sensory evaluation by CATA and 9-point hedonic scale test. Based on the results, A. oryzae NTUAFM-M001 had higher b-glucosidase activity compared with commercial A. oryzae. Yoshino-1, Tainan-11 and Tai-Nong-1 increased 60, 63 and 32% higher b-glucosidase activity respectively. Sake fermented by the co-culture of S. cerevisiae/H. uvarum improved the aroma compound contents, Yoshino-1 and Tainan-11 increased 15 and 12% higher content of the total ester than the pure culture of S. cerevisiae respectively. Yoshino-1 and Tainan-11 enhanced 14 and 8% higher content of the total higher alcohol. Furthermore, the sensory evaluation showed that the co-fermentation by S. cerevisiae and H. uvarum enhanced the sake flavor. This study provides a contribution to answer the influence of the non-Saccharomyces yeast on sake organoleptic properties.