不同米種對米麴和鹽麴製備之影響

不同米種作為米麴菌（Aspergillus oryzae）固態發酵基質，所製造的米麴含有多種酵素，混合鹽水後可以製成鹽麴，生成的還原糖會提供甘甜味，胺基酸則作為風味物質。本研究分別使用稉米、秈米和預煮稉米作為基質發酵製成米麴，並加入鹽水再發酵以製備鹽麴，以探討不同米麴對鹽麴液中還原糖和酪胺酸含量的影響。首先，先將稉米、秈米及預煮米蒸煮，冷卻後加入米麴菌進行發酵3天後，以冷風乾燥6h使其乾基水分含量降至約0.1g水/g乾物，得以保存。測量三種米麴的顏色可發現秈米麴有較高明亮度，L*為69.49，預煮米麴則有較高紅色度，a*為0.28，可能因預煮米本身紅色度較高所致。將不同的米麴與12%鹽水以1：5（w/w）混合於40℃培養3天，最後分析梗米、秈米及預煮米製成鹽麴液的還原糖含量分別為37.967、40.300及46.133 mg/mL，酪胺酸含量則分別為1.813、1.918及2.048 ppm，其中以預煮米麴製成的鹽麴有較高還原糖和酪胺酸含量，可製成風味較佳的鹽麴。

關鍵字

米；米麴菌；米麴；發酵；鹽麴

並列摘要

Different rice species are used as Aspergillus oryzae solid-state fermentation media, and the resulting rice koji contains a variety of enzymes. When combined with brine, salt koji is obtained, which produces reducing sugars to provide sweetness and amino acids as flavor substances. The objective of this study was to use different rice as media for Aspergillus oryzae fermentation to produce rice koji, which was then brined to produce salt koji. The effect of different rice koji preparation on reducing sugar and tyrosine contents of salt koji was investigated in this study. First, Aspergillus oryzae fermented japonica rice, indica rice and parboiled rice for three days to produce rice koji, which was then dried by cold air drying for six hours to reduce moisture content to about 0.1 g water/g dry material for preservation. Indica rice koji had a higher L* of 69.49, and parboiled rice koji had a higher a* of 0.28, which could be attributed to the higher a* of parboiled rice itself. Different types of rice koji was mixed with 12% brine as 1:5 and fermented for 3 days at 40℃. After analyzing, the reducing sugar content of japonica rice, indica rice and parboiled rice was 37.967, 40.300 and 46.133 mg/mL respectively; the tyrosine content was 1.813, 1.918 and 2.048 ppm respectively. The parboiled rice koji has a higher reducing sugar and tyrosine contents; therefore, it can be used to make salt koji with a better flavor.

並列關鍵字

rice ； Aspergillus oryzae ； rice koji ； fermentation ； salt koji

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