Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Biosci Biotechnol Biochem. 2024 Sep 20;88(10):1180-1187. doi: 10.1093/bbb/zbae096.
Starch degradation in malted barley produces yeast-fermentable sugars. In this study, we compared the amylolytic enzymes and composition of the malt starch hydrolysates of two barley cultivars, Hokudai 1 (the first cultivar established in Japan) and Kitanohoshi (the currently used cultivar for beer production). Hokudai 1 malt contained lower activity of amylolytic enzymes than Kitanohoshi malt, although these cultivars contained α-amylase AMY2 and β-amylase Bmy1 as the predominant enzymes. Malt starch hydrolysate of Hokudai 1 contained more limit dextrin and less yeast-fermentable sugars than that of Kitanohoshi. In mixed malt saccharification, a high Hokudai 1 malt ratio increased the limit dextrin levels and decreased the maltotriose and maltose levels. Even though Kitanohoshi malt contained more amylolytic enzymes than Hokudai 1 malt, addition of Kitanohoshi extract containing the amylolytic enzymes did not enhance malt starch degradation of Hokudai 1. Hokudai 1 malt starch was less degradable than Kitanohoshi malt starch.
麦芽中淀粉的降解产生酵母可发酵糖。在这项研究中，我们比较了两个大麦品种——北海道 1 号（日本第一个品种）和北之幻（目前用于啤酒生产的品种）的麦芽中淀粉酶和淀粉水解物的组成。尽管这两个品种都含有 α-淀粉酶 AMY2 和 β-淀粉酶 Bmy1 作为主要酶，但北海道 1 号麦芽中的淀粉酶活性低于北之幻麦芽。北海道 1 号麦芽淀粉水解物的极限糊精含量高于北之幻，而可发酵糖含量较低。在混合麦芽糖化过程中，较高的北海道 1 号麦芽比例会增加极限糊精的含量，降低麦芽三糖和麦芽糖的含量。尽管北之幻麦芽中的淀粉酶比北海道 1 号麦芽多，但添加含有淀粉酶的北之幻提取物并不能增强北海道 1 号麦芽淀粉的降解。北海道 1 号麦芽淀粉比北之幻麦芽淀粉更难降解。
