Abstract Maltose increases the activity and thermostability of barley β-amylase at high mashing temperatures. Here we examined the effects of maltose on malt β-amylase activity and thermostability at reduced mashing temperatures. The β-amylase activity was relatively thermostable at both 52 and 58 °C with or without added maltose. At 52 °C, only 500 mM maltose significantly increased (P = 0.0004 to P < 0.0001) Harrington β-amylase activity over mashes without maltose (controls) from 30 to 90 min of mashing. With Morex, at 52 °C, 50 to 500 mM maltose significantly increased β-amylase activity (P = 0.0004 to P < 0.0001) compared to controls at 60 and 120 min. At 58 °C, Harrington β-amylase activity was significantly increased (P = 0.017) only at 120 min with additions of 200 to 500 mM maltose. In contrast, maltose additions to Morex mashes at 58 °C significantly increased β-amylase activities at 30 min (400 and 500 mM), at 60 and 90 min (50 to 500 mM), and at 120 min (100 to 500 mM). This suggests that genotypes with a Morex-like β-amylase phenotype could benefit from low initial mashing temperatures. Incubations with 0 to 500 mM mannitol at 52 and 58 °C were compared with incubations containing maltose and in general mannitol had fewer effects than maltose.

中文翻译：

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在低等温糖化温度下麦芽糖对大麦麦芽 β-淀粉酶活性和热稳定性的影响

摘要 麦芽糖在高糖化温度下可提高大麦 β-淀粉酶的活性和热稳定性。在这里，我们研究了麦芽糖在降低糖化温度下对麦芽 β-淀粉酶活性和热稳定性的影响。无论是否添加麦芽糖，β-淀粉酶活性在 52 和 58°C 下都相对耐热。在 52 °C 下，在 30 至 90 分钟的糖化过程中，仅 500 mM 麦芽糖显着增加（P = 0.0004 至 P < 0.0001）Harrington β-淀粉酶活性超过不含麦芽糖的麦芽糖（对照）。使用 Morex，在 52 °C 下，50 至 500 mM 麦芽糖在 60 和 120 分钟时与对照相比显着增加了 β-淀粉酶活性（P = 0.0004 至 P < 0.0001）。在 58 °C 下，Harrington β-淀粉酶活性仅在 120 分钟时显着增加（P = 0.017），并添加 200 至 500 mM 麦芽糖。相比之下，在 58 °C 下向 Morex 醪添加麦芽糖可显着增加 30 分钟（400 和 500 mM）、60 和 90 分钟（50 至 500 mM）和 120 分钟（100 至 500 mM）时的 β-淀粉酶活性。这表明具有 Morex 样 β-淀粉酶表型的基因型可能受益于较低的初始糖化温度。将 0 至 500 mM 甘露醇在 52 和 58 °C 下的孵育与含有麦芽糖的孵育进行了比较，并且通常甘露醇的影响比麦芽糖小。