Abstract

An assay-based method was developed to determine the residual activity of the maltogenic amylase from Geobacillus stearothermophilus in white bread. It was found that the important step for amylase extraction from the bread matrix was the addition of 10% (w/v) maltodextrin in the extraction buffer. The endogenous amylase activity in dough was investigated, and its inactivation during bread baking was proven. Thus, all amylase activities measured after baking have an exogenous origin. The amylase activities in the loaf of self-baked white bread containing defined dosages of exogenous amylase (10–100 μg per g flour) were reproducibly determined with 17.8 ± 1.24% residual activity. Moreover, an amylase activity of 369 ± 34.3 pkat g_bread⁻¹ was determined in three batches of a commercial white bread. The real temperature impact on the amylase during bread baking was investigated. The highest temperature in the crumb was 97 °C and, therefore, is significantly lower than the oven temperature (230 °C).

中文翻译：

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白面包中嗜热地热芽孢杆菌致麦芽糖淀粉酶的直接活性测定

摘要

开发了一种基于分析的方法来确定白面包中嗜热地热芽孢杆菌的产麦芽糖淀粉酶的残留活性。已经发现，从面包基质中提取淀粉酶的重要步骤是在提取缓冲液中添加10％（w / v）的麦芽糖糊精。研究了面团中的内源淀粉酶活性，并证明了面包烘烤过程中其失活。因此，烘烤后测得的所有淀粉酶活性都具有外源性。可重复测定自烘烤白面包中含有确定剂量的外源淀粉酶（每克面粉10-100μg）的淀粉酶活性，残留活性为17.8±1.24％。此外，淀粉酶活性为369±34.3 pkat g_面包^-1在三批次的商业白面包中确定。研究了面包烘烤过程中实际温度对淀粉酶的影响。面包屑中的最高温度为97°C，因此，明显低于烤箱温度（230°C）。