Abstract The spent brewer yeast (SBY) is a by-product with great potential for the production of peptides. Protein hydrolysates of SBY with improved physicochemical and antioxidant properties were produced by a system containing mixtures of proteases (Alcalase™, Brauzyn ® and Protamex™). The amount of solids and crude proteins recovered from the raw material after the protein hydrolysis was, in average, 57% and 70% (w/w), respectively. Hydrolysis resulted in intermediate degrees of hydrolysis (15%), promoting the release of hydrophobic residues (8% higher related to the control) with antioxidant properties. The presence of all three enzymes influenced the degree of hydrolysis but the darkening and browning of the hydrolysates were mainly affected by Protamex™. Most of the hydrolyzed proteins presented a molecular weight (MW) of 35 kg mol-1, as confirmed after membrane separation and electrophoresis. The membrane fractionation step using 30 kg moL-1 membranes effectively produced peptide-enriched fractions of 30-35 kg moL-1. In addition, it was possible to correlate the degree of hydrolysis, solids release, color parameters L*, Browning Index and antioxidant properties by FRAP and DPPH in function of the hydrolysis conditions, showing the potential use of SBY protein hydrolysates as a source of peptides in value-added functional foods.

中文翻译：

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蛋白水解酶正向调节废酵母蛋白水解物的理化和抗氧化特性

摘要 啤酒酵母（SBY）是一种具有生产多肽潜力的副产品。具有改进的物理化学和抗氧化特性的 SBY 蛋白质水解物是通过包含蛋白酶混合物（Alcalase™、Brauzyn® 和 Protamex™）的系统生产的。蛋白质水解后从原料中回​​收的固体和粗蛋白质的量分别平均为 57% 和 70% (w/w)。水解导致中等程度的水解（15%），促进具有抗氧化特性的疏水残基的释放（比对照高8%）。所有三种酶的存在都会影响水解程度，但水解产物的变黑和褐变主要受 Protamex™ 影响。大多数水解蛋白的分子量 (MW) 为 35 kg mol-1，膜分离和电泳后证实。使用 30 kg moL-1 膜的膜分离步骤有效地产生了 30-35 kg moL-1 的富肽级分。此外，可以将 FRAP 和 DPPH 的水解程度、固体释放、颜色参数 L*、褐变指数和抗氧化特性与水解条件相关联，这表明 SBY 蛋白水解物作为肽源的潜在用途在增值功能食品中。