Abstract The aim of this work was to develop antifungal films from whey protein isolate (WPI) added with low quantities of a water soluble derivative of chitosan (WSCh), which was obtained through a Maillard reaction with glucosamine hydrochloride. Glycerol was used as plasticizer and sodium tripolyphosphate was added to neutralize WSCh charges, at a working pH of 6.4, to avoid coacervation due to the opposite charges interaction of both biopolymers. Nevertheless, this WSCh derivative also acted as a crosslinking agent mainly through hydrogen bonding with whey proteins, which generated a decrease in the films' solubility and elongation. Possibly a conformational change of the WPI proteins increased the films' surface hydrophobicity (with contact angles greater than 90°), but there were no increases in their mechanical resistance or in barrier to water vapor. WPI/WSCh films showed excellent fungistatic and barrier effects against the growth of fungus strains associated with food spoilage. Aspergillus niger was 100% inhibited when a suspension containing 1 × 103 spores/mL was inoculated on the films' surface (barrier effect), while Penicillium roqueforti was the strain more resistant to WSCh activity. The obtained results suggest interesting properties of these materials to use them as active edible coatings.

中文翻译：

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用少量水溶性壳聚糖活化的抗真菌乳清蛋白膜

摘要 这项工作的目的是从乳清蛋白分离物 (WPI) 中开发抗真菌薄膜，添加少量壳聚糖水溶性衍生物 (WSCh)，该衍生物是通过与盐酸氨基葡萄糖的美拉德反应获得的。在 6.4 的工作 pH 值下，使用甘油作为增塑剂并添加三聚磷酸钠以中和 WSCh 电荷，以避免由于两种生物聚合物的相反电荷相互作用而导致凝聚。然而，这种 WSCh 衍生物也主要通过与乳清蛋白的氢键作用作为交联剂，这导致薄膜的溶解度和伸长率降低。可能是 WPI 蛋白质的构象变化增加了薄膜的表面疏水性（接触角大于 90°），但它们的机械阻力或对水蒸气的阻隔没有增加。WPI/WSCh 薄膜对与食品腐败相关的真菌菌株的生长显示出优异的抑菌和屏障作用。当将含有 1 × 103 个孢子/mL 的悬浮液接种在薄膜表面（屏障效应）时，黑曲霉被 100% 抑制，而罗克福尔青霉是对 WSCh 活性更具抵抗力的菌株。获得的结果表明这些材料具有有趣的特性，可将它们用作活性可食用涂层。而Penicillium roqueforti 是对WSCh 活性更具抵抗力的菌株。获得的结果表明这些材料具有有趣的特性，可将它们用作活性可食用涂层。而Penicillium roqueforti 是对WSCh 活性更具抵抗力的菌株。获得的结果表明这些材料具有有趣的特性，可将它们用作活性可食用涂层。