Enzymatic cross-linking is frequently used in bio-processing of dairy products since it could change the physiochemical and functional characterization. In our study, bovine α-lactalbumin was cross-linked by polyphenol oxidase from Agaricus bisporus and the changes in the structure, digestibility and allergenicity of α-lactalbumin were explored after cross-linking, and the structural alterations of the polymers were analyzed by circular dichroism spectroscopy, ultraviolet absorption spectroscopy and fluorescence spectroscopy. The digestibility of cross-linked α-lactalbumin was evaluated by simulated digestion in vitro. After that, the allergenicity of α-lactalbumin polymers was evaluated by detection of the specific IgE binding ability using an animal model. The results showed that the secondary and tertiary structures of various α-lactalbumin polymers exhibited a significant variation compared with those of untreated α-lactalbumin, and the cross-linked α-lactalbumin was relatively less susceptible to digestion. Moreover, the allergenicity of cross-linked polymers decreased significantly. These results suggested that there was a direct correlation between a loss of an α-helix and IgE binding to α-lactalbumin, which indicated that enzymatic cross-linking might be an efficient approach to reduce the allergenicity of bovine α-lactalbumin.

中文翻译：

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酶促交联的牛α-乳清蛋白聚合物的结构分析和变应原性评估。

酶促交联经常用于乳制品的生物加工中，因为它可以改变理化和功能特性。在我们的研究中，牛双歧杆菌中的多酚氧化酶将牛α-乳白蛋白交联，并探讨了交联后α-乳白蛋白的结构，消化率和变应原性的变化，并通过圆形分析了聚合物的结构变化。二向色光谱，紫外吸收光谱和荧光光谱。通过体外模拟消化评估交联的α-乳清蛋白的消化率。之后，通过使用动物模型检测特异性IgE结合能力来评估α-乳白蛋白聚合物的变应原性。结果表明，与未经处理的α-乳白蛋白相比，各种α-乳白蛋白聚合物的二级和三级结构表现出显着变化，并且交联的α-乳白蛋白相对较不易消化。而且，交联聚合物的致敏性显着降低。这些结果表明，α-螺旋的丧失与IgE与α-乳白蛋白的结合之间存在直接相关性，这表明酶促交联可能是降低牛α-乳白蛋白变应原性的有效方法。