Abstract In this study, polygalacturonase (PG) was immobilized in calcium alginate microspheres prepared using endogenous emulsification method and its application in apple juice clarification was evaluated. Preparation conditions of calcium alginate microspheres prepared by endogenous emulsification were optimized, additionally, the formed microspheres were characterized. Under optimal conditions, microspheres with the particle size of 38.0 ± 0.2 μm showed good sphericity, storage stability and a narrow particle size distribution. Meanwhile, single factor experiment and response surface experiment were combined to get the optimum conditions of immobilizing PG. The immobilized enzyme presented the optimum temperature at 60.0 °C, which was almost 10.0 °C higher than the free PG and the activity was less dependent upon pH within the interval of 3.0–4.5 than free enzyme, supporting the immobilized enzyme more stable in apple juice clarification (pH = 4.3 ± 0.1). The immobilized enzyme also exhibited good operational stability and 63.0% of its initial activity retained after three batch reactions. In the present of the immobilized PG, the turbidity of apple juice decreased, as well as apple juice had good thermal and freezing ability.

中文翻译：

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果胶酶固定在海藻酸钙微球中用于果汁应用

摘要 本研究将聚半乳糖醛酸酶（PG）固定在采用内源乳化法制备的海藻酸钙微球中，并评价其在苹果汁澄清中的应用。优化了内源乳化法制备海藻酸钙微球的制备条件，并对形成的微球进行了表征。在最佳条件下，粒径为 38.0 ± 0.2 μm 的微球表现出良好的球形度、储存稳定性和较窄的粒径分布。同时，结合单因素实验和响应面实验，得到固定PG的最佳条件。固定化酶的最适温度为 60.0°C，比游离 PG 高近 10.0°C，且活性在 3 区间内对 pH 的依赖性较小。0–4.5 比游离酶，支持固定化酶在苹果汁澄清中更稳定（pH = 4.3 ± 0.1）。固定化酶还表现出良好的操作稳定性，在三批反应后保留了其初始活性的 63.0%。在固定化PG的存在下，苹果汁的浊度降低，并且苹果汁具有良好的耐热性和冷冻性。