Background

The dairy industry is among the most important food industries worldwide. However, the increase in the global dairy industry has led to public environmental problems due to the disposal of whey. A promising approach for the sustainable utilization of whey is converting lactose to valuable lactose derivatives. Epilactose is an interesting bioactive lactose derivative that is enzymatically produced from lactose by cellobiose 2-epimerase (CEase).

Scope and approach

This review focuses on the health effects and enzymatic production of epilactose. In particular, the enzymatic properties and kinetics, molecular structures, modifications, and practical application of CEases are reviewed.

Key findings and conclusions

Epilactose is a nondigestible carbohydrate that shows promising prebiotic activity and potentially promotes intestinal mineral absorption, alleviates postgastrectomy osteopenia and anemia, reduces the plasma cholesterol level, and prevents obesity and metabolic disorders. Since 2007, thirty microbial CEases have been identified, and five of their crystal structures have been determined. Most CEases catalyze only the C-2 epimerization of lactose to epilactose, but some hyperthermophilic CEases are bifunctional enzymes that catalyze isomerization and epimerization and produce lactulose as the main product. Food-grade expression of CEases and downstream purification of epilactose have been attempted. However, studies on the molecular modification of CEases for enhanced epilactose productivity remain limited, and enzymatic immobilization and downstream processing should be greatly improved for practical industrialization of epilactose.

中文翻译：

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功能性乳糖衍生物表乳糖的健康影响和酶法生产的最新进展

背景

乳制品行业是全球最重要的食品行业之一。然而，全球乳制品行业的增长却因乳清的处理而引发了公共环境问题。可持续利用乳清的一个有前景的方法是将乳糖转化为有价值的乳糖衍生物。表乳糖是一种有趣的生物活性乳糖衍生物，由纤维二糖 2-差向异构酶 (CEase) 从乳糖酶促产生。

范围和方法

本综述重点关注乳糖的健康影响和酶促生产。特别是，对 CEase 的酶性质和动力学、分子结构、修饰和实际应用进行了综述。

主要发现和结论

表乳糖是一种不易消化的碳水化合物，具有良好的益生元活性，可能促进肠道矿物质吸收，缓解胃切除术后骨质减少和贫血，降低血浆胆固醇水平，并预防肥胖和代谢紊乱。自 2007 年以来，已鉴定出 30 种微生物 CEase，并确定了其中 5 种晶体结构。大多数CEases仅催化乳糖的C-2差向异构化为表乳糖，但一些超嗜热CEases是双功能酶，催化异构化和差向异构化并产生乳果糖作为主要产物。已经尝试了CEase 的食品级表达和表乳糖的下游纯化。然而，通过对 CEase 进行分子修饰来提高乳糖生产率的研究仍然有限，为了实现乳糖的实际工业化，酶固定化和下游加工还需要大大改进。