Laboratory of Bioaromas and Bioactive Compounds, Department of Food Science, Faculty of Food Engineering, State University of Campinas, 80 Monteiro Lobato st., University city Zeferino Vaz, Campinas, São Paulo CEP: 13083-862, Brazil.
Faculty of Farmaceutical Sciences, Federal University of Amazonas, Manaus CEP: 69077-000, Amazonas, Brazil.
Food Res Int. 2019 Oct;124:78-85. doi: 10.1016/j.foodres.2018.09.019. Epub 2018 Sep 11.
Galacto-oligosaccharides (GOS), molecules with prebiotic properties are considered promising in the food industry. Its synthesis can be performed by enzymatic pathway, using commercial microbial enzymes. The reaction, known as transgalactosylation, is mediated by the enzyme β-galactosidase and its catalysis is influenced during the process by substrate concentration present (in this case lactose), pH, and temperature, among others. The use of whey permeate, a by-product of the dairy industry, demonstrates the interest in making such processes viable from an economic and technological point of view. The main of this work was to use whey permeate as raw material in an enzymatic GOS synthesis, comparing three commercial enzymes of different microbial sources. For better performance, the results on lactose conversion, yield, and specific productivity were evaluated. The commercial enzyme of Kluyveromyces lactis (Lactozyme™ 2600 L) showed the best results for lactose conversion (89.27%), yield (25 g GOS/100 g lactose) and specific productivity (51 g GOS/g enzyme*h). Thus, it can be considered suitable for further technological development. Aspergillus oryzae commercial enzyme also showed good results and could be used for other studies either. However, the Escherichia coli commercial enzyme did not present good results in GOS synthesis, being more appropriate to lactose hydrolysis reactions. All the three enzymes showed a decrease in the production and even depletion of GOS molecules, and therefore, smaller reaction times should be established. New stages of optimization and processes development should be considered in future works, in order to obtain best yields and productivities.
半乳糖寡糖（GOS）是具有益生元特性的分子，被认为在食品工业中有很大的发展潜力。它可以通过酶促途径合成，使用商业微生物酶。这种反应被称为半乳糖基转移反应，由β-半乳糖苷酶介导，其催化作用受到反应过程中存在的底物浓度（在这种情况下是乳糖）、pH 值和温度等因素的影响。利用乳清渗透物（乳制品工业的副产品），从经济和技术角度来看，展示了使这些过程可行的兴趣。这项工作的主要目的是使用乳清渗透物作为原料，通过比较三种不同微生物来源的商业酶来合成 GOS。为了获得更好的性能，评估了乳糖转化率、产率和比生产率等方面的结果。来源于乳糖酶（Lactozyme™ 2600L）的商业酶对乳糖转化率（89.27%）、产率（25g GOS/100g 乳糖）和比生产率（51g GOS/g 酶*h）表现出最好的结果。因此，可以认为它适合进一步的技术开发。来源于米曲霉的商业酶也表现出良好的结果，也可以用于其他研究。然而，来源于大肠杆菌的商业酶在 GOS 合成中没有表现出良好的结果，更适合于乳糖水解反应。这三种酶在 GOS 分子的生产中都表现出产量下降，甚至耗尽，因此，应该建立更短的反应时间。在未来的工作中，应该考虑新的优化阶段和工艺开发，以获得最佳的产率和生产率。
