Food Science and Technology, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia; School of Chemical Engineering, Faculty of Industrial and Technology, Parahyangan Catholic University, Ciumbuleuit 94, Bandung 40141, Indonesia.
School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
Food Chem. 2020 Nov 15;330:127324. doi: 10.1016/j.foodchem.2020.127324. Epub 2020 Jun 13.
Enzymes currently used in cheesemaking have various drawbacks, and there is a continual need to find new coagulants. This study describes the extraction and biochemical characterization of two proteases from the red alga Gracilaria edulis. The proteases were extracted with phosphate buffer and partially purified by ammonium sulphate precipitation and dialysis. The enzymes exhibited optimum caseinolytic activity at 60 °C and a pH range of 6-8. They showed a high ratio of milk-clotting over caseinolytic activity, indicating they had an excellent milk-clotting ability. The proteases were confirmed to be serine protease and metalloprotease with molecular weight (MW) of 44 and 108 kDa. They exhibited high hydrolytic activity on κ-caseins, cleaving κ-casein at four main sites, one of which being the same as that of calf rennet, which is the first reported for an algal protease. The findings demonstrated that the proteases could potentially be used as a milk coagulant in cheesemaking.
用于奶酪制作的酶目前存在各种缺点，因此需要不断寻找新的凝固剂。本研究描述了从红藻石花菜中提取两种蛋白酶的过程及其生化特性。使用磷酸盐缓冲液提取蛋白酶，并通过硫酸铵沉淀和透析进行部分纯化。酶在 60°C 和 pH 值为 6-8 的范围内表现出最佳的酪蛋白分解活性。它们具有较高的凝乳活性与酪蛋白分解活性之比，表明其具有出色的凝乳能力。蛋白酶被证实为丝氨酸蛋白酶和金属蛋白酶，分子量（MW）分别为 44 和 108 kDa。它们对κ-酪蛋白具有很高的水解活性，在四个主要部位切割 κ-酪蛋白，其中一个部位与小牛凝乳酶相同，这是首次在藻类蛋白酶中报道。研究结果表明，这些蛋白酶有可能在奶酪制作中用作凝乳剂。
