Ong Lydia, Dagastine Raymond R, Kentish Sandra E, Gras Sally L
Particulate Fluid Processing Centre, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, VIC 3010, Australia.
The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia.
Foods. 2013 Jul 18;2(3):310-331. doi: 10.3390/foods2030310.
Milk protein is often standardised prior to cheese-making using low concentration factor ultrafiltration retentate (LCUFR) but the effect of LCUFR addition on the microstructure of full fat gel, curd and Cheddar cheese is not known. In this work, Cheddar cheeses were made from cheese-milk with or without LCUFR addition using a protein concentration of 3.7%-5.8% w/w. The fat lost to sweet whey was higher in cheese made from cheese-milk without LCUFR or from cheese-milk with 5.8% w/w protein. At 5.8% w/w protein concentration, the porosity of the gel increased significantly and the fat globules within the gel and curd tended to pool together, which possibly contributed to the higher fat loss in the sweet whey. The microstructure of cheese from cheese-milk with a higher protein concentration was more compact, consistent with the increased hardness, although the cohesiveness was lower. These results highlight the potential use of LCUFR for the standardization of protein concentration in cheese-milk to 4%-5% w/w (equivalent to a casein to total protein ratio of 77%-79% w/w) to increase yield. Beyond this concentration, significant changes in the gel microstructure, cheese texture and fat loss were observed.
在制作奶酪之前，乳蛋白通常使用低浓缩因子超滤截留物（LCUFR）进行标准化处理，但添加LCUFR对全脂凝胶、凝乳和切达干酪微观结构的影响尚不清楚。在这项研究中，使用蛋白质浓度为3.7%-5.8%（w/w）的奶酪乳制作切达干酪，其中一部分添加了LCUFR，一部分未添加。未添加LCUFR的奶酪乳或蛋白质含量为5.8%（w/w）的奶酪乳制作的奶酪中，进入甜乳清的脂肪损失更高。在蛋白质浓度为5.8%（w/w）时，凝胶的孔隙率显著增加，凝胶和凝乳中的脂肪球倾向于聚集在一起，这可能导致了甜乳清中较高的脂肪损失。蛋白质浓度较高的奶酪乳制作的奶酪微观结构更致密，这与硬度增加一致，尽管内聚性较低。这些结果突出了使用LCUFR将奶酪乳中的蛋白质浓度标准化至4%-5%（w/w）（相当于酪蛋白与总蛋白的比例为77%-79%（w/w））以提高产量的潜力。超过这个浓度，凝胶微观结构、奶酪质地和脂肪损失会出现显著变化。
