The ARC Dairy Innovation Hub, The University of Melbourne, Parkville, Victoria 3010, Australia; School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
The ARC Dairy Innovation Hub, The University of Melbourne, Parkville, Victoria 3010, Australia; School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
Food Chem. 2018 Apr 1;244:36-43. doi: 10.1016/j.foodchem.2017.10.029. Epub 2017 Oct 7.
Rennet gelation is used to produce many types of cheese. The effect of native whey protein on rennet gelation kinetics was investigated. Milks with a wide range of whey protein:casein (WP:CN) ratios (with standardised casein concentrations) were made from powders produced by microfiltration. Measurements of casein macro peptide release showed that native whey protein inhibited the enzymatic action of chymosin, which delayed the onset and reduced the subsequent rate of gelation. Experiments in which increased chymosin concentrations compensated for the inhibition, demonstrated that other factors also contributed to the reduced gelation rate. Neither an increase in viscosity nor a reduction in soluble calcium was responsible, leading to the conclusion that in addition to inhibiting chymosin, native whey proteins present a physical barrier to para-casein aggregation. This study demonstrates and explains how casein-enriched retentates from microfiltration gel faster than regular cheese milk that contains higher amounts of native whey protein.
凝乳酶凝胶作用被用于生产多种类型的奶酪。本研究调查了天然乳清蛋白对凝乳酶凝胶动力学的影响。利用微滤法制得的乳粉，制备了乳清蛋白/酪蛋白（WP：CN）比值（标准化的酪蛋白浓度）范围较宽的牛奶。对酪蛋白大肽释放的测量表明，天然乳清蛋白抑制了皱胃酶的酶促作用，从而延迟了凝胶化的开始并降低了随后的凝胶化速率。用增加皱胃酶浓度来补偿抑制作用的实验表明，其他因素也导致了凝胶化速率的降低。增加的粘度和可溶性钙的减少都不是原因，因此得出的结论是，除了抑制皱胃酶外，天然乳清蛋白还对副酪蛋白聚集形成物理障碍。本研究证明并解释了为什么富含酪蛋白的微滤截留物比含有较高天然乳清蛋白的常规奶酪乳更快地凝胶。
