Alves L S, Merheb-Dini C, Gomes E, da Silva R, Gigante M L
Faculty of Food Engineering, University of Campinas - UNICAMP, PO Box 6121, CEP 13083-970, Campinas, SP, Brazil.
J Dairy Sci. 2013;96(12):7490-9. doi: 10.3168/jds.2013-7119. Epub 2013 Oct 24.
The objective of this research was to compare the effect of 2 fungal proteases, one that is already commercially established as a milk-clotting agent and another produced at the laboratory scale, on Prato cheese composition, protein and fat recovery, yield, and sensory characteristics. Cheeses were produced according to the traditional protocol, using protease from the fungus Thermomucor indicae-seudaticae N31 and commercial coagulant from Rhizomucor spp. as clotting agents. A 2×6 factorial design with 3 replications was performed: 2 levels of coagulants and 6 levels of storage time. After 5, 12, 19, 33, 43, and 53d of refrigerated storage (12°C), cheeses were monitored for proteolysis, firmness, and casein degradation by capillary electrophoresis. Sensory acceptance was evaluated after 29d of manufacturing. The different coagulants did not statistically affect Prato cheese composition, protein and fat recovery, and yield. Both cheeses presented good sensory acceptance. Proteolysis increased and firmness decreased for both cheeses during the storage time, as expected for Prato cheese. Caseins were well separated by capillary electrophoresis and the results showed, with good resolution, that the cheeses exhibited similar protein hydrolysis profile. Both cheeses presented good sensory acceptance. The gathered data showed that the protease from T. indicae-seudaticae N31 presented similar action compared with the commercial enzyme, indicating its efficiency as clotting agent for Prato cheese manufacture.
本研究的目的是比较两种真菌蛋白酶的效果，一种已作为凝乳剂在商业上得到应用，另一种是在实验室规模生产的，它们对普拉托奶酪的成分、蛋白质和脂肪回收率、产量及感官特性的影响。奶酪按照传统工艺制作，使用来自印度嗜热毛霉N31的蛋白酶和来自根霉属的商业凝乳剂作为凝乳剂。进行了一个2×6析因设计，重复3次：2种凝乳剂水平和6个储存时间水平。在冷藏储存（12°C）5、12、19、33、43和53天后，通过毛细管电泳监测奶酪的蛋白水解、硬度和酪蛋白降解情况。在制作后29天评估感官接受度。不同的凝乳剂对普拉托奶酪的成分、蛋白质和脂肪回收率以及产量没有统计学上的显著影响。两种奶酪都具有良好的感官接受度。正如普拉托奶酪所预期的那样，在储存期间，两种奶酪的蛋白水解均增加，硬度均降低。通过毛细管电泳能很好地分离酪蛋白，结果以良好的分辨率显示，两种奶酪呈现出相似的蛋白质水解谱。两种奶酪都具有良好的感官接受度。收集的数据表明，来自印度嗜热毛霉N31的蛋白酶与商业酶相比具有相似的作用，表明其作为普拉托奶酪生产凝乳剂的有效性。
