This study aimed to optimize the formulation of milk coagulant and coagulation conditions for improved quality and productivity of milk cake (Chinese cheese) produced from fresh Holstein cow milk and milk-coagulating protease from the stems of Dregea sinensis var.corrugata using combination of one-factor-at-a-time method and response surface methodology.The results showed that the best formulation of milk coagulant consisted of the protease from Dregea sinensis var.corrugata 17.95％,citric acid 0.023 3％,and calcium chloride 0.009 85％,and the best coagulation temperature was 83.25 ℃.The sensory score of milk cake made by the optimized process was 85.7 ± 1.32,which was significantly higher than that made by the traditional acidic water method (P ＜ 0.05).Water,crude protein and crude fat contents of our product were (52.94 ± 1.03)％,(20.09 ± 0.57)％,and (22.54 ± 0.48)％,respectively.The contents of ash,calcium,and phosphorus were increased significantly as compared with that obtained using the traditional process (P ＜ 0.05).The contents of free amino acid and free fatty acid in milk cake obtained in this study were (77.64 ± 5.80) and (1 953.76 ± 53.53) mg/100 g,respectively.It was a good source of vitamin containing significantly contents of fat-soluble VA and VE (P ＜ 0.05).The microstructure of milk cakes made by the traditional and new methods was different;the former showed a lamellar or cluster structure,whereas the latter presented a three-dimensional network structure.Moreover,the milk cake made by the optimized process was bright in color,having a homogeneous texture,unique flavor and plant aroma.It was a highly nutritional product with improved quality compared with that made by the traditional process.%以贯筋藤蛋白酶、新鲜荷斯坦牛奶等为原料,通过单因素筛选和响应面试验优化凝乳剂配方、凝乳工艺,研究优化工艺乳饼的产品质量.结果表明,新型凝乳剂的最佳配方为贯筋藤蛋白酶液(蛋白酶质量分数0.15％)添加量17.95％,柠檬酸添加量0.023 3％,氯化钙添加量0.009 85％;最佳凝乳温度为83.25℃.优化工艺乳饼感官评分为(85.7±1.32)分,高于传统酸水工艺(P＜0.05);水分、粗蛋白、粗脂肪含量分别为(52.94±1.03)％、(20.09±0.57)％、(22.54±0.48)％,灰分、钙、磷含量较传统酸水工艺提高(P＜0.05);游离氨基酸、游离脂肪酸总量分别为(77.64±5.80)、(1 953.76±53.53) mg/100 9;维生素含量丰富,脂溶性VA、VE含量提高(P＜0.05).2种工艺加工乳饼微观结构存在差异,传统酸水乳饼呈现片状或团状结构,优化工艺乳饼呈现三维网状结构.优化工艺乳饼色泽鲜亮、质地均匀,具有乳饼特有的滋气味和植物清香,较传统酸水工艺产品质量进一步提高,是一种风味独特的高营养产品.
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