牛奶乳饼加工工艺优化及其营养成分分析

Optimization of Processing Parameters and Nutritive Composition Analysis of Milk Cake(Chinese Cheese)

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 g;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。

This study aimed to optimize the formulation of milk coagulant and coagulation conditions for improved qualityand productivity of milk cake(Chinese cheese)produced from fresh Holstein cow milk and milk-coagulating proteasefrom the stems of Dregea sinensis var.corrugata using combination of one-factor-at-a-time method and response surfacemethodology.The results showed that the best formulation of milk coagulant consisted of the protease from Dregea sinensisvar.corrugata17.95%,citric acid0.0233%,and calcium chloride0.00985%,and the best coagulation temperature was83.25℃.The sensory score of milk cake made by the optimized process was85.7±1.32,which was significantly higherthan that made by the traditional acidic water method(P<0.05).Water,crude protein and crude fat contents of our productwere(52.94±1.03)%,(20.09±0.57)%,and(22.54±0.48)%,respectively.The contents of ash,calcium,and phosphoruswere increased significantly as compared with that obtained using the traditional process(P<0.05).The contents of freeamino acid and free fatty acid in milk cake obtained in this study were(77.64±5.80)and(1953.76±53.53)mg/100g,respectively.It was a good source of vitamin containing significantly contents of fat-soluble VA and VE(P<0.05).Themicrostructure of milk cakes made by the traditional and new methods was different;the former showed a lamellar orcluster 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 highlynutritional product with improved quality compared with that made by the traditional process.