白牦牛乳硬质干酪加工工艺技术研究

以甘肃天祝牧区白牦牛乳为原料制作硬质干酪，优化加工白牦牛乳硬质干酪的工艺参数，并用扫描电镜(SEM)观察成熟期干酪的微观结构。结果表明，白牦牛乳硬质干酪在发酵剂添加量3%，凝乳酶添加量30μl/100ml，凝乳温度40℃，凝乳pH6.1，氯化钙添加量0.03% 时，品质较好，其成熟30d 时蛋白质含量为27.82%，脂肪含量为36.43%，出品率为15.5%；成熟30d 和90d 的白牦牛乳干酪微观结构变化明显。

Processing Technology of Hard Cheese from Milk of White Yak

Milk of white yaks grazing pastures in Tianzhu county, Gansu province was processed into hard cheese. The processing parameters were optimized using one-factor-at-a-time and orthogonal array design in which the interactions between the variables were neglected. In addition, cheese products in ripening period were subjected to analysis of proximate composition and microstructure observation under SEM. High hard cheese yield and good sensory quality both could be achieved when addition amounts of fermentation starter, rennet and CaCl2 were 3%, 30 μl/100 ml and 0.03%, respectively, temperature 40℃, and pH 6.1. The product on the 30th day of ripening contained 27.82 % protein and 36.43% fat, and the yield was 15.5%; no significant microstructure changes were founded during ripening (observed on the 30th, 60th and 90th day).