地衣芽孢杆菌D3.11凝乳酶对切达干酪质地特性的影响

Effect of Bacillus licheniformis D3.11 Milk-Clotting Enzyme on Texture Properties of Cheddar Cheese

为揭示地衣芽孢杆菌D3.11凝乳酶对切达干酪成熟过程中质地的影响,利用地衣芽孢杆菌D3.11凝乳酶制作切达干酪(C_(DF)组)和切达干酪类似物(C_(D3)组),采用商品凝乳酶作为对照(C_(CF)组),分析干酪成熟过程中质构、流变特性、微观结构的变化规律。结果表明:3组干酪的硬度随着干酪的成熟而增加,而弹性和咀嚼性则呈现下降趋势,C_(DF)组干酪硬度、弹性、咀嚼性均最小;蛋白结构的致密性随干酪成熟度的增加而减弱,C_(DF)组干酪结构相比于C_(CF)组干酪较为松散;在6个月的成熟期内,3组干酪的储能模量和损耗模量随着成熟时间和扫描温度的增加而降低,损耗角正切值(tanδ)在成熟期内下降,表明干酪流动性随着成熟时间的延长而减弱,其中C_(DF)组干酪流动性和熔融性更好。以上结果表明,地衣芽孢杆菌D3.11凝乳酶所制干酪机械性能优于商品凝乳酶所制干酪,商品凝乳酶所制干酪质地更硬且蛋白网络结构更为致密。

This study was conducted to reveal the effect of milk-clotting enzyme(MCE)produced by Bacillus licheniformis on the texture of Cheddar cheese during ripening.Cheddar cheese and Cheddar cheese analogue were prepared with the MCE and designated as C_(DF) and C_(D3),respectively,and commercial chymosin was used as a control(C_(CF)).The changes in the texture,rheology and microstructure of cheese during ripening were analyzed.The results were as follows:The hardness of the three cheeses increased with maturation time,while the elasticity and chewiness presented a downward trend.The hardness,springiness and chewiness of C_(DF) were the lowest.The scanning electron microscope(SEM)results showed that the compactness of the protein structure decreased with increasing maturity,and the structure of C_(DF) was looser than that of C_(CF).The rheological results showed that the storage modulus and loss modulus decreased with increasing ripening time up to six months and increasing sweep temperature.The tanδvalue decreased during the ripening process,indicating that the fluidity of cheese decreased with increasing ripening time.The fluidity and fusibility of C_(DF) were better than those of the other groups.The above results indicated that the mechanical properties of cheese made with Bacillus licheniformis MCE were better than those made with commercial rennet,while the latter had harder texture and denser protein network structure.