不同乳化盐对Mozzarella再制干酪结构的影响

Effects of Different Emulsifying Salts on the Structure of Cheese Prepared from Mozzarella

采用傅里叶变换红外光谱(FTIR)和扫描电镜分析不同乳化盐对Mozzarella再制干酪的结构的影响。结果表明:再制干酪的酪蛋白中有α-螺旋、β-折叠、无规则卷曲和β-转角4种蛋白质二级结构,但不同乳化盐的使用使得各结构所占的比重不同。由不同的乳化盐制得的再制干酪的酪蛋白二级结构均以β-折叠为主;添加磷酸氢二钠(DSP)和六偏磷酸钠(SHMP)制得的再制干酪比较特殊,均无α-螺旋结构;而其他样品中无规则卷曲结构所占比例均较少。从电镜图可以看出由2%柠檬酸钠、0.37%焦磷酸钠、0.2%多聚磷酸钠(均以原料奶酪计)复配乳化盐制得的再制干酪蛋白交联比较好,结构均匀,脂肪几乎全被水合后的副酪蛋白包裹。

The effects of different emulsifying salts on the structure of processed Mozzarella cheese was analyzed by using PTIR and scanning electron microscopy （SEM）. The results showed that there were four types of secondary structures including a-helix, fl-sheet, random coil and fl-turu in processed cheese, but they were in different proportions due to the type of emulsifying salt. fl-sheet accounted for major proportion of the secondary structure in processed cheese made with different emulsifying salts. The processed cheeses made with DSP and SHMP were special and neither possessed a-helix; while random coil accounted for a smaller proportion in the processed cheeses made with each of three other salts. Based on scanning electron micrographs, the interactions between proteins were different and the structure was uniform in the processed cheese made with 2% sodium citrate, 0.37% sodium pyrophosphate and 0.2% sodium polyphosphate （calculated by weight relative to the raw Mozzarella cheese）. Moreover, fat globules were nearly coated by hydrated paracaseinate.