环境条件对乳清蛋白凝胶特性和微观结构的影响

 【目的】研究离子种类、离子强度、加热温度、pH、蛋白浓度等条件对乳清蛋白凝胶的质地性质、持水性、微观结构的影响。【方法】利用质构仪测定添加不同浓度的NaCl和CaCl2对所形成的乳清蛋白凝胶硬度、弹性、内聚性的影响，利用扫描电镜观察凝胶微观结构。【结果】盐对凝胶性质影响很大，相同条件下钠盐形成凝胶需较高浓度且弹性和持水性好于钙盐凝胶；蛋白浓度达到8%～10%时凝胶质地较好。在微观结构上钠盐凝胶比钙盐凝胶内部更加致密结实。这在宏观上表现为钠盐凝胶硬度相对较大，持水性更好。【结论】钠盐凝胶具有更好的凝胶质地和功能性质。

Influence of Environmental Conditions on Whey Protein Gels Properties and Gels Microstructure

The effects of ionic variety, ionic strength, heating temperature, pH value and protein concentration on texture properties，water-holding capacity and microstructure of whey protein gels were investigated. The influence of different concentration NaCl and CaCl2 on gels hardness，springiness and cohesiveness was studied by using TA-XT plus instrument；the microstructure was observed with scanning electron microscopy (SEM). The results showed that salts could greatly vary gels properties, it need higher concertation of NaCl than that of CaCl2 at the same gels conditions. The springiness and water-holding capacity (WHC) of NaCl gels was better than that of calcium chloride gels. The better texture would be obtained for protein concentration between 8～10％. The microstructure of NaCl gels was more compact than that CaCl2 gels, and it showed that NaCl gels have more hard texture and better water-holding capacity in macrostructure. Therefore, textural properties and functional properties of NaCl gels were better than that of CaCl2 gels.