提高牛油基凝胶乳冻融稳定性的研究

Improving the freeze-thaw stability of tallow-based emulsion gel

牛油基凝胶乳可用作制备人造雪花牛肉脂肪替代物,然而现阶段凝胶乳冻融稳定性差的问题限制了其作为脂肪替代物的应用。基于实验室前期工作基础,分析质量分数为3.0%的明胶型牛油基凝胶乳冻融稳定性差的原因,并通过添加外源小分子葡萄糖和三聚磷酸钠的方式提高其冻融稳定性。结果表明:在降温过程中脂肪缓慢结晶,形成了颗粒较大的β型晶体,油脂晶体和冰晶的共同作用,破坏了乳液的界面层和胶体的空间网状结构,导致凝胶乳的冻融稳定性变差;添加1.0%的葡萄糖可以减小冰晶颗粒的大小,减小对凝胶乳结构的破坏,添加0.8%三聚磷酸钠的凝胶乳Zeta电位降低至-21.50 mV,乳液的平均粒径减小至1182.7 nm,二者对提高凝胶乳的冻融稳定性具有协同作用,可减小冻融对凝胶乳硬度和弹性的影响,同时可将持水力提升至98.0%。

The tallow-based emulsion gel can be used as a substitute for artificial snowflake beef fat,however,the problem of poor freeze-thaw stability limits its application as a fat substitute.Based on the preliminary work of the laboratory,the gelatin-type tallow-based emulsion gel(with a mass fraction of gelatin 3.0%)was analyzed for its poor freeze-thaw stability,and its freeze-thaw stability was improved by adding exogenous small molecule glucose and sodium tripolyphosphate.The results showed that the fat slowly crystallized during the cooling process,and formed a largeβ-type crystal.The combination of the oil crystal and ice crystal destroyed the interfacial layer of the emulsion and the spatial network structure of the colloid,which resulted in the poor freeze-thaw stability.Adding 1.0%glucose could reduce the size of ice crystal particles and reduced the damage to the gel structure.Adding 0.8%sodium tripolyphosphate could reduce the Zeta potential to-21.50 mV,and the average particle size of the emulsion decreased to 1182.7 nm.1.0%glucose and 0.8%sodium tripolyphosphate had a synergistic effect on improving the freeze-thaw stability of the tallow-based emulsion gel,which could reduce the effect of freeze-thaw on the hardness and elasticity of the gel,and increase the water holding capacity to 98.0%.