干热处理和pH偏移对汉麻分离蛋白/卡拉胶接枝物凝胶性质的影响

Effects of dry heating treatment and pH shifting on gel properties of hemp protein isolate/carrageenan grafted hydrogel

中文关键词:  汉麻分离蛋白、卡拉胶、干热处理、pH偏移、凝胶性质

英文关键词:hemp protein isolate  carrageenan  dry heating treatment  pH shift  gel property

中文摘要:

      目的 研究不同pH偏移和干热处理时间对汉麻分离蛋白/卡拉胶接枝物凝胶性质的影响。方法 以未经pH偏移及干热处理组分为空白对照, 研究了不同干热处理时间(0、24、48、72 h)和pH偏移(2、12)条件对汉麻分离蛋白/卡拉胶接枝物凝胶硬度、流变特性、水分分布和微观结构的影响。结果 与对照组相比, 经干热处理和pH偏移处理的蛋白凝胶硬度、持水性和储能模量(G')整体上有所提高, 其中干热处理48 h和pH 2偏移处理组分是对照组的1.38、1.10和19.45倍。干热处理和pH偏移增加了凝胶中不可流动水的含量(92.88%)且电镜结果显示凝胶的微观结构逐渐致密, pH 2偏移和干热处理48 h更加致密均匀, 复合凝胶中蛋白的α-螺旋的含量减少, β-折叠含量增加, 这表明蛋白分子内部的有序结构增加。结论 在pH 2偏移干热处理48 h条件下, 汉麻分离蛋白凝胶性质最佳, 这为汉麻分离蛋白在食品工业中的应用提供了新的理论依据。

英文摘要:

      Objective To study the effects of different pH shifts and dry heating treatment times on the gel properties of hemp protein isolate/carrageenan grafted hydrogel. Methods The effects of different dry heating treatment times (0, 24, 48, 72 h) and pH shifts (2, 12) on the gel hardness, rheological properties, water distribution, and microstructure of hemp isolate protein/carrageenan grafts were investigated using the un-pH-shifted and dry heat-treated fractions as a blank control. Results The hardness, water-holding capacity, and energy storage modulus (G') of the protein gels treated with dry heat treatment and pH shift increased overall compared with those of the control group, with the fractions treated with dry heat treatment for 48 h and pH 2 shift being 1.38, 1.10 and 19.45 times higher than those of the control group. Dry heat treatment and pH shift increased the content of immobile water in the gels (92.88%) and the electron microscopy results showed that the microstructure of the gels was gradually denser, with pH 2 shift and dry heat treatment for 48 h became more dense and uniform. The content of α-helix of the protein in the composite gels decreased, and the content of β-sheet increased, which indicated that the internal ordering of the protein molecules increased. Conclusion Under the condition of pH 2 shifts dry heat treatment for 48 h, the gel properties of hemp protein isolate are the best, which provides a new theoretical basis for the application of hemp protein isolate in the food industry.