保水剂及冷风干燥对鱼糜溶胶水分状态的影响研究

Effects of water retaining agents and cold-drying on the moisture state of surimi sols

目的:探讨保水剂及冷风干燥对鱼糜溶胶水分状态的影响。方法:将鱼糜中添加不同保水剂制成溶胶,经冷风干燥一定时间后进行高温处理,测量冷风干燥不同时间后水分含量、水分活度和水分状态的变化,通过5分法评分标准评定鱼糜溶胶高温处理后的凝胶特性。结果:随着冷风干燥时间的延长,空白组及添加保水剂组的鱼糜溶胶的水分含量均呈现下降趋势,添加保水剂组的水分含量降低速率均小于空白组;水分活度也呈现一定的下降趋势,添加保水剂可显著降低鱼糜溶胶的水分活度,弛豫时间T21和T22明显向低的弛豫时间方向迁移,鱼糜溶胶中的结合水和自由水含量随冷风干燥时间的延长均呈现上升趋势,而不易流动水呈现下降趋势,另外,鱼糜溶胶高温处理后的凝胶特性呈现上升的趋势。结论:降低水分含量可有效提高鱼糜溶胶高温处理后的凝胶特性,同时可通过添加保水剂改变水分活度和水分状态从而进一步提高鱼糜溶胶的高温处理热稳定性。

Objective：Effects of water retaining agents and cold-drying on the moisture state of surimi sols were explored. Methods：The surimi sols were made of surimi and different water retaining agents. After a different period cold-drying,the moisture content,water activity and moisture status changes of the sols were measured. Then the surimi sols were treated with high temperature and afterwards their gel properties were evaluated by a five-point grading system. Results..With cold-drying time increasing,the moisture content of the surimi sols showed a downward trend. The decreasing rate of the surimi sols with different water retaining agents was lower than that of the blank. The water activity also showed a downward trend. Water retaining agents significantly improved the water activity of the surimi sols. The relaxation time T21 and T~ became shorter and shorter. The hydration water and immobilized water content of the surimi sols showed an upward trend, while the free water content showed a downward trend. Moreover,the gel properties of the surimi sols after high-temperature treatment showed an upward trend. Conclusion：Decreasing the moisture content effectively improved the gel properties of the surimi sols with high-temperature treatment while changing the water activity and moisture state by adding water retaining agents further improved the thermal stability of the surimi sols.