苜蓿冰结构蛋白对冷冻面团质地的影响

为了拓展了植物冰结构蛋白(Ice-structuring proteins,ISPs)资源,本研究采用硫酸铵沉淀法从紫花苜蓿干草中提取苜蓿冰结构蛋白(Alfalfa ice-structuring proteins,AISPs),测定热滞活性并观察冰晶变化。将AISPs添加到冷冻面团中,测定不同冻融周期、不同AISPs的添加量对冷冻面团质构特性、拉伸特性以及微观结构的影响。结果表明:AISPs热滞活性为0.61℃,与NaCl及蔗糖溶液相比,AISPs溶液经四次冻融后其冰晶数量多体积小,说明AISPs具有一定的抗冻活性。随冻融周次的增加,AISPs添加量为2.0%～2.5%时,冷冻面团的硬度降低,弹性和内聚性稳定增加,黏附性显著增加(p <0.05);拉伸面积和延展性增大;淀粉颗粒遭受破坏小,面筋网络结构清晰。说明AISPs对冷冻面团具有很好的抗冻保护作用,改善了冷冻面团的质地,使其冻藏稳定性得以明显提高。

Effect of Alfalfa Ice Structural Proteins on Quality of Frozen Dough

In order to develop the resource of plant ice structure proteins( ISPs),alfalfa ice structural proteins( AISPs) were extracted from alfalfa hay by ammonium sulfate precipitation method in this study. The thermal hysteresis activity( THA) was measured and the changes of ice crystals were observed. Then AISPs was added to frozen dough,and the texture properties tensile properties and micro-structure of frozen dough after several periods of freeze-thaw cycles were measured. The results showed that the THA of AISPs was 0.61 ℃.When AISPs were compared with NaCl and sucrose solution,it had more ice crystals and smaller volume after four times of freeze-thaw cycles.It identified that AISPs had antifreeze activity in a certain extent.With the increasing of freeze-thaw cycles,when AISPs were added from 2.0% to 2.5%,many performance of frozen dough were increased observably,such as elasticity,cohesiveness,adhesion,extension area and ductility( p < 0.05).The hardness of frozen dough was reduced.The tarch granules were destroyed less and the gluten networks were became clearly.AISPs displayed good protection effect on frozen dough to improve the quality of frozen dough,and the frozen storage stability was improved obviously.