斑点叉尾鮰鱼皮明胶制备及其胶凝性能优化研究

Preparation of gelatin from Channel Catfish skin and its gelling performance optimization

以斑点叉尾鮰鱼皮为原料制备食用明胶,通过单因素试验比较NaOH处理浓度和处理时间、醋酸处理浓度和处理时间、熬胶温度和熬胶时间对明胶品质的影响,并通过正交试验优化工艺条件,探究斑点叉尾鮰鱼皮明胶的最佳制备工艺.分别选择卡拉胶、海藻酸钠和黄原胶3种亲水胶体与斑点叉尾鮰鱼皮明胶进行复配,以改善鱼皮明胶胶凝性能.结果表明:1)斑点叉尾鮰鱼皮明胶制备的最佳工艺为,先用0. 2 mol/L NaOH溶液浸泡2 h,然后用0. 2 mol/L醋酸溶液浸泡4 h,最后在60℃条件下热水浴提取4 h.在此工艺条件下,明胶得率达73. 36%,凝胶强度为434. 86 g,胶凝温度和熔化温度分别为19℃和26℃,等电点pI为6. 8. SDS-PAGE分析结果表明,鱼皮水解制备的明胶是多组分的混合物,没有确定的分子量,但具有分子量段. 2)当鱼皮明胶质量分数为1. 6%,卡拉胶质量分数为0. 4%,复配胶临界质量分数为2. 0%时,鱼皮明胶与卡拉胶的复配效果最优.此配方所得复配凝胶的胶凝温度和熔化温度分别为17. 6℃和35. 1℃,相较于空白组,其胶凝温度和熔化温度分别提高了13. 8℃和22. 8℃.可见,卡拉胶的加入可提高鱼皮明胶的热稳定性,对改善鱼皮明胶加工性能具有重要作用.

The effect of NaOH treatment concentration and treatment time, acetic acid treatment concentration and treatment time, temperature and treatment time of preparation process on the quality of gelatin were compaled by single factor test, and orthogonal test optimization process was performed, to explore the optimal preparation process of channel catfish skin gelatin. Then thine hydrocolloids including carrageenan, sodium alginate and xanthan gum were selected to be compounded with channel catfish skin gelatin to improve its gel- ling performance. The results showed that ： 1 ） The optimal preparation process of gelatin for channel catfish skin was first soaked in 0.2 mo]/L NaOH solution for 2 h, then soaked in 0.2 mol/L acetic acid solution for 4 h, and finally extracted in hot water bath at 60 ℃ for 4 h. Under this process conditions, the yield of gelatin reached 73.36% , the gel strength was 434.86 g, and the gelling temperature and mehing temperature were 19℃ and 26 ℃, respectively. The isoelectric point pI was 6.8. The result of SDS-PAGE analysis showed that gelatin prepared by hydrolysis of fish skin was a muhi-component mixture with no definite molecular weight, but a molecular weight segment. 2 ） When the fish skin gelatin concentration was 1.6% , the carrageenan added amount was 0.4% , and the critical concentration of the compounding gel was 2.0% , the fish skin gelatin and carrageenan had the best compounding effect. The gelling and mehing temperatures of the gel were 17.6 ℃ and 35.1 ℃ , respectively, compared with the blank group, the gelling temperature and mehing temperature were increased by 13.8 ℃ and 22.8 ℃, respectively. The addition of carrageenan can improve the thermal stability of fish skin gelatin, which is of important role for improving the processing performance of fish skin gelatin.