脱钙罗非鱼鱼鳞明胶提取工艺优化及其理化性质

Extraction optimization and physicochemical properties of gelatin from demineralized scale of Oreochromis nilotica

文章以罗非鱼(Oreochromis nilotica)鱼鳞为原料,经乙二胺四乙酸二钠(EDTA-Na2)脱钙处理后采用酸法提取明胶。根据中心组合试验设计(center combination of experimental design,CCD)原理展开试验,考察提取时间(h,X1)、提取温度(℃,X2)、浸酸时间(h,X3)和柠檬酸质量浓度(g.L-1,X4)对明胶得率(%,Y)的影响,并对所得明胶的理化性质与牛骨明胶进行比较。响应面分析结果表明,提取温度、提取时间和浸酸时间与明胶得率之间具有显著相关性;优化的提取条件为提取温度65℃、提取时间3.6 h、柠檬酸质量浓度200 g.L-1、浸酸时间11.3 h。在此条件下的明胶得率为28.4%,与预测值30.1%相近。制得的鱼鳞明胶粗蛋白含量为89.9%,氨基酸组成中每1 000总氨基酸残基中甘氨酸为352个,亚氨基酸(脯氨酸和羟脯氨酸)173个;凝胶强度高达245 Bloom(g),熔点为27.0℃,而比浓对数粘度及成胶质量浓度分别为0.030 L.g-1和8.0 g.L-1。

According to the center combination of experimental design, decalcification by acid extraction with EDTA-Na2 to study the effects of we extracted the gelatin from Oreochromis nilotica scale after extracted time （ h, X1 ） , extracted temperature （ ℃, X2 ）, acid treated time （h, X3 ） and citric acid concentration （g.L-1, X4） on the yield （%, Y） of gelatin, and compared the physico- chemical properties of the gelatin with bovine bone gelatin. The results of response surface methodology （RSM） indicate that the extrac- ted temperature, extracted time and acid treated time affect significantly the yield of gelatin. The optimum conditions are 200 g.L-1cit- ric acid concentration, 11.3 h treated time, 65 ~C extraction temperature and 3.6 h extraction time. Under these conditions, the measured yield of gelatin is 28.4%, which is close to 30. 1% of the predicted value. The content of crude protein, gel strength, melting point, logarithmic viscosity and the least concentration of the gelatin are 89.9%, 245 Bloom （g） , 27.0 C, 0. 030 L.g-1 and 8.0 g-L 1, respectively. The contents of glycine and imino acids （proline and hydroxyproline） are 352 and 173 per 1 000 total a- mino acids, respectively.