响应面法优化壳聚糖固定化果胶酶对玛咖汁澄清的效果

Optimization by Response Surface Methodology of Clarification of Maca Juice Using Chitosan-Immobilized Pectinase

采用壳聚糖固定化果胶酶澄清玛咖汁,以解决在玛咖汁贮存过程中出现的果胶、水溶性蛋白质和多酚导致的混浊现象,达到快捷、经济的目的。在单因素试验的基础上,采用响应面分析法(RSM)模拟出壳聚糖固定化果胶酶用量、澄清时间和澄清温度对玛咖汁澄清度影响的二次多项式回归数学模型。结果表明:壳聚糖固定化果胶酶用量43.50g/L、澄清时间104min、澄清温度50℃,玛咖汁的澄清度为95.78%。玛咖汁澄清后,易引起果汁混浊的果胶、水溶性蛋白质、总酚的沉降率依次为60.73%、32.93%和9.06%,玛咖汁中主要活性成分芥子油苷、水溶性生物碱、VC和总糖的损失率依次为6.92%、3.35%、3.25%和1.82%,表明在响应曲面法优化条件下,壳聚糖固定化果胶酶澄清能较好的保留玛咖汁中的的主要活性成分。在其最优条件下,壳聚糖固定化果胶酶连续使用10次后,玛咖汁的透光率仍能达到75.49%,说明该固定化酶具有一定的操作稳定性。

Chitosan-immobilized pectinase was applied to clarify maca juice in order to avoid turbidity caused by pectin,water-soluble proteins and/or phenloics during storage.Three operating parameters including pectinase dosage,temperature and time were optimized based on clarification efficiency by response surface methodology.A quadratic polynomial regression model was developed indicating the effect of the three operating parameters on clarification efficiency.After treatment with 43.50 g/L of the immobilized enzyme at 50 ℃ for 104 min,the clarity of maca juice was 95.78%.In addition,the removal rates of pectin,water-soluble proteins and phenloics were 60.73%,32.93% and 9.06%,respectively,and glucosinolates,water soluble alkaloids,VC and total sugar,respectively,lost only 6.92%,3.35%,3.25% and 1.82% of the original amounts,suggesting the major bioactive constituents in maca juice can be mostly retained under the optimized clarification conditions.After ten cycles of repeated use,the immobilized pectinase provided a clarity of 75.49% when used to treat a new maca juice,illustrating good repeated usability.