海藻酸钠凝胶(C_6H_7NaO_6)_x交联Ca^(2+)包埋风味酶的工艺优化及应用稳定性研究

OPTIMIZATION AND STABILITY OF IMMOBILIZED FLAVOR ENZYME

以海藻酸钠为载体,Ca2+为交联剂,对风味酶进行固定化。以固定化酶活力回收率为指标,在单因素试验基础上,通过响应面分析方法优化了固定化风味酶的工艺,并考察了固定化风味酶使用的稳定性。通过对回归模型进行分析,确定最佳的固定化工艺参数为海藻酸钠浓度2.43%,加酶量(酶液体积/海藻酸钠体积)1:1.76,固定化时间2.89 h,此时固定化酶的活力回收率可达81.88%,考虑到实际操作时对参数精度的控制水平,将固定化酶的优化工艺确定为海藻酸钠浓度2.50%,加酶量(酶液体积/海藻酸钠体积)1:2,固定化时间3.00 h,固定化酶的活力回收率达到80.05%±1.33%。优化工艺下制得的固定化风味酶最适使用温度为60?C,热敏感性降低,稳定性提高;最适p H 8.0,比游离酶向碱偏移了1.0,酸碱适用范围增大;可多次使用,冷藏条件下储藏3周后活力依然保持在80%以上。

The flavor enzyme was immobilized by sodium alginate and interacted with Ca2+. Based on the results of single-factor tests, a response surface method was designed to optimize the preparation of immobilized flavor enzyme in three factors, i.e., the concentration of sodium alginate, amount of enzyme addition in ratio of enzyme solution volume / sodium alginate volume), and the duration of immobilization on carrier. The results show that the optimal immobilization conditions were 2.43%, 1/1.76, and 2.89 h, respectively, at which the recovery of immobilized flavor enzyme reached 81.88%. Considering the convenience and accuracy in practice, the three factors could be rounded to 2.50%, 1 : 2, and 3.00 h, at which the recovery could reach 80.05%±1.33%. In addition, the recovered product under the optimal conditions can be best used in 60?C, which reduces the thermal sensitivity and increases the stability, and at p H 3.0, shifting 1.0 toward alkali and the p H range of application is expended. The product could be reusable for many times; and the activity remained high to 80% after storage at 4?C for three weeks. Therefore, the immobilized flavor enzyme produced features easy production and storage, and good stability to heat in a wide p H range.