Department of Biotechnology and Food Analysis, Wroclaw University of Economics and Business, 53-345 Wroclaw, Poland.
Molecules. 2019 Nov 21;24(23):4234. doi: 10.3390/molecules24234234.
Naringinase is an enzyme complex which exhibits α-l-rhamnosidase and β-d-glucosidase activity. This enzymatic complex catalyzes the hydrolysis of naringin (4',5,7-trihydroxy flavanone 7-rhamnoglucoside), the main bittering component in grapefruit. Reduction of the level of this substance during the processing of juice has been the focus of many studies. The aim of the study was the immobilization of naringinase on chitosan microspheres activated with glutaraldehyde and, finally, the use of such immobilized enzyme for debittering grapefruit juice. The effect of naringinase concentration and characterization of the immobilized enzyme compared to the soluble enzyme were investigated. The maximum activity was observed at optimum pH 4.0 for both free and immobilized naringinase. However, the optimum temperature was shifted from 70 to 40 °C upon immobilization. The K value of the immobilized naringinase was higher than that of soluble naringinase. The immobilization did not change the thermal stability of the enzyme. The immobilized naringinase had good operational stability. This preparation retained 88.1 ± 2.8% of its initial activity after ten runs of naringin hydrolysis from fresh grapefruit juice. The results indicate that naringinase immobilized on chitosan has potential applicability for debittering and improving the sensory properties of grapefruit juices.
柚苷酶是一种酶复合物，具有α-L-鼠李糖苷酶和β-D-葡萄糖苷酶活性。这种酶复合物催化柚皮苷（4'，5，7-三羟基黄酮 7-鼠李糖苷）的水解，柚皮苷是葡萄柚中主要的苦味成分。在果汁加工过程中降低这种物质的水平一直是许多研究的重点。本研究的目的是将柚皮苷酶固定在戊二醛活化的壳聚糖微球上，最后，将这种固定化酶用于葡萄柚汁的脱苦。研究了柚皮苷酶浓度的影响，并对固定化酶与可溶性酶的特性进行了比较。游离和固定化柚皮苷酶的最大活性均在最适 pH4.0 下观察到。然而，固定化后最适温度从 70°C 转移到 40°C。固定化柚皮苷酶的 K 值高于可溶性柚皮苷酶。固定化没有改变酶的热稳定性。固定化柚皮苷酶具有良好的操作稳定性。该制剂在从新鲜葡萄柚汁中进行十次柚皮苷水解后，仍保留初始活性的 88.1±2.8%。结果表明，固定在壳聚糖上的柚皮苷酶在脱苦和改善葡萄柚汁感官特性方面具有潜在的应用前景。
