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[摘要]
车厘子和樱桃番茄是主要的热带和亚热带水果。然而,由于高活性的酶会降解成熟果实的内部植物细胞壁大分子,世界年产量的 30%左右被损失。开发工业规模的车厘子汁可以减少每年的损失并带来额外的价值。在这里,我们发现了一种商业化的黑曲霉果胶酶,Pectinex XXL,它在pH4.5和60℃ 时活性最高。它在 3~4.5和40℃时几乎稳定。这种酶试剂对1mM的Na+,K+,Mg+,Cu2+,或Co2不敏感。培养1小时后,该酶明显提高了车前草和樱桃番茄汁的产量和透光率,分别为119.03%±2.35%和15.97%±0.43%,以及37.65%±0.92%和12.35%±0.49%。它使车前草和樱桃番茄汁的粘度分别降低了88.29%+0.62%和29.5%±0.72%。总之,Pectinex XXL 在车前草和樱桃番茄汁的工业生产中具有潜力。
[Key word]
[Abstract]
Pectin is widely found in plant cell wall and inner layer, which promotes the formation of plant morphology through cross-linking with cellulose and hemicellulose. Pectinase is a kind of enzyme that can degrade pectin. After being treated with pectinase, the cell contents of fruits pulp can be better released. Plantain is a kind of major tropical and subtropical fruit. However, about 30% of the annual world yield was lost due to the highly active internal plant cell wall macro molecules degrading enzymes of ripe plantain. Developing industrial-scale plantain juice can reduce the annual lost and bring additional value. Here, we found a commercial Aspergillus niger pectinase Pectinex XXL was most active at pH value 4.5 and was almost stable at pH 3-4.5. The optimal pH value and pH stability range of this enzyme were similar to the pH values of some tropical and subtropical fruits. In addition, the enzyme also exhibited a good thermal stability. The optimal temperature of Pectinex XXL was 60 oC, and after a 40 oC bath for 1 hour, the enzyme remained stable. Metal ions tolerance experiment found that the enzyme activity of Pectinex XXL was not inhibited by 1 mmol/L Na+, Mg2+, Ba2+, Co2+, Zn2+, Fe2+, slightly inhibited by 2 mmol/L K+ and Fe2+, and partially inhibited by 1 mmol/L and 2 mmol/L Ca2+ and Mn2+. After one-hour incubation, the enzyme (16 U/mL) significantly increased the yield and light transmittance of plantain / cherry tomato juice for 119.03% / 15.97% and 37.65% / 12.35%, respectively; and reduced the velocity of juice for 88.29% / 29.50%. In this study, the enzymatic properties of Pectinase XXL were described, and the results showed that the enzyme had a good acid stability and thermal catalytic characteristics. The juice extraction experiment proved that the enzyme could significantly improve the juice yield and light transmittance of plantain, and reduce the viscosity of plantain. Thus, Pectinex XXL has potential in industrial plantain juice production.
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