Enzymatic Extraction Of Star Gooseberry (Phyllanthus acidus) Juice With High Antioxidant Level

摘要

Ascorbic acid and phenolic compounds are main antioxidants in star gooseberry (Phyllanthus acidus) fruit. In this study, Pectinex Ultra SP-L preparation with pectinase activity was used in the extraction of star gooseberry juice. The effects of pectinase concentration and biocatalytic time on the content of ascorbic acid, phenolic compounds and antioxidant activity of the fruit juice were firstly investigated. Response surface methodology was then used to optimize the conditions of enzymatic extraction for maximizing the antioxidant activity of the star gooseberry juice. The optimal pectinase concentration and biocatalytic time were 19 polygalacturonase units per lOOg pulp dry weight and 67 min, respectively under which the maximal antioxidant activity achieved 5595±6 μmol Trolox equivalent per lOOg juice dry weight. On the basis of kinetic model of second-order extraction, the extraction rate constant of ascorbic acid and phenolic compounds in the enzymatic extraction increased approximately 21% and 157%, respectively in comparison with that in the conventional extraction. Application of pectinase preparation to the fruit juice extraction was therefore potential for improvement in antioxidant level of the product.