An on-line method for pressurized hot water extraction and enzymatic hydrolysis of quercetin glucosides from onions.

Highlights: [•] Total quercetin content was determined in different onion varieties. [•] Hot water extraction was combined with hydrolysis using thermostable β-glucosidase. [•] Enzyme activity was highest in water containing 5% ethanol at 84°C and pH 5.5. [•] The immobilized enzyme showed good stability over 72h at the optimized conditions. [•] The developed method gave comparable yield of quercetin compared to conventional methods. [ABSTRACT FROM AUTHOR]