Effect of ultra-high pressure homogenisation processing on phenolic compounds, antioxidant capacity and anti-glucosidase of mulberry juice

In this study, the effects of ultra-high pressure homogenisation (UHPH) processing at 200 MPa for 1-3 successive passes (inlet temperatures at 4 °C) were compared with pasteurisation (95 °C, 1 min) processing on phenolic compounds, antioxidant capacity (ORAC value) and anti-glucosidase of mulberry juice. Compared with thermal pasteurisation processing, the more reductions in the anthocyanins, phenolic acids (gallic, protocatechuic, caffeic and p-coumaric acids, and a unknown hydroxycinnamic acid) and quercetin aglycone contents, as well as ORAC value were observed during UHPH processing of mulberry juice, whereas all reductions above during UHPH processing could be inhibited by adding ascorbic acid to mulberry juice. Besides, no significant change (p > 0.05) in the α-glucosidase inhibitory activity was observed during UHPH processing of mulberry juice, but showed a 14% reduction in mulberry juice processed by thermal pasteurisation.