Impact of an in vitro dynamic gastrointestinal digestion on phenolic compounds and antioxidant capacity of apple treated by high-pressure processing

The aim was to evaluate the effect of an in vitro dynamic gastrointestinal digestion (GID) on the recovery index and bioaccessibility, the stability of phenolic compounds, and the changes in antioxidant capacity (AC) of apples 'Golden Delicious' treated by high-pressure processing (HPP-treated). All the phenolic compounds decreased during GID in untreated and HPP-treated apple and in consequence a decrease in the antioxidant capacity (DPPH, ABTS+, TP-FC and FRAP) and in the effect on the inhibitory capacity of lipoxygenase (LOX) and xanthine oxidase (XO) activities was also observed. The dynamic-GID increased the release of quercetin-aglycone and led to low quercetin-glycosides bioaccessibility (~10%). HPP-treated compared to untreated-apple presented higher recovery index for hydroxycinnamic acids (~67% and 52%) and higher bioaccessibility for hydroxycinnamic acids (40% and 31%) and dihydrochalcones (30% and 19.5%). The bioaccessible fraction of HPP-treated apple showed a high retention of the undigested AC: 24% (DPPH), 14% (ABTS+), 86% (TP-FC), 48% (FRAP) and the 68% and 100% of XO and LOX inhibitory capacities.