Phenolic compounds, microstructure and viscosity of onion and apple products subjected to in vitro gastrointestinal digestion

摘要

Microstructure, viscosity and their relationship with bioaccessibility of phenolic compounds in onion and apple products (untreated and HPP) and commercial quercetin supplement throughout a dynamic gastrointestinal digestion (GID) model were investigated. In non-digested (ND) samples, untreated and HPP-onion presented higher total phenolic and flavonol content (TFC-HPLC and TPC-FC) than apple counterparts. TFC-HPLC decreased throughout GID phases in all samples studied. TFC-HPLC bioaccessibility was higher in onion (similar to 17.6%) than in apple (similar to 10%) and in quercetin supplement (0.027%). HPP did not improve TFC-HPLC bioaccessibility. Throughout GID, onion and apple showed a significant decrease in both consistency (K) and apparent viscosity at 10 s(-1) but higher values were found in apple. These data agree with TFC-HPLC and TPC-FC decrease and with the lower bioaccessibilities of apple compared with onion. Food matrix had a more significant effect than HPP on TFC-HPLC bioaccessibility, which is related to the rheological behavior of the GID-phases.