Protection of Epigallocatechin Gallate against Degradation during in Vitro Digestion Using Apple Pomace as a Carrier

Apple pomace, a byproduct of the apple juice processing industry, may be used as a matrix for carrying phytochemicals. High-pressure processing (600 MPa for 5 min) or heat treatment (121 °C for 5 min) of wet apple pomace can increase the shelf life of the pomace but may influence the carrier properties of the wet pomace for phytochemicals. We examined the effects of these processing treatments on the adsorption capacity of apple pomace for epigallocatechin gallate (EGCG) and the stability of EGCG in simulated gastrointestinal fluids in vitro. Both processing treatments reduced the adsorption capacity but protected EGCG against degradation in the simulated gastrointestinal fluids. The extent of EGCG degradation in simulated gastrointestinal fluids in vitro in the presence of apple pomace was not influenced by gastric and intestinal enzymes, suggesting that pH had the overriding influence on EGCG degradation. This study showed the potential of apple pomace as a carrier for EGCG in functional food applications.