High-Pressure and Thermal Pasteurization Applied to Smoothies Enhances (Poly)Phenol Bioaccessibility along the Gastrointestinal Tract

This research aimed to explore the effect of nonthermal (High-Pressure Processing) and thermal (High-Temperature Short-Time) pasteurization applied to a fruit and vegetable based smoothie on the bioaccessibility of (poly)phenols and their biotransformation by human gut microbiota. Untreated and pasteurized smoothies were subjected to an <i>in vitro</i> gastrointestinal digestion and colonic fermentation. Native (poly)phenols and their gut-related metabolites were analyzed by LC-MS. Both pasteurization techniques showed a protective effect against degradation of (poly)phenols along the gastrointestinal tract. Thermal processing led to a more than 2-fold higher (poly)phenol bioaccessibility (44%) compared to the untreated (17%) and nonthermally treated (21%) smoothies. Native (poly)phenols were almost completely converted (83-87%) into low-molecular-weight catabolites by the gut microbiota in all smoothies. However, thermal treatment favored the generation of gut-related metabolites after colonic fermentation for 48 h compared to untreated and high pressure-treated smoothies, mainly due to the improved bioaccessibility observed after <i>in vitro</i> gastrointestinal digestion.