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 in vitro 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 in vitro gastrointestinal digestion.