The impact of chemical structure on polyphenol bioaccessibility, as a function of processing, cell wall material and pH: A model system

Polyphenols are suggested to hold various health benefits, however, their absorption is often poor. The impact of processing (unprocessed, pasteurization (PT), high-pressure (HPP)), pH (6.5, 2.5) and added cell-wall was studied using semi-dynamic in-vitro digestion of a model polyphenol extract (PE). Structure-dependent bioaccessibility was observed, affected by stability in the digestive conditions. Processing was the most affecting parameter (3-way ANOVA) impacting all identified 15 polyphenols while the presence of added CWM had a minimal impact, affecting only 4. On the average HPP, compared to unprocessed, mildly affected the bioaccessibility, while PT had the largest negative impact, especially in the intestinal conditions. Anthocyanins and flavonols were the most negatively affected by PT resulting in up to 70% decrease bioaccessibility compared to unprocessed, in a pH and structure-dependent manner. Despite the lacking complex food matrix in the PE, processing affected the bioaccessibility in advanced digestive stages, even if no influence was observed at the beginning.