Insights into the digestion of chestnut (Castanea sativa) shells bioactive extracts—ultrasound vs. microwave‐assisted extraction.

This article focuses on evaluating the impact of in vitro gastrointestinal digestion on the bioaccessibility and bioactivity of polyphenol-rich extracts from chestnut (Castanea sativa) shells (CSS) obtained by two eco-friendly extraction methods: microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE). The study found that total phenolic and flavonoid contents, antioxidant/antiradical activities, and reactive oxygen/nitrogen species scavenging capacities of both extracts decreased during digestion, with bioaccessibility around 25–26%. Key phenolic compounds such as gallic acid, caftaric acid, and catechin were identified as the most bioaccessible, and the extracts exhibited notable hypoglycaemic and neuroprotective enzyme inhibition after digestion. Overall, MAE extracts showed slightly higher bioaccessibility post-digestion, and the findings support the potential use of CSS extracts as sustainable nutraceutical ingredients with antioxidant, anti-ageing, hypoglycaemic, and neuroprotective properties.