In-vitro gastrointestinal digestion of functional cookies enriched with chestnut shells extract: Effects on phenolic composition, bioaccessibility, bioactivity, and α-amylase inhibition

Chestnut (Castanea sativa) shells (CS) are an appealing source of antioxidants. In previous studies, the research team validated a nutraceutical extract from CS, recovered by an eco-friendly technology, by in-vitro and in-vivo assays, and developed functional cookies enriched with this extract. This study attempts, for the first time, to investigate the impact of the in-vitro gastrointestinal digestion in the phenolic composition, bioaccessibility, antioxidant/antiradical properties, and α-amylase inhibition of CS extract-enriched cookies. The outcomes revealed higher polyphenols concentrations retained after intestinal digestion, endorsing its better antioxidant, antiradical, and hypoglycemic properties. The phenolics recovery enhanced in the following order: oral < gastric < intestinal phases, achieving 93.50% of maximum bioaccessibility and unveiling a protective effect of the cookie matrix and slow phenolics release during digestion. Regardless the identical composition in phenolic acids, changes in their concentrations were attested between digested and undigested cookies. Multivariate analysis predicted the outstanding contribution of polyphenols to the bioactivity of cookies. This study highlighted the valorization of CS as nutraceutical ingredient for functional cookies, proving its efficacy after in-vitro digestion.