Impact of fermentation and in vitro gastrointestinal digestion on the bioaccessibility of phytochemicals and antioxidant capacity of tiger nut, carob and rice beverages

This study unveils the transformative effects of lactic acid fermentation and in vitro digestion on the phytochemical profile (UHPLC-QTOF) and antioxidant capacity (total polyphenols, TEAC and ORAC) of plant-based beverages made from local crops. Fermentation with the probiotic consortium VEGE061 and subsequent INFOGEST 2.0 digestion triggered antioxidant changes. Tiger nut beverages showed a dramatic increase in ORAC activity (1.8–4.0 mmol L⁻¹ Trolox) while preserving polyphenol levels, with the b-isomer of hydroxyoleic acid exhibiting high potential bioaccessibility (>90 %) and sinapoyl alcohol stability improving markedly. Carob beverages displayed elevated polyphenol content (348–413 mg GAE/L) and TEAC activity (1.9–2.3 mmol L⁻¹ Trolox), with 3-propyl malic acid bioaccessibility rising from 10 % to 64 % with fermentation. Rice beverages displayed modest improvements. Overall, digestion severely reduced phenolic stability (∼8 % retention), highlighting the urgent need for strategies to improve the bioaccessibility and maximize health benefits. These findings open new avenues for innovative functional beverage design.