EFFECT OF "IN VITRO" DIGESTION ON THE ANTIOXIDANT CAPACITY AND CELLULAR PROLIFERATION OF SPANISH CIDERS

Introduction: Several studies show the antioxidant capacity of cider determined by different chemical methods. The studies are mostly carried out using undigested cider and/or chemical extraction methods. Objectives: The aim of the work was to know the influence of two "in vitro" digestion protocols on the antioxidant capacity of cider and its effects on cell proliferation. Methods: Two digestion procedures: one that simulates gastrointestinal digestion (GID) and another that also includes digestion in the mouth by amylase action (AD) were applied to nine Spanish ciders. Different assays were performed with undigested ciders (UD) and soluble fractions (SF) of the digestion. Polyphenol content and antioxidant capacity were determined by FRAP, ABTS, DPPH and ORAC methods. The effect on cell proliferation was measured by MTT assay in SW480 cells with 72h of incubation. Results: Both digestion procedures reduced, with respect to undigested cider, the polyphenol content and the antioxidant capacity determined by any of the employed methods (between 65 and 85% of UD), except for ABTS which resulted in 125% UD. No significant differences in the antioxidant capacity were observed between the two used digestion protocols (GID and AD). Cell proliferation inhibition was higher for both digested fractions than for undigested cider independently of the digestion type (GID or AD). Conclusions: 1. "In vitro" digestion reduces the polyphenol content and the antioxidant capacity of ciders according to most of used methods. 2. The inhibitory effect of cider on cell proliferation increases with "in vitro" digestion processes.