Total phenolics, flavonoids, anthocyanins and antioxidant activity following simulated gastro-intestinal digestion and dialysis of apple varieties: Bioaccessibility and potential uptake

► Decreased availability of phenolics following gastro-intestinal digestion. ► Degradation of apple anthocyanins during simulated digestion. ► Dialysability as a means to study soluble, potential bioavailable phytochemicals. ► Reduced antioxidant activity of apple antioxidants following in vitro digestion. ► Overestimation of phytochemical concentration and activity by chemical extraction.