Bioaccessibility of functional ingredients

Bioaccessibility is defined as the amount of a food constituent transferred to the micelle fraction after digestion in the gut, when compared with the original amount of the constituent present in the food. Bioaccessible constituents may be able to pass through the intestinal barrier and hence become bioavailable within the body. Bioaccessibility is commonly determined by in vitro methods simulating the human digestion and is assumed to be a good starting point for estimating potential bioavailability of a food constituent. The study of bioaccessibility of functional ingredients is necessary in addition to studies on their potential beneficial nutritional effects. This review discusses the benefits and limitations of methods used to assess bioaccessibility, in addition to factors affecting bioaccessiblity, both dietary and physiological. Evidence regarding the bioaccessibility of specific functional ingredients, including carotenoids and flavonoids is especially highlighted. Potential approaches to enhance bioaccessibility of functional ingredients are also discussed.