2 - Methods for determining bioavailability and bioaccessibility of bioactive compounds and nutrients

Abstract

The health advantages of bioactive compounds and nutrients are based on intake levels and the amount of these compounds that become bioavailable and bioaccessible. The determination of bioactive compounds directly in food is not sufficient to evaluate the bioavailability and bioaccessibility and consequently their effects in vivo, since the compounds reaching the blood system result from a complex digestion process. Bioavailability is assessed by in vivo methodologies using gastrointestinal digestion, absorption, metabolism, tissue distribution, and bioactivity. In vitro methodologies allow for determining the bioaccessibility of the bioactive compounds and nutrients through liberation from the food matrix, simulation of gastrointestinal digestion, and assimilation by intestinal epithelium. This chapter presents the similarities and differences between the distinct techniques used to quantify bioavailability and bioaccessibility, as well as a brief description of the methodologies applied to determine different bioactive compounds and nutrients.