Effect of simulated gastrointestinal digestion on plant sterols and their oxides in enriched beverages

This study evaluates the bioaccessibility (percentage of soluble compound available for absorption) of plant sterols (PS) and their oxides (phytosterol oxidation products, POPS) after simulated gastrointestinal digestion in fruit (Fb), milk (M) and fruit-based milk beverages with (FbM(a)) or without (FbM(b)) tangerine juice. In beverages and their bioaccessible fraction (BF), campesterol, campestanol, stigmasterol, beta-sitosterol and sitostanol were detected. Bioaccessibility of total PS ranged between 2.62 and 6.48%, FbM(b) yielding the highest value, followed by FbM(a) > Pb > M. Campesterol/campestanol were the most bioaccessible PS. Only oxides of beta-sitosterol were detected in beverages and BF (7 alpha-hydroxy, 7 beta-hydroxy, beta-epoxy, alpha-epoxy, sitostanetriol and 7-ksitosterol). Bioaccessibility of total POPs ranged between 19.08 and 49.29%, sitostanetriol yielding the highest value. Bioaccessibility of POPs was higher than that of PS, suggesting different patterns of solubility for these compounds. (c) 2013 Elsevier Ltd. All rights reserved.