Bioaccesibility of plant sterols and their oxides in enriched fruit and/or milk-based beverages

Plant sterols (PS) have many beneficial functions, like LDL-cholesterol reduction upon other effects on lipid parameters. PS are prone to oxidation and can give rise to plant sterol oxidation products (POPs), which have been suggested to be cytotoxic. The aim was to evaluate the bioaccesibility of phytosterols and their oxides in fruit and/or milk based beverages enriched with PS after a simulated gastrointestinal digestion. Four PS-fortified beverages were analyzed (fruit beverages without milk (Fb), with milk (Fb’M), with β-cryptoxanthin (FbM) and only milk (M)) and their corresponding bioaccessible fractions (BF). PS source was the same (0.7 g/100 g) for all the samples. The applied in vitro digestion method was according to Granado et al. (2007) to obtain the BF (soluble fraction). The extraction and purification of PS and POPs was achieved by lipid extraction (for the beverages), followed by saponification, unsaponificable extraction and silica SPE purification (only for POPs). They were determined by GC-FID (PS) and GC-MS (POPs). Total contents of PS in the analyzed beverages ranged between 607.08 and 743.05 mg/100 g beverage. The concentration order of PS was β-sitosterol > sitostanol > campesterol > stigmasterol > campestanol. A statistically significative (p