Absorption of whey protein isolated (WPI)-stabilized beta-Carotene emulsions by oppositely charged oxidized starch microgels

13-Carotene is a natural antioxidant that is beneficial for human health. beta-Carotene is well known for its aqueous insolubility and its sensitivity to environmental stimuli. To achieve the targeted delivery of beta-Carotene to human intestine, a microgel system was developed. The microgel is made of oxidized potato starch polymers, which are obtained by chemical cross-link process by sodium trimetaphosphate (STMP). At pH pI, as in the intestinal condition, WPI-p-Carotene nanoemulsion droplets and microgel particles both carry negative charges. Under this condition, beta-Carotene will be released from microgel. In this study, we investigated the absorption capacity of beta-Carotene nanoemulsion droplets by oxidized starch microgel particles of various degrees of oxidation (DO) and the cross-link density (R o linkeripoiymer(w/w)) is investigated as a function of pH and salt concentrations. We found that D030% with R linkeripoismer(wiw) 0.1 was the optimal gel type for nanoemulsion droplets absorption, and pH 3 and ionic strength of 0.06 M were the optimal conditions for nanoemulsion droplets absorption. The swelling capacity of the microgel particles rather than its potential was dominant in governing the absorption capacity. The in vitro release experiment under stimulated gastrointestinal fluids suggested that beta-Carotene emulsions droplets remained stable at the gastric condition and were majorly released under the intestinal condition. The results suggested that the oxidized starch microgel could be used to prevent the early release of beta-Carotene in the stomach and target delivery of them to the intestine. (C) 2014 Elsevier Ltd. All rights reserved.