First in vitro insights into the digestive stability of polysorbate 80 micelles

The improvement in bioavailability of various bioactives e.g. curcumin, digoxin and resveratrol, after polysorbate 80 (PS80) micellization, has been attributed, in part, to increased digestive stability of the bioactives. This research aimed to evaluate the role of the digestive stability of the PS80 micelles in increasing the in vitro bioaccessibility of bioactive compounds (curcumin, naringenin, Beta-carotene, CoQ10). This was done by comparing pre-micellization (solvent evaporation method) of bioactives in PS80 compared to co-digestion (simulated co-consumption) with PS80 (compared to that of olive oil). Additionally, the effects of relevant digestive compounds, lipase and bile extract, on the particle/micellar surface charge and curcumin bioaccessibility, were investigated. The solubility of the compounds in olive oil or PS80, played a substantial role in the modulation of their bioaccessibility. Co-digestion with PS80 resulted in similar or higher amounts of bioaccessible compounds, but pre-micellization was more efficient in increasing bioaccessibility, indicating some measure of digestive stability of the micelles. The modulating effect of lipase and bile extract on the bioaccessibility of curcumin however, suggests that not all micelles remain intact during the gastrointestinal digestion. While the extent of the digestive stability is still unclear, there is currently no available methods to quantify this.