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Food Matrix Effects on Nutraceutical Bioavailability: Impact of Protein on Curcumin Bioaccessibility and Transformation in Nanoemulsion Delivery Systems and Excipient Nanoemulsions

Zou, Liqiang, Zheng, Bingjing, Zhang, Ruojie, Zhang, Zipei, Liu, Wei, Liu, Chengmei, Xiao, Hang, McClements, David Julian
Food biophysics 2016 v.11 no.2 pp. 142-153
bioavailability, caseinates, curcumin, droplets, food matrix, functional foods, heat treatment, lipids, micelles, models, mouth, nanoemulsions, small intestine, solubility, solubilization, stomach, temperature
Powdered curcumin was either dissolved in the lipid phase of a nanoemulsion delivery system or it was directly mixed with an excipient nanoemulsion. The influence of thermal treatment (30 or 90 °C) and protein addition (caseinate) on the bioaccessibility and transformation of curcumin was then investigated using a simulated gastrointestinal tract (GIT) model: mouth; stomach; small intestine. Curcumin solubility was high in nanoemulsion delivery systems exposed to both thermal treatments because it was already present in the lipid phase. Conversely, curcumin solubility of a powder mixed with an excipient nanoemulsion was appreciably lower when exposed to 30 °C than 90 °C. This effect was attributed to the greater transfer of curcumin to the lipid phase of the excipient nanoemulsions at elevated temperatures. For the heated samples, the bioaccessibility and transformation of curcumin was not greatly affected by original curcumin location or protein addition. However, curcumin bioaccessibility was appreciably higher in the presence of nanoemulsion lipid droplets than in their absence, which was attributed to an increase in the solubilization capacity of the mixed micelle phase. This study provides some useful information for improving the design of functional foods to improve the oral bioavailability profile of lipophilic nutraceuticals.