Brazil nut (Bertholletia excelsa) oil emulsions stabilized with thermally treated soy protein isolate for vitamin D3 encapsulation

Abstract The main goal of this study was to investigate the possibility of encapsulating vitamin D3 (VD3) in Brazil nut (Bertholletia excelsa) oil emulsions stabilized with thermally treated soy protein isolate (SPI). SPI dispersions were analyzed using intrinsic tryptophan fluorescence, surface hydrophobicity and circular dichroism for a better comprehension of the ingredient’s properties. The emulsions produced with SPI dispersions treated at temperatures between 60 and 70 °C showed higher average droplet diameters (10-40 μM) than those treated at 75 and 80 °C. Despite these different droplet diameters, all formulations showed phase separations, requiring the incorporation of xanthan gum (XG) as thickener. Different XG concentrations were, then, tested (0.1 to 0.3% w/v). The formulation with 0.2% (w/v) XG and SPI treated at 75 °C for 15 min showed the highest stability, and, therefore, was used to produce emulsions encapsulating VD3 at two concentrations (120 and 200 μg/mL). After 21 days of storage, the emulsion stabilized with 1.0% (w/v) SPI and 200 µg VD3/mL preserved 97% of the vitamin. Therefore, the results revealed it is possible to obtain an efficient formulation for the encapsulation of VD3 using Brazil nut oil as an oily phase and thermally treated SPI as an emulsifier. (AU)