Soy protein isolate as a nanocarrier for enhanced water dispersibility, stability and bioaccessibility of β-carotene

The incorporation of β-carotene, one of the most common pigments or bioactives, into food formulations has attracted increasing interest from the food industry, due to its good nutrition and potential health effects. However, it is poorly soluble and unstable in water, which greatly limits its applications in foods. This work presented an effective approach to improve the water dispersibility, stability and even bioaccessibility of β-carotene, using soy protein isolate (SPI) to perform as effective nanocarriers for this molecule.

The complexation with SPI remarkably improved the water dispersibility and stability against heating and freeze-drying of β-carotene. However, the encapsulation efficiency and stability of β-carotene in the nanocomplexes with SPI were closely dependent on the applied β-carotene-to-protein ratio, at which the complexation occurred. The best improvement of stability was observed at appropriate β-carotene-to-protein ratios, e.g. 10-20 g kg^-1 . The complexation with β-carotene mainly occurred on the surface of SPI nanoparticles, through hydrophobic interactions. The complexation resulted in inter-particle aggregation, in a concentration-dependent manner. Almost all of the β-carotene molecules in the nanocomplexes could be progressively released into the aqueous phase.

SPI exhibits a good potential to perform as a nanocarrier for enhanced water dispersibility, stability and bioaccessibility of β-carotene. © 2016 Society of Chemical Industry.