Physicochemical stability of corn protein hydrolysate/tannic acid complex-based -carotene nanoemulsion delivery system

Moderate non-covalent interaction of protein and polyphenols can improve the emulsifying property of protein itself. The corn protein hydrolysate (CPH) and tannic acid (TA) complex was successfully used to construct nanoemulsion for algal oil delivery. There has been no study on the feasibility of this nanoemulsion delivery system for other food functional components, for example, beta-carotene (beta-CE). CPH/TA complex-based nanoemulsion system for beta-CE delivery was studied, focusing on the effect of beta-CE content on the physicochemical stability of the nanoemulsions. The nanoemulsion delivery systems (dia. 150 nm) with low viscosity and good liquidity were easily fabricated by two-step emulsification. The nanoemulsions with high beta-CE content (>71.5 mu g/mL) significantly increased (p < .05) the emulsion droplet size. However, there was no significant (p > .05) effect of beta-CE content on polydispersity index (PDI) and zeta potential of the nanoemulsions. The storage (30 days) experiment results demonstrated that the droplet size of the nanoemulsions with varying beta-CE content increased slightly during storage. However, the PDI values showed a slightly decreasing trend. Zeta potentials of the nanoemulsions showed no noticeable change during storage. Moreover, after storage of 30 days, the retention ratios of beta-CE were found to be up to 90%, which suggests an excellent protective effect for beta-CE by the nanoemulsion systems. The CPH/TA complex stabilized nanoemulsions could aggregate in gastric condition, but the beta-CE content did not have obvious effect on the digestive stability of the nanoemulsions. The CPH/TA complex could be employed as an emulsifier to construct a physicochemical stable nanoemulsion delivery system for lipophilic active components.