Synergistic enhancement of loading contents and chemical stability of lycopene distributing both inside and on the oil/water interface.

Abstract

Loading contents and chemical stability of lycopene were synergistically enhanced after dispersion in genipin-crosslinked-chitosan (CS) stabilized high internal phase emulsions (HIPEs). HIPEs could be prepared with the parameters for the emulsifiers of CS concentration from 0.5 to 5mg/mL, pH value from 5.5 to 7.5, and CS/genipin mass ratio from 2:1 to 20:1. High loading content of lycopene, up to 0.25 wt% was achieved, with emulsifier in the final system only 1mg/mL. As the loading contents were elevated, increasing amount of lycopene distributed in HIPEs in the form of insoluble crystals. Meanwhile, density of oil droplets decreased and the shape changed from polygon to sphere, which is supposed to be related to the interaction between the crystal and the oil-water interface. Stability of lycopene against ultraviolet, temperature, hydrogen peroxide, and iron ions was improved significantly, which could be ascribed to the layer of genipin-crosslinked-CS on oil droplet surface and the crystal status of lycopene. The storage stability of lycopene was improved tremendously after encapsulation by HIPEs. PRACTICAL APPLICATION: Low loading content of lycopene in emulsion systems is not conducive to the evaluation of its biological function in subsequent experiments, as well as their real application in food industry. It is also crucial to improve the stability of lycopene for the practical application in food industry. In this work, the loading content in delivery system and the chemical stability of lycopene are improved through encapsulation with high internal phase emulsions (HIPEs). The significance of these results may have implications in fields spanning from colloidal science to functional foods applications.