High internal phase emulsions fabricated by sonochemically induced cross-linking of pecan protein and xanthan gum: a novel carrier for improving β-carotene stability and bioaccessibility.

A sonochemical approach was used to fabricate high internal phase emulsions (HIPEs) without the help of any surfactants and colloidal particles. Pecan protein and xanthan gum as wall materials were cross-linked at the oil-water interface under acoustic cavitation, which can rigidify HIPEs with high oil phase (up to 85 %) and prevent droplet coalescence. A higher xanthan gum concentration led to more solid-like HIPEs. The sonochemical HIPEs can effectively retain β-carotene and inhibit its leakage during storage of 4 weeks at 4, 25, and 37 °C, depending on β-carotene concentration. Moreover, β-carotene loaded in HIPEs had high resistance against thermal treatment, ultraviolet irradiation, and exposure to iron ions and hydrogen peroxide. The bioaccessibility of β-carotene was also significantly improved from 17.65 % to 43.01 % after HIPE encapsulation. These effects were attributed to the protection effect from the dense cross-linked layer of pecan protein and xanthan gum, as well as the closely packed oil droplets. This study may guide the continued development of sonochemistry as a universal tool for engineering HIPEs as delivery systems in the functional food.