Thermal-induced-stable high internal phase emulsion for lycopene encapsulation and delivery: Pre-heat treatment mediated facilitation on the isomerization, stabilization, and release of lycopene

Abstract

Lycopene possesses many beneficial physiological effects, especially the Z-isomer, but the hydrophobic property, poor stability, lower percentage of Z-isomer and bioaccessibility highly limited its practical applications. Herein, the purpose of this study is to provide an alternative delivery system for lycopene isomerization and delivery by using thermal-induced-stable high internal phase emulsion (TIS-HIPE). The results shows that encapsulation of lycopene in TIS-HIPE significantly improved its storage stability, and pre-heat treatment on the lycopene-loaded TIS-HIPE can enhance the protective effect of lycopene against temperature and UV exposures. After storage at 40 °C for 14 days, the retention rate of lycopene increased from 40% to 86%. More importantly, pre-heat treatment promoted the conformational conversion of lycopene into more absorbable Z-isomers. Meanwhile, the protective effect of TIS-HIPE effectively inhibited the degradation of converted Z-isomers during storage. Besides, the pre-heated TIS-HIPE is more stable in the gastrointestinal tract and is more prone to form micelle phase. Moreover, as compared to lycopene in oil, the bioaccessibility in TIS-HIPE increased almost 2 times, and pre-heat treatment can further improve its bioaccessibility. Therefore, the TIS-HIPE could serve as excellent vehicles for lycopene delivery, and pre-heat treatment can facilitate the stability improvement, Z-isomerization, release and absorption of lycopene.