Utilisation of flavonoids from Lycium barbarum L. leaves cross-linked with whey protein for the stabilisation and delivery of β-carotene emulsions

Although β-carotene is an essential nutrient for the maintenance of human health, it is insoluble in water and extremely unstable, which limits its application. Here, we prepared a stable emulsification system of whey protein (WP)-Lycium barbarum L. leaves flavonoids (LBLF) complex as a carrier to load β-carotene. The rheological properties, antioxidant properties and stability of emulsion were studied, and the effects of emulsion on the biological retention of β-carotene and stability were investigated. The results indicate that, compared with WP, the WP-LBLF emulsion has smaller particles, a smaller creaming index, and significantly enhanced chemical stability under light and heat treatment conditions. The thiobarbituric acid value of the WP-LBLF emulsion (0.031 ± 0.016 mg/kg) was dramatically lower than that of the WP emulsion (0.045 ± 0.012 mg/kg) (P < 0.05). In the simulated gastrointestinal digestion experiment, the retention rate of β-carotene was higher in WP-LBLF emulsion. Additionally, the WP-LBLF emulsion loaded with β-carotene has good salt tolerance and heat stability. In our study, WP-LBLF was used as an emulsifier to load β-carotene emulsion to improve its bioavailability and stability, which provides a new preparation and application method for a complex functional emulsifier.