Thermal-induced impact on physicochemical property and bioaccessibility of β-carotene in aqueous suspensions fabricated by wet-milling approach

The physicochemical properties of β-carotene in aqueous system were scarcely explored before. Herein, β-carotene aqueous suspensions were fabricated by wet-milling, and the impact of milling temperature on thermal degradation kinetics, coloring mechanism, recrystallization behavior and bioaccessibility of β-carotene in aqueous system was investigated. The thermodynamic parameters indicated that the degradation of total β-carotene and all-trans isomer in aqueous suspensions was endothermic and energetically unfavorable. The hue of aqueous suspensions was dependent on the particle size and cis isomer ratio of β-carotene (especially in the formation of 13-cis isomer). The reduced conjugation effect of CC groups was responsible to the hypochromicity and amorphization of isomerized β-carotene. The recrystallization rate of β-carotene in aqueous suspensions was decreased owing to the presence of higher magnitude of steric hindrance between the isomerized β-carotene. The bioaccessibility of β-carotene was significantly increased through the nanoencapsulation and elevating the level of cis isomers of β-carotene.