Encapsulation of β-carotene by self-assembly of rapeseed meal-derived peptides: Factor optimization and structural characterization

Rapeseed meal rich in protein serves as one of the major agricultural processing by-products; however, it is currently used as a fertilizer or feed, which causes a great waste of protein resources. The aim of this study was to enzymatically prepare rapeseed peptides (RPs) that can be self-assembled and used as a nanocarrier for encapsulation of hydrophobic beta-carotene. During this process, the effects of rapeseed protein hydrolysis time, encapsulation time, and the ratio of beta-carotene to RPs on the encapsulation results were investigated. The encapsulation efficiency (EE) and drug loading amount (LA) were used as the evaluation indicators. Through optimization of conditions, the optimal parameters of encapsulation were obtained, namely enzymatic hydrolysis for 60 min, encapsulation time for 3 h, the optimal ratio of beta-carotene to peptide for 3/5, the EE for >80%, and the LA for 0.55 mg/mg. In addition, the encapsulation structure of RPs and beta-carotene was systematically characterized by FTIR, TEM and CLSM, suggesting that beta-carotene was successfully encapsulated by RPs. The present study contributes to a deep understanding of encapsulation of beta-carotene by self-assembly of RPs.