Effects of casein on the stability, antioxidant activity, and bioavailability of lotus anthocyanins

Effects of casein on the stability, antioxidant activity, and bioavailability of lotus anthocyanins were investigated. Casein could inhibit the unsatisfactory pH-induced color change of lotus anthocyanins, and improved their photo, oxidation, and thermal stabilities. During the simulated digestion, the anthocyanin retention increased from 65.39 to 76.14 mg C3G/L with the protection of casein, while the DPPH and ABTS scavenging activities of lotus anthocyanins with casein increased to 62.33% and 46.58%, respectively. However, casein with lower concentration showed a better protective effect on lotus anthocyanins due to its self-aggregation tendency at high dose. The zebrafish model further verified that casein could enhance the bioavailability of lotus anthocyanins. Furthermore, molecular docking revealed that casein could interact with anthocyanin by hydrogen bond and hydrophobic interaction, which led to the stronger stability and bioavailability of lotus anthocyanins. The results conveyed that casein could be used as a wall material to protect anthocyanins. PRACTICAL APPLICATIONS: Anthocyanins are natural colorants with multiple biological activities, but the poor stability during processing and digestion limits their application in food industry. In the present research, casein exhibited conspicuous ability to enhance the stability of lotus anthocyanins toward detrimental conditions. Additionally, casein could preserve anthocyanins from degradation during digestion and thus improve the bioavailability. These findings indicated that casein could serve as a potential carrier for encapsulating and delivering anthocyanins. The better stability and bioavailability would promote the application of anthocyanins in food products and human health.