Evaluation of the physicochemical stability and digestibility of microencapsulated esterified astaxanthins using in vitro and in vivo models

•A well-dispersed microcapsule containing esterified astaxanthins was designed.•A strategies to protect the esterified astaxanthins against chemical degradation was achieved.•A delivery system with good bioavailability was evaluated by in vitro and in vivo models. Esterified astaxanthins are used as functional nutraceuticals in many food products. Unfortunately, their utilization is currently limited owing to their poor water solubility, chemical instability, and low bioavailability. In this study, esterified astaxanthin microcapsules were fabricated through electrostatic complexation of whey protein and gum arabic by adjusting the pH to 4.0. After their encapsulation, the stability of the esterified astaxanthins was effectively better than that of the oleoresin. In vitro tests revealed a 26% rate of astaxanthin release from the microcapsules, which was significantly higher than the 14.6% rate from the oleoresin (P