Encapsulation with a complex of acidic/alkaline polysaccharide-whey protein isolate fibril bilayer microcapsules enhances the stability of β-carotene under acidic environments

Background: Recent studies have highlighted the potential of protein fibrils for the microencapsulation of lipophilic bioactive molecules. Given their biocompatible and biodegradable properties, as well as their enhanced material stability, proteins are ideal for this purpose. However, β-carotene, a common antioxidant, degrades in acidic environments. In light of this, the present study explored the stability and antioxidant properties of acidic/alkaline polysaccharide–whey protein isolate fibril (WPF) bilayer microcapsules containing β-carotene under acidic conditions. Methods: WPFs were prepared and then homogenized with a β-carotene/limonene solution to form microcapsules. The addition of pectin and chitosan created polysaccharide–WPF bilayer microcapsules. Zetasizer was used to analyze the microcapsules’ size and stability, while confocal microscopy was used to observe their morphology under acidic conditions. The β-carotene concentration was determined via heptane/ethanol extraction. Significant findings: The results show that the pectin–WPF bilayer microcapsules exhibited excellent stability under acidic conditions, which can enhance stability and retain the antioxidant activity of β-carotene. Thus, this work suggests pectin–WPF bilayer microcapsules to be promising carriers for lipophilic bioactive molecules due to enhancing their bioavailability.