Whey protein isolate-procyanidin lutein microcapsules against blue light-induced retinal damage

The increasing prevalence of prolonged exposure to electronic devices has made ocular health risks a major public health concern. Natural food pigments, such as procyanidins (PCs) and lutein, exhibit excellent antioxidant properties, but their poor stability greatly limits their bioavailability. To overcome these limitations, a noncovalent whey protein isolate-procyanidin complex (WPI-PC) was designed and its binding interactions were investigated using FTIR and fluorescence spectroscopy. After high-pressure homogenization and spray drying, the lutein retention rate in the resulting microcapsules reached 83.2%. Structural characterization showed that microcapsules prepared with 3 wt% WPI-PC had higher total oil content, lower surface oil content, lower hygroscopicity and water activity and good powder fluidity. Moreover, the lutein microcapsules remained stable under simulated gastric conditions and were efficiently digested in simulated intestinal fluid, supporting lutein release and potential intestinal absorption. In vitro and in vivo experiments further demonstrated that lutein microcapsules effectively reduced reactive oxygen species accumulation and inflammatory factor secretion and ultimately alleviated blue light-induced retinal damage in mice. Overall, these microcapsules represent promising nutraceutical formulations that synergistically enhance the stability, bioaccessibility and ocular protective efficacy of lutein and PCs, showing potential for dietary interventions related to eye health.