Development and evaluation of lutein‐loaded alginate microspheres with improved stability and antioxidant

Abstract Background Lutein has been of great interest to the food processing and pharmaconutrient industries owing to its beneficial effects on human health. However, lutein is very sensitive to heat, light, pH and oxidative conditions, which limits its application in food systems. The present study aimed to prepare lutein–alginate microspheres by a calcium chloride gelation method with the purpose of improving the stability and antioxidant abilities of lutein. Results The loading capacity of lutein in the microspheres was approximately 5.3% (w/w) and the entrapment efficiency was about 63%. The loaded microspheres were nearly spherical with an average size of 150 μm. They exhibited a crimped surface by scanning electron microscopy. The lutein was in amorphous state by X‐ray powder diffraction. Analysis by Fourier transform infrared spectroscopy and molecular docking revealed an intermolecular hydrogen bond interaction between lutein and sodium alginate. In vitro release experiments showed that the microspheres presented slower release at acidic conditions than at neutral intestinal conditions. The 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity of the microencapsulated lutein was higher than that of free lutein. The stability of lutein in the microspheres was improved significantly when compared with that of free lutein at various temperatures. Conclusion The present work successfully developed well‐protected lutein–alginate microspheres. This indicates that it is feasible to use microspheres loaded with lutein as antioxidant functional ingredients in food products. © 2019 Society of Chemical Industry