Efficient solid state Maillard conjugation of ovalbumin and EGCG grafted β-glucan for NHDC liposome coating with enhanced phagocytic and anti-inflammatory activities

Although the solid state Maillard preparation is effective for preparation of protein and polysaccharide conjugates, the complicated humidity control protocols limit practical use. In this study, an optimized Maillard reaction protocol was developed based on the traditional solid state method through direct water addition and greatly simplified the operation. It was revealed that epigallocatechin gallate (EGCG) radical grafting to β-Glucan instead of ovalbumin (OVA) was more effective in Maillard reaction and afforded the OVA-β-glucan-EGCG ternary conjugate with enhanced emulsifying and antioxidant activities. Identities of the Maillard conjugates were analyzed by electrophoresis, Fourier transform infrared and circular dichroism spectroscopies. The ternary conjugate was employed to coat neohesperidin dihydrochalcone (NHDC) liposomes and promoted phagocytic activities in RAW264.7 cell model. Further evaluation demonstrated that the coated NHDC liposomes significantly reduced LPS-induced inflammation (NO and ROS levels). The developed strategy holds great promise for development of ternary protein-polysaccharide-polyphenol conjugate and promotion of biological performance.