Synergistic Antioxidant Performance of Lignin and Quercetin Mixtures

A natural, effective, and inexpensive hindered phenolic antioxidant mixture was prepared by blending lignin into quercetin. The antioxidant performance of lignin and quercetin mixture was analyzed by determining the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and a low-cost and high-efficiency ratio was found to be 4:1 (w/w). After UV radiation for 4 h, the DPPH scavenging ratio of the quercetin/lignin mixture decreased only 13.8%, while that of quercetin and lignin decreased 42.9% and 28.6%, respectively. The UV and fluorescence analysis indicated that quercetin molecules inserted into the lignin to weaken its aggregation and form new conjugated structures. Adding lignin may provide a green alternative to the expensive quercetin or synthetic antioxidants used in food, cosmetics, and pharmaceuticals.