Nanoprecipitates of ?-cyclodextrin/epigallocatechin-3-gallate inclusion complexes as efficient antioxidants for preservation of shrimp surimi products: synthesis, performance and mechanism

BACKGROUND: Epigallocatechin-3-gallate (EGCG) is well known for excellent chain-breaking antioxidant capability. However, browning by oxidation and aggregation of EGCG is a non-negligible defect that hinders its applications as an antioxidant in various foodstuffs. Therefore, how to eliminate or mitigate browning efficiently, while retaining functionalities as food additive is a challenge in the food industry.RESULTS: Our results demonstrated that EGCG could be anchored within the internal cavity of gamma-cyclodextrin (gamma-CD) to form an inclusion structure, where hydrophobic interaction, hydrogen bonding, and pi-stacking were identified to be the primary drivers. The interplay between two molecules and the steric hindrance from gamma-CD could restrict the motion and aggregation of EGCG efficiently, thus alleviating the browning effect. In addition, the conformational adaption of EGCG within the inclusions would result in general decreases in hydrogen-bond dissociation enthalpies for the pyrogallol-type structure on the b ring, thus enhancing the antioxidant capability. In practical application, the nanoscale gamma-CD/EGCG inclusion complexes were validated preliminarily as efficient additives in the preservation of shrimp surimi, presenting significant effects on prolonging the shelf-life of products.CONCLUSION: Here, nanoscale gamma-CD/EGCG inclusion complexes as alternatives to EGCG were tailored as food antioxidants for the preservation of shrimp surimi products, exerting antioxidant effects while mitigating the browning effects of EGCG on products. Through self-assembly, EGCG would be anchored with the cavity of gamma-CD, which could regulate the release modes and restrict the aggregation of EGCG. This facile strategy has great potential in food preservation.(c) 2023 Society of Chemical Industry.