Unraveling the inhibition mechanism of cyanidin-3-sophoroside on polyphenol oxidase and its effect on enzymatic browning of apples

The hunt for anti-browning agents in the food and agricultural industries aims to minimize nutritional loss and prolong post harvest storage. In the present study, the effect of cyanidin-3-sophoroside (CS) from Garcinia mangostana rind, on polyphenol oxidase (PPO) activity was investigated. The non-competitive inhibition mode of CS was determined by Lineweaver Burk plot. CS forms a ground-state complex by quenching the intrinsic fluorescence of PPO. The static quenching was temperature-dependent with an activation energy of 4.654 ± 0.1091 kJ mol−1 to withstand the disruption of amino acid residues of the enzyme binding site. The enzyme conformational change was validated by 3D fluorescence and CD spectrum. Docking (binding energy −8.124 kcal/mol) and simulation studies confirmed the binding pattern and stability. CS decreased PPO activity and browning index of fresh cut apples and prolonged the shelf life. Thus, CS appears to be a promising anti-browning agent to control enzymatic browning.

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