Objective To address the browning issue during chestnut processing.Methods Taishan chestnuts were used as the raw materials. The color protection process conditions were determined through a single-factor experiment. Three factors-melatonin concentration, malic acid mass fraction, and citric acid mass fraction-were selected for a response surface optimization experiment to determine the optimal concentrations of the color protection agents. The effects of different treatments on the physicochemical properties of the chestnuts were assessed by measuring the total phenol content, reducing sugar content, ascorbic acid content, malondialdehyde content, DPPH and ABTS free radical scavenging rates, and water content.Results The optimal color protection process conditions were determined as follows: soaking in the color protection agent at 40 ℃ for 60 min, followed by boiling in the color protection agent at 100 ℃ for 10 min. The optimal concentrations of the color protection agents were: melatonin at 0.5 mmol/L, malic acid at 0.87%, and citric acid at 1.08%. The determined color protection process effectively reduced the browning index of the chestnuts, increased the L^* value, and demonstrated good browning inhibition. Additionally, the total phenol content, reducing sugar content, ascorbic acid content, and DPPH and ABTS free radical scavenging rates increased, while malondialdehyde content decreased. There was no significant difference in water content.Conclusion The adopted color protection process can effectively inhibit browning during chestnut processing.