Abstract:The effects of postharvest application of chitosan and carbon monoxide (CO) on fruit browning and softening during cold storage (8 ℃) were evaluated. CO (10 µmol/L) significantly delayed the internal browning of peach fruit, and the effect was enhanced in combination with chitosan (1%, w/w). Further studies showed that treatment with CO and chitosan reduced the increase of PPO and POD activities, maintained PAL activity and total phenoilics content at a higher level. Moreover, it also reduced fruit tissue softening by retarded the increase of PE, PG activities and water soluble pectin content, inhibited the decline of flesh firmness as well as sustained the balance of PG and PE activities, improved the ability of chilling injury tolerance. Therefore, peaches treated with chitosan and CO obviously delayed the fruit browning and softening during cold storage, and it indicates that combined treatment with chitosan and CO can be effective in reducing browning and softening of peach fruit and inhibited chilling injury during cold storage.