Abstract: Severe skin browning of ‘Huangguan’ pears usually occurs during long-term cold storage. In order to develop a new technique to solve this problem, the effect of dipping treatment with 3 or 20 mmol/L H2O2 on cellular antioxidant defense systems, skin browning and fruit quality during postharvest cold storage of ‘Huangguan’ pear fruits. The results showed that compared with control (without H2O2 treatment), the treatment with 20 mmol/L H2O2 reduced markedly skin browning spot index, decreased polyphenol oxidase (PPO) activity and polyphenol contents especially chlorogenic acid, arbutin and catechins, increased peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity as well as DPPH radical scavenging capacity, decreased MDA content, and maintained higher firmness, titratable acid (TA), acid-to-sugar ratio, and total soluble solids (TSS) content, thereby resulting in better overall sensory quality during cold storage and shelf life. In sum, the treatment with 20 mmol/L H2O2 could reduce skin browning of ‘Huangguan’ pear during long-term storage through inducing antioxidant defense, inhibiting PPO activity , and reducing polyphenol contentss.

Key words: hydrogen peroxide, ‘Huangguan’ pear, skin browning, sensory quality