Abstract: Oriental sweet melons Jinheng No. 2 were immersed in enhanced freshness formulation (1% or 2% EFF solution) or plain water (as control) for 3 min before storage in incubators for 20 d at 10 ℃ and a relative humidity of 85%. Postharvest physiological properties of oriental sweet melons were determined at 7-day intervals during storage. EFF treatment alleviated the decrease of weight, firmness, water content and soluble solid, delayed the appearance of the ethylene peak and extremely significantly reduced the ethylene peak height (P ＜0.01). Meanwhile, EFF treatment significantly promoted the activities of superoxide dismutase (SOD) and catalase (CAT) (P ＜ 0.05), and extremely significantly inhibited the activities of polyphenol oxidase (PPO) and peroxide (POD) (P ＜0.01). Therefore, EFF treatment delayed the maturation and the following senescence of sweet melons, and thus prolonged their storage life. During the early part of the storage period, 2% EFF treated sweet melons had significantly higher aldehydes content than those in the control group and 1% EFF treated sweet melons (P ＜0.05). During the later part, 2% EFF treated sweet melons revealed a significantly increase in the contents of total aroma compounds, esters, acetic and oxalates, and the appearance of the aroma peak was delayed for 3 days, thus reducing the loss of aroma compounds and maintaining the quality of sweet melons. Collectively, these results indicate that 2% EFF treatment is more beneficial to delay the senescence of oriental sweet melons and maintain their quality.

Key words: oriental sweet melon, enhanced freshness formulation, postharvest physiology, fruit quality