Abstract: To clarify the regulatory effect of nitric oxide (NO) treatment on the postharvest flavor quality of apricot fruits, Chuanzhihong apricots were treated with 0.2 mmol/L sodium nitroprusside (SNP) as an exogenous NO donor or distilled water (control) before storage at 25 ℃ and 80% relative humidity (RH). The effect of NO treatment on the flavor quality of apricots was investigated by determining the contents of sugars and organic acids, and the activities of key enzymes, as well as volatile organic compounds (VOCs). The results showed that SNP treatment inhibited the increase in the contents of sucrose, fructose and glucose, maintained the contents of malic acid, citric acid and oxalic acid, suppressed the activity of NAD-dependent malic enzyme (NAD-ME), enhanced the activity of NAD-dependent malate dehydrogenase (NAD-MDH) in the late storage period, and delayed the occurrence of peak lipoxygenase (LOX) activity. Meanwhile, the activity of alcohol dehydrogenase (ADH) was promoted in the early storage period but inhibited in the late storage period by SNP treatment. A total of 40 VOCs were identified by gas chromatography-ion mobility spectrometry (GC-IMS). The fingerprint showed that SNP treatment promoted the accumulation of esters and ketones in apricot fruits in the early storage period to enhance fruity and creamy aromas, and inhibited the production of aldehyde oxidation products and off-flavor substances in the middle and late storage periods. In conclusion, 0.2 mmol/L SNP treatment effectively delayed the loss of aroma components and inhibited flavor deterioration in apricot fruits during storage by regulating the contents of sugars and organic acids, the activities of key enzymes, and the contents of volatile flavor substances.

Key words: apricot fruits; nitric oxide treatment; flavor; gas chromatography-ion mobility spectrometry