Abstract:In this study, winter jujube fruits were used as experimental materials. Winter jujube fruits were subjected to a 3 h fumigation with 20 μL/L of nitric oxide (NO) and stored at 0 oC and 90%~95% of relative humidity for 75 d. Changes in volatile compounds, ethanol metabolites and activities of key enzymes of the winter jujube fruits were measured regularly during the storage. The results showed that a total of 47 volatile compounds were identified in the winter jujube fruits, mainly including alcohols, aldehydes, esters, acids, and ketones. After 45 and 75 days of the storage, 24, 37, 38, 45 and 46 volatile components were detected in the control and NO fumigated groups, respectively. During cold storage, the aldehydes in fruit mostly increased first and then decreased, while the types and contents of alcohols and esters generally increased. The effects of NO fumigation on aldehydes varied depending on the storage time and the type of aldehyde, whilst NO could effectively inhibit the increases in the contents of alcohols and esters. Meanwhile, NO fumigation significantly inhibited the activities of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH), thereby suppressing the accumulation of ethanol and acetaldehyde in the winter jujube fruit during storage. These results suggested that NO treatment could preserve the contents of volatile substances and delay the generation of off-flavor in the winter jujube fruit during cold storage.
