Biochemistry behind firmness retention of jujube fruit by combined treatment of acidic electrolyzed water and high-voltage electrostatic field

Harvested jujube (Zizyphus jujuba Mill) is prone to softening due to active metabolism. This study investigated the effects of acidic electrolyzed water (AEW), high-voltage electrostatic field (HVEF) and their combination (AEW + HVEF) on softening and associated cell wall degrading enzymes (CWDEs), cell membrane integrity and antioxidant system of 'Huping' jujube during storage at 0 ± 1 °C. The results indicated that fruit subjected to AEW + HVEF, AEW or HVEF treatments maintained firmness 15.7%, 10.7%, and 5.3% higher than that of untreated control fruit at the end of 90 days cool storage. Fruit treated with AEW + HVEF could better maintain cell membrane integrity and exhibit lower activities of CWDEs and higher antioxidant capacity than that treated with either AEW or HVEF. Correlation analysis suggested that inhibition of softening was associated with reduction of CWDEs activities, and maintenance of membrane integrity and antioxidant system.