Influences of low temperature on the postharvest quality and antioxidant capacity of winter jujube (Zizyphus jujuba Mill. cv. Dongzao)

Abstract

Winter jujube inevitably suffers from rapid oxidation after harvest, leading to quality deterioration. Temperature plays an important role in the ripening and senescence of fruit. This study aimed to investigate the effect of different temperatures on the quality parameters, antioxidant enzyme activities, and antioxidant enzyme-related gene expressions of winter jujube. Jujube fruit were stored at room temperature (RT: 25 °C) and low temperature (LT: 0 °C) for 35 days, respectively. Compared with RT, LT maintained higher firmness and lower respiratory rate, inhibited the increase of weight loss, decay rate, total soluble solids (TSS) and reddening rate, delayed the decrease of titratable acid (TA) and ascorbic acid (AsA) content. LT-stored jujube fruit also showed higher antioxidant enzyme activities and related gene expression (Mn-SOD, APX, and GR, except CAT). We observed a significant correlation between fruit quality parameters and antioxidant enzymes, suggesting that fruit senescence is closely related to antioxidant ability. In short, LT delayed the ripening rate by inducing a series of physiological and molecular reactions, thereby improving antioxidant levels and storage quality.