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In this study, headspace solid‐phase microextraction coupled with gas chromatography‐mass spectrometry (HS‐SPME‐GC/MS) was used to identify individual volatile compounds in five jujube varieties, and E‐nose was used to identify their flavor. The results showed that a total of 45 volatile compounds were detected by GC‐MS in the five varieties, and the proportion of acids was the highest (38.29%–54.95%), followed by that of aldehydes (22.94%–47.93%) and esters (6.33%–26.61%). Moreover, different varieties had obviously different volatile components. E‐nose analysis showed that the R7 and R9 sensors were more sensitive to the aroma of jujube than other sensors. The strong response of R7 sensor was attributed to terpenes (or structurally similar substances) in jujube fruit, such as 1‐penten‐3‐one, 2‐octenal, (E)‐2‐heptanaldehyde, and (E)‐2‐hexenal and that of R9 sensor was attributed to the cyclic volatile components such as benzaldehyde, benzoic acid, and methyl benzoate. The multivariate data analysis (PCA, OPLS‐DA, and HCA) of the results of GC/MS and E‐nose showed that the five varieties could be divided into three groups: (1) Ziziphus jujuba Mill. cv. Huizao (HZ) and Z. jujuba cv. Junzao (JZ). Acids were the main volatile components for this group (accounting for 47.44% and 54.95%, respectively); (2) Z. jujuba cv. Hamidazao (HMDZ). This group had the most abundant volatile components (41), and the concentrations were also the highest (1285.43 µg/kg); (3) Winter jujube 1 (Z. jujuba cv. Dongzao, WJ1) and Winter jujube 2 (Z. jujuba cv. Dongzao, WJ2). The proportion of acids (38.38% and 38.29%) and aldehydes (40.35% and 38.19%) were similar in the two varieties. Therefore, the combination of headspace solid‐phase microextraction coupled with gas chromatography‐mass spectrometry and E‐nose could quickly and accurately identify the volatile components in jujube varieties from macro‐ and microperspectives. This study can provide guidance for the evaluation and distinguishing of jujube varieties and jujube cultivation and processing. [ABSTRACT FROM AUTHOR]

The black rot disease of winter jujube causes considerable losses to the jujube industry in Xinjiang. Methyl salicylate (MeSA) and methyl jasmonate (MeJA) are elicitors of plant disease resistance; therefore, the inhibitory effects of 1 mmol/L MeSA and 0.1 mmol/L MeJA on the black rot disease of winter jujube caused by Alternaria tenuissima were investigated herein. Both MeSA and MeJA reduced the fruit decay index, and the effect of MeJA was superior. MeSA and MeJA enhanced the activities of enzymes related to phenylpropane metabolism and pathogenesis-related proteins, and the expression of their corresponding genes. MeSA and MeJA increased the accumulation of phenylpropane metabolites, containing the lignin, total phenol, and total flavonoid contents. These findings indicated that MeSA and MeJA may enhance the resistance of winter jujube to A. tenuissima by enhancing the phenylpropane metabolism pathway and the activity of pathogenesis-related proteins. • MeSA and MeJA enhanced the phenylpropane metabolism pathway of winter jujube. • Exogenous MeSA and MeJA improved the disease resistance of winter jujube. • Decay index of treatment groups was closely related to the phenylpropane metabolism. • MeJA was superior to MeSA in suppressing the black rot disease of winter jujube. [ABSTRACT FROM AUTHOR]

• The effects of storage temperature on Diaogan apricot were investigated. • Ice-temperature storage helped retain fruit firmness and pectin/cellulose content. • Ice-temperature storage enhanced the activities of antioxidant enzymes. • Ice-temperature storage ameliorated weight loss and respiration. • Ice-temperature is effective for maintaining apricot quality during storage. Ice-temperature storage is a new refrigeration method with temperatures ranging from sub-zero to the freezing point of the product being stored. However, few reports have evaluated the effects of ice-temperature (IT) storage on the cell wall metabolism and reactive oxygen metabolism of Xinjiang-grown Diaogan apricots. In this study, to determine the effects of ice-temperature storage on cell wall metabolism and reactive oxygen metabolism in Diaogan apricots, apricots were stored at −1.5 °C to−2.0 °C (ice temperature, IT), 0 °C–1 °C (low temperature), and 10 °C (control) for 70 d with sampling and evaluation every 10 d. Compared to storage at low temperature and 10 °C, IT storage (1) better maintained the firmness, ascorbic acid content, pectin content, and cellulose content of the fruit; (2) suppressed the activities of polygalacturonase and cellulase; (3) inhibited the rate of weight loss, respiration rate, ethylene production, plasma membrane permeability, and malondialdehyde accumulation; and (4) improved the activities of peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase, thereby inhibiting the accumulation of hydrogen peroxide and superoxide anion during storage. Overall, the results show that IT storage is an effective way to improve the storage quality and antioxidant capacity of Diaogan apricots. [ABSTRACT FROM AUTHOR]