| Winter jujube(Ziziphus jujuba Mill.cv.Dongzao)is a traditional characteristic fresh jujube variety with the largest cultivated area and the best quality in China,which is widely favored by consumers because of its crispy taste and rich nutrition.In recent years,with the promotion and application of facility cultivation methods,the winter jujube industry has been continuously transformed and upgraded,and the logistics industry has promoted mid-to-highend market sales.However,due to the lack of storage of winter jujube fruits after harvest and the short shelf life,the market supply of winter dates is limited.Therefore,this study aims to clarify the physiological basis and metabolite change law of winter jujube fruit during postharvest room temperature storage,which is of great significance for in-depth exploration of the postharvest quality maintenance basis,room temperature storage preservation and marketization technology of winter jujube fruit.In this study,the changes of winter jujube fruits under different storage periods after harvest were studied by combining physiological determination and metabolome test using the white mature and beginning red stage of cold shed cultivation as the test material.The main conclusions of the study are as follows:(1)The postharvest water loss rate of winter jujube in the white ripening stage and the early red stage was high,and the water loss rate of the white ripening fruits was higher than that in the early red stage,and the water loss rate could reach 21.06 %.The sensory evaluation score,edible rate,soluble solids,soluble sugar content and sugar-acid ratio of fruits in the first red stage were higher than those in the white ripening stage,indicating that the fruits in the first red stage were more suitable for picking.During the storage process at room temperature,the hardness and soluble solids of winter jujube did not increase with the increase of storage time,indicating that there was no post-ripening phenomenon of winter jujube after harvest.After 7 days of storage at room temperature,the fruits of winter jujube turned red rapidly,and they appeared wrinkled,their antioxidant capacity decreased,and the appearance quality of the fruits decreased.(2)During the storage of jujube at room temperature after harvest,the accumulation levels of fructose,glucose,succinic acid,citric acid and vitamin C decreased,and the taste and main nutrients of jujube fruit decreased.Epicatechin is the most abundant flavonoid in jujube,which decreases significantly during storage,and the content is 3.23 times that of 9 d when stored for 1d;most of the other flavonoids have the highest content in storage for 5d and decrease after 5d,indicating that the antioxidant capacity of jujube fruit decreases after 5 d.(3)Metabolomics detected 915 compounds in 13 categories,and 428 differential metabolites were screened;The changes of metabolites in different storage stages of postharvest winter jujube were mainly focused on the biosynthesis of amino acids,carbohydrate metabolism,phenylpropanoid metabolism and flavonoid biosynthesis pathways.In summary,the changes of main nutrients and fruit characteristics of winter jujube fruits under room temperature storage conditions were studied by sensory evaluation,physiological index determination and metabolomics test analysis.The physiological changes and metabolic network of winter jujube fruit postharvest senescence were constructed.The main characteristics of the postharvest senescence process of winter jujube fruit were revealed,and the optimal shelf life of winter jujube fruit at room temperature after harvest was determined to be 5 ～ 7 d,which provided a basis for mature harvest,postharvest quality maintenance,room temperature storage and market sales of winter jujube. |
