Abstract:To fully develop the resources of carrots and apple-pears， a not from concentrate （NFC） composite fruit and vegetable juice was prepared and the relationship between aroma substances and the change of the product flavor during storage was studied. Using selenium-enriched carrots and apple-pears as raw materials and sensory scores as indicators， single-factor experiments and response surface methodology were employed to optimize the processing conditions of NFC selenium-rich carrot composite fruit and vegetable juice. Headspace solid-phase microextraction and gas chromatography-mass spectrometry were used to determine and analyze the aroma compositions and their changing rules in NFC selenium-rich carrot composite fruit and vegetable juice during different storage periods at room temperature. The results showed that the optimal formula was composite fruit and vegetable juice of 91.8% （with the mass ratio of selenium-rich carrot juice to applepear juice 3∶1）， the white granulated sugar of 8%， and the citric acid of 0.2%. The sensory score of the developed NFC selenium-enriched carrot composite fruit and vegetable juice was 92.88. 96 kinds of volatile odor substances of 7 categories were detected by the technology of solid-phase microextraction and gas chromatography-mass spectrometry. The volatile odor substances in the NFC selenium-enriched carrot composite fruit and vegetable juice in different storage periods were 0 d 41 species， 7 d 44 species， 14 d 48 species， 21 d 55 species， 28 d 58 species， which showed an increasing trend with the extension of storage period. The NFC selenium-rich carrot composite fruit and vegetable juice prepared under the optimal process conditions， after storage， was conducive to the formation of various flavor components， thereby improving the product's taste and imparting its typical flavor. It had a moderate sweet and sour taste， rich nutrition， and a strong composite aroma of carrots and apple-pears.