Objective To investigate the effects of near-freezing temperature (NFT) on fruit quality, phenolic compounds, antioxidant enzymes and antioxidant capacity of prune fruits during storage, as well as sensory evaluation after storage.
Methods Fresh ‘French’ prune fruits from Xinjiang were used as test materials. Three treatment groups were set up: NFT storage, 1–2 ℃ storage and 4–6 ℃ storage, with a relative humidity of 90%–95%. Samples were taken at regular intervals.
Results The freezing point of prune fruits in this experiment was –2.8 ℃, and the selected NFT storage temperature was –1.5 ℃ to –1.0 ℃. The results showed that NFT storage effectively maintained the firmness, moisture content and color of prune fruits, and resulted in better sensory evaluation scores. It preserved higher levels of total phenolics, flavonoids, anthocyanins and tannins, significantly maintained the activities of peroxidase (POD) and phenylalanine ammonia lyase (PAL) in the fruits, while inhibiting the activity of polyphenol oxidase (PPO). In addition, NFT storage maintained the activities of ascorbate peroxidase (APX) and glutathione reductase (GR), delayed the decline of ascorbic acid (AsA) and reduced glutathione (GSH) contents, and sustained the ascorbate-glutathione (AsA-GSH) cycle. In terms of antioxidant capacity, NFT-stored prunes exhibited higher 1,1-di-phenyl-2-picrylhydrazyl (DPPH) free radical scavenging rate and 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging ability.
Conclusion These findings indicate that near-freezing temperature storage effectively maintains the antioxidant capacity of prune fruit tissues, thereby preserving fruit quality. This study provides a theoretical basis and technical reference for postharvest low-temperature storage and quality maintenance of prunes.
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