Evaluate the impact of temperature fluctuations during transportation on the quality of Chinese cherry: Color transformation and cell wall polysaccharide evolution

Temperature fluctuations during cold chain transportation of Chinese cherry serve as a critical stress factor. This study systematically elucidated both the immediate and persistent physiological effects of temperature fluctuations on Chinese cherry quality. Compared with constant storage at 5°C, three consecutive temperature fluctuations between 5 and 10°C induced progressive and significant changes in fruit phenotypic traits. At the end of temperature fluctuations (Day 4), Chinese cherry showed 135.22% higher ΔE and 9.02% lower firmness versus 5°C isothermal controls. Post-storage damage reached 78-93% of that under constant 10°C conditions. The observed effects primarily stem from temperature fluctuations triggering rapid accumulation of malondialdehyde, a key cell membrane oxidation byproduct, along with elevated ATP levels, which in turn enhance the activities of polyphenol oxidase and peroxidase to promote anthocyanin synthesis and phenolic oxidation, thereby inducing color transformation. Additionally, the specific upregulation of pectin metabolism-related genes ( cCPG1-3 and cCPME3-4 ) enhanced polygalacturonase and pectin methylesterase activities, accelerating pectin demethylesterification and driving nanoscale structural transitions in pectin polymers. The study comprehensively demonstrated the immediate and persistent effects of temperature fluctuations on color transformation and softening-related quality deterioration in Chinese cherry fruits, providing a scientific foundation for developing precision cold-chain logistics strategies. • ΔE rose 135.22% under temperature fluctuations vs 5°C isothermal in Chinese cherry. • 5–10°C fluctuations caused 78–93% of the 10°C storage damage in Chinese cherry. • MDA accumulation and PPO/POD activation drive color transformation. • Pectin gene upregulation alters nanostructure, accelerating softening.