Early harvesting is undesirable in kiwifruit production: Insights from metabolomics and physiological evidence

The effects of early harvesting (EH) on storage characteristics, nutritional quality and metabolite profiles of kiwifruit at harvesting, room-temperature post-ripening, and low-temperature post-ripening (LTP) modes were comprehensively investigated. Overall, EH resulted in significant losses of soluble solids and dry matter, and significantly higher decay and weight loss rates after post-ripening. Meanwhile, during LTP, EH caused higher cold sensitivity in fruit manifested by higher incidence and index of chilling injury, also led to severe loss of ascorbic acid and total phenolics. Additionally, EH induced insufficient accumulation of organic acids, sugars, and amino acids in fruit at harvest, as well as an enrichment of bitter flavonoids, impairing fruit flavor. Remarkably, EH upregulated flavonoids, phenolic acids, lignans and coumarins, terpenoids, and alkaloids metabolites, particularly under LTP mode, which might be a potential pathway of fruit response to cold adversity. Six metabolites were screened as potential biomarkers to differentiate normal and early harvested kiwifruit.