Postharvest Treatments of Arginine, Asparagine, and Glycine Reduce Chilling Injury and Improve Okra Pod Quality

Okra (Abelmoschus esculentus L.) belongs to the Malvaceae family and is sensitive to chilling injury. To evaluate the effect of amino acids on preventing okra pods from chilling injury and maintaining their quality during storage, an experiment was performed to evaluate the possible role of amino acids in maintaining okra quality during cold storage. In this regard, okra pods were dipped for 10 min in distilled water (as control) and four solutions containing 2mM arginine, asparagine, or glycine individually as well as a combination of the aforementioned amino acids. The samples were then stored at 4°C for 14 days. Results showed that glycine and asparagine individually reduced the rate of pods’ weight loss by as much as 43% and 37%, respectively. Moreover, pretreatment of okra with amino acids, particularly glycine, remarkably diminished chilling disorders because of their roles in inducing antioxidant activity and declining lipid peroxidation in the pods. Results also revealed that pretreatment of okra with amino acids significantly mitigated polyphenol oxidase activity, and this could delay the appearance of pods’ browning lesions during cold storage. In conclusion, the results suggest that pretreatment of okra pods with amino acids, especially glycine, could reduce biochemical changes that occurred in pods due to chilling in cold storage.