Effects of anti-coloring agents on blackening inhibition and maintaining physical and chemical quality of fresh-cut okra during storage

Abstract

Fresh-cut okra pods were stored in sealed polypropylene bags at 5 °C and 95% RH for 8 days. Pods were dipped in 0.5% solution of cysteine, ascorbic acid, CaCl2, or citric acid for 5 min before storage. The main observed undesirable physiological and morphological alterations were weight loss, increasing microbial load, softening texture, and decreasing the phenolic content with blackening in color. CaCl2 was effective in increasing cell membrane integrity leading to improving texture, minimizing weight loss, decreasing microbial load, and preventing polyphenoloxidase (PPO) from contacting its phenolic substrates and thus reducing blackness. Ascorbic acid and cysteine were best anti-coloring agents since their strong ability to inhibit PPO and reacting with the resulted colored quinones to give colorless products. Reducing blackness was found parallel to decreasing phenolic content, indicating the role of the phenolic oxidation in the blackening process in okra pods during storage. Citric acid was less effective in enhancing the examined physical and chemical properties.