Tropical and subtropical plants, having evolved in warm climates, lack the necessary cellular mechanisms to withstand prolonged exposure to cold temperatures. Chilling injury manifests in various ways, including surface lesions, internal browning, pitting, increased susceptibility to pathogens, and failure to ripen properly. Fruits such as bananas, mangoes, peaches, and papayas exhibit noticeable symptoms like darkened spots, irregular ripening, and textural degradation. Vegetables like zucchini, cucumbers, and bell peppers also experience chilling injury, leading to symptoms such as water-soaked tissues and decay. Even leafy greens like basil and lettuce develop discoloration and increased ethylene production, hastening spoilage.
One of the primary factors influencing chilling sensitivity is the maturity of the produce at harvest. Tomatoes, honeydew melons, and peppers, for example, are particularly vulnerable when harvested at immature stages. Additionally, exposure duration and temperature fluctuations exacerbate damage, making postharvest handling crucial in mitigating chilling injury. Research has shown that storing susceptible produce at temperatures just above the chilling threshold can reduce damage while maintaining freshness. Modified atmosphere packaging (MAP) and controlled atmosphere (CA) storage, which regulate oxygen and carbon dioxide levels, have also been effective in minimizing chilling effects and extending shelf life.
Beyond chilling injury, low temperatures can cause freezing injury, where ice crystals form within plant tissues, leading to cell rupture and irreversible damage. Some crops, such as carrots and potatoes, exhibit a greater ability to recover from freezing stress compared to others. However, improper thawing can further deteriorate texture and flavor.
Advancements in postharvest technology are focusing on natural treatments, such as the application of heat shock proteins, antioxidants, and calcium-based solutions, to enhance chilling tolerance. Understanding the specific temperature sensitivities of different fruits and vegetables allows for better storage practices, reducing food waste and ensuring economic sustainability for farmers and suppliers. Thus, refining refrigeration strategies remains critical in preserving both quality and longevity in the global food supply chain.
The Hidden Risks of Refrigeration: Chilling Injury in Fruits and Vegetables
