The Promising Role of UV-C Irradiation in Enhancing Fruit and Vegetable Quality

Maintaining the quality of fruits and vegetables is key to extending their shelf life and nutritional value. While traditional practices such as low temperature and high humidity can slow respiration rates, controlling microbial growth is important. Chemical disinfection is not ideal, and physical treatments such as heat and steam are being explored as options. UV-C irradiation, a form of electromagnetic radiation, is a viable physical disinfection method that not only controls spoilage but also contributes to the quality of fruits and vegetables by producing phytoalexins and antioxidant phytonutrients. Continued research is needed to understand the true potential of UV-C irradiation to provide quality benefits to fruits and vegetables. * * * To maintain the quality of fruits and vegetables, their storage conditions and postharvest treatments are critical. Basic methods such as low temperature and high humidity can reduce respiration rates. Another technique used to control respiration is to manage the gas environment, such as modified atmosphere packaging and controlled atmosphere storage. Microbial control is necessary to reduce the spoilage of fruits and vegetables. Chemical disinfection is not preferred due to concerns about chemical residues on produce. Therefore, physical treatments such as hot water and steam are being studied as alternative methods.? Heat treatments transfer heat to microorganisms by conduction and convection, inactivating microbial proteins and enzymes. They also oxidize and degrade biomolecules, preventing biological activity. This treatment not only controls spoilage but also improves the quality of fruits and vegetables. Several studies have reported the inhibition of ripening and quality improvement in apples, grapefruit, potatoes, and tomatoes using heat treatments. However, they can damage tissue and texture quality before sufficient bactericidal effects are achieved. Recently, electromagnetic radiation, particularly infrared (IR) and ultraviolet (UV) radiation, has been considered a physical disinfection technique. IR irradiation raises the temperature of microbial cells through radiant heat transfer, making it an effective method of sterilization. However, this treatment can cause desiccation and heat damage to fruits and vegetables. UV-C, on the other hand, has a high bactericidal effect and is used for sterilization due to its peak absorption band around 260 nm, which coincides with the wavelength band of UV-C.? When UV-C irradiates pyrimidine bases, a dimer is formed, resulting in the loss of the replication function of nucleic acids. This irradiation also induces biological stress in plants, resulting in the production of phytoalexin compounds. Postharvest UV-C treatment enhances antioxidant phytonutrients, including polyphenols, ascorbic acid, ?-carotene, and chlorophyll. Several studies have demonstrated the inhibition of softening and enhancement of antioxidant capacity in mushrooms and tomatoes by UV-C irradiation. In 2018, the journal Postharvest Biology and Technology published a study that investigated whether UV-C irradiation could help improve the shelf life of cucumbers and persimmons. In this study, they used these vegetables to observe significant variations in their responses to UV-C irradiation. However, they did not find any striking differences in responses within the irradiation time examined. Their initial expectation that UV-C irradiation could increase the phytonutrient content was not supported by the results, and they examined only a limited number of phytonutrients, so it is crucial to evaluate the changes in other phytonutrients as well. In the case of cucumber, they observed an increase in brightness, surface hardening and changes in electrical properties after UV-C irradiation. Some of these changes could be considered positive phenomena, indicating the potential of UV-C irradiation to improve the shelf life of cucumbers. Further research should include a comprehensive evaluation of fruit quality, including texture. * * * The use of UV-C irradiation as a physical disinfection technique shows promise for preserving the quality of fruits and vegetables. Its power to stimulate the production of phytoalexins and antioxidant phytonutrients enhances the nutritional content of products while reducing microbial growth. Although more research is needed to better understand its benefits, initial results are promising. Future studies should include a full evaluation of fruit quality, including texture, to fully realize the potential of UV-C irradiation in improving fruit and vegetable quality. Author:?Jorge Luis?Alonso G. (with ChatGPT)?Maximizing Agribusiness Profits with Expert Postharvest Storage Strategies | Horticultural Writing Specialist.?This article was written exclusively for the business platform Postharvest. Cover photo: Pixabay.