RESUMO
Electron beam (EB) technology typically consists of high-energy electron streams produced by a linear accelerator. Although promising, the use of EB irradiation as a technique to delay ripening and prevent spoilage in tomatoes has not been extensively investigated. In this study, the effectiveness of EB irradiation in prolonging the shelf life of tomatoes postharvest was investigated. The results indicated that EB irradiation successfully reduced microbial contamination and decay, preserved key quality attributes (such as total soluble solids, titratable acidity, pH, and firmness), and significantly minimized weight loss. Notably, the treatment delayed the biosynthesis of lycopene, a key indicator of ripening, without adversely affecting phenolic content and antioxidant activity, which remained consistent regardless of irradiation. Additionally, different methods for detecting irradiation were evaluated. Thermoluminescence analysis proved to be the most dependable technique, especially for doses exceeding 600 Gy, due to its high sensitivity and specificity. In contrast, photostimulated luminescence and electron spin resonance analyses showed limitations in accurately identifying the irradiation status of foods with high moisture content, such as tomatoes. This study confirms that EB irradiation, while maintaining postharvest quality, extends the shelf life of tomatoes by 5-10 days, suggesting its potential for commercial application in food preservation.
RESUMO
BACKGROUND: Tomato (Solanum lycopersicum) has a relatively short shelf life as a result of rapid ripening, limiting its transportability and marketability. Recently, gamma irradiation has emerged as a viable method for delaying tomato fruit ripening. Although few studies have shown that gamma irradiation delays the ripening of tomatoes, the underlying mechanism remains unknown. Therefore, the present study aimed to examine the effects of gamma irradiation on tomato fruit ripening and the underlying mechanisms using transcriptomics. RESULTS: Following gamma irradiation, the total microbial count, weight loss, and decay rate of tomatoes significantly reduced during storage. Furthermore, the redness (a*), color change (∆E), and lycopene content of gamma-irradiated tomatoes decreased in a dose-dependent manner during storage. Moreover, gamma irradiation significantly upregulated the expression levels of genes associated with DNA, chloroplast, and oxidative damage repairs, whereas those of ethylene and auxin signaling-, ripening-, and cell wall metabolism-related, as well as carotenoid genes, were downregulated. CONCLUSION: Gamma irradiation effectively delayed ripening by downregulating the expression of ripening-related genes and inhibiting microbial growth, which prevented decay and prolonged the shelf life of tomatoes. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.