Modulated UV-C Radiation for Disease Control and Quality Preservation in Postharvest Papaya and Orange Fruits

Postharvest losses remain a major issue in fruit production systems, affecting both climacteric fruits such as papaya and non-climacteric fruits such as orange. Ultraviolet-C (UV-C) radiation has emerged as a sustainable alternative to chemical fungicides, although its effectiveness depends on the applied dose and delivery mode.

This study evaluated the comparative effects of continuous and frequency-modulated UV-C radiation on postharvest disease control and fruit quality in papaya and orange. Two independent experiments were conducted: the first assessed modulation frequencies (0, 15, 30, and 45 Hz) on disease progression, while the second combined the most effective frequencies with different exposure times to determine optimal conditions.

In papaya, 30 Hz modulation for 20 seconds (0.44 kJ m⁻²) reduced anthracnose incidence by 67% without visible epidermal damage. In orange, continuous UV-C exposure (0 Hz) for 30 seconds (1.99 kJ m⁻²) completely suppressed sour rot without peel injury.

Results show that UV-C application mode is species-specific. Modulated UV-C improved disease control efficiency while reducing tissue damage. It also enhanced defense-related enzyme activities (PAL, PPO, POD, and CAT) and preserved firmness, acidity, and color stability, maintaining postharvest quality.

Overall, modulated UV-C radiation represents a promising non-chemical technology for disease control and quality preservation in fruits.

Source

Silva, A. M. da, Terao, D., Silva, I. S. O., Maia, A. H. N., Melo, W. L. de B., Nechet, K. de L., Halfeld-Vieira, B. de A., Vilela, E. S. D., & Fracarolli, J. A. (n.d.).
Modulated UV-C radiation as an innovative strategy for postharvest disease control and quality preservation in papaya and orange fruits. ScienceDirect.

https://www.sciencedirect.com/science/article/pii/S0925521426002371