Combinative Effect of Salicylic Acid Immersion and UV-C Illumination on Chilling Injury-Related Factors of Longan (Dimocarpus longan Lour.) Fruit

ABSTRACT

The aim of this study was to investigate the effect of salicylic acid (SA) immersion incorporated with UV-C irradiation alleviating chilling injury (CI) of longan fruit cv. “E-Dor”. The fruit were immersed in 2 mM SA for 1 hour and then illuminated under UV-C light at the dose of 4.4 kJ·m⁻² (SA + UV-C), and the untreated fruit were used as control. All treatments were held at 4°C and 90 ± 2% relative humidity for 8 days. The determined parameters were browning score of skin and electrolyte leakage (EL), lipoxygenase (LOX) activities, malondialdehyde (MDA) contents, fatty acid contents, and free radical scavenging activities of both skin and flesh fruit. SA + UV treatment apparently delayed and lowered skin browning incidence by preventing the increases in EL, LOX activity, and MDA content, induced the ratio of unsaturated fatty acids per saturated fatty acid content, and maintained free radical scavenging activity. The treatment also lowered EL and LOX activity and maintained free radical scavenging activity of the fruit flesh during cold storage. These indicated that the use of SA + UV-C is an effective alternative preventing skin browning caused by CI of longan fruit during cold storage.

KEYWORDS:

• Longan fruit
• UV-C
• salicylic acid
• chilling injury
• browning incidence

Acknowledgments

The authors would like to acknowledge Postharvest Technology Innovation Center, Commission on Higher Education, Bangkok, and Kasetsart University Graduate School, Thailand, for providing grants.