EFFECT OF LIGHT-EMITTING DIODE WAVELENGTHS ON THE QUALITY-INDEX OF MARKET-DISPLAYED TOMATOES

Анотація

This study investigated the effects of light-emitting diode (LED) wavelengths as a postharvest pre-treatment to improve the physiological quality index and delay the deterioration of market-displayed tomatoes (Solanum lycopersicum). Tomatoes are highly perishable climacteric fruits characterized by rapid developmental and ripening processes, which cause significant economic losses within the postharvest supply chain, particularly at wholesaler and retailer outlets. To address this problem, fresh tomato samples were subjected to a 5-day pre-treatment phase inside a cooling chamber at a temperature of 5 degrees Celsius and 90% relative humidity under a 16/8-hour light/dark photoperiod. The administered treatments included white LED, 5Blue:1Red (5B:1R) LED, 5Red:1Blue (5R:1B) LED, and a control group kept in complete darkness. Following this phase, the tomatoes were transferred to simulated retail market environment conditions (24 degrees Celsius and 78% relative humidity) for a 24-day shelf display period, with data collection occurring every three days. The experimental results demonstrated that the 5B:1R LED pre-treatment was the most effective waveband for preserving the intrinsic qualities of the fruit. Compared to the control group, the 5B:1R LED successfully delayed fruit ripening and red color accumulation, showing a 19.9% decrease in the a-value and a 7.71% decrease in the L-value, while simultaneously boosting the accumulation of yellow-orange carotenoid pigments by increasing the b-value by 20.3%. Furthermore, this treatment maintained the highest physical integrity of the fruit, resulting in a 43.1% increase in flesh firmness over the control group. The 5B:1R LED also recorded the highest acidity level with an 8.7% increase over the control samples, which implies a stronger resistance against microbial and pathogenic attacks. Regarding sugar concentration, the 5R:1B LED performed best during short-term display, accelerating total soluble solids accumulation by 1.2% over the control within 12 days. However, for an extended display period of up to 18 days, the 5B:1R LED provided a more sustained increase in sugar concentrations due to its capacity to delay senescence. In conclusion, the application of a 5B:1R LED pre-treatment offers a highly effective and sustainable technique to enhance the postharvest shelf life of tomatoes, providing valuable practical benefits for producers and retailers to minimize commercial losses and boost economic growth.