The effect of ultraviolet A and B light application on some quality values in post-harvest lettuce (Lactuca sativa)

In this study, different doses of UV-A and UV-B light were applied to curled lettuce (Lactuca sativa var. crispa), which can be grown for 12 months in our country, and the effects of these applications on some quality values of lettuce were investigated. For this purpose, a UV cabinet was created, preliminary tests were carried out, and UV light applications were carried out at the determined intensity and duration. After the determined intensity and applications, total phenolic substance, antioxidant activity, ascorbic acid amount and color changes were determined in lettuce. The effect of UV light applications was investigated. As a result of the study, the highest phenolic content was detected in the high-dose UV-B samples (46.1 mg GAE / 100 g lettuce) on the seventh day of storage in the lettuce samples treated with UV. The lowest phenolic content was found in low-dose UV-B (13.7 mg GAE / 100 g lettuce), low-dose UV-A (16.3 mg GAE / 100 g lettuce), and medium-dose UV-B samples (16.5 mg GAE / 100 g lettuce), respectively. After 7 days of storage, an increase of 53.7% was observed in the total amount of phenol in the lettuce samples treated with high-dose UV-B, while an increase of 29.7% was observed in antioxidant activity. The most effective dose in terms of protection and improvement of the amount of ascorbic acid was in high-dose UV-A lettuce samples. In general, when all the results were evaluated, it was not found that UV-A or UV-B had a more effective role in curly lettuce. However, it was determined that high-dose UV-A (4.55 kJ / m²) and high-dose UV-B (4.56 kJ / m²) applications gave positive results in lettuce samples. According to the color change parameter, UV applications did not have a statistically significant effect. In future studies, it would be beneficial to investigate different doses of both UV-A and UV-B and to make optimizations over these doses.