Oxalic acid treatment delays quality loss and biochemical changes of minimally processed leeks during storage

In the present study, it was aimed to determine the effects of preharvest oxalic acid (OA) treatments on the biochemical content and quality of minimally processed leeks during storage. For this purpose, leeks were treated with solutions containing 0 (control), 1, 2 and 3 mM OA and 0.1% Tween-20 with a pump 6, 4 and 2 weeks before harvest. The packaged leeks were stored at 0 °C and 90 ± 5% relative humidity (RH) for 50 days. After the cold storage, the leeks were kept at 20 °C and 60 ± 5% RH for 3 days to determine the shelf-life. The effects of OA treatments on the weight loss, external appearance and bioactive compounds were remarkable. At the end of storage, the losses of ascorbic acid (AsA) content were determined as 55.53% in the control group and 22.89% in the 3 mM OA treatment. Similarly, the decrease in total phenolic (TP) content and antioxidant activity (AOA) in the control group was 37.34% and 45.70%, respectively, while these values were determined as 26.94% and 32.65% in the 3 mM OA treatment, respectively. With 3 mM OA treatment, the high dose in this study, the AsA, TP, and AOA contents of leeks were better preserved. The change in the external appearance scores at the end of cold storage was determined as 46.33% in the control group whereas it was determined between 31.44% (2 mM OA) and 42.55% (1 mM OA) in OA treatments. As a result, OA-treated and minimally processed leeks were successfully stored for 50 days at 0 °C and 90 ± 5% RH. Moreover, the efficacy of OA increased in a dose-dependent manner in the study.