Effects of some postharvest applications on cold storage and shelf life of tomato and lettuce

In this study, the effects of postharvest applications of calcium chloride dihydrate (CaCl2.2H2O), hexanal, orange peel essential oil (OPEO), and grape seed oil (GSO) on the quality, storage, and shelf life of 'Komutan F1' tomatoes harvested at the pink ripening stage and 'Presidential' lettuce were investigated. Tomatoes and lettuce were dipped in solutions of 6% and 8% CaCl2.2H2O, 2 mM and 4 mM hexanal, 2% and 4% OPEO, and 2% and 4% GSO. The tomatoes were stored at 5°C with 90–95% relative humidity for 35 days, with analyses conducted at 7-day intervals. The lettuce was stored at 4°C with 90–95% relative humidity for 20 days, with analyses performed every 4 days. At each analysis period, tomato and lettuce samples were removed from storage and kept at 20°C with 60–65% relative humidity for 2 days, after which shelf life analyses were conducted. During cold storage and shelf life conditions, weight loss, TA, TSS, total flavonoid content, total phenolic content, total antioxidant activity, fruit and leaf color parameters (L*, chroma, and hue angle), decay rate, and overall appearance were evaluated. Additionally, fruit firmness, lycopene, and carotene content were analyzed in tomatoes, while SPAD values and overall acceptability were assessed in lettuce. Results showed that 2 mM and 4 mM hexanal and 4% GSO treatments preserved tomato firmness, color, sensory quality, and weight loss, while maintaining TA, TSS, and biochemical quality. In lettuce, these treatments better preserved TA, TSS, flavonoids, phenolics, antioxidant activity, color, SPAD, chroma, hue, decay, and appearance