Mohsen Moradi - Department of Horticulture, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Farhang Razavi - Department of Horticulture, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Vali Rabiei - Department of Horticulture, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Morteza Soleimani Aghdam - Department of Horticultural Science, Imam Khomeini International University, Qazvin, Iran

Tomato (Lycopersicon esculentum) fruit is one of the most important vegetables in the tropical region, which plays an important role in human health due to its high levels of antioxidants such as lycopene, vitamin C, vitamin E and phenolic compounds. In order to investigate the effect of phenylalanine treatment on some antioxidant properties of tomato fruit, a factorial experiment was conducted in a completely randomized design with three replications at the postharvest laboratory of Zanjan University. fruits were harvested at the green stage and were dipped in different concentrations of aqueous solutions of 0 (control), 0.1, 1 and 5 mM of phenylalanine for 10 min and control ones dipped in distilled water. All fruits were then air dried for approximately 60 min and stored at 3°C and 80–85% RH for 28 days. During cold storage control and phenylalanine treated fruits were subjected to physicochemical analysis once a week. The results showed that phenylalanine treatment had a significant effect on the vitamin C, phenol, flavonoid and total antioxidant properties of the fruit compared with the control and increased these traits. The maximum amount of antioxidant capacity and flavonoid content was observed in the treatment of 5 mM and the highest content of vitamin C and total phenol at 1 and 0.1 mM concentration, respectively. These results suggested that exogenous phenylalanine treatment could be a useful technique to enhance the antioxidant capacity of tomato fruit during cold storage.

Postharvest, Vitamin C, Flavonoid, Phenylalanine