Evaluation of phytochemicals and the role of oxidative stress pathways during fruit development in strawberries (Fragaria×ananassa)

Abstract

Strawberries (Fragaria × ananassa) are one of the Rosaceae family, considered economically and nutritionally important berry fruits. Phytochemicals are crucial ingredients that contribute to characteristics such as the fruit?s aroma and flavor. The current study investigated the phytochemical characteristics of strawberry fruit at three developmental stages (green, white, and red). HPLC measurements determined the glucose, fructose, and sucrose concentrations significantly increased in the red fruit, whereas glucose was identified as the major sugar in ripe fruit (2.8 g.g-1FW). Evaluation of the phenylpropanoid pathway implied that the amount of total phenol and flavonoid following phenylalanine ammonia-lyase enzyme activity decreased during fruit development. Unlike phenolic compounds, vitamin C was considerably increased in the red stage, while antioxidant capacity was almost constant in all stages of fruit development. The activities of all antioxidant enzymes at the ripe fruit stage were higher than in the green fruit. At the final stage, the superoxide dismutase enzyme had the highest activity. Increasing carbohydrates in the red fruit is due to the role of these compounds in regulating metabolic pathways during fruit ripening. The reduction of phenolic contents and the stability of antioxidant capacity indicates the role of nonphenolic antioxidant compounds such as vitamin C in the ripening and preservation of antioxidant properties. Identifying the phytochemicals and antioxidant capacity of strawberries during ripening reveals the role of various compounds and oxidative stress pathway signaling in fruit ripening; it can also contribute to the widespread application of strawberries in the edible and nonedible industries at different stages of fruit development.