Effect of foliar application with sodium selenate on selenium biofortification and fruit quality maintenance of 'Starking Delicious' apple during storage.

Background: Selenium (Se) is an essential micronutrient due to its anticarsinogenic properties and positive influence on human immune system. Fortification of some fruits based on their rates of consumption and availability all year round appears to be an effective way to supplement Se in the human diet. In this study the possibility of augmenting Se content in 'Starking Delicious' apple fruit during two growing seasons was investigated. In 2016, the impact of 0, 0.5, 1 and 1.5 mg Se L by foliar application on Se accumulation and fruit ripening as well as quality attributes was investigated. In 2017, the effects of 1.5 mg Se L foliar application on fruit Se content and changes in the antioxidant system and storability were studied with a 30-day interval during 6 months storage at 0 ± 1 °C.

Results: Foliar application of Se significantly increased both leaf and fruit Se concentration. The increase in Se content enhanced the flesh firmness, titrable acidity, and soluble solid content of the fruit. The activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were markedly amplified by Se treatments as compared to the control, resulting in lower superoxide anion radical (O ) and hydrogen peroxide (H O ) contents, correspondingly higher membrane integrity as revealed by lower ion leakage and malondialdehyde accumulation and the fruit with lower water core.

Conclusion: Application of Se was efficient in increasing fruit Se content and nutraceutical properties, retarding the flesh firmness reduction, and postponing fruit ripening resulting from lower ethylene biosynthesis rate, thereby positively affecting apple fruit quality and storability. © 2019 Society of Chemical Industry.