The effect of ZnSO4 and KNO3 on quantitative and qualitative properties of Punica granatum L.

Abstract

We investigated the effect of foliar application of potassium nitrate (KNO₃) and zinc sulfate (ZnSO₄) on the fruit quality of pomegranate (Punica granatum L. cv. Malas-E–Torsh in Saveh). Potassium was applied as KNO₃ at concentrations of 0%, 0.25%, and 0.5% and zinc was applied as ZnSO₄ at concentrations of 0%, 0.5%, and 1% in a completely randomized block design. To determine the effect of the treatments on fruit quality, we measured fruit weight, peel thickness, aril diameter, phenol content of the juice, pH, total soluble solids (TSS), titratable acidity (TA), and antioxidant capacity. Foliar application of KNO₃ significantly increased fruit weight, 100 aril weight, peel weight, peel thickness, TTS, and antioxidant capacity. In contrast, pH, TA, TSS/TA, and phenol content of the juice were not influenced by foliar application of KNO₃. ZnSO₄ significantly increased fruit weight, aril diameter, and phenol content of the juice. KNO₃ 1% and ZnSO₄ 0.5% were identified as the most appropriate treatments in improving quality and quantity of pomegranate. The fatty acid profile of the pomegranate oil was primarily composed of punicic acid, linoleic acid, oleic acid, palmitic acid, and stearic acid.