Biochemical properties of pomegranate (Punica granatum L.) juice as influenced by severe water stress

Abstract

This research investigates the influence of two irrigation regimes on juice chemical and biochemical characteristics of eleven Mediterranean pomegranate (Punica granatum L.) cultivars during two consecutive years (2019–2020). Control trees were fully irrigated (FI) at 100% of crop evapotranspiration (ETc), and the stressed ones were subjected to a sustained deficit irrigation (SDI) of 50% ETc. Results showed that water stress effect on juice quality attributes significantly varied depending on genotype with divergent amplitude variations and patterns under each year. There were significant decreases in soluble solids content (TSS), titratable acidity and pH on 8 cultivars. Soluble sugars content showed a significant decrease in 5 cultivars, combined with a decrease in amino acids content (AAC) for 2 cultivars. The SDI treatment decreased phenolic compounds content in 8 cultivars, with an often significant effect on anthocyanins content, thereby reducing the antioxidant activity level. According to principal component analysis, variations in TSS and AAC were the most discriminating changes induced by water stress applied over all studied cultivars. Overall, this study showed that SDI often leads to produce pomegranate juice with lower quality. However, the significant genotypic differences herein revealed suggest to move forward with in-depth analyzes to select resilient genotypes to cope with the climate change, particularly in arid lands.