The effect of irrigation treatments at different development stages on the bioactive components of sunflower cake

Abstract

The aim of the study was to determine the effect of water deficiency at different development stages on the bioactive content and phenolic compounds in sunflower (Helianthus annuus L.) cake, the residue left after oil is extracted from sunflower seeds. A sunflower genotype was randomly planted in a complete block design with eight different combinations of irrigation (T1-T8) by increasing the available soil moisture measured at different plant growth stages (vegetative, flowering and grain formation). Results indicated that the total phenolics of extracts varied between 1.03-2.03 times more than under drought stress (T8). The antioxidant capacity response of seed cake was 14-39% lower than under drought stress. Irrigation treatment, except in the grain formation stage, was found to enhance the biosynthesis of phenolic compounds such as vanillic and caffeic acids. Irrigation only in the grain formation stage induced the accumulation of phenolic compounds such as coumaric acid and rutin hydrate. The present study established that residues resulting from oil extraction could be converted to a polyphenol-enrichment agent for food systems by manipulating the irrigation treatments.

Keywords

• oilseed
• bioactive compound
• drip irrigation, semi-arid region
• climate change, phytonutrients