UPLC–PDA–ESI–MS analysis and TLC–DPPH· activity of wheat varieties

Abstract

Wheat is a major crop, an important component of the human diet and important source of animal fodder in the world. Characterization of phenolic profiles of the leading wheat cultivars is important for new opportunities for breeding and eventual commercial production of value-added cultivars rich in beneficial components. A method using ultra-performance liquid chromatography combined with photodiode-array detector–electrospray ion source–mass spectrometry (UPLC–PDA–ESI–MS) has been developed for determination of phenolic compounds contained in twelve winter and thirteen spring wheat varieties. The antioxidant activity was determined by the thin-layer chromatography–2,2-diphenyl-1-picrylhydrazyl (TLC–DPPH•) test with image processing by means of the ImageJ program. Based on retention time, the mass of deprotonated molecule [M−H]− and ultraviolet (UV) spectra, seven phenolic acids, and twelve flavonoids were identified and quantitated in the 80% aqueous methanol extract of the wheat varieties. The average concentrations of total researched compounds were definitely higher in spring wheat cultivars than in winter ones. Varieties Trappe and Kandela showed the most elevated values of total free phenolic acids. Kandela and Ostka Smolicka had the highest content of flavonoids, and isoorientin was detected as the main phenolic in wheat cultivars. Additionally, a correlation between radical scavenging activity and total phenolic acids content was observed. UPLC combined with PDA–ESI–MS could be applied to complete characterization of natural products (e.g., phenolics) in alcoholic extracts from wheat varieties.