Abiotic stress combinations improve the phenolics profiles and activities of extractable and bound antioxidants from germinated spelt (Triticum spelta L.) seeds

[Display omitted] •Combined stress of 25 mM NaCl and 50 mM sorbitol promoted the accumulation of phenolics.•Mechanical stress increased ROO and decreased DPPH, ABTS+ and O2− scavenging activities of bound antioxidants.•Ferulic, p-coumaric, caffeic and p-hydroxybenzoic acids prevailed among bound antioxidants.•Despite considerable lower content, extractable antioxidants were quite more heterogeneous.•Yeast cells exposed to germinated seed extracts showed no effects on intracellular oxidation. The aim of this study was to investigate the effects of germination of spelt seeds under different stress conditions on the antioxidant characteristics of their extractable and bound phenolics. Germination under combined stress of 25 mM NaCl and 50 mM sorbitol without subsequent mechanical stress had considerable impact on total phenolics contents and scavenging activities against different free radicals (DPPH, ABTS+, O2−, ROO). Alkaline hydrolysis of extracts from germinated seeds provided the majority of their phenolic acids, where ferulic and p-coumaric acids were the most representative. The phenolics liberated from their bound form also had greater antioxidant activities. For the extractable phenolics, p-coumaric hexoside increased the most (146%), while among the bound phenolics identified, the highest relative increase was for p-coumaric acid (171%). The germinated seeds showed no effects on intracellular oxidation in cells of the yeast Saccharomyces cerevisiae.