The aim was to investigate the effects of the cold dehulling of buckwheat seeds on their germination, total phenolic content (TPC), antioxidant activity (AA) and phenolics composition. Cold dehulling had no negative effects on germination rate and resulted in faster rootlet growth compared to hulled seeds. Although the dehulling of the seeds significantly decreased TPC and AA, the germination of dehulled seeds resulted in 1.8-fold and 1.9-fold higher TPC and AA compared to hulled seeds. Liquid chromatography coupled to mass spectrometry identified several phenolic compounds in free and bound forms. Rutin was the major compound in hulled seeds (98 µg/g dry weight), orientin and vitexin in 96-h germinated dehulled seeds (2205, 1869 µg/g dry weight, respectively). During germination, the increases in the major phenolic compounds were around two orders of magnitude, which were greater than the increases for TPC and AA. As well as orientin and vitexin, high levels of other phenolic compounds were detected for dehulled germinated seeds (e.g., isoorientin, rutin; 1402, 967 µg/g dry weight, respectively). These data show that dehulled germinated seeds of buckwheat have great potential for use in functional foods as a dietary source of phenolic compounds with health benefits.

In this study, we investigated the effects of germination on the secondary metabolite composition in spelt grains. Germination significantly increased the content of various metabolites in free and bound forms. Benzoxazinoids were the most important compounds in the free fraction of the 96 h germinated grains (MBOA content as the predominant compound was 277.61 ± 15.29 µg/g DW). The majority of phenolic acids were present in the bound fraction, with trans-ferulic acid as the main component, reaching 753.27 ± 95.87 µg/g DW. The often neglected cis-isomers of phenolic acids accounted for about 20% of the total phenolic acids. High levels of apigenin di-C-glycosides were found in spelt grains, and the schaftoside content was most affected by germination, increasing threefold. The accumulation of secondary metabolites significantly increased the antioxidant activity of germinated spelt. According to the results of this study, the content of most bioactive compounds was highest in spelt grains after 96 h of germination. These data suggest that germinated spelt could potentially be valuable for the production of functional foods.