Sugar and Free Amino Acid Contents in Winter Wheat Flour Under Fusarium Head Blight Treatment and Natural Infection

Fusarium head blight (FHB) is one of the most devastating diseases in wheat. Besides its negative impact on grain yield, FHB also negatively influences quality. Changes in sugar and free amino acid content were analyzed in flour from Fusarium-infected and non-infected grains of six wheat varieties differing in Fusarium resistance. The concentrations of sugars and free amino acids were determined using a high-performance liquid chromatography device. In flour from FHB-infected grains, the average total amount of fructose, glucose, maltose, total sugars, and total reducing sugars was significantly increased, compared to non-treated flour from the Tika Taka variety, which was the most FHB-susceptible. The total content of free amino acids in flour from FHB-infected varieties increased in proportion to their susceptibility. In Tika Taka, there was a significant increase in free amino acid content of about 46%, while a significant decrease of 16% was observed in the highly resistant Vulkan variety. A highly significant correlation was established between the degree of FHB susceptibility and the content of aspartic acid, glutamic acid, glutamine and histidine, glycine, alanine, methionine, valine, tryptophan, phenylalanine, leucine, and threonine. Most amino acids had strong positive correlations with each other, but among the sugars, only fructose and glucose content showed a strong positive correlation with specific amino acids that were induced by Fusarium infection. Overall, it can be concluded that FHB-susceptible varieties have a high risk of FHB infection, which results in the hydrolysis of sucrose into fructose and glucose, together with an increase in free amino acids, which deteriorates the quality of wheat.