Karakterizacija albumina i biohemijski aspekti kvaliteta pšenice (Triticum aestivum) / Characterization of albumin and biochemical aspects of wheat quality (Triticum aestivum)

In this dissertation, the influence of variety and microclimatic conditions that prevailed during the two production years on the content and structure of wheat albumins were investigated; characterization of albumins was performed by Lab-on-a-Chip capillary electrophoresis; the proteolytic and α- amylolytic activity, as well as the content of free sulfhydryl and free amino groups were also determined; the rheological properties of dough were estimated using conventional methods for the assessment of flour technological quality and characterization of the final product- bread was performed. One part of the research covered the period of postharvest wheat and flour maturation. Heat stress was characteristic of both production years; however, in 2012, maximum temperatures exceeded 35 °C and the number of days with maximum temperatures above 30 °C was markedly higher than in the 2011 production year. These conditions have caused the changes in the composition and quality of protein and starch in wheat kernels. The albumin content of wheat flour samples from 2012 was significantly lower compared to 2011 production year. Results of proteolytic and amilolytic activities of wheat flour samples from two production years, showed that the values of these indicators were significantly lower for 2012 in relation to the 2011 production year, and that the enzyme activity is primarily varietal characteristic. The content of free sulfhydryl groups of wheat flour samples from the 2012 production year was significantly higher while the content of disulfide bonds was lower than in 2011. The content of free amino groups differed between samples from two production years. Differences in the amount of free amino content were evident between the varieties and between different treatments of gluten incubation. Significant differences between the values of the free amino groups measured after gluten incubation at 37 °C, indicate a different proteolytic activity of tested wheat flour samples. In comparison with the samples from the 2011 production year, samples from 2012 had significantly lower values of specific bread volume. The addition of double amount of its own albumins to the selected samples indicated that the flour samples from 2011 had a deficit of amylolytic enzymes and samples from 2012 had a deficit of proteolytic enzymes for achieving optimal technological quality.