Damir Magdić

Characterization of Bread Wheat Cultivars (Triticum aestivum L.) by Glutenin Proteins

Glutenin polymers composed of HMW and LMW subunits are important contributors to the wheat end-use properties. Twenty-six winter wheat cultivars differing in bread processing quality were collected at the experimental fields of the Agricultural Institute Osijek, Croatia and Institute of the Field and Vegetable Crops Novi Sad, Serbia, in 2008/2009 season. The HMW glutenins composition and glutenin proteins content were determined by SDS-PAGE and RP-HPLC, respectively, with aim to determine the relationship between glutenin protein fractions and wheat quality properties. Significant differences were found between Croatian and Serbian cultivars in several quality attributes (GI, WA, DDT, DS and R/EXT) as well as in the content of total glutenins and LMW glutenins and GLI/GLU ratio. The dominant HMW subunits in analyzed cultivars were 2*, 7 + 9/7 + 8 and 5 + 10. Principal component analysis (PCA) confirmed the presence of association between HMW glutenins composition and GI, dough E, R and R/EXT, while the glutenins quantitative data showed pronounced relation with P, DDT, DS, E, R and R/EXT. GLI/GLU ratio had the opposite effect on these parameters.

The influence of Fusarium infection on wheat (Triticum aestivum L.) proteins distribution and baking quality

Under artificial Fusarium infection the total glutenin content determined by chromatographic (RP-HPLC) method was significantly reduced in comparison to gliadins which were increased. Among protein types, α-GLI and HMW-GS were the highest affected. Artificial Fusarium infection significantly increased GLI/GLU ratio when compared with the natural infected samples. Artificial Fusarium infection dramatically decreased the dough mixing tolerance and had a considerable negative effect on dough energy, maximum resistance, and resistance/extensibility ratio. Disturbed GLI/GLU ratio and an increased amount of mycotoxin DON under artificial Fusarium infection showed a strong negative impact on affected functional properties of dough and bread. Total and γ-GLI as well as GLI/GLU ratio were significantly positively affected by mycotoxin DON in contrast to total GLU, HMW-GS and LMW-GS which were negatively affected. Results indicated that the stability of baking quality parameters of cultivars more tolerance to the Fusarium infection can be well define by lower accumulation of mycotoxin DON.

Benefits and Limitations of Lab-on-a-Chip Method over Reversed-Phase High-Performance Liquid Chromatography Method in Gluten Proteins Evaluation

RP-HPLC (reversed-phase high-performance liquid chromatography) is widely used to determine the amounts of the different gluten protein types. However, this method is time-consuming, especially at early stages of wheat breeding, when large number of samples needs to be analyzed. On the other hand, LoaC (Lab-on-a-Chip) technique has the potential for a fast, reliable, and automatable analysis of proteins. In the present study, benefits and limitations of Lab-on-a-Chip method over RP-HPLC method in gluten proteins evaluation were explored in order to determine in which way LoaC method should be improved in order to make its results more compliant with the results of RP-HPLC method. Strong correlation () was found between numbers of HMW glutenin peaks determined by LoaC and RP-HPLC methods. Significant correlations () were obtained between percentages of HMW and LMW glutenin subunits calculated with regard to total HMW

Prediction of the genetic similarity of wheat and wheat quality by reversed-phase high-performance liquid chromatography and lab-on-chip methods

The aim of this study was to compare efficiency of RP-HPLC (Reversed-Phase High-Performance Liquid Chromatography) and LOC (Lab-on-Chip) methods for wheat gluten protein quantification regarding clustering of wheat cultivars according to the genetic similarity (HMW-GS combinations), as well as to explore relations of these two methods to wheat quality parameters. For that purpose, wheat quality parameters (protein content, falling number, wet gluten content, gluten index, Farinograph, Extensograph, and Amylograph), as well as amounts of gliadin and glutenin fractions by RP-HPLC and LOC methods were determined in two different sets of wheat cultivars (Croatian and Serbian). The percentages of gluten proteins and the values of quality parameters were used to characterize the samples by principal component analysis (PCA). Gluten protein quantification performed by method based on the protein fraction separation by molecular weights (LOC) was better for grouping of genetically similar wheat cultivars than quantification of proteins separated by their different solubility in specified solvent gradient (RP-HPLC). LOC method showed higher potential in wheat quality prediction.