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Field trials were conducted to evaluate the effect of nitrogen level on wheat protein content and composition in 16 cultivars over two years at three locations. The nitrogen treatment comprised two nitrogen levels, 0 kg ha−1 as low and 100 kg ha−1 as high nitrogen, applied as top dressings of 50 kg nitrogen per ha at tillering and stem extension growth stages. Increased nitrogen level generally enhanced grain protein by 11.3% (11.5% vs. 12.8%). Considering protein composition determined by reversed phase–high-pressure liquid chromatography, higher nitrogen supply generally enhanced the proportion of total gliadins, α-gliadins, γ-gliadins and high-molecular-weight glutenin subunits by 1.1%, 2.0%, 3.7%, 0.6% and 0.9%, respectively, and reduced albumins and globulins, ω-gliadins, total glutenins and low-molecular-weight glutenin subunits by 1.1%, 1.7%, 1.9% and 3.2%. Under a high nitrogen level, the historical cultivars Libellula, San Pastore and U-1 had a higher protein content (13.1–15.2%) with significantly higher total gliadins, which resulted in a significantly higher gliadin/glutenin ratio (1.68–1.92). In the modern cultivars, protein content varied between 11.4% and 14.6% with a well-balanced gliadin/glutenin ratio (1.08–1.50), except for cultivar MV Nemere which had a high gliadin/glutenin ratio at both nitrogen levels (1.81 vs. 1.87). In summary, increasing nitrogen level enhanced grain protein content while the composition of gliadin and glutenin fractions was changed to a lesser extent and was largely cultivar specific and therefore should be considered for wheat baking quality assessment and breeding purposes.

Phenolic acids (PAs) are a dominant group of phenolic compounds in cereals, existing mostly bound to compounds of cell wall. In this study, a total of 25 cereal grain samples, including wheat, winter and spring barley, corn, and popcorn, were evaluated for bound PAs and antioxidant activity in a two-year field trial. The PA contents, determined by HPLC, were significantly affected by cereal type. The mean total PA content was highest in popcorn and corn (3298 and 2213 &mu, g/gdm, respectively), followed by winter and spring barley (991 and 908 &mu, g/gdm, respectively) and wheat (604 &mu, g/gdm). Ferulic acid was the most abundant, accounting from 62% to 83% of total PAs (in popcorn and winter and spring barley, respectively). Across cereals, p-coumaric (35&ndash, 259 &mu, g/gdm) and p-hidroxybenzoic (45&ndash, 79 &mu, g/gdm) were also dominant, while in corn and popcorn o-coumaric (71 and 89 &mu, g/gdm, respectively) also occurred in higher content. The mean total phenol content ranged from 853 &mu, g GAE/gdm (wheat) to 1403 &mu, g GAE/gdm (winter barley) with DPPH scavenging activity from 14% to 67%, respectively. A significant influence of crop years on the ferulic acid and total PA content was found, while the variability of other PAs was dependent on the cereal type. The results indicated a high health benefit potential of selected cereals.

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 crude protein and protein components of fourteen commercial bread wheat cultivars grown in Eastern Croatia over two years and three locations were evaluated. Protein components were measured by reversed phase – high pressure liquid chromatography. A dominant effect of genotypes was obtained for the proportion of albumins and globulins, γ- gliadins and total glutenins, while year had a more pronounced impact on crude protein, total gliadins and high molecular weights and low molecular weights glutenin subunits. Locations had the strongest influence on total extracted proteins. Variability of gliadins to glutenins ratio was at the same extent influenced by the genotype and the year. Among interactions, genotype x year and year x location had the highest impact on evaluated proteins. The principal component analysis showed that wheat cultivars were differentiated according to variability of grain protein components. Considering the significant impact of proteins on the wheat bread-making quality, cultivar classification by protein components significantly contributes to the improvement of breeding program towards the creation of high quality cultivars. Keywords: wheat, protein components, environments, RP-HPLC

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, a-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 g-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.

The end-use quality of ten winter wheat cultivars was evaluated during the two years period 2004 and 2005 and through multi location trials. A better end-use quality of cultivars was noticed in 2004 compared with 2005. The highest protein, sedimentation value and wet gluten were realized at location Nova Gradiška, while at location Osijek the highest falling number and the highest grain hardness were found. The best flour yield was noticed at location Tovarnik and Nova Gradiška. A lack of protein with the smallest wet gluten production capacity was shown at location Požega, however at this location, as well as at location Osijek, the highest gluten index was noticed. The better mixing tolerance, regarding the degree of softening, was obtained at location Osijek and Nova Gradiška, while the best dough stretching and elasticity properties were obtained at location Osijek. Based on the average values, cultivar Golubica showed the optimal values for the most indirect quality traits. Concerning the mixing behaviour of dough, cultivars Golubica, Zrnka and Janica had the highest farinograph quality number, while cultivars Srpanjka and Alka had the lowest degree of softening. Cultivars Srpanjka and Demetra showed the best dough stretching and elasticity properties., Namjenska kakvoća deset kultivara ozime pšenice je analiziran tijekom dvije 2004. i 2005. godine na višelokacijskom pokusu. U 2004. godini kultivari su na razini prosječnih vrijednosti ostvarili bolju namjensku kakvoću u usporedbi s 2005. Najveće vrijednosti proteina, sedimentacijske vrijednosti i vlažnog glutena ostvarene su na lokaciji Nova Gradiška, dok su na lokaciji Osijeku dobivene najveće vrijednosti broja padanja i tvrdoće zrna. Najbolje izbrašnjavanje je zabilježeno na lokaciji Tovarnik. Lokacija Požega je imala najniži udio proteina s najmanjim kapacitetom produkcije vlažnog glutena, međutim na ovoj lokaciji kao i na lokaciji Osijek ostvarena je najveća vrijednost gluten indeksa. Bolja tolerancija na zamjes, obzirom na stupanj omekšanja tijesta, o stvarena j e n a l okaciji O sijek i N ova G radiška, d ok s u n ajveći o tpor n a rastezanje tijesta i najbolja elastičnost tijesta, obzirom na energiju i maksimalni otpor, ostvareni na lokaciji Osijek. Sveukupno, kultivar Golubica je imao najbolje vrijednosti za većinu indirektnih pokazatelja kakvoće. Promatrajući svojstva tijesta pri zamjesu, kultivari Golubica, Zrnka i Janica su imali najveći farinografski broj kakvoće, dok su najmanji stupanj omekšanja tijesta imali kultivari Srpanjka i Alka. Što se tiče otpora tijesta na rastezanje i svojstva elastičnosti, najbolja svojstva su ostvarili kultivari Srpanjka i Demetra.

Wheat consists mixture of 20 amino acids which are determining specific traits of proteins. Amino acids have specificity according to metabolic transformation and participation in biosynthesis of important organic constituents. It is typical to relate the protein quality to the balance of structure of essential amino acids contained within. Contents of amino acids were analyzed in 15 genotypes of Triticum aestivum L. (G 3001, G-3046, G-3044, G-3601, G-3590, G-3034, G-3040, G-3614, G-3626, G-3627, G-3662, G-3089, G-3619, G-3607, G-3606). Presence of free amino acids was analyzed by chromatography and their concentration was analyzed by spectrophotometer. Variability of amino acid composition was established. The glutamine acid is present in higher concentration in comparison to remain amino acids registered in analyzed wheat genotypes. Considering to wheat importance as human food, it is very important presence of essential amino acids, out of which the amino acid valine is prevalent. Total concentration of free amino acids in seeds of wheat lines Triticum aestivum varied in ratio from 6.2% (G-3606) to 13% (G-3619).

Glutenin is a group of polymeric gluten proteins. Glutenin molecules consist of glutenin subunits linked together with disulphide bonds and having higher (HMM-GS) and lower (LMM-GS) molecular mass. The main objective of this study is the evaluation of the influence of HMM-GS on flour processing properties. Seven bread wheat genotypes with contrasting quality attributes and different HMM-GS composition were analyzed during three years. The composition and quantity of HMM-GS were determined by SDS-PAGE and RP-HPLC, respectively. The quality diversity among genotypes was estimated by the analysis of wheat grain, and flour and bread quality parameters. The presence of HMM glutenin subunits 1 and 2* at Glu-A1 and the subunits 5+10 at Glu-D1 loci, as well as a higher proportion of total HMM-GS, had a positive effect on wheat quality. Cluster analysis of the three groups of data (genotype and HMM-GS, flour and bread quality, and dough rheology) yielded the same hierarchical structure for the first top three levels, and similarity of the corresponding dendrograms was proved by the principal eigenvalues of the corresponding Euclidian distance matrices. The obtained similarity in classification based on essentially different types of measurements reflects strong natural association between genetic data, product quality and physical properties. Principal component analysis (PCA) was applied to effectively reduce large data set into lower dimensions of latent variables amenable for the analysis. PCA analysis of the total set of data (15 variables) revealed a very strong interrelationship between the variables. The first three PCA components accounted for 96 % of the total variance, which was significant to the level of 0.05 and was considered as the level of experimental error. These data imply that the quality of wheat cultivars can be contributed to HMM-GS data and should be taken into account in breeding programs assisted by computer models with the aim to improve flour technological quality., Glutenini su skupina polimernih bjelančevina glutena. Gluteninske molekule sadrže podjedinice međusobno povezane disulfidnim vezama. Gluteninske podjedinice imaju višu (HMM-GS) i nižu (LMM-GS) molekularnu masu. Glavna je svrha rada bila procijeniti utjecaj HMM-GS na tehnološka svojstva brašna. Tijekom tri godine analizirano je sedam genotipova krušne pšenice čija je kakvoća različita kao i sastav HMM-GS. Sastav i količina HMM-GS određeni su SDS-PAGE elektroforezom i RP-HPLC-om. Razlika u kvaliteti genotipova pšenice procijenjena je analiziranjem parametara kakvoće zrna pšenice, brašna i kruha. Prisutnost HMM podjedinica glutenina 1 i 2* na Glu-A1 i podjedinica 5+10 na Glu-D1 lokusu, a i veći udio HMM-GS, pozitivno utječu na kakvoću pšenice. Klaster analizom tri skupine podataka (genotip-HMM-GS, brašno i svojstva kruha, te reologija tijesta) dobivena je ista hijerarhijska struktura za prve tri glavne razine, a sličnost pratećih dendograma objašnjena je definiranjem glavnih svojstvenih vrijednosti (engl. principal eigenvalues) preko odgovarajućih Euklidova matrica udaljenosti. Vrlo slična klasifikacija genotipova i parametara kakvoće ostvarena je bitno različitim tipovima mjerenja, što odražava jaku prirodnu povezanost između gena, kakvoće proizvoda i fizikalnih svojstava sirovine. Analizom glavnih komponenata (PCA), veliki skup podataka smanjuje se na manji broj međusobno relativno nezavisnih novih varijabla pogodnih za daljnju analizu. PCA analiza ukupnoga seta podataka (15 varijabla) upućuje na vrlo jaku međupovezanost varijabla. Na razini značajnosti p=0,05, prve dvije PCA komponente objašnjavaju 96 % ukupne varijance. Primjenom kemometrijske analize dobiveni su podaci koji upućuju na važan doprinos HMM-GS u definiranju kakvoće pšenice, što treba uzeti u obzir u procesu stvaranja novih genotipova pšenice poboljšanih tehnoloških značajka.

Background and Purpose: The objective of this study was to estimate the effect of high molecularweight glutenin subunits(HMW-GS) composition of the Glu-1 loci on the quality of winter wheat cultivars created at the Agricultural Institute Osijek. Materials and Methods: Ten winter wheat cultivars were grown in 4 different locations during two years in a randomized complete block (RCB) experimental design with three repetitions at each location. Samples were collected and subjected to quality analysis and determination of HMW-GS composition by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Results: Considering theHMW-GS composition, the most frequent subunit at the Glu-A1 locus was N, at the Glu-B1 locus 7+9 and at the Glu-D1 locus 2+12. The analyzed cultivar Demetra, with subunits 5+10 at the Glu-D1 locus, has shown the best bread-making quality. Among cultivars with subunits 2+12 at the Glu-D1 locus, the cultivars with subunits 7+8 at the Glu-B1 locus have shown on average better characteristics of gluten strength with regard to higher values of Gluten Index and resistance to exstensibility ratio (R/Ext). The results of the linear correlation between quality parameters and HMW-GS composition, expressed as the Glu-1 score, have shown the most significant (P

Bjelančevine pšenice u značajnoj mjeri utječu na tehnološke karakteristike brašna. Cilj istraživanja bio je ispitati utjecaj albumina i globulina na pekarsku kakvoću pšenice primjenom visokotlačne tekućinske kromatografije obrnutih faza (RP-HPLC). U radu je ispitano 15 kultivara ozime pšenice uzgojenih na Poljoprivrednom institutu Osijek. Pekarska kakvoća ispitivanih kultivara definirana je određivanjem indirektnih parametara kakvoće i reoloških svojstava tijesta. Rezultati istraživanja ukazuju na značajnu negativnu korelaciju između albumina, globulina i sedimentacijske vrijednosti, indeksa glutena, stabilnosti, energije tijesta, otpora i omjera otpora i rastezljivosti., Wheat proteins mainly determine the technological properties of wheat flour. The aim of the study was to determine the relative quantity of albumins and globulins in wheat cultivars and their contribution to bread-making quality by Reversed Phase High Pressure Liquid Chromatography (RP-HPLC). Investigations were carried out on 15 wheat cultivars growing at the Agriculture Institute Osijek. The bread-making quality of wheat cultivars was defined by indirect quality parameters and rheological properties of flour. The negative linear correlation was observed between albumins and globulins content of and sedimentation value, gluten index, dough stability, dough energy, resistance and resistance to extension ratio.

The gluten proteins of 15 winter wheat cultivars grown in eastern Croatia were studied for their contribution to the bread-making quality. Composition of high-molecular-weight glutenin subunits (HMW-GS) was analyzed by SDS-PAGE, while the quantity of gluten proteins was determined by combined extraction/RP-HPLC procedure. The results of the linear correlation analysis carried out on the particular gluten proteins and technological properties showed that the amount of total gluten content highly correlates with protein content. Among gluten proteins, the glutenins showed higher correlation with protein content, with pronounced influence of HMW-GS, than gliadins. Wet gluten content was significantly correlated to total gliadin quantity. Gluten index as gluten quality parameter was positively influenced by total glutenins and low-molecular-weight glutenin subunits (LMW-GS), and negatively, by the ratios of gliadin to glutenin (Gli/Glu), whereas the amount of gliadins was not important. Dough development time was strongly correlated with total gluten content, total glutenins and the Gli/Glu ratio. Dough mixing resistance was strongly affected by total glutenin content with pronounced influence of HMW-GS. Degree of dough softening is mainly negative influenced by total glutenins and ratio of Gli/Glu. Farinograph quality number as flour quality index was highly positively correlated with total glutenins, with emphasized influence of HMW-GS. The Gli/Glu ratio had the highest influence on dough maximum resistance. Dough extensibility showed moderate correlation with total gliadins. The results of the linear correlation indicated that loaves volumes were significantly influenced by total gluten proteins, HMW-GS and LMW-GS.