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  • Author or Editor: G. Šimić x
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β-Glucan content and β-glucanase activity of winter and spring barley cultivars grown under different environments were evaluated. There were significant differences in both β-glucan content and β-glucanase activity between analysed barleys. The results showed that, for all cultivars and locations, approximately 75% of β-glucan present in grains was degraded after malting, and that marked differences existed among winter and spring type of cultivars in malt β-glucan content. The correlation analysis of β-glucan content and malt quality parameters showed that malt β-glucan content was significantly positively correlated with viscosity and extract difference, and negatively with malt β-glucanase activity and friability. Regarding malt β-glucanase activity, significantly higher activity was found in spring cultivars in contrast to winter cultivars.

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Authors: D. Horvat, Z. Jurković, G. Drezner, G. Šimić, D. Novoselović and K. Dvojković

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.

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Authors: A. Torbica, D. Horvat, D. Živančev, M. Belović, G. Šimić, D. Magdić, N. Đukić and K. Dvojković

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.

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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.

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Authors: D. Horvat, N. Ðukić, D. Magdić, J. Mastilović, G. Šimić, A. Torbica and D. Živančev

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.

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Authors: D. Horvat, N. Ðukić, D. Magdić, J. Mastilović, G. Šimić, A. Torbica and D. Živančev
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Authors: G. Šimić, R. Sudar, A. Lalić, Z. Jurković, D. Horvat and D. Babić

The hordein proteins of ten barley ( Hordeum vulgare L.) cultivars grown in region of eastern Croatia were studied for their contribution to the malting quality, particularly relating hordein influence on malt extract yield. The analysis of hordein proteins was carried out by reversed-phase high-performance liquid chromatography (RP-HPLC). The micromalting of investigated barley cultivars and malt analyses were done according to the EBC official methods. The quantitative analysis of hordein proteins has showed that B-hordein was major component, followed by C- and D-hordeins. Among investigated cultivars the malt extract yield varied from 76.8% (cv. Angora) to 82.6% (cv. Scarlett). Spring barleys had on the average higher malt extract yield in contrast to winter barleys. The significant negative correlation between the total hordein content and malt extract yield was found. Among hordein fractions the B-hordein and D-hordein significantly contributed to lower malt extract yield. RP-HPLC analysis of malt hordeins revealed that the amount of hordein degraded during malting significantly correlated with Kolbach index.

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