The present paper is focused on rheology dough properties of winter wheat cultivars in relation to bread crumb properties. The rheological characteristics of wheat fl our were evaluated by using Farinograph and Extensograph tests. The image analysis for bread crumb grain assessment was applied as alternative technique for more rapid and efficient measurement of bread characteristics. The highest significant positive correlation (P<0.05) was found between bread crumb properties and extensographic parameters: dough energy, maximum dough resistance and resistance to extensibility ratio. Cultivars ‘Klara’, ‘Barbara’, ‘Žitarka’ and ‘Golubica’ have shown finer and uniform bread crumbs with regard to optimal dough physicochemical characteristics

Damir Magdić

Daniela Horvat

Georg Drezner

Gordana Šimić

Krešimir Dvojković

English

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9ORIGINAL SCIENTIFIC PAPERSummaryTh e present paper is focused on rheology dough properties of winter wheat cultivars in relation to bread crumb properties. Th e rheological characteristics of wheat fl our were evaluated by using Farinograph and Extensograph tests. Th e image analysis for bread crumb grain assessment was applied as alternative technique for more rapid and effi  cient measurement of bread characteristics. Th e highest signifi cant positive correlation (P<0.05) was found between bread crumb properties and extensographic parameters: dough energy, maximum dough resistance and resistance to extensibility ratio. Cultivars ‘Klara’, ‘Barbara’, ‘Žitarka’ and ‘Golubica’ have shown fi ner and uniform bread crumbs with regard to optimal dough physicochemical characteristics.Key wordsbread; dough rheology; bread crumb properties; image analysisAgriculturae Conspectus Scientifi cus | Vol. 73 (2008) No. 1 (9-12)Th e Relation between Dough Rheology and Bread Crumb Properties in Winter Wheat Daniela HORVAT 1( )Damir MAGDIĆ 2Gordana ŠIMIĆ 1Krešimir DVOJKOVIĆ 1Georg DREZNER 11 Agricultural Institute Osijek, Južno predgrađe 17, 31000 Osijek, Croatia e-mail: daniela.horvat@poljinos.hr2 University of Osijek, Faculty of Food Technology, F. Kuhača 18, 31000 Osijek, CroatiReceived: June 27, 2007 | Accepted: September 3, 2007Agric. conspec. sci. Vol. 73 (2008) No. 110 Daniela HORVAT, Damir MAGDIĆ, Gordana ŠIMIĆ, Krešimir DVOJKOVIĆ, Georg DREZNERIntroductionTh e bread-making quality of wheat is strongly aff ected by gluten characteristics. Suffi  cient expansion and good distribution of the gas cells within dough depend on degree of the gluten strength and extensibility (Veraverbeke and Delcour, 2002; Prabhasankar et al., 2002; Lasztity, 2003). Bread crumbs and their properties depend on wheat cul-tivar, fermentation conditions, baking and storage param-eters (Giovanelli et al., 1997; Magdić et al., 2006; Karaoglu, 2006). Diff erent tests as farinograph, extensograph, alve-ograph and mixograph can be used to provide an assess-ment of gluten quality through determination of physical dough properties. For the evaluation of wheat end use quality the bread crumb properties are certainly one of the most important. In general, the gluten quality is inherent in a genotype and is not greatly aff ected by environmen-tal conditions or cultural practices. In assessment of bread crumb the image analysis has been used as an objective and highly confi dent method (Zayas, 1993; Zghal et al., 1999, 2001; Magdić et al., 2004). For applying image analysis in bread crumb evalua-tion, bread loaves should be correctly sliced and slices must be properly illuminated for obtaining objective results of image analysis. Later image processing is optional and de-pends on a sample area that can be rectangular medium part or total surface of a slice. Finally, main bread crumb attributes can be evaluated by computer programs based on diff erent algorithms (Heijden, 1998; Zghal et al., 1999; Crowley et al., 2002; Gallagher et al., 2003). Material and methodsCultivars ‘Žitarka’, ‘Srpanjka’, ‘Barbara’, ‘Klara’, ‘Golubica’, ‘Kata’, ‘Monika’, ‘Ana’, ‘Demetra’, ‘Divana’ and ‘Sana’ were grown in the experimental fi eld of the Agricultural Institute Osijek in 2001 and 2002. Th e ex-periment was set up as Randomized Complete Block Design (RCBD) with three replications. Cultural practices were as recommended for optimum wheat production in this area. All plots were machine-planted and harvested. Rheological dough properties and bread crumb properties of the eleven cultivars were analyzed on samples pooled over replications.Th e water absorption of fl ours and the mixing behav-iour of dough, made from them, were determined by using Brabender Farinograph (Brabender, Duisburg, Germany) in accordance with HRN ISO 5530-1:1999. Farinogram evaluation was performed using software Brabender Farinograph for Windows ver. 2.3.7. Th e stretching and elas-ticity characteristics of dough were measured by Brabender Extensograph (Brabender, Duisburg, Germany) accord-ing to HRN ISO 5530-2:1999. Extensogram evaluation was automatically performed using soft ware Brabender Extensograph for Windows ver. 2.1.5. All analyses were done in duplicates. Data analysis was performed using SAS Stat Soft ware ver. 8.2. Baking test was done according to ICC No 131. Th is method is applicable for untreated fl our, experimentally or commercially milled from wheat for the production of yeast raised bread. In preparing for quality assessment by image analy-sis, bread loaves were sliced in the middle, providing two cross sections. Slices were properly illuminated (700 lux)    Figure 1. Original image before and after applying the threshold operationby low voltage, halogen, and indirect illumination with four lamps. Images were captured and presented with a surfaces size of 10 x 8 cm (960 pixels per cm2). Th ree loaves were produced from each of ten wheat cultivars and images of each loaf cross-section were recorded as 8-bit bitmap fi le with 256 grey levels. Th e threshold value 128 was chosen as appropriate for all samples. Th e same image processing operations were applied to all records (Fig. 1). Aft er image pre-processing, evaluation of bread crumb appearance was performed. Th e slice crumb analysis was done by calculating the total area of cells (sum of all spots where more than 5 pixels were connected), number of cells bigger than 5 pixels, average cell area, average radius, pe-rimeter, minimum and maximum radius and roundness of crumbs/cells (measure of roundness is in the range be-tween 0 - not round and 1 - perfectly circular). Th e value was calculated as roundness = 4 π total area / perimeter Agric. conspec. sci. Vol. 73 (2008) No. 111The Relation between Dough Rheology and Bread Crumb Properties in Winter Wheatsquared. Th e bread crumb attributes were evaluated by use of Global LabImage Soft ware ver. 2.6. Results and discussion Prominent diff erences among cultivars were found for dough rheological properties as well as for bread crumb characteristics (Table 1 and Figure 2). Farinograph water absorption of the analyzed cultivars varied between 60.0 % for cultivar Ana and 66.7 % for cultivar Golubica. Flour water absorption is favourable genotype character-istic from miller’s and baker’s point of view because the increase of water absorption for 1 or 2 % causes 1 or 2 % higher profi t. Concerning the mixing behaviour of dough, cultivars ‘Divana’ and ‘Golubica’ have shown properties of strong fl our with the longest dough development time (12 min and 5 min, respectively) as well as the lowest degree of soft ening (7 FU and 53 FU, respectively) Th e lowest mixing tolerance index has been shown for the cultivars ‘Kata’, ‘Monika’ and ‘Sana’ with degree of soft ening over 100 FU (Table 1). Regarding the resistance to stretching and elasticity of dough, the maximum height (over 400 EU) and area under the extensogram curve (over 100 cm2) have been shown for the cultivars ‘Srpanjka’, ‘Demetra’, ‘Divana’ and ‘Ana’. Th e cultivars ‘Klara’, ‘Barbara’, ‘Žitarka’ and ‘Golubica’ with medium gluten characteristics, according to both, the farinographic and extensographic properties, had smaller crumbs on slices (12.60-15.32 pixels in total per crumb), while the cultivars ‘Srpanjka’, ‘Ana’, ‘Demetra’ and ‘Divana’ with very strong gluten characteristics had bigger crumbs (17.16-21.07 pixels per crumb) (Table 1 and Figure 2). In our previous dough rheological studies (Jurković et al., 2000; Horvat et al., 2006), the cultivars ‘Srpanjka’, ‘Ana’, ‘Demetra’ and ‘Divana’ have also shown very strong gluten characteristics regarding gluten index value, farinographic and extensographic properties. Th e highest positive correlation (P<0.05) was found be-tween all bread crumb attributes, except roundness, and gluten strength expressed as dough energy (r=0.59-0.84), dough resistance expressed as maximum resistance to ex- Cultivars WAa DDT STA R DS E EXT RMAX R/EXT Žitarka 66.2 3.3 0.7 4.0 87 58 203 206 0.8 Srpanjka 60.8 1.9 2.3 4.2 82 107 176 466 1.8 Barbara 66.5 3.8 1.4 5.2 77 69 193 267 1.0 Klara 64.9 3.1 0.8 3.8 79 76 183 311 1.2 Golubica 66.7 5.4 1.1 6.4 53 79 232 252 0.7 Kata 64.7 3.1 0.2 3.3 102 41 207 146 0.6 Monika 62.7 3.8 0.5 4.2 104 41 156 202 1.0 Ana 60.0 3.4 0.9 4.3 49 114 205 414 1.3 Demetra 60.9 4.2 1.3 5.5 66 129 218 462 1.3 Divana 65.8 12.0 1.7 13.7 7 139 254 422 0.9 Sana 61.7 2.8 0.5 3.3 110 45 192 171 0,7 X  63.7 4.3 1.0 5.5 75 82 202 303 1.0 SD 2.53 2.84 1.03 3.82 30.70 37.27 28.97 123.87 0.38 aWA=Water absorption (%); DDT=Dough development time (min); STA=Stability (min); R=Resistance (min); DS=Degree of softening (FU); E=Dough energy (cm2); EXT=Extensibility (mm); RMAX=Maximum resistance (EU); R/EXT=Resistance to Extensibility ratio Table 1. Mean values of rheological dough properties of analyzed wheat cultivars0510152025ŽitarkaSrpanjkaBarbaraKlaraGolubicaKataMonikaAnaDemetraDivanaSanaArea Radius Perimeter Min Radius Max Radius RoundnessFigure 2. Bread slice image analysis results (all in pixels except Roundness (dimensionless)) for eleven wheat cultivarsAgric. conspec. sci. Vol. 73 (2008) No. 112 Daniela HORVAT, Damir MAGDIĆ, Gordana ŠIMIĆ, Krešimir DVOJKOVIĆ, Georg DREZNERtension (r=0.73-0.89) and dough elasticity expressed as re-sistance to extensibility ratio (r=0.73-0.86) (Table 2), which is in agreement with results of other authors (Scanlon et al., 2000; Zghal et al., 2001).Among farinographic dough properties, the highest positive correlations (P<0.05) were noticed between stabil-ity and area (r=0.59), radius (r=0.64) and minimum radius (r=0.65). Signifi cant negative correlations (P<0.05) were found between water absorption and perimeter (r=-0.60) and maximum radius (r=-0.64), as well as between mini-mum radius and degree of soft ening (r=-0.62) (Table 2).ConclusionsTh e cultivars ‘Klara’, ‘Barbara’, ‘Žitarka’ and ‘Golubica’ have shown the best loaf medium part porosity with op-timal gluten quality regarding analyzed dough and bread crumb parameters. Th e highest positive correlation was found between bread crumbs attributes and gluten strength properties evaluated by extensographic analysis. In accord-ance with the obtained results of dough rheological and bread crumb properties it would be possible to evaluate the cultivars suitability for bread making industry.ReferencesCrowley P., Schober T. J., Clarke, C. I. Arendt, E. K. (2002). Th e eff ect of storage time on textural and crumb grain characteristics of sourdough wheat bread. Eur Food Res Tech 214:489-496Gallagher E., Gormley T. R., Arendt E. K. (2003). Crust and crumb characteristics of gluten free breads. J Food Eng 56:153-161Giovanelli G., Peri C., Borri V. (1997). Eff ects of baking temperature on crumb-staling kinetics. Cereal Chem 74:710-714Global Lab Image/2 ver. 2.6, Data Translation Inc., Marlboro, USAHeijden F. (1998). Image Operations. In: Image Based Measurement Systems (John Wiley & Sons, eds), University of Twente, Th e Netherlands, 69-129Horvat D., Drezner G., Jurković Z., Šimić G., Magdić D., Dvojković K. (2006). Th e importance of high-molecular-weight glutenin subunits for wheat quality evaluation. Poljoprivreda 12:53-57 HRN ISO 5530-1:1999 Fizikalna svojstva 1: Određivanje apsorpcie vode i reoloških svojstava farinografom.HRN ISO 5530-2: 1999 Fizikalna svojstva 2: Određivanje reoloških svojstava ekstenzografom.ICC No. 131: Baking Test for Wheat Flour Jurkovic Z., Sudar R., Drezner G., Horvat D. (2000). Th e HMW glutenin subunit composition of OS wheat cultivars and their relationship with bread-making quality. Cereal Res Comm 28:271-277Karaoglu M. M. (2006). Eff ect of baking procedure and storage on the pasting properties and staling of part-baked and rebaked white pan bread crumb. Int. J Food Prop 9:609-622Lasztity R. (2003). Prediction of Wheat Quality-Succes and Doubts. Periodica politechnica Ser Chem Eng 46:39-49Magdić D., Horvat D., Drezner G., Jurković Z., Šimić G. (2006). Image analysis of bread crumb structure in relation to gluten strength of wheat. Poljoprivreda 12:58-62Magdić D., Horvat D., Baranyai L. (2004). Examination of slice rotation and zoom infl uence on results of bread slice image analysis. In: Ž Ugarčić-Hardi (eds) Proc of International Congress “Flour-Bread’03”, 4th Croatian Congress of Cereal Technologists, Osijek, Croatia, pp 45-249Prabhasankar P., Manohar R. S., Gowda L. R. (2002). Physicochemical and biochemical characterisation of selected wheat cultivars and their correlation to chapati making quality. Eur Food Res Tech 214:131-137SAS System 8.2 Soft ware (SAS Institute Inc. Cary, NC. USA, SAS/STAT User’s Guide 1989)Scanlon M. G., Sapirstein H. D., Fahloul D. (2000). Mechanical properties of bread crumb prepared from fl ours of diff erent dough strength. J Cereal Sci 32:235-243Zayas IY. (1993). Digital image texture analysis for bread crumb grain evaluation. Cer Foods World 38:760-766Veraverbeke W. S., Delcour J. A. (2002). Wheat protein composition and properties of wheat glutenin in relation to breadmaking functionality. Crit Rev Food Sci Nutr 42:179-208Zghal M. C., Scanlon M. G. Sapirstein H. D. (1999). Prediction of bread crumb density by digital image analysis. Cereal Chem 76:734-742 Zghal M. C., Scanlon M. G., Sapirstein H. D. (2001). Eff ects of fl our strength, baking absorption, and processing conditions on the structure and mechanical properties of bread crumb. Cereal Chem. 78:1-7. Parameters WAa DDT STA R DS E EXT RMAX R/EXT Area –0.57 0.03 0.59* 0.18 –0.42 0.64* –0.22 0.78* 0.84* Radius –0.57 –0.01 0.64* 0.14 –0.47 0.70* –0.20 0.83* 0.86* Perimeter –0.60* 0.05 0.48 0.17 –0.42 0.62* –0.23 0.73* 0.78* Min radius –0.33 0.28 0.65* 0.44 –0.62* 0.84* 0.12 0.89* 0.73* Max radius –0.64* –0.06 0.57 0.07 –0.37 0.59* –0.30 0.74* 0.83* Roundness 0.53 0.10 0.08 0.09 –0.01 –0.11 0.30 –0.16 –0.26 aRheological dough properties: WA=Water absorption (%); DDT=Dough development time (min); STA=Stability (min);  R=Resistance (min); DS=Degree of softening (FU); E=Dough energy (cm2); EXT=Extensibility (mm); RMAX=Maximum resistance (EU); R/EXT=Resistance to Extensibility ratio Table 2. Correlation between bread crumb properties and rheological dough properties acs73_02

The Relation between Dough Rheology and Bread Crumb Properties in Winter Wheat

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