Hearth Bread Characteristics: Effect of Protein Quality, Protein Content, Whole Meal Flour, DATEM, Proving Time, and Their Interactions. Anette Aamodt,1–4 Ellen Merethe Magnus,2 and Ellen Mosleth Færgestad2 ABSTRACT
Cereal Chem. 82(3):290–301
The effects of protein quality, protein content, ingredients, and baking process of flour blends on hearth loaves were studied. The flour blends varied in protein composition and content. Flours of strong protein quality produced hearth loaves with larger loaf volume, larger bread slice area, and higher form ratio (height/width) than flours of weak protein quality. The effect of protein content on hearth loaf depended on the size distribution of the proteins. Increasing protein content was associated with increased percentage of the largest glutenin polymers, and loaf
volume and slice area increased significantly. The form ratio, however, remained unchanged with increasing flour protein content. Strong protein quality flours tolerated addition of whole meal flour better than weak protein quality flours. Increased amount of flour with strong protein quality improved hearth bread characteristics to a larger extent than increased protein content. Diacetyl tartaric acid ester of monoglycerides (DATEM) improved hearth bread characteristics, but the effect was small compared with the effect of protein composition.
The unique ability of wheat to produce viscoelastic dough is mainly due to storage proteins. The viscoelastic character depends both on polymeric proteins (glutenins) that contribute to elasticity of dough, and monomeric proteins (gliadins) that contribute to extensibility (Eliasson 1990; Cornec et al 1994; Khatkhar et al 1995). Studies performed on pan bread have shown positive effects of both protein quality and protein content on loaf volume (Finney and Barmore 1948; Bushuk 1985). Differences in baking quality among cultivars have been related to differences in gluten protein composition and, in particular, to the variability among the high molecular weight glutenin subunits (HMW-GS) (Payne et al 1987; reviewed by Shewry et al 1992; Schofield 1994; Weegels et al 1996). In the study of Aamodt et al (2003), the different effects of increased protein content on form ratio (height/width) were seen for two wheat cultivars. This could be explained in terms of the size distribution of the proteins, as the contrasting effects of protein content were related to different changes in the percentage of unextractable polymeric proteins (%UPP). In other studies, where variability in protein content was obtained by increased nitrogen fertilization, enhanced protein content was associated with greater increase in the amount of monomeric proteins than in the amount of polymeric proteins (Doekes and Wennekes 1982; Gupta et al 1992; Tronsmo et al 2002). Hearth bread is baked without the support of a pan. In contrast to the pan bread loaf, the hearth loaf will expand horizontally as well as vertically during proving. This provides the basis for another important bread characteristic, the form ratio (height/width). The hearth bread baking procedure described by Færgestad et al (2000) using optimal water addition and mixing time and fixed proving time is a good model system to distinguish between the effects of protein quality and protein content (Færgestad et al 2000; Tronsmo et al 2002, 2003a). However, as discussed above, protein content is not a unique concept, and neither is protein quality. Studies of the effects of protein quality and protein content on hearth bread have therefore been performed on different materials to represent different changes related to variability in protein content and protein quality, and to explore what changes are
the most important (Færgestad et al 1999, 2000, 2004; Tronsmo et al 2002, 2003a,b; Berget et al 2003; Aamodt et al 2003, 2004; Uhlen et al 2004). In practice, bread dough commonly consists of ingredients other than flour, water, salt, and yeast. When the other ingredients are added, the requirements of the gluten proteins to expose elasticity and viscosity characteristics may change. The present study also focused on the effects of ingredients and processing on the baking properties of flour differing in protein quality and protein content. Nonendosperm components of whole meal flour and bran interrupt the continuous gluten matrix in dough as revealed by scanning electron microscopy. The crumb structure of the baked bread became coarse and consisted of thick cell walls with physical interruption by the nonendosperm components (Gan et al 1989, 1990). The loss of loaf volume (Pomeranz et al 1977; D’Appolonia and Youngs 1978; Shogren et al 1981; Moder et al 1984) with addition of bran or whole meal flour to wheat dough was mostly due to physical interaction and only to a small extent to biochemical mechanisms (Gan et al 1992). Dough strength decreases with bran addition (Zhang and Moore 1997). Addition of diacetyl tartaric acid ester of monoglycerides (DATEM) increases loaf volume of pan bread baked with whole meal flour or bran (Shogren et al 1981; Moder et al 1984). A synergetic effect was found when ascorbic acid was added together with DATEM (reviewed by Galliard 1986). Studies performed on hearth bread have shown that DATEM improved the area and loaf volume, but variable effects were found on form ratio (height/ width) (Aamodt et al 2003, 2004). The aim of the present study was to investigate the effect of protein quality, protein content, ingredients, baking process, and their interactions on hearth bread.
1 Norwegian
University of Life Science, Department of Chemistry, Biotechnology and Food Science, P.O. Box 5036, N-1432 Ås, Norway. AS – Norwegian Food Research Institute, Osloveien 1, N-1430 Ås, Norway. 3 Current address: TNO Quality of Life, Utrechtsweg 48, P.O. Box 360, 3700 AJ Zeist, The Netherlands. 4 Corresponding author. Phone: +31 (0)30 6944431. Fax: +31 (0)30 6944295. Email:
[email protected] 2 Matforsk
DOI: 10.1094/CC-82-0290 © 2005 AACC International, Inc.
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MATERIALS AND METHODS The wheat material consisted of two cultivars, Bastian and Mjølner, representing strong and weak protein quality, respectively. Bastian contains HMW-GS 5+10 and Mjølner contains HMW-GS 2+12. Two protein levels of each cultivar were used. The wheat was grown in the eastern part of Norway in 2002, collected, and milled at commercial mill (Bühler, capacity of 200 tons/24 hr) at Norgesmøllene (Buvika, Norway). The grain was conditioned for 12 hr to 16% water content. At the mill, the falling number (Standard no. 107, ICC Geneva) was measured before milling. Both white wheat flour and whole meal wheat flour were produced from the two cultivars. The particle size of the whole meal flour was 15% remaining on a 1.110-µm sieve, 45% remaining on a 150-µm sieve, and 40% through a 150-µm sieve with the values
varying ±5%. Ascorbic acid (40 ppm) was added to the flour at the mill. Flour Blends Four white wheat samples (Mjølner at 11.0 and 11.7% protein; Bastian at 10.5 and 13.6% protein) and three whole meal samples (Mjølner at 11.0 and 12.3% protein, and Bastian at 11.1% protein) were milled. From these seven flours, 27 flour blends were made. Table I shows the amount of flour used in the different blends as well as the protein contents for the 27 flour blends. The protein content in blends 5–27 was estimated on the basis of the protein content measured in blends 1–4. The whole meal flour of Bastian at 11.1% protein was used for all blends with Bastian whole meal flour. Four of the white wheat flours (blends 1–4) represent corners in a design and span the largest variation in protein content of the white wheat flour blends (Table I, Fig. 1).
The design of the flour blends can be considered as three levels of strong wheat flour (0 = HMW-GS 2+12; 0.5 = HMW-GS 2+12 and HMW-GS 5+10; and 1 = HMW-GS 5+10); three levels of protein content (1 = low protein content; 2 = medium protein cotent; and 3 = high protein content), and three levels of whole meal flour (0, 30, and 60%). Figure 1A shows the design of the 27 flour blends. Figure 1B shows the protein contents for the different flour blends. The total range in protein content in the 27 flour blends was 10.5–12.4%. Because the high protein content flour of whole meal Bastian was not used, the change in protein content with increased amounts of whole meal flour was reduced from 12.4 to 11.6% for the strong protein quality (protein quality level 1) at high protein content (protein content level 3). For the protein quality 0 at protein level 3, the protein content was increased from 11.7 to 12.1% with increased level of whole meal flour. This is taken into account in the statistical analyses.
Fig. 1. Design with flour blends (A) and protein content (B) indicated. Whole meal flour content: 0–30–60% of flour weight. Protein content: 1= low protein content; 2 = medium protein content; 3 = high protein content. Protein quality: 0 = flour containing HMW-GS 2+12; 0.5 = blend of flour containing HMW-GS 2+12 and 5+10; 1 = flour containing HMW-GS 5+10. 1 = Mjølner low protein content, 2 = Mjølner high protein content, 3 = Bastian low protein content, 4 = Bastian high protein content. TABLE I Flour Qualities (%) in 27 Flour Blends White Wheat Flour Blend No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Mjølner 11.0%
Mjølner 11.7%
Bastian 10.5%
Whole Meal Flour Bastian 13.6%
Mjølner 11.0%
Mjølner 12.3%
Bastian 11.1%
100 100 100 50 50 50
50 25 70
50
50
25
50 25 75 37.5
25 25 12.5 30
70
30 70 35
35 35
35 35
17.5 40
17.5
35 17.5 52.5 26.25
30 30
35 15 15 17.5 17.5 8.75
15 7.5 60
40
10
10
20 10 30 15
60 60
20
20 20
7.5
15 15 30 15
60 40 20
20 20
15
30 30 10 10 5
30 30
15
15
30 30 60 30
Protein in Flour Blend (% db) 11.0 11.7 10.5 12.4 11.4 10.8 12.1 11.5 11.4 11.0 11.9 10.7 12.0 11.5 10.9 11.9 11.4 11.4 11.0 12.1 10.9 11.6 11.6 11.0 11.9 11.3 11.4
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Flour Analysis For the white wheat flours of Mjølner and Bastian at low and high protein content (blends 1–4 in Table I) and the three whole meal flours (Table I), ash content (Approved Method 08-01 AACC International 2000), and protein content, measured by the combustion method (Perkin Elmer 2400 CHN elemental analyzer, N × 5.7) were analyzed. Mixing properties were analyzed for flour blends 1–9 with a Brabender Farinograph (Standard 5530-1; ISO 1978), and the mixing time was also determined when mixing at double speed (126 rpm) (Færgestad et al 2000). Mixograms were recorded in duplicate on a 10-g mixograph for flour blends 1–9 with water addition according to farinograph absorption at 500 BU for each flour. Mixogram data were collected and analyzed by MixSmart software (National Mfg., Lincoln, NE).
Dough Rheology Dough resistance to extension (Rmax) and dough extensibility (Ext) were measured for doughs made from flour blends 1–9 with the SMS/Kieffer dough and gluten extensibility rig (Kieffer et al 1998). Doughs were mixed to optimal development in a 10-g mixograph. The dough rheology experiment was analyzed in a randomized full-factorial design with addition of 0 and 0.45% DATEM and two replicates. The doughs were prepared without salt. Water addition was according to farinograph absorption at 500 BU. Protein Size Distribution The size distribution of the proteins was analyzed by SE-FPLC (ÄKTA FPLC) as described by Tronsmo et al (2002). This method is a sequential extraction method including sonication of the SDSunextractable fraction. Both extracts were analyzed by SE-FPLC. The chromatogram from the SDS-unextractable extraction contains one main peak (F1*), which contains the largest glutenin polymers. The chromatogram from the SDS-extractable extraction contains four main peaks (F1–F4). The relative amount of each fraction was calculated according to the total extracted fraction from the two chromatograms. In addition to each fraction, the ratio of monomeric to polymeric proteins was calculated as (F3+F4)/(F1*+ F1+F2), and the percentage of unextractable polymeric proteins (%UPP) was calculated as [F1*/(F1*+F1)] × 100. Baking Experiment A small-scale (150 g) straight-dough hearth bread baking procedure (Færgestad et al 2000) was used. The doughs were mixed to optimum dough development as determined for blends 1–9 in the farinograph at 126 rpm. The dough development time found for the white wheat flour was used for the corresponding blend with whole meal flour (after evaluation of dough consistency in preliminary study). Water was added according to consistency corresponding to farinograph absorption at 500 BU for both the white wheat flour and whole meal flour blend (after evaluation of dough consistency in preliminary study). Based on flour weight at 14% moisture, 3.5% fat (vegetable fat and oil, A/S Pals, Oslo, Norway), 1.25% NaCl, 1% dry yeast (Saf Instant, S.I. Lesaffre, France) were added to the dough. The dough was rested for 10
Fig. 2. Part of the flour design where ANOVA was performed on the hearth loaf characteristics (letters A–E are used in text).
TABLE II Characteristicsa of Flour and Flour-Water Doughs of Blends 1–9 Flour Blend Mjølner
Protein (%) Ash (%) WA 500 BU (%) MPT (min) MPH (%) MBW8M (%) DDT63rpm (min) DDT126rpm (min) %F1* %F1 %F2 %F3 %F4 Mono/poly %UPP Ext (mm) Rmax (N) Rmax/Ext (N/mm) a
Bastian
1
2
3
4
5
6
7
8
9
11.0 0.63 62.0 3.0 40 7 2.0 2.7 11.4 23.9 8.3 18.6 29.6 1.10 32.3 45.02 0.13 0.0029
11.7 0.71 63.8 3.3 42 11 2.5 3.2 13.8 21.6 8.7 18.0 28.9 1.06 39.0 37.31 0.19 0.0051
10.5 0.73 62.3 5.3 42 12 1.8 4.5 16.5 19.2 8.4 20.4 24.2 1.01 46.3 34.01 0.24 0.0071
12.4 0.71 63.2 6.2 46 14 2.7 5.0 17.9 18.4 8.4 21.8 25.0 1.05 49.3 31.52 0.29 0.0092
11.4 0.67 62.5 4.0 41 13 2.4 2.7 13.0 22.1 8.8 18.2 29.5 1.09 37.1 31.74 0.24 0.0075
10.8 0.68 61.9 5.4 43 11 2.2 3.8 15.3 20.8 8.4 19.3 26.7 1.04 42.3 27.36 0.25 0.0089
12.1 0.71 63.0 4.7 47 14 2.7 3.8 16.0 19.9 7.8 20.4 26.8 1.08 44.6 30.91 0.32 0.010
11.5 0.72 62.9 6.0 46 16 2.4 4.9 17.6 18.9 7.9 21.4 24.7 1.04 48.3 30.74 0.30 0.0097
11.4 0.70 62.8 4.7 45 12 2.4 3.8 16.0 20.4 8.2 19.8 26.9 1.05 44.0 30.63 0.25 0.0083
Protein, protein content (db); Ash, ash content (db); WA 500 BU, water addition according to farinograph absorption at 500 BU; MPT, mixograph peak time; MPH, mixograph peak height; MBW8M, mixograph band width at 8 min; DDT63rpm, dough development time in farinograph operating at 63 rpm; DDT126rpm, dough development time in farinograph operating at 126 rpm. Size-exclusion separation: %F1*, proportion of fraction 1 of SDS-insoluble protein; %F1 to %F4, proportion of fractions 1–4, respectively, of SDS-soluble protein; mono/poly, ratio of monomeric to polymeric proteins = (F3+F4)/(F1*+F1+F2); %UPP, unextractable polymeric proteins = [F1*/(F1*+F1)] × 100. Uniaxial extension: Ext, extensibility; Rmax, resistance to extension; Rmax/Ext, ratio between resistance to extension and extensibility.
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min after mixing in a fermentation cabinet (Lillnord A/S, Odder, Denmark) at 27°C before molding in the extensigraph. The dough was divided into two pieces that were proved for 35 and 45 min, respectively, in a proving cabinet (Lillnord A/S, Odder, Denmark) at 37.5°C and 70% rh. The hearth loaves were baked in a rotating hearth oven equipped with a fan (Bago-line type BEX 1.0, Fjellebroen A/S, Faaborg, Denmark) for 20 min. Live steam was injected during the first 35 sec of baking (1.5L), and the temperature was reduced from 250 to 220°C immediately after the loaves were put
into the oven. The baking experiment followed a split-plot design with three levels of whole meal flour (0, 30, and 60%) and two levels of DATEM (0 and 0.45%) (Danisco, Denmark delivered through Idun, Oslo, Norway) as the main plot, and two proving times within each dough (35 and 45 min) as the subpot. All together, 216 hearth loaves were baked. After cooling to room temperature for 1 hr, the loaves were weighed. The loaf volume was measured (BVM, Tex-Vol Instruments, Höganäs, Sweden). Images of the loaves were taken, and
Fig. 3. Change in ratio between A, monomeric and polymeric proteins (mono/poly); B, percent unextractable polymeric proteins (%UPP); C, resistance to extension (Rmax, N); and D, extensibility (Ext, mm) with increased protein content for flour containing HMW-GS 5+10 and 2+12. TABLE III Mean Values Over Protein Quality and Protein Content for Flour Blends 1–9a
Protein quality (Pq) 0 0.5 1 P Protein content (Pc) 1 2 3 P Pq × Pc P a
(HMW-GS 2+12) (HMW-GS 2+12 / 5+10) (HMW-GS 5+10)
Mono/Poly
%UPP
Rmax (N)
Ext (mm)
Rmax/Ext (N/mm)
1.09 1.05 1.03 **
36 44 48 ***
0.19 0.27 0.28 ***
38.0 29.6 32.1 ***
0.0052 0.0092 0.0087 ***
1.05 1.06 1.06 ns
40 43 45 **
0.21 0.26 0.27 ***
35.5 31.0 33.3 **
0.0063 0.0085 0.0082 ***
*
ns
**
***
*
***, **, * = P < 0.001, < 0.01, and < 0.05, respectively; ns, not significant at 5% level. P, significant level by ANOVA; mono/poly, ratio of monomeric to polymeric proteins = (F3+F4)/(F1*+F1+F2); %UPP, percent unextractable polymeric proteins = [F1*/(F1*+F1)] × 100; Ext, extensibility; Rmax, resistance to extension; Rmax/Ext, ratio of resistance to extension and extensibility. Vol. 82, No. 3, 2005
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area, height, and width were calculated using software Image ProPlus (v. 4.5, Media Cybernetics, Silver Spring, MD). Statistical Analyses Principal component analysis (PCA) using Unscrambler (v. 8.05, CAMO, Oslo, Norway) was performed on the wheat flour characteristics and flour-water dough characteristics for flour blends 1–9. This multivariate technique projects the information in the original variables onto a smaller number of underlying variables called principal components (pc). The pc are bilinear because they are estimates as linear functions of both the original variables and the observations. The pc give the best prediction of the variability in the data (Martens and Martens 2001) in decreased order. The pc build a link between samples and variables by scores and loading. The orientation of the variables along the pc in the loading plot is used to visualize the sample orientation in the score plot. Variables that are oriented close to each other vary in the same way and are highly correlated. Variables oriented along the same pc but in opposite direction are negatively correlated. Variables oriented orthogonally along the pc in the plot are independent. Partial least squares regression (PLSR) (Martens and Næs 1989; Martens and Martens 2001) is a multivariate statistical method belonging to the same family as PCA. PLSR is a method for relating the variations in one or several response variables (x-variables = flour and dough characteristics) to the variations of several predictors (y-variables = hearth loaf characteristics). All variables were weighted to equal variance before analysis. Marten’s uncertainty test, which is cross-validation combined with a modified jack-knifing procedure for bilinear data, was used to determine the optimal number of pc and to identify significant x-variables in predicting the y-variables (Martens and Martens 2000, 2001). The PCA and PLSR methods perform particularly well when there is a large amount of correlation or collinearity among the variables. The PCA and PLSR utilize the intercorrelations and visualize the relationships among variables. Pearson correlation using SYSTAT software (v. 9.01, SPSS, Richmond, VA) was performed in addition to PLSR and PCA to support the interpretation of the correlations. Analysis of variance (ANOVA) was performed on the flour and dough characteristics for flour blends 1–9. The significance level was P < 0.05 if not otherwise stated. Because the protein content of the flour blends
at protein level 3 (high) changed with increasing percentage of whole meal flour added to the blend (Fig. 1), ANOVA was performed on different parts of the design separately to study main effects and interaction effects on hearth bread characteristics. ANOVA was performed as a split-plot, with proving time as a subplot. First, ANOVA was performed on the full design to predict error at main and subplot. The reduced designs where ANOVA was performed are indicated in Fig. 2 (A–E). From part A to C, the effect of protein quality, protein content, DATEM, proving time, and their interactions were studied with whole meal flour added to the blend at 0, 30, and 60%, respectively. In these sections, both protein quality and protein content varied, and their interaction could be studied. From part D, the effect of protein quality, whole meal flour, DATEM, proving time, and their interactions were studied because the protein content was constant in section D. From part E, the effect of protein level, whole meal flour, DATEM, proving time, and their interactions were studied because the protein quality was constant in section E, and protein content was constant within each of the protein levels (1, 2, and 3). For 12 of the samples, there were missing values. For 10 of the samples, missing value estimates for slice area, slice height, and slice width were based on loaf volume, height, and width by BVM analysis of hearth bread of the corresponding baking. For two of the samples, both BVM analysis and photo were missing, so the total means of the variables were used as values for these two bakings. RESULTS AND DISCUSSION Flour and Dough Characteristics for Blends 1–9 Flour and flour-water dough characteristics for flour blends 1–9 are shown in Table II. Wheat materials are often split into two groups based on presence of HMW-GS 5+10 or HMW-GS 2+12 when subjected to PCA and PLSR of flour, gluten, dough, and hearth bread characteristics (Færgestad et al 1999, 2000; Tronsmo et al 2002, 2003a; Aamodt et al 2003,2004). Mjølner flour has weak protein quality (containing HMW-GS 2+12). Bastian flour has strong protein quality (containing HMW-GS 5+10). There was larger variation in protein content for the Bastian flour compared with the Mjølner flour (Table II). Protein content in the white wheat flour of Mjølner increased only 11.0–11.7%, while the protein content in the white wheat flour of Bastian increased 10.5–12.4%.
TABLE IV Variability (%) in x-Variables Used for Prediction and y-Variables Explained by Principal Components (pc) Variables x-Variables Whole meal DATEMa Proving time Protein content Bastian Mjølner F-%ash F-%F1* F-%F1 F-%F2 F-%F4 F-%UPP F-mono/poly D-DDT 63rpm D-DDT 126rpm y-Variables Volume Area Width Height Form ratio a
Definition Flour, dough, and process parameters 60% whole meal 0.45% DATEM 45 min proving time % protein content 100% Bastian 100% Mjølner % ash in flour (db) SDS-unextractable proteins SDS-extractable proteins SDS-extractable proteins SDS-extractable proteins % unextractable polymeric proteins Ratio of monomeric to polymeric proteins Dough development time in farinograph at 63 rpm Dough development time in farinograph at 126 rpm Hearth bread characteristics Loaf volume of hearth bread Area of bread slice Width of bread slice Height of bread slice Form ratio of bread slice (height/width)
Diacetyl tartaric acid esters of monoglycerides.
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pc1
pc1–2
pc1–3
pc1–4
pc1–5
–6 –9 –10 –10 92 92 6 92 90 11 92 92 57 –8 93
67 –17 –7 –16 96 96 24 93 91 1 97 93 60 –16 96
82 –29 56 6 95 95 25 96 94 –9 96 96 58 8 96
81 –44 99 87 96 96 18 98 96 –14 99 98 74 93 95
84 –52 99 86 96 96 89 98 95 8 99 98 71 92 95
32 53 -2 56 50
81 85 28 78 56
83 88 64 87 81
85 88 70 87 82
88 90 70 90 85
The %UPP increased significantly with increased protein content, and the strong protein quality flour (containing HMW-GS 5+10) had higher %UPP than the weak protein quality flour (containing HMW-GS 2+12) (Table III, Fig. 3). Flours containing HMW-GS 2+12 had a higher monomeric-to-polymeric ratio (mono/ poly) of proteins than the flour containing HMW-GS 5+10. There was a significant interaction effect between protein quality and protein content on mono/poly proteins, as the effect of protein content differed for the two flours. For Bastian, mono/poly ratio increased, whereas for Mjølner, the ratio decreased. Notably, changes in the size distribution of the proteins were seen both for the strong protein quality flour and the weak protein quality flour with increased protein content, even though the change in protein content was less for the weak protein quality flour compared with the strong protein quality flour. The present material consisted of samples collected from different locations, similar to the situation within the cereal industry. Environmental effects (soil, fertilization, temperature) have most likely affected the protein composition. The resistance to extension (Rmax) was higher for flour samples containing HMW-GS 5+10 than for flour samples containing HMW-GS 2+12 (Table III, Fig. 3). Rmax increased also with increased protein content. Doughs made from flours containing HMW-GS 5+10 were less extensible than doughs made from flours containing HMW-GS 2+12. Furthermore, the extensibility (Ext) of the doughs decreased with increased protein content when flours were grouped according to HMW-GS 5+10 and 2+12 content. As seen in Fig. 3, the decrease in Ext with increased protein content was greater for the dough made from flour containing HMW-GS 2+12 compared with the dough made from flour containing HMW-GS 5+10. The change in viscoelastic properties of the doughs was associated with changes in %UPP with increased protein quality and increased protein content. The change in monomeric and polymeric proteins had less influence on the rheological properties of the dough measured with the Kieffer-extensibility rig than the change in %UPP. The effect of increased mono/poly ratio for the flour containing HMW-GS 5+10, which often is associated with increased Ext of dough, has probably been reduced because of the increased %UPP with increased protein content. The association between the changes in viscoelastic behavior of the dough and the changes in %UPP is in accordance with the study by Aamodt et al (2003). The PCA loading plot (Fig. 4A) shows how the different flour and flour-water parameters are related to each other along pc1 and pc2. In the corresponding score plot (Fig. 4B), flour blends 1–9 are shown along pc1 and pc2. As much as 79% of the total variability in the data was explained by the first two pc. Flour blends 1, 2, and 5 consisted of Mjølner containing HMW-GS 2+12. Flour blends 3, 4, and 8 consisted of Bastian containing HMW-GS 5+10. Flour blends 6, 7, and 9 consisted of both Mjølner and Bastian (Table I) containing HMW-GS 2+12 and HMWGS 5+10. Flour blends 1, 2, and 5 were located on the right-handside of the score plot, associated with SE-FPLC fractions F-%F1, F-%F2, F-%F4 from SDS-soluble proteins, high level of dough extensibility (D-Ext), and mono/poly ratio (F-mono/poly) as seen in the corresponding loading plot. Flour blends 3, 4, and 8 were located on the left-hand-side of the score plot, associated with percent of unextractable polymeric proteins (F-%UPP), fraction one from SDS-insoluble proteins (F-%F1*), fraction three from SDS-soluble proteins (F-%F3), dough resistance to extension (DRmax), and mixograph peak time (D-MPT) as seen in the corresponding loading plot. High protein content blends were located upwards in the score plot, which corresponds to the location of protein content (F-%protein) as seen in the corresponding loading plot. The flour group containing HMW-GS 5+10 had a larger variation in protein content than the flour group containing HMW-GS 2+12. This is shown by longer distance between samples in the score plot within the group containing HMW-GS 5+10 compared with the distance between samples within the group containing
HMW-GS 2+12. The flour blends containing both HMW-GS 2+12 and HMW-GS 5+10 were localized in the middle of the score plot. The location of the flour blends in the score plot and the position of the variables in the loading plot indicates that when the percentage of cultivar containing HMW-GS 5+10 was increased in the flour blend, %UPP increased, the dough required longer mixing time (D-MPT, D-DDT126rpm) and had increased dough resistance to extension (Rmax). The dough development time in a farinograph operating at 63 rpm (D-DDT63rpm) was correlated with the protein content of the flour (F-%protein) (r = 0.95) and localized together with protein content along the second pc. Flour, Dough, and Hearth Bread Characteristics An overview of the effects of flour quality, dough ingredients, and baking process on hearth bread quality was obtained using multivariate analysis PLSR. The PLSR was performed on the full experimental design. Protein contents measured and estimated for each of the different flour blends were used in the model instead of protein levels 1, 2, and 3. The PLSR model shown in Fig. 5
Fig. 4. Principal component analysis (PCA) of flour and flour-water dough characteristics. Loading plot (A) of variables and score plot (B) of flour samples. Abbreviations: F = measurements on flour; D = measurements on dough; Bastian = flour containing HMW-GS 5+10; Mjølner = flour containing HMW-GS 2+12; %protein = protein content (db); %ash = ash content (db). Size-exclusion analysis: %F1* = proportion of fraction 1 of SDS-insoluble proteins; %F1-%F4 = proportion of fractions 1– 4, respectively, of SDS-soluble proteins; %UPP = percent unextractable polymeric proteins = [F1*/(F1*+F1)] × 100; mon/poly = ratio of monomeric to polymeric proteins = (F3+F4)/(F1*+F1 +F2). Mixing properties: MPT = mixograph peak time; MPH = mixograph peak height; MBW8M = mixograph bandwidth at 8 min; DDT63rpm = dough development time in farinograph operating at 63 rpm; DST63rpm = dough stability time in farinograph operating at 63 rpm; DDT126rpm = dough development time in farinograph operating at 126 rpm; DST 126rpm = dough stability time in farinograph operating at 126 rpm. SMS/Kieffer dough and gluten extensibility rig: Rmax = resistance to extension; Ext = extensibility evaluated as distance to rupture; ARmax/Ext = area under force-distance curve; Rmax/Ext = ratio between resistance to extension and extensibility. Vol. 82, No. 3, 2005
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includes only variables that were significant according to Marten’s uncertainty test in describing variability in hearth bread characteristics. Five significant pc were identified and they accounted for 77% of the variability in the flour and dough characteristics (x-variables) and 85% of the variability in hearth bread characteristics (y-variables). Explained variability of the different x- and y-variables is presented in Table IV. A loading plot of the variables along pc1 and pc2, is given in Fig. 5A and along pc3 and pc4 in Fig. 5B. The corresponding score plot is given in Fig. 5C for pc1 and pc2 and in Fig. 5D for pc3 and pc4. Protein quality, expressed as the relative amount of Bastian (HMW-GS 5+10) vs. Mjølner (HMW-GS 2+12), fractions from SE-FPLC (F-%F1*, F-%F4, %UPP), and dough development time (D-DDT126rpm) were the most important parameters spanning the variability along the first and the most important pc (Fig. 5A, Table IV). Furthermore, the whole meal flour contributed somewhat negatively along the first pc as it was located at the lefthand-side of pc1. The pc2 was largely related to the presence of whole meal flour and to a smaller extent to proving time. The pc3 described effects of both proving time and protein content (F%protein). DATEM did not contribute to the PLSR model shown in Fig. 5 (Table IV). Effect of Protein Quality and Content on Hearth Bread The parameters F-%UPP, F-%F1*, and D-DDT126rpm, which were all located at right-hand-side along the pc1 axis in the loading plot (Fig. 5A), all had higher values for samples containing Bastian than for samples containing Mjølner (Table II). The loaf volume, area, height and width, and form ratio (height/width) characteristics were all located positively along pc1 vs. pc2 (Fig. 5A). The hearth bread characteristics were located at the right-handside along the pc1 axis together with %UPP, %F1*, and DDT126
rpm, which indicates a positive influence of protein quality on the hearth bread characteristics. This is also seen in Table V. The loaf width was less described by pc1 than were the other hearth bread characteristics, shown by closer location to pc2 and poor explanation along pc1 (Table IV). The results presented in Table IV showed no significant effect of protein quality on loaf width. In the loading plot of pc3 vs. pc4 (Fig. 5B), the loaf width was expressed mostly along pc3 but also positively along pc4. In the PLSR loading plot of pc1 and pc2 (Fig. 5A), protein content (F-%protein) was located in the center of the plot together with dough development time determined by a farinograph operated at 63 rpm (D-DDT63rpm). Protein content was expressed in pc3 and pc4 (Table IV). In the PLSR loading plot of pc3 and pc4 (Fig. 5B), protein content was located positively along pc3 and negatively along pc4, together with D-DDT63rpm. Figure 6 shows the effect of protein quality and protein content on the form ratio and area of bread slice. Hearth breads baked from the white wheat flour containing HMW-GS 5+10 had higher form ratio and larger slice area than hearth loaves baked from flour containing HMW-GS 2+12. Form ratio was not significantly affected by protein content, whereas the area of bread slice increased significantly with increased protein content (Table V). Bread baked from flour containing HMW-GS 5+10 had significantly larger loaf volume, area of bread slice, height, and form ratio than breads baked from flour containing HMW-GS 2+12. This can be explained by the higher %UPP in flour containing HMW-GS 5+10, compared with flours containing HMW-GS 2+12. The greater ability of the HMW-GS 5+10, through crosslinking and entanglement, to produce larger glutenin polymers than the HMW-GS 2+12 has been explained by the extra cysteine residue in the Dx5 compared with the Dx2 (Shewry et al 1992; Lafiandra et al 1993; Kasarda 1999; Popineau 2001).
TABLE V Mean Valuesa of Hearth Bread Characteristicsb
a
b
***, **, * = P < 0.001, < 0.01, and < 0.05, respectively; P, significant level; ns, not significant at 5% level. Protein content: 1, low protein content; 2, medium protein content; 3, high protein content. Protein quality: 0, flour containing HMW-GS 2+12; 0.5, flour containing both HMW-GS 2+12 and 5+10; 1, flour containing HMW-GS 5+10. Calculated over 0, 30, and 60% whole meal, respectively; (reduced flour designs A–C in Fig. 2) with significant levels found by ANOVA.
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The higher %UPP in flour containing HMW-GS 5+10 compared with flour containing HMW-GS 2+12 might increase the gas-holding capacity, as well as improve the rheological properties and thereby contribute to larger hearth loaves with better form ratio. The expansion of hearth loaves has been seen in relation to either increased mono/poly ratio (Tronsmo et al 2002) or a change in %UPP (Aamodt et al 2003). In the present study, there was a significant increase in %UPP with increasing protein content, whereas no interaction effect was seen between protein quality and protein content on the mono/poly ratio. The shift in the mono/poly ratio was, however, counteracted by the effect of increased %UPP with increased protein content. The area of the bread slice and the loaf volume were more strongly correlated with the height of the bread (r = 0.97 and 0.78, respectively) than with the width of the bread (r = 0.32 and 0.67, respectively). This indicates that the hearth loaves have expanded more in the vertical direction than in the horizontal direction for the present material. Increased levels of Bastian as well as increased protein content were associated with increased %UPP and increased Rmax (Fig. 3), which probably has contributed to the vertical expansion. In our laboratory, hearth loaf baking trials with different wheat materials showed that the effect of protein content is complex and can be related to changes in size distribution of proteins. The ability of a hearth loaf to retain its shape during proving time depends on the balance between the largest glutenin polymers as well as the balance between monomeric and polymeric proteins.
Effect of Whole Meal Flour In the PLSR loading plot of pc1 and pc2 (Fig. 5A), whole meal flour was located along pc2 in the opposite direction of the hearth bread characteristics. This location indicates a negative influence on the hearth bread characteristics. Loaf volume, area, height, width, and form ratio decreased significantly with increased levels of whole meal flour in the flour blends when analyzed by ANOVA (Tables VI and VII). A decreased width of hearth bread might have a positive influence on the form ratio. The height, however, decreased more than the width, resulting in a net negative influence on the form ratio. Decreased width was also found in the study by Aamodt et al (2004) when bran was included in the recipe. The decreased loaf volume was most likely a result of decreased gas-holding capacity, due to nonendosperm particles disrupting the continuous protein film surrounding the gas cells in the dough (Gan et al 1989, 1990). Significant interaction effects were seen between whole meal flour and proving time on loaf volume, the area of the bread slice, form ratio, and height when ANOVA was performed on the samples from reduced design E in Fig. 2. When ANOVA was performed on reduced design D in Fig. 2, significant interaction effects were seen between whole meal flour and proving time on loaf volume, area of bread slice, and height. With increased percentage of whole meal flour in the dough, the effect of increasing proving time on loaf volume decreased. This is seen in Fig. 7A with a smaller increase in loaf volume with increasing proving time for the hearth loaves baked from flour blends with 60% whole meal compared with hearth breads baked from flour blends
Fig. 5. A and B: PLSR loading plot showing the distribution of x-variables (flour and dough characteristics, ingredients, and processes) and y-variables (hearth bread characteristics). C and D: PLSR score plot showing the distribution of the flour samples. Abbreviations: F = measurements on flour; D = measurements on dough; B = measurements on bread; Bastian = flour containing HMW-GS 5+10; Mjølner = flour containing HMW-GS 2+12; %protein = protein content (db); %ash = ash content (db). Size-exclusion analysis: %F1* = proportion of fraction 1 of SDS-insoluble proteins; %F1-%F4 = proportion of fractions 1–4, respectively, of SDS-soluble proteins; %UPP = percent unextractable polymeric proteins = [F1*/(F1*+F1)] × 100; mono/poly = ratio of monomeric to polymeric proteins = (F3+F4)/(F1*+F1+F2). Mixing properties: DDT63rpm = dough development time in farinograph operating at 63 rpm; DDT126rpm = dough development time in farinograph operating at 126 rpm. Whole meal = whole meal flour added to the flour; Proving time = 45 min of proving time; DATEM = 0.45% diacetyl tartaric acid esters of monoglycerides added to the dough. Hearth bread characteristics: Volume = loaf volume of the bread; Area = area of bread slice; Height = height of bread slice; Width = width of bread slice; Form ratio = height/width; 01–09 = flour blend number; 35 and 45 = 35 and 45 min of proving time. Vol. 82, No. 3, 2005
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with 0% whole meal. The decreased effect of increasing proving time when 60% whole meal flour was added was also seen by nonsignificant effect of proving time on the area of bread slice when 60% whole meal flour was added to the dough (Table V, Fig. 7B). The doughs made from flours containing HMW-GS 5+10 tolerated addition of 60% whole meal better than the doughs made from flours containing HMW-GS 2+12. This was seen as less reduced form ratio for hearth breads baked from flour containing HMW-GS 5+10 than for hearth breads baked from flour containing HMW-GS 2+12 when increasing the whole meal addition from 0 to 60% (Fig. 8) and significant interaction effect between protein quality and whole meal (Table VI). The inter-
action effect between protein content and whole meal flour (Table VII) was only significant for width. This indicates that protein quality was more important than protein content when producing hearth breads containing high levels of whole meal. Effect of DATEM In the PLSR loading plot of pc1 and pc2 and in the loading plot of pc3 and pc4 (Fig. 5A and B), DATEM was located close to the center. Marten’s uncertainty test did, however, include DATEM in the model, although the contribution was small (Fig. 5, Table IV). This indicates a small influence on the hearth bread characteristics compared with protein quality, protein content, whole meal
Fig. 6. Effect of protein content and protein quality on form ratio (A) and area of bread slice (B) with 0% whole meal added to dough. TABLE VI Mean Valuesa of Hearth Bread Characteristics for Protein Level 1b Volume (mL)
Area (cm2)
Form Ratio
Height (cm)
Width (cm)
460 498 525 ***
52 58 63 ***
0.50 0.55 0.60 ***
5.8 6.3 6.9 ***
11.6 11.6 11.5 ns
545 497 442 ***
63 59 51 ***
0.58 0.55 0.51 ***
6.8 6.4 5.7 ***
11.7 11.5 11.4 **
485 503 **
57 59 ***
0.54 0.56 ***
6.2 6.4 ***
11.6 11.5 ns
471 518 ***
57 58 *
0.56 0.53 ***
6.4 6.3 ns
11.3 11.8 ***
* ns * ns *** ns ns ns ns ns ns
ns ns ns ns ** ns ns ns ns ns ns
* ns ns ns ns ns ns ns ns ns ns
ns ns ns ns ** ns ns ns ns ns ns
ns ns ns ns ns ns ns ns ns ns ns
Protein quality (Pq) 0 0.5 1 P Whole meal (%) (w) 0 30 60 P DATEM (%) (D) 0 0.45 P Proving time (min) (Pr) 35 45 P Interaction effects Pq*W Pq*D Pq*Pr W*D W*Pr D*Pr Pq*W*D Pq*W*Pr Pq*D*Pr W*D*Pr Pq*W*D*Pr a
***, **, * = P < 0.001, < 0.01, and < 0.05, respectively; P, significant level; ns, not significant at 5% level. Protein quality: 0, flour containing HMW-GS 2+12; 0.5, flour containing both HMW-GS 2+12 and 5+10; 1, flour containing HMW-GS 5+10. b Calculated over protein level 1 (reduced design D in Fig. 2) with significant levels found by ANOVA. 298
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flour, and proving time. DATEM was located on the same side as the hearth loaf characteristics in the PLSR loading plot of pc1 and pc2, indicating a positive effect. In the ANOVA performed on the different reduced designs (Fig. 2, Tables V–VII), DATEM had a significant effect on loaf volume, area of bread slice, form ratio, and height. All of these hearth bread characteristics increased with addition of 0.45% DATEM, as indicated by increased Rmax with addition of DATEM to the dough. In Table V, we can see that the effect of DATEM on the area of the bread slice and the form ratio were significant when 30 and 60% whole meal was added to the dough, whereas there was no effect of DATEM on hearth loaves baked with white wheat flour. There was, however, no significant interaction effect between DATEM and whole meal flour on the hearth bread characteristics (Tables VI and VII). The effect of DATEM should be considered together with the effect of the other factors in a baking process. In several studies, the effect of DATEM was small compared with the effect of flour quality and proving time (Aamodt et al 2003, 2004). For bakers, the effect of an ingredient has to be evaluated in light of what is accomplished by using the additive. Effect of Proving Time Proving time was located along the second pc in the PLSR loading plot of pc1 and pc2, and along both the third and fourth pc in the loading plot of pc3 vs. pc4 (Fig. 5A and B). Proving time was mostly described along the third pc (Table IV). In the corresponding score plot, there was a grouping of the samples according to proving time with long proving times towards the right and short proving time towards the left of the plot (Fig. 5D). In the PLSR loading plot of pc3 vs. pc4, the hearth bread characteristics were located along an axis from the x-variable proving time. Width and loaf volume were both positively localized along pc3, while the area of bread slice, height, and form ratio were
negatively located along pc3. Form ratio and height were both negatively located along pc4, while area of bread slice was positively located along pc4. The orientation of the hearth loaf characteristics according to proving time indicates that proving time had a large influence on width, loaf volume, and form ratio. The increased expansion of the dough during long proving time was mainly in the horizontal direction, revealed by significantly increased width and nonsignificant change in height (Tables VI and VII) with increased proving time. The area of bread slice was less affected by long proving time than the loaf volume, which corresponds to the larger effect of change in width on the loaf volume compared with the area of bread slice (Færgestad et al 2004). In the PLSR loading plot of pc3 vs. pc4, proving time was located at the same side of pc3 as width, loaf volume, and area of bread slice, indicating a positive effect of proving time on these parameters. The positive effect on size and negative effect on form ratio is in accordance with earlier studies on the effect of increased proving time on hearth bread (Færgestad et al 1999, 2000; Tronsmo et al 2003a; Aamodt et al 2004). The negative effect on form ratio was associated with more flow of the dough than expansion vertically during longer proving times. There was a significant three-factor interaction effect between protein quality, protein content, and proving time on loaf volume (Table V) for the white wheat flour blends, and there was a significant two-factor interaction effect between protein quality and proving time on loaf volume for all flour blends (Tables V and VI). Figure 9 shows the three-factor interaction effect on loaf volume. The loaf volume of hearth loaves baked from flours containing only HMW-GS 5+10 increased more with increased proving time than the loaf volume of hearth loaves baked from flours containing only HMW-GS 2+12. For the hearth loaves baked from the flour blends containing both HMW-GS 2+12 and HMW-GS 5+10, both the low and high protein content flour responded positively to increased proving time, but the flour blend with high protein
TABLE VII Mean Valuesa of Hearth Bread Characteristics for Protein Quality Level 0.5b
Protein content (Pc) 1 2 3 P Whole meal (%) (W) 0 30 60 P DATEM (%) (D) 0 0.45 P Proving time (min) (Pr) 35 45 P Interaction effects Pc*W Pc*D Pc*Pr W*D W*Pr D*Pr Pc*W*D Pc*W*Pr Pc*D*Pr W*D*Pr Pc*W*D*Pr
Volume (mL)
Area (cm2)
Form Ratio
Height (cm)
Width (cm)
498 518 530 ***
58 59 60 *
0.55 0.55 0.56 ns
6.3 6.4 6.5 **
11.6 11.7 11.7 ns
560 524 462 ***
65 60 53 ***
0.59 0.55 0.52 ***
6.9 6.4 5.9 ***
11.8 11.7 11.5 ***
506 525 **
58 60 *
0.54 0.56 **
6.3 6.5 ***
11.6 11.7 ns
486 545 ***
58 60 ***
0.57 0.53 ***
6.4 6.4 ns
11.3 12.0 ***
ns ns * ns *** ns ns ns ns ns ns
ns ns ns ns *** ns ns ns ns ns ns
ns ns ns ns * ns ns ns ns ns ns
ns ns ns ns *** ns ns ns ns ns ns
* ns * ns ns ns ns ns ns ns ns
a
***, **, * = P < 0.001, < 0.01, and < 0.05, respectively; P, significant level; ns, not significant at 5% level. Protein content: 1, low protein content; 2, medium protein content; 3, high protein content. b Calculated over protein quality level 0.5 (reduced design E in Fig. 2) with significant levels found by ANOVA. Vol. 82, No. 3, 2005
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Fig. 7. Interaction effect of whole meal flour and proving time on loaf volume (A) and area of bread slice (B). Proving time: 35 min (O) and 45 min (Q).
Fig. 8. Interaction effect between protein quality and whole meal flour on form ratio (height/width).
Fig. 9. Three-factor interaction effect of protein quality, protein content, and proving time on loaf volume.
content had more of a response than the flour blend with low protein. The doughs made from flours containing HMW-GS 5+10 needed longer proving time to bring out the potential of the flour caused by strong protein quality. This is probably why there was a larger increase in loaf volume for hearth breads baked from flour containing HMW-GS 5+10 vs. those containing HMW-GS 2+12. The protein content had less influence on tolerance for proving time, except for the flour blend containing HMW-GS 2+12 and 5+10.
LITERATURE CITED
CONCLUSIONS The flours containing HMW-GS 5+10 had higher %UPP, higher Rmax, and produced hearth breads with larger loaf volume and higher form ratio compared with the flour containing HMWGS 2+12. %UPP increased with increased protein content. The mono/poly ratio decreased in flour containing HMW-GS 2+12 and increased in flour containing HMW-GS 5+10 with increased protein content. The increase of the %UPP was associated with increased Rmax of the doughs and increased loaf volume and no change in form ratio with increasing protein content. Hearth loaves baked with whole meal flour had reduced loaf volume and form ratio. The influence of whole meal flour was largest for blends of weak protein quality. When increasing the level of strong protein quality flour, the negative effect of whole meal flour was reduced. Long proving time reduced the form ratio and increased the loaf volume of hearth bread. The decrease in loaf volume and form ratio when whole meal flour content was increased from 30 to 60% was largest for hearth loaves proved for 45 min compared with those proved for 35 min. The addition of DATEM to dough did not mask differences in protein quality between the different flour blends, and the effects on hearth bread characteristics were small compared with the effect of flour quality and baking process. ACKNOWLEDGMENTS We thank the bakers John-Tore Syversen and Hans Helge Raae Olsen for skilful performance of the baking experiments. We thank the Norgesmøllene for providing grain and flour used in the present study. The project was supported by the Research Council of Norway (grant no. 133137/130). 300
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AACC International. 2000. Approved Methods of the American Association of Cereal Chemists, 10th Ed. The Association: St. Paul, MN. Aamodt, A., Magnus, E. M., and Færgestad, E. M. 2003. Effect of flour quality, ascorbic acid, and DATEM on dough rheological parameters and hearth loaves characteristics. J. Food Sci. 68:2201-2210. Aamodt, A., Magnus, E. M., and Færgestad, E. M. 2004. Effect of protein quality, protein content, bran addition, DATEM, proving time and their interaction on hearth bread. Cereal Chem. 81:722–734. Berget, I., Aamodt, A., Færgestad, E. M., and Næs, T. 2003. Optimal sorting of raw materials for use in different products. Chemometrics Intelligent Lab. Syst. 67:79-93. Bushuk, W. 1985. Flour proteins: Structure and functionality in dough and bread. Cereal Foods World 30:447-451. Cornec, M., Popineau, Y., and Lefebvre, J. 1994. Characterisation of gluten subfractions by SE-HPLC and dynamic rheological analysis in shear. J. Cereal Sci. 19:131-139. D’Appolonia, B. L., and Youngs, V. L. 1978. Effect of bran and highprotein concentrate from oats on dough properties and bread quality. Cereal Chem. 55:736-743. Doekes, G. J., and Wennekes, L. M. J. 1982. Effect of nitrogen fertilization on quality and composition of wheat flour protein. Cereal Chem. 59:276-278. Eliasson, A.-C. 1990. Rheological properties of cereal proteins. Pages 67111 in: Dough Rheology and Baked Product Texture. H. Faridi and J. M. Faubion, eds. Van Nostrand Reinhold: New York. Færgestad, E. M., Magnus, E. M., Sahlström, S., and Næs, T. 1999. Influence of flour quality and baking process on hearth bread characteristics made using gentle mixing. J. Cereal Sci. 30:61-70. Færgestad, E. M., Molteberg, E. L., and Magnus, E. M. 2000. Interrelationships of protein composition, protein level, baking process and the characteristics of hearth bread and pan bread. J. Cereal Sci. 31:309-320. Færgestad, E. M., Tronsmo, K. M., Aamodt, A., Bjerke, F., Magnus, E. M., Dingstad, G., and Baardseth, P. 2004. The effects of protein size distribution and dough rheology on hearth bread characteristics baked at different processes and scales. J. Food Sci. 69:524-535. Finney, K. F., and Barmore, M. A. 1948. Loaf volume and protein content of hard winter and spring wheats. Cereal Chem. 25:291-312. Galliard, T. 1986. Whole meal flour and baked products: Chemical aspects of functional properties. Pages 199-215 in: Chemistry and Physics of Baking. J. M. V. Blanshard, P. J. Frazier, and T. Galliard, eds. R. Soc Chem.: London.
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[Received June 30, 2004. Accepted January 28, 2005.] APPENDIX DATEM SE-FPLC %F1* %F1-%F4 Mono/poly %UPP WA 500BU DDT63rpm DST63rpm DDT126rpm DST126rpm MPT MPH MBW8M Rmax Ext Rmax/Ext ARmax/Ext Pc 1 2 3 Pq 0 0.5 1 35 45 01–09 Volume Area Height Width Form ratio
Diacetyl tartaric acid esters of monoglycerides Size-exclusion fast protein liquid chromatography Proportion of fraction one of SDS-insoluble proteins Proportion of fraction 1-4, respectively, of SDS-soluble proteins Ratio between monomeric and polymeric proteins = (F3 + F4)/(F1* + F1 + F2) Percent unextractable polymeric proteins = [F1*/(F1* + F1)] × 100 Water absorption according to farinograph absorption at 500 BU Dough development time in farinograph operating at 63 rpm Dough stability time in farinograph operating at 63 rpm Dough development time in farinograph operating at 126 rpm Dough stability time in farinograph operating at 126 rpm Mixograph peak time Mixograph peak height Mixograph band width at 8 min Resistance to extension Extensibility Ratio between resistance to extension and extensibility Area under force-distance curve Protein content Low protein content Medium protein content High protein content Protein quality Flour containing HMW-GS 2+12 Flour containing HMW-GS 2+12 and 5+10 Flour containing HMW-GS 5+10 35 min proving time 45 min proving time Flour blend number Loaf volume of the bread Area of bread slice Height of bread slice Width of bread slice Height/width Vol. 82, No. 3, 2005
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