Effect of glutenin subunits on the baking quality of Brazilian wheat genotypes

ABSTRACT

This study aimed to evaluate the effect of the high and low molecular weight glutenin subunits on the grain traits of sixteen Brazilian wheat genotypes. Grain hardness index, milling traits, physicochemical and rheological properties of the flour, and specific volume and firmness of the bread were evaluated. Physicochemical properties of the flour were not influenced by glutenin subunits. Genotypes with subunits at the Glu-B1 (17+18 or 7+8), Glu-D1 (5+10), and Glu-A3 (b) were associated with strong flours and bread with high specific volume and low firmness. The subunits at the Glu-A1 and Glu-B3 had no effect on the rheological properties of the dough and bread quality, while the subunit 2+12 at Glu-D1 negatively affected the resistance to extension, and specific volume and firmness of the bread. Specific volume and firmness of the bread were influenced by the rheological properties of the dough, while the flour protein content was not important to define wheat quality. The identification of glutenin subunits at different loci along with the rheological tests of the flour are fundamental in estimating the potential use of different materials developed in wheat breeding.

Key words
high and low molecular weight glutenin subunits; rheology; baking

INTRODUCTION

The wheat storage proteins (gliadin and glutenin) are the main components of gluten and determine the technological characteristics of different bakery products (Li et al. 2010). Glutenin can be separated into high-molecular-weight (HMW-GS) and low-molecular-weight (LMW-GS) subunits. HMW-GS are encoded by Glu-A1, Glu-B1, and Glu-D1 loci on the long arms of chromosomes 1A, 1B, and 1D, respectively, while LMW-GS are encoded by Glu-A3, Glu-B3, and Glu-D3 loci on the short arms of chromosomes 1A, 1B, and 1D, respectively (Payne et al. 1987). It has been noted that allelic differences in the composition of HMW-GS and LMW-GS induce changes in the structure and properties of the glutenin polymers and, consequently, the baking quality (Payne et al. 1987; Shewry et al. 2003). The wheat genes that encode HMW-GS constitute 5 to 10% of the grain storage proteins and are related to the strength and elasticity of the dough (Shewry et al. 2003; Blechl and Vensel 2013).

Several studies have reported the effect of HMW-GS on the wheat quality characteristics. The Glu-D1 locus has been reported as the one that has the greatest effect on the rheological properties and baking quality of the flour. The 5+10 alleles at this locus have been associated with flours with more suitable viscoelastic properties for bread making and that also result in bread with higher volume (Payne et al. 1987; Luo et al. 2001; Liang et al. 2010; Li et al. 2010; Hernández et al. 2012; Blechl and Vensel 2013). Vázquez et al. (2012) reported that 1 and 2* alleles at Glu-A1 are also associated with greater gluten strength and good baking quality, while Peña et al. (2005) found that 17+18 and 7+8 alleles at Glu-B1 are also associated with high bread volume, especially the 17 allele, which has a positive effect on the rheological properties of the flour.

For the LMW-GS, several authors have observed that Glu-A3d, Glu-B3b and Glu-B3g subunits also stand out for their positive effect on baking quality (Luo et al. 2001; Branlard et al. 2003; Liang et al. 2010). In breeding programs, these subunits would also be desirable when selecting wheat with high gluten strength.

At the early stages of the breeding programs, rapid and specific tests (sedimentation volume, sedimentation index, and gluten protein subunits) are used to evaluate the physicochemical and genetic characteristics of wheat. However, a better characterization of wheat flour is achieved by evaluating the visco-elastic properties of the dough.

The effect of HMW-GS and LMW-GS on the grain physicochemical characteristics of the 16 Brazilian wheat genotypes was evaluated in a previous study (Costa et al. 2013). Among the genotypes evaluated those that had subunits 1 at Glu-A1, 5+10 at Glu-D1, c at Glu-A3, and b or g at Glu-B3 stood out from the others because they resulted in a superior grain quality for bread making. Generally, these subunits are preferred in breeding programs for developing new materials with adequate gluten strength and extensibility for bread. The aim of this study was to evaluate the effect of the high and low molecular weight glutenin subunits on the physicochemical wheat grain traits, the rheological characteristics and the baking quality of the flour for 16 Brazilian wheat genotypes.

MATERIAL AND METHODS

Four wheat cultivars (IAPAR 78, IPR 85, IPR 130, and IPR Catuara TM) and 12 advanced lines (LD 101108, T 081099, T 091006, T 091008, T 091015, T 091027, T 091028, T 091031, T 091033, T 091056, T 091069, and T 091088) from the 2010 harvest obtained from cross blocks from the experimental station at the Paraná Agricultural Institute (IAPAR) in Londrina, Paraná, Brazil, were used. Each experimental plot consisted of 5 rows each 6 m long and with 0.17 m between rows, giving a total area of 5.1 m². Granular fertilizer (350 kg∙ha⁻¹, N-P-K, 04-30-10) was used at sowing. Controls for pests, diseases and weeds were performed when necessary. The harvest was carried out when the grains reached physiological maturity (stage 11.4, Feekes scale) and the grains were stored at 13% moisture content. For the laboratory experiment, 6 kg of grains of each material were separated and stored in a cold chamber at 4 °C until the moment of use.

The identification of HMW-GS and LMW-GS in these same genotypes has been performed and described previously (Costa et al. 2013). In HMW-GS, 4 allelic variations were observed at Glu-A1 [subunits 2* (43.8%), 1 (37.5%), Null (12.5%), and 1/2* (6.2%)], 5 at Glu-B1 [subunits 7+9 (50.0%), 7+8 (37.5%), and 17+18 (12.5%)], and 4 at Glu-D1 [subunits 5+10 (81.3%), 2+12 (18.7%)]. In LMW-GS, 3 allelic variations were observed at Glu-A3 [c (56.3%), d (25.0%), and b (18.7%]) and 5 at Glu-B3 [b (33.3%), h (25.0%), e (16.7), f (16.7%), and g (8.3%)]. The 1B/1R translocation was found to be present in the T 091099, T 091033, and T 091056 lines, as well as in the IAPAR 78 cultivar. The total score of the genotypes, calculated based on the identification of HMW-GS (Payne et al. 1987), varied between 5 and 10.

Grain hardness index and wheat milling

The grain hardness index was analyzed using the Single Kernel Characterization System (model 4100, Perten Instruments, Hägersten, Sweden) according to the Approved Method 55-31 of the American Association of Cereal Chemists (AACC 2000). All dockage was removed from the samples using a seed cleaner and 20 g of seed was used for analysis. The moisture content of the grains ranged from 9.3 to 10.6%. Grain hardness was classified from extra hard to extra soft (AACC 2000).

Grains were conditioned for 16 h until reaching 16% moisture and milled in a Chopin mill (model CD1, Chopin Technologies, Villeneuve-la-Garenne, France) following the manufacturer instructions. The flour yield was calculated according to the AACC method 26-10 (AACC 2000).

Physicochemical and rheological characterization of the flour

The protein content (N% × 5.7) was evaluated using the Kjeldahl method according to the AACC method 46-30 (AACC 2000) and damaged starch content was determined using the Chopin SDmatic (Chopin Technologies, Villeneuve-la-Garenne, France) according to the AACC method 76-33 (AACC 2000).

The CIELAB system was used to determine the flour color using a colorimeter (Chromo Meter CR-400, Konica Minolta, Tokyo, Japan). The equipment was calibrated with the standard provided by the manufacturer and adjusted for measuring the luminosity (L*) and the chromatic components green/red (a*) and blue/yellow (b*).

The solvent retention capacity (SRC) test was performed according to the AACC method 56-11 (AACC 2000). Samples of 5 g of wheat flour were suspended in 25 g of 5% sodium carbonate (Na₂CO₃) solution, 25 g of 50% sucrose (C₁₂H₂₂O₁₁) solution, and 25 g of 5% lactic acid (C₃H₆O₃) solution. The samples were stirred for 25 min and centrifuged at 1,000 g for 15 min. The precipitates were weighed and the SRC was calculated as the sum of the precipitate weight less the original flour weight divided by the original flour weight multiplied by 100. Units were expressed as %.

Farinograph analysis was performed using a 300 g (14% moisture basis) Farinograph (Brabender OHG, Duisburg, Germany) according to the AACC method 54-21 (AACC 2000). The water absorption rate (%), dough development time (min), dough stability (min), and mixing tolerance index (Brabender units — BU) were determined. Extensograph analysis was performed using an Extensograph (Brabender OHG, Duisburg, Germany) according to the AACC method 54-10 (AACC 2000). The dough resistance to constant deformation after 50 mm stretching (BU), extensibility (mm), and maximum resistance (BU) were determined at 45, 90, and 135 min.

Bread making

Bread dough was formulated with the following ingredients: dry yeast (Saccharomyces cerevisae) (2%), salt (1.5%), sugar (4%), hydrogenated vegetable fat (3%) and water (60%) following the procedure described by Oliveira et al. (2014). The weight of ingredients was based on the weight of the flour. Flour, sugar and fat were mixed for 1 min in a planetary mixer (model BP-12SL, Lieme, Caxias do Sul, Brazil). Yeast and most of the water (90%) were then added to the dough and mixed for 1 min. Finally, the salt diluted with the remaining water was added to the dough, mixed for approximately 15 min for gluten development. The dough was left to set for 15 min at 32 °C and 80% relative humidity, divided into 100 g portions and then left to set for another 15 min before being rolled and mechanically shaped (MQ, Universo, São Paulo, Brazil) and placed in baking pans (15 × 8 cm). The dough was then proofed at 32 °C for 1 h and baked at 180 °C in an industrial oven (Pasiani, Itajobi, Brazil) for 15 min. After baking, the loaves were cooled for 2 h at room temperature before analysis.

The bread volume was measured using rapeseed displacement according to the AACC method 10-05 (AACC 2000). The specific volume of the bread was calculated as the ratio between the volume and the weight of the bread (cm³∙g⁻¹). Six replicates of each sample were analyzed. Bread crumb firmness was determined using a Texture Analyzer (TA-XT2i, Stable Microsystems, Surrey, UK) according to the AACC method 74-09 (AACC 2000). Bread crumb samples (25 mm thickness and 20 mm diameter) were obtained using a metal molder. The firmness value of the crumb was defined as the maximum force (Newton) needed to compress a bread crumb sample to 40% of its original height using a probe that was 25 mm in diameter and at 5 s intervals between compressions. Ten replicates of each sample were analyzed.

Statistical analysis

The experimental design for the physicochemical and rheological analyses was completely randomized and three or more repetitions were carried out according to specific methodology. Analysis of variance (ANOVA) and Tukey’s test (p < 0.05) were used for comparison of means (Statistica 7.0, STATSOFT 2007). Pearson’s correlation among different parameters of quality of grain, flour and bread was performed from the standardized means (Statistica 7.0). Principal component analysis (PCA) and cluster analysis were performed using XLstat, version 2010. The data for the central point were taken to be the means of the analysis. The PCA was performed with a correlation matrix and without factor rotation. The means of the physicochemical and rheological characteristics of the flour, and specific volume and firmness of the bread were fixed in columns (variables) and the different genotypes in rows (cases), and the data were standardized before analysis.

RESULTS AND DISCUSSION

Grain hardness index and wheat milling

The grain hardness index (GHI) of the different genotypes varied from 34 to 90 (Table 1). Most of the genotypes (87.5%) were found to have hard and very hard textures except for the T 091027 and T 091033 lines, which were found to have semi-hard and soft textures, respectively. The hardness of wheat is affected mainly by starch and protein contents and their ordering in the endosperm of the grain (Pomeranz and Williams 1990). According to Pauly et al. (2013), the presence and functionality of the puroindoline a (PINA) and b (PINB) proteins together with polar lipids determine the wheat endosperm texture. The level of hardness determines the wheat milling conditions because it indicates the grain resistance to fracturing and reducing to flour (Kaur et al. 2013). Harder texture grains require greater force to be disintegrated and thus provide flour with heavier, larger, and more homogeneous particles, whereas soft texture grains result in flour with lighter particles and irregular fragments stuck to each other (Hrušková and Švec 2009).

Table 1
Grain hardness index, break flour yields, extraction rate, protein content and damage starch of the flours from different genotypes^*.

Genotypes		GHI				BFY (%)		ER (%)		pc (%)		ds (%)
IAPAR 78		86 ± 1ab		Very hard		9.60 ± 0.32g		63.70 ± 1.55def		11.52 ± 0.22def		6.46 ± 0.06ab
IPR 130		90 ± 1a		Very hard		8.55 ± 0.22h		60.16 ± 1.93fg		10.54 ± 051fgh		6.79 ± 0.03a
IPR 85		75 ± 3def		Hard		12.73 ± 0.34d		67.89 ± 2.27abc		10.54 ± 0.26fgh		6.00 ± 0.04cd
IPR Catuara TM		79 ± 1de		Hard		11.35 ± 0.29f		66.40 ± 3.16abcde		10.30 ± 0.06gh		5.81 ± 0.02cde
LD 101108		88 ± 1ab		Very hard		10.09 ± 0.15g		58.60 ± 1.96g		13.67 ± 0.41bc		5.74 ± 0.11def
T 081099		74 ± 1efg		Hard		1708 ±0.37c		67.85 ± 1.93abcd		11.56 ± 0.19def		4.65 ± 0.16h
T 091006		80 ± 2cd		Hard		13.15 ± 0.13d		63.59 ± 1.47cdef		10.04 ± 0.14h		5.99 ± 0.06cd
T 091008		84 ± 0bc		Hard		12.75 ± 0.09d		64.08 ± 2.42cdef		11.73 ± 0.15de		5.34 ± 0.11fg
T 091015		72 ± 1fg		Hard		18.50 ± 0.39b		69.02 ± 2.03ab		11.18 ± 0.17defg		5.97 ± 0.05cd
T 091027		59 ± 1i		Semi-hard		13.14 ± 0.38d		69.01 ± 1.91ab		14.05 ± 0.65bc		6.22 ± 0.17bc
T 091028		80 ± 1cd		Hard		11.59 ± 0.21ef		65.78 ± 1.91bcde		10.96 ± 0.14efgh		5.36 ± 0.06efg
T 091031		70 ± 2gh		Hard		12.70 ± 0.45d		65.21 ± 1.69bcde		13.27 ± 0.22c		5.30 ± 0.01fg
T 091033		34 ± 0j		Soft		29.25 ± 0.21a		64.28 ± 1.88cdef		12.21 ± 0.52d		3.29 ± 0.14i
T 091056		76 ± 0def		Hard		12.69 ± 0.16d		65.99 ± 1.97bcde		14.27 ± 0.27abc		5.13 ± 0.10g
T 091069		66 ± 0h		Hard		18.06 ± 0.22b		70.71 ± 1.97a		14.33 ± 0.48ab		4.64 ± 0.21h
T 091088		80 ±1cd		Hard		12.00 ± 0.40e		63.31 ± 1.95ef		15.10 ± 0.06a		5.48 ± 0.19efg

• ^*
  Average of 3 replicates ± standard deviation. Different letters in the same column are significantly different (p ≤ 0.05). GHI = Grain hardness index — very hard: 81 - 90, hard: 65 - 80, semi-hard: 45 - 64, and soft: 23 - 34 (AACC 2000); BFY = Break flour yield; ER = Extraction rate of flour; PC = Protein content; DS = Damaged starch.

The extraction rate of flour (ER) ranged from 58.6 to 70.7% for LD 101108 and T 091069 lines, respectively, while the break flour yield (BFY) ranged from 8.5 to 29.2% among the different genotypes (Table 1). The wheat genotypes that had a very hard texture (IAPAR 78, IPR 130, and LD 101108) produced a low BFY. There was a strong negative correlation (r = −0.89, p < 0.05, Table 2) between BFY and GHI of the different genotypes. These results indicate that the soft texture of the grains was determinant for the higher BFY.

Physicochemical and rheological characteristics of the wheat flours

The protein content (PC) of the wheat flours varied from 10.04 to 15.10%. An interesting fact to highlight is the high PC (> 14%) for the T 091056, T 091069, T 091027, and T 091088 lines (Table 1). Although there was a large variation in flour protein contents for different genotypes, there was no correlation between PC and GHI or between PC and ER.

The damaged starch (DS) content varied significantly among the samples, with values between 3.29 and 6.79% (Table 1). During milling of the grains the endosperm is reduced to small particle size, and some starch granules are mechanically damaged. This damage influences the physicochemical and rheological characteristics of the dough (Hrušková and Švec 2009). As expected, the grains classified as having hard and very hard textures (GHI > 65) produced more DS (r = 0.79, p < 0.05, Table 2). According to Pomeranz and Williams (1990) and Hrušková and Švec (2009), the texture of the grain affects the particle size distribution and damaged starch content and thus alters the quality of the final product. Hard texture grain flour contains larger amount of damaged starch. The presence of DS is desirable up to a certain amount (about 8%) for bread making, especially in recipes without added sugar. DS is susceptible to amylolytic enzymes, thus providing fermentable sugars to the yeast in sufficient amounts to maintain the fermentation (Pauly et al. 2013).

Table 2
Pearson correlation between grain, flour, and bread characteristics.

Variables		GHI		BFY		ER		PC		DS		L*		b*		Na2CO3 SRC		Suc SRC		LA SRC
GHI		1.00*
BFY		-0.89*		1.00*
ER		-0.43		0.37		1.00*
PC		-0.23		0.08		0.07		1.00*
DS		0.79*		-0.90*		-0.29		-0.28		1.00*
L*		-0.62*		0.54*		0.07		-0.11		-0.47		1.00*
b*		0.28		-0.24		-0.17		0.27		0.04		-0.07		1.00*
Na2CO3SRC		0.26		-0.51*		-0.31		-0.08		0.68*		-0.02		-0.05		1.00*
Suc SRC		0.49		-0.64*		-0.38		0.03		0.73*		-0.45		-0.02		0.81*		1.00*
LA SRC		-0.07		-0.09		0.08		0.40		0.13		-0.11		-0.17		0.06		0.22		1.00*
TS		-0.06		-0.10		0.24		0.14		0.12		-0.24		-0.49		0.21		0.35		0.24
WA		0.75*		-0.81*		-0.46		0.08		0.78*		-0.58*		0.19		0.60*		0.74*		-0.05
DT		0.32		-0.29		-0.09		0.26		0.18		-0.26		-0.04		0.02		0.32		0.42
ST		0.23		-0.24		-0.25		0.31		0.12		-0.10		0.35		0.17		0.20		0.21
MTI		-0.20		0.32		0.02		-0.38		-0.26		0.02		-0.01		-0.12		-0.12		-0.43
RE		-0.24		-0.01		0.24		0.14		0.15		0.27		-0.38		0.54*		0.39		0.26
MR		-0.27		0.11		0.28		0.17		-0.07		-0.10		-0.34		0.16		0.36		0.50*
EXT		0.10		0.13		0.08		-0.10		-0.27		-0.30		-0.06		-0.64*		-0.44		-0.04
SV		-0.33		0.18		0.36		0.26		-0.17		-0.06		-0.39		0.00		0.19		0.37
FB		-0.46		0.28		0.14		-0.07		-0.26		0.62		-0.18		-0.16		-0.40		0.39
Variables		TS		WA		DT		ST		MTI		RE		MR		EXT		SV		FB
TS		1.00*
WA		0.03		1.00*
DT		0.51*		0.02		1.00*
ST		0.25		0.01		0.76*		1.00*
MTI		-0.20		-0.07		-0.71*		-0.66*		1.00*
RE		0.63*		-0.08		0.39		0.39		0.38		1.00*
MR		0.75*		-0.21		0.47		0.20		-0.01		0.58*		1.00*
EXT		-0.23		-0.08		-0.15		-0.43		0.30		-0.73*		-0.16		1.00*
SV		0.60*		-0.29		0.53*		0.20		-0.33		0.66*		0.75*		-0.22		1.00*
FB		-0.20		-0.55*		-0.16		-0.13		-0.08		0.06		0.05		-0.06		0.05		1.00*

• *p ≤ 0.05. GHI = Grain hardness index; BFY = Break flour yield; ER = Extraction rate of flour; PC = Protein content; DS = Damaged starch; L* = Luminosity; b* = Chromaticity coordinate of yellow/blue; Na₂CO₃ SRC = Sodium carbonate retention capacity; Suc SRC = Sucrose retention capacity; LA SRC = Lactic acid retention capacity; TS = Total score; WA = Water absorption; DT = Development time; ST = Stability; MTI = Mixing tolerance index; RE = Resistance to extension; MR = Maximum resistance; EXT = Extensibility; SV = Specific volume; BF = Bread firmness.

The flours from T 081099, T 091006, T 091027, and T 091033 lines were found to have the lightest colors (L* > 94), and the flours from IAPAR 78 and T 081099 genotypes, the highest b* values (> 10) (Table 3). There were positive and negative weak correlations between L* and BFY (r = 0.54, p < 0.05, Table 2) and between L* and GHI (r = −0.62, p < 0.05, Table 2), respectively. However, there was no correlation between the color parameters and ER or between the color parameters and PC. These results suggest that the color of the flour was mainly influenced by the degree of ordering of starch and protein in the grain.

The solvent retention capacity profile allows evaluating the functional contribution of each wheat flour component. The sodium carbonate retention capacity (Na₂CO₃ SRC) is associated with the DS level of the flour, while the sucrose retention capacity (Suc SRC) helps to evaluate the functional contribution of arabinoxylans on the quality of the final product (Guttieri et al. 2001). The Na₂CO₃ SRC ranged from 68.4 to 95.6% (Table 3). A comparison between these data and the DS contents revealed that the materials that had a higher Na₂CO₃ SRC content also exhibited a higher DS content (r = 0.68, p < 0.05, Table 2). The Suc SRC ranged from 74.5 to 91.1% (Table 3) and had a positive correlation with DS (r = 0.73, p < 0.05, Table 2) and a weak negative correlation with BFY (r = −0.64, p < 0.05, Table 2). Arabinoxylans, present mainly in the wheat grain aleurone layer, are incorporated into the flour during the milling process. When combined with DS, they increase the amount of water that can be absorbed by the flour. This increase in water absorption up to a certain limit is a desirable feature for bread making (Kweon et al. 2011). Lactic acid retention capacity (LA SRC) is associated with the glutenin fraction of gluten proteins. The LA SRC ranged from 101.8 to 159.9% (Table 3), values which indicate high variability in gluten strength among the different studied wheat genotypes.

Table 3
Color parameters, solvent retention capacity and total score of the flours from different wheat genotypes^*.

Genotypes		CIELAB color parameters						Na2CO3 SRC (%)		Suc SRC (%)		LA SRC (%)		TS
		L*		a*		b*
IAPAR 78		93.64 ± 0.01def		-0.54 ± 0.01i		10.93 ± 0.06a		91.6 ± 0.8a		88.8 ± 0.2ab		101.8 ± 1.4i		5
IPR 130		93.72 ± 0.03de		-0.63 ± 0.01e		8.90 ± 0.06d		93.5 ± 0.6a		91.1 ± 0.3a		121.1 ±1.6fg		9
IPR 85		93.59 ± 0.06ef		+0.26 ± 0.00b		772 ± 0.04g		85.2 ± 0.1bc		88.9 ± 1.4ab		130.9 ± 4.3de		10
IPR Catuara TM		93.75 ± 0.02de		+0.28 ± 0.02b		776 ± 0.03g		81.8 ± 1.0bcd		84.6 ± 1.1bcde		125.9 ± 2.0ef		10
LD 101108		93.41 ± 0.01g		-0.14 ± 0.01f		9.34 ± 0.03c		85.5 ± 0.6b		88.2 ± 0.3ab		138.2 ± 0.1c		9
T 081099		94.56 ± 0.04c		-0.99 ± 0.01j		10.87 ± 0.05a		68.4 ± 0.1g		74.5 ± 0.4h		111.8 ± 0.1h		7
T091006		94.68 ± 0.04b		-0.22 ± 0.01g		8.34 ± 0.04e		79.1 ± 0.1de		78.7 ± 1.0fgh		133.0 ± 0.2i		7
T 091008		93.80 ± 0.03d		+0.06 ± 0.01d		786 ± 0.04g		76.3 ± 0.1ef		82.0 ± 0.5def		159.9 ± 0.6a		5
T 091015		93.22 ± 0.06h		+0.28 ± 0.02b		8.14 ± 0.02f		79.9 ± 0.0de		85.6 ± 2.1bcde		111.7 ± 1.8cd		10
T 091027		95.04 ± 0.08b		-0.35 ± 0.00h		7.37 ± 0.05h		95.6 ± 4.7a		85.9 ± 3.0bcd		1170 ± 0.0b		10
T 091028		92.94 ± 0.01i		+0.04 ± 0.01d		9.44 ± 0.04c		79.6 ± 0.4de		81.4 ± 0.5efg		1176 ± 0.0h		9
T 091031		93.20 ± 0.06h		+0.50 ± 0.02a		738 ± 0.02h		75.9 ± 0.3ef		83.5 ± 0.4cde		1578 ± 0.8b		9
T 091033		95.42 ± 0.06a		-0.56 ± 0.01i		7.69 ± 0.10g		76.1 ± 0.6ef		773 ± 0.2gh		126.8 ± 0.5gh		7
T 091056		93.20 ± 0.02h		-0.24 ± 0.00g		9.83 ± 0.03b		78.9 ± 1.0de		83.6 ± 0.0cde		117.6 ± 0.6g		7
T 091069		93.54 ± 0.01fg		-0.04 ± 0.01e		8.85 ± 0.02d		73.1 ± 0.4fg		80.0 ± 0.5fg		126.8 ± 0.5e		9
T 091088		93.39 ± 0.14g		+0.12 ± 0.03c		8.39 ± 0.18e		80.3 ± 0.0cde		874 ± 0.3abc		135.3 ± 0.2cd		10

• ^*
  Average of 3 replicates ± standard deviation. Different letters in the same column are significantly different (p ≤ 0.05). L* = Luminosity; a* = Chromaticity coordinate of red/green (red positive and green negative); b* = Chromaticity coordinate of yellow/blue (yellow positive and blue negative); Na₂CO₃ SRC = Sodium carbonate retention capacity; Suc SRC = Sucrose retention capacity; LA SRC = Lactic acid retention capacity; TS = Total score.

Water absorption (WA) is influenced by the components of flour, particularly by proteins, damaged starch, and arabinoxylans (Kweon et al. 2011). In this study, the wheat flours had WA values between 56.4 and 70.2% (Table 4).

Table 4
Flour rheological parameters, bread specific volume, and bread firmness from different wheat genotypes^*.

Genotypes		WA (%)		DT (min)		ST (min)		MTI (BU)		RE (BU)		MR (BU)		EXT (mm)		SV** (cm3∙g-1)		BF*** (N)
IAPAR 78		70.2a		2.3 ± 0.0i		72 ± 0.2gh		100 ± 0ab		300 ± 13hi		360 ± 14e		166 ± 8hi		3.13 ± 0.10i		2.98 ± 0.05c
IPR 130		67.8b		6.9 ± 0.1cd		12.9 ± 0.3def		80 ± 0bc		555 ±19c		768 ± 37b		156 ± 16i		4.52 ± 0.12a		1.93 ± 0.08efg
IPR 85		64.8f		9.5 ± 0.7a		23.5 ± 0.5c		50±14de		690 ± 34b		>1000		170 ± 8ghi		4.07 ± 0.11bc		1.71 ± 0.01fg
IPR Catuara TM		61.8j		8.2 ± 0.2b		43.8 ± 2.1a		60 ± 0cde		510 ± 20cd		910 ± 33a		185 ± 7efg		3.70 ± 0.06defg		3.01 ± 0.06c
LD 101108		67.8b		9.0 ± 0.0ab		40.0 ± 1.0a		60 ± 0cde		460 ± 0def		770 ± 42b		189 ± 8cdefg		3.77 ± 0.10bcdefg		1.69 ± 0.06fg
T 081099		58.2k		72 ± 0.2c		43.8 ± 2.3a		65 ± 0cde		420 ± 16fg		550 ± 14c		172 ± 6fghi		3.60 ± 0.13fgh		3.11 ± 0.07c
T091006		63.6h		3.0 ± 0.0hi		2.7 ± 0.5h		110 ± 14a		338±15h		450 ±17cd		203±8bd		3.69 ± 0.18dfg		4.48 ± 0.08a
T 091008		65.4e		72 ± 0.2c		16.1 ± 0.1de		40 ± 0e		333±12hi		510 ± 23c		215 ± 7ab		3.29 ± 0.13hi		4.23 ± 0.20a
T 091015		63.6h		6.0 ± 0.0e		9.2 ± 1.2fg		120 ± 0a		847 ± 31a		>1000		131 ± 5j		4.02 ± 0.07bcde		2.08 ± 0.12de
T 091027		66.0d		6.3 ± 0.0cde		31.1 ± 0.4b		40 ± 0e		410 ± 14fg		915±38a		184 ± 2efgh		3.60 ± 0.15gh		3.60 ± 0.20b
T 091028		64.2g		4.0 ± 0.0g		3.0 ± 0.4h		70 ±14cd		284 ± 9i		432 ± 13de		207±10abcd		3.76 ± 0.01cdefg		2.35 ± 0.12d
T 091031		63.0i		5.0 ± 0.0f		10.4 ± 1.7fg		100±0ab		507±12cd		950 ± 37a		191 ± 8cde		3.81 ± 0.16bcdefg		3.833 ± 0.20b
T 091033		56.4l		3.4 ± 0.1gh		9.4 ± 0.5fg		100±0ab		475 ± 19de		720 ± 30b		173 ± 7fghi		3.96 ± 0.13bcdef		3.61 ± 0.18b
T 091056		64.8f		6.2 ± 0.2 de		18.2 ± 0.1de		80 ± 0bc		445 ± 19ef		728 ± 29b		187 ± 5cdef		4.12 ± 0.14b		1.99 ± 0.07ef
T 091069		63.6h		7.2 ± 0.2c		11.5 ± 3.5efg		50 ± 14de		396 ±17g		718 ± 22b		221 ± 9a		3.95 ± 0.13bcdef		1.62 ± 0.04g
T 091088		674c		9.2 ± 0.2a		32.5 ± 0.7b		40 ± 0e		560±28c		720 ±17b		156 ± 9i		4.02 ± 0.18bcd		2.18 ± 0.12de

• ^*
  Average of 3 replicates ± standard deviation. Different letters in the same column are significantly different (p ≤ 0.05);
• ^**
  Average of 6 replicates;
• ^***
  Average of 10 replicates. WA = Water absorption; DT = Development time; ST = Stability; MTI = Mixing tolerance index; RE = Resistance to extension; MR = Maximum resistance; EXT = Extensibility; SV = Specific volume; BF = Bread firmness.

There was no correlation between WA and PC; however, WA was positively correlated with DS content (r = 0.78, p < 0.05, Table 2), with Na₂CO₃ SRC (r = 0.60, p < 0.05), and with Suc SRC (r = 0.74, p < 0.05). The dough development time (DT) ranged from 2.3 to 9.5 min (Table 4). The IPR 85, LD 101108, and T 091088 genotypes had the highest DT. Flour stability (ST) varied from 3 to 44 min, while the mixing tolerance index (MTI) varied from 40 to 120 BU. ST was negatively correlated with the MTI (r = −0.66, p < 0.05, Table 2) and was positively correlated with DT (r = 0.76, p < 0.05). Resistance to extension (RE) varied from 284 to 847 BU, while extensibility (EXT) varied from 131 to 221 mm (Table 4). The IPR 130, IPR 85, IPR Catuara TM, T 091015, T 091031, and T 091088 genotypes had more elastic flours (RE > 500 BU). The flours from IPR 130 cultivar and T 091088 and T 091015 lines had the lowest EXT. The maximum resistance (MR) of the samples ranged from 360 to 950 BU, with the exception of the IPR 85 cultivar and T 091015 line that had MR higher than 1000 BU (Table 4).

The PC did not affect the rheological characteristics of the dough (Table 2), indicating that, in the case of the Brazilian genotypes studied, the protein quality was more important than the protein content itself. Vázquez et al. (2012) studied the effect of genotype, environment, and the interaction between them on the quality of wheat produced in Latin America. These authors did not find any correlation between the protein content and quality parameters of the grain and flour in Brazilian wheat genotypes, either.

Baking quality

The loaves from different genotypes exhibited specific volumes (SV) that ranged from 3.13 to 4.52 cm³∙g⁻¹ for IAPAR 78 and IPR 130 cultivars, respectively (Table 4). SV was positively correlated with DT (r = 0.53, p < 0.05, Table 2), RE (r = 0.66, p < 0.05), and MR (r = 0.75, p < 0.05). According to Williams et al. (1988), the most suitable farinograph parameters for bread were found to be: DT (8 – 10 min), ST (10 – 15 min), and MTI (0 – 49 BU). Furthermore, suitable extensograph parameters were found to be: RE (250 – 350 BU) and EXT (140 – 180 mm). In this study, the bread obtained from flours whose rheological parameters were within these ranges had higher SV. There was no correlation between SV and flour PC (Table 2); however, the variation of protein subunits probably influenced SV (Table 5). Bread firmness (BF) showed significant variation among the different genotypes (Table 4). The bread obtained from wheat flour of the T 091069 line had the lowest BF (1.62 N), while that made with wheat flour of the T 091006 line the highest BF (4.48 N). In a similar study, Barak et al. (2013) observed that the gliadin and glutenin contents were negatively correlated with BF and were positively correlated with SV. These correlations show the importance of determining the balance between these proteins for evaluating the bread quality of flours of different wheat varieties.

Table 5
Allelic frequencies and statistical analysis of the effects of HMW-GS and LMW-GS on flour and bread quality parameters^*.

Locus		Subunit		DT (min)		ST (min)		MTI (BU)		RE (BU)		MR (BU)		EXT (mm)		L*		b*		SV (cm3∙g-1)		BF (N)
Glu-A1		1		6.3a		11.7a		85a		454a		753a		198a		93.47a		8.16a		3.90a		2.61a
		2*		6.3aa		26.9a		68a		516a		778a		170a		94.23a		8.88a		3.83a		2.73a
		1/2*		9.2 a		32.5a		40a		560a		720a		156a		93.39a		8.39a		4.02a		2.18a
		N		4.7a		11.6a		70a		319a		405a		185a		94.16a		9.64a		3.41a		3.73a
Glu-B1		17+18		8.2a		18.1a		65a		600a		955a		176a		97.63a		7.74a		4.29a		1.82a
		7+8		6.3a		23.8a		74a		542a		778a		168a		94.39a		9.83a		3.92a		2.80a
		7+9		5.7a		16.8a		74a		385a		615a		193a		94.10a		8.98a		3.61b		3.00a
Glu-D1		5+10		6.8a		22.1a		70a		504a		440a		179a		94.04a		9.64a		3.92a		2.52b
		2+12		4.2 a		8.6a		83a		324b		783a		195a		94.16a		8.34a		3.37b		3.90a
Glu-A3		b		6.3a		29.7a		65a		462a		744a		171a		94.44a		9.05a		3.66a		2.80a
		c		7.0a		19.0b		69a		467a		734a		185a		93.81a		8.99a		3.89a		2.64a
		d		4.4a		13.4b		88a		485a		665a		182a		94.31a		7.92a		3.76a		3.07a
Glu-B3		b		7.6a		9.2a		78a		566a		907a		176a		93.69a		8.13a		4.04a		2.29a
		e		5.6a		20.9a		70a		566a		716a		169a		93.20a		8.14a		3.89a		2.22a
		f		6.0a		21.3a		85a		397a		640a		202a		93.41a		9.34a		3.50a		3.62a
		g		72a		11.5a		50a		396a		718a		221a		93.54a		8.84a		3.95a		1.62a
		h		6.8a		17.2a		50a		436a		695a		181a		94.86a		786a		3.77a		3.42a
1B/1R		No 1B/1R		6.8a		11.5a		68a		490a		762a		184a		93.91b		8.22b		3.85a		2.73a
		1B/1R		4.6a		19.3a		86a		410a		590a		175a		96.40a		9.83a		3.70a		2.92a

• ^*
  Different letters in the same column, for each locus, differ significantly (p ≤ 0.05). DT = Development time; ST = Stability; MTI = Mixing tolerance index; RE = Resistance to extension; MR = Maximum resistance; EXT = Extensibility; L* = Luminosity; b* = Chromaticity coordinate of yellow/blue; SV = Specific volume; BF = Bread firmness.

Effect of glutenin subunits on the flour rheological characteristics and bread

Branlard et al. (2003) reported that the allelic variation at HMW-GS and LMW-GS and environmental conditions are important factors that influence the wheat flour quality parameters. Alleles encoded at the Glu-A1 had no effect on color, dough rheological characteristics, and bread quality (Table 5). Oury et al. (2010) also reported that 1 and 2* subunits had no significant effects on alveograph parameters and baking properties. However, these subunits were associated with a higher loaf volume compared to the Null subunit (Peña et al. 2005; Vázquez et al. 2012). Glu-B1 alleles had an effect on SV (p < 0.05). The flours containing 17+18 and 7+8 subunits produced breads with higher SV than those with 7+9 subunits (Table 5). Liang et al. (2010) also reported that 7+9 subunits are associated with low baking quality, whereas 17+18 and 7+8 subunits are associated with good baking characteristics. The allelic variations at the Glu-D1 locus had an effect on RE, SV, and BF (p < 0.05). The flours containing 5+10 subunits, which are associated with good baking quality (Peña et al. 2005; Vázquez et al. 2012), had higher RE, higher SV, and lower BF (Table 5). The allelic variation of the Glu-A3 locus had an effect on the ST (p < 0.05) and flours that contained b subunit had higher ST. Li et al. (2010) reported that the b allele at Glu-A3 showed positive effects for all mixograph parameters mainly mixing tolerance. Glu-B3 subunits had no effect on the rheological properties of the dough or on the bread quality mainly due to large genetic variability of the genotypes. The rye translocation 1B/1R has been described as a factor that negatively affects baking quality by decreasing gluten protein quality and worsening the technological properties of the bread (Vázquez et al. 2012). In this study, the 1B/1R did not influence the rheological properties of the dough, SV, or BF, but had an effect on the color of the flour. The presence of the 1B/1R allele was associated with lighter (higher L*) and more yellow (higher b*) flours (Table 5).

Scores from 1 to 4 were calculated for each HMW-GS, and the Total Score (TS) was represented by the sum of the scores of Glu-A1, Glu-B1, and Glu-D1 (Payne et al. 1987). The TS was positively correlated with the DT (r = 0.51, p < 0.05, Table 2), RE (r = 0.63, p < 0.05), and MR (r = 0.75, p < 0.05). These results suggest that subunits with higher scores are associated with greater gluten strength. There was also a positive correlation between TS and SV (r = 0.60, p < 0.05, Table 2). The 17+18 and 7+8 subunits at Glu-B1 and 5+10 at Glu-D1 stood out, indicating wheat genotypes with higher baking quality.

The principal component analysis (PCA) was applied in order to verify the relationship between samples and variables. The rheological characteristics of the flour, SRC, color, SV, BF, and TS were used to describe samples with a number of components smaller than those of the original variables. Thus, the first two components retained 49.10% of the variability between the samples. The first component (PC1) was formed by WA, DS, RE, EXT, L*, Na₂CO₃ SRC, Suc SRC, SV, BF, and TS, which explained 30.38% of the initial variability between the samples, while DT, ST, and b* variables largely made up the second component (PC2). The other variables made a smaller contribution to the formation of these components. The dispersion of the genotypes in the space formed by PC1 and PC2 is shown in Figure 1a. These components (PC1 and PC2) allowed for the separation of the samples according to their physicochemical and rheological characteristics.

Figure 1
(a) Principal component analysis of the physicochemical and rheological properties of the flour, bread characteristics, and HMW-GS of the wheat genotypes. (b) Dendrogram of the 16 wheat genotypes based on the physicochemical and rheological properties of the flour, bread characteristics, and evaluation of HMW-GS.

PC2 was responsible for the separation or discrimination of genotypes in the horizontal direction of the biplot. In this projection, the genotypes that had high values of WA, DS, RE, Na₂CO₃ SRC, Suc SRC, SV, and TS are located on the right side. The IPR 130, IPR 85, IPR Catuara TM, T 091015, T 091088, and LD 101108 genotypes, which had high GHI and bread with very good quality, are in this position. The genotypes that had soft grain, high L*, extensible flour, and high MTI are in the opposite position (PC1 negative side). The T 091006, T 091008, T 081099, and T 091033 lines are in this position and their flours are associated with low baking quality. The T 091056, T 091031, T 091069, and T 091027 lines are associated with characteristics of intermediate quality. Although IAPAR 78 cultivar typically is associated with intermediate quality, its flour had low ST and DT and resulted in loaves with small SV (Table 4).

Another approach to finding groups in a sample population is a cluster analysis. This analysis aims to classify the samples into a small number of mutually exclusive groups based on similarities or dissimilarities between the genotypes of the sample population.

The representative dendrogram of the cluster analysis (Figure 1b) classified the genotypes into 3 groups (G1, G2, and G3) according to their baking qualities. G1 stood out from the others because the flours in this group have characteristics associated with superior baking quality, especially DT, MTI, ST, RE, and EXT (Table 6). These flours also have a lower intensity of yellow chromaticity, intermediate levels of DS, WA, and Suc SRC, and their breads had higher SV and lower BF. The flours from this group had the highest TS (10).

Table 6
Rheological parameters, color parameters, SCR values, specific volume, bread firmness, and total score of the wheat genotypes in the group obtained from cluster analysis^*.

		G1		G2		G3
DT (min)		7.86a		2.30c		5.38b
ST (min)		27.57a		7.20 c		14.39b
MTI (BU)		64.29c		100.00a		76.88b
WA (%)		65.60b		70.20a		62.40c
RE (BU)		576.00a		300.00c		399.75b
EXT (mm)		167.29b		166.00c		196.13a
DS (%)		6.00b		6.46a		4.96c
L*		93.73b		93.64c		93.92a
b*		8.23c		10.93b		8.78a
Na2CO3 SRC (%)		85.97b		91.60a		75.93c
Suc SRC (%)		8739b		88.80a		80.13c
LA SRC (%)		125.73b		101.80c		131.41a
SV (cm3∙g-1)		3.96a		3.13c		3.77b
BF (N)		2.31c		2.98b		3.15a
TS		10.00a		5.00c		8.00b

• ^*
  Different letters in the same line differ significantly (p ≤ 0.05). DT = Development time; ST = Stability; MTI = Mixing tolerance index; WA = Water absorption; RE = Resistance to extension; EXT = Extensibility; DS = Damage starch; L* = Luminosity; b* = Chromaticity coordinate of yellow/blue; Na₂CO₃ SRC = Sodium carbonate retention capacity; Suc SRC = Sucrose retention capacity; LA SRC = Lactic acid retention capacity; SV = Specific volume; BF = Bread firmness; TS = Total score.

As verified through the PCA, the IAPAR 78 cultivar stood out from the others because of its very poor baking quality. This cultivar was also the only one to be classified in G2 through the cluster analysis. Its flour was found to have the lowest DT and ST, and also a high MTI. The amount of DS was greater than that found in the G1 group genotypes, and the Na₂CO₃ SRC was higher than that of the G1 and G3 groups (Table 6). In addition, the flour color was found to be more yellow. These features resulted in loaves with low SV and intermediate BF. The flour from this cultivar had the lowest TS (5.0). The cultivars grouped in G3 had lower DS and low WA, Na₂CO₃ SRC, and Suc SRC, despite high LA SRC (Table 6). Despite having an intermediate SV, the loaves were quite firm. The flours from G3 received intermediate grades of TS (8.0).

However, when observing TS of each genotype grouped in G3, it was found that the T 091028, T 091031, and T 091015 lines had high TS (9-10) due to the presence of the 5+10 subunits at the Glu-D1. These subunits are associated with increased gluten strength and SV (Liang et al. 2010; Hernández et al. 2012).

The genotypes that had rye translocation (Costa et al. 2013) were grouped in G3 (except IAPAR 78 cultivar). Although the rye translocation negatively affects baking quality, when in the presence of subunits from A, B, and D chromosomes this effect is decreased, as observed for flours from T 081099, T 091033, and T 091056 lines that had intermediate baking quality. Comparing the results obtained in this study with those presented in a previous study (Costa et al. 2013), it was possible to observe that for some samples, the results from the physicochemical and rheological analysis of the flour did not confirm those from the grain physicochemical analysis and some genotypes that were previously classified as of low and intermediate qualities had their classification changed to intermediate and high, respectively in this study. These results suggest that the HMW- and LMW-glutenin subunits associated with good dough rheological properties and good baking quality prevailed over those associated with grain physicochemical characteristics.

CONCLUSION

The HMW-GS and LMW-GS have influence on the baking quality of the wheat. The Glu-D1 locus is the most significant in affecting the rheological characteristics of the flour and bread quality parameters. The 5+10 allele is associated with the best characteristics for bread making, while the 2+12 one is associated with weak flours. The Glu-D1 locus is very important at the first stages of breeding programs for selecting wheat lines for different products.

ACKNOWLEDGEMENTS

The authors thank the Brazilian National Council for Scientific and Technological Development (CNPq) for financial support.

REFERENCES

• American Association Cereal Chemists (2000). Approved Methods of the American Association of Cereal Chemists. 10. ed. Saint Paul: Approved Methods Committee.
• Barak, S., Mudgil, D. and Khatkar, B. S. (2013). Relationship of gliadin and glutenin proteins with dough rheology, flour pasting and bread making performance of wheat varieties. LWT- Food Science and Technology Journal, 51, 211-217. http://dx.doi.org/10.1016/j.lwt.2012.09.011
  » http://dx.doi.org/10.1016/j.lwt.2012.09.011
• Blechl, A. E. and Vensel, W. H. (2013). Variant high-molecular-weight glutenin subunits arising from biolistic transformation of wheat. Journal of Cereal Science, 57, 496-503. http://dx.doi.org/10.1016/j.jcs.2013.02.005
  » http://dx.doi.org/10.1016/j.jcs.2013.02.005
• Branlard, G., Dardevet, M., Amiour, N. and Igrejas, G. (2003). Allelic diversity HMW and LMW glutenin subunits and Omegagliadins in French bread wheat (Triticum aestivum L). Genetic Resources and Crop Evolution, 50, 669-679. http://dx.doi.org/10.1023/A:1025077005401
  » http://dx.doi.org/10.1023/A:1025077005401
• Costa, M. S., Scholz, M. B. S. and Franco, C. M. L. (2013). Effect of high and low molecular weight glutenin subunits, and subunits of gliadin on physicochemical parameters of different wheat genotypes. Ciência e Tecnologia de Alimentos, 33, 163-170. http://dx.doi.org/10.1590/S0101-20612013000500024
  » http://dx.doi.org/10.1590/S0101-20612013000500024
• Guttieri, M. J., Bowen, D., Gannon, D., O’Brien, K. and Souza, E. (2001). Solvent retention capacities of irrigated soft white spring wheat flours. Crop Science, 41, 1054-1061. http://dx.doi:10.2135/cropsci2001.4141054x
  » http://dx.doi:10.2135/cropsci2001.4141054x
• Hernández, Z. J. E., Figueroa, J. D. C., Rayas-Duarte, P., Martínez-Flores, H. E., Arámbula, G. V., Luna, G. B. and Peña, R. J. (2012). Influence of high and low molecular weight glutenins on stress relaxation of wheat kernels and the relation to sedimentation and rheological properties. Journal of Cereal Science, 55, 344-350. http://dx.doi.org/10.1016/j.jcs.2012.01.009
  » http://dx.doi.org/10.1016/j.jcs.2012.01.009
• Hrušková, M. and Švec, I. (2009). Wheat hardness in relation to other quality factors. Czech Journal of Food Sciences, 27, 240-284.
• Kaur, A., Singh, N., Ahlawat, A. K., Kaur, S., Singh, A. M., Chauhan, H. and Singh, G. P. (2013). Diversity in grain, flour, dough and gluten properties amongst Indian wheat cultivars varying in high molecular weight subunits (HMW-GS). Food Research International, 53, 63-72. http://dx.doi.org/10.1016/j.foodres.2013.03.009
  » http://dx.doi.org/10.1016/j.foodres.2013.03.009
• Kweon, M., Slade, L. and Levine, H. (2011). Solvent retention capacity (SRC) testing of wheat flour: principles and value in predicting flour functionality in different wheat-based food processes and in wheat breeding — A Review. Cereal Chemistry, 88, 537-552. http://dx.doi.org/10.1094/CCHEM-07-11-0092
  » http://dx.doi.org/10.1094/CCHEM-07-11-0092
• Li, Y., Zhou, R., Branlard, G. and Jia, J. (2010). Development of introgression lines with 18 alleles of glutenin subunits and evaluation of the effects of various alleles on quality related traits in wheat (Triticum aestivum L). Journal of Cereal Science, 51, 127-133. http://dx.doi.org/10.1016/j.jcs.2009.10.008
  » http://dx.doi.org/10.1016/j.jcs.2009.10.008
• Liang, D., Tang, J., Peña, R. J., Singh, R., He, X., Shen, X., Yao, D., Xia, X. and He, Z. (2010). Characterization of CIMMYT bread wheats for high- and low-molecular weight glutenin subunits and other quality-related genes with SDS-PAGE, RP-HPLC and molecular markers. Euphytica, 172, 235-250. http://dx.doi.org/10.1007/s10681-009-0054-x
  » http://dx.doi.org/10.1007/s10681-009-0054-x
• Luo, C., Griffin, W. B., Branlard, B. and Mcneil, D. L. (2001). Comparison of low- and high molecular-weight wheat glutenin alleles effects on flour quality. Theoretical and Applied Genetics, 102, 1088-1098. http://dx.doi.org/10.1007/s001220000433
  » http://dx.doi.org/10.1007/s001220000433
• Oliveira, D. S., Telis-Romero, J., Silva, R. and Franco, C. M. L. (2014). Effect of a Thermoascus aurantiacus thermostable enzyme cocktail on wheat bread quality. Food Chemistry, 143, 139-146. http://dx.doi.org/10.1016/j.foodchem.2013.07.103
  » http://dx.doi.org/10.1016/j.foodchem.2013.07.103
• Oury, F., Chiron, H., Faye, A., Gardet, O., Giraud, A., Heumez, E., Rolland, B., Rousset, M., Trottet, M., C, G. and Branlard, G. (2010). The prediction of bread wheat quality: joint use of the phenotypic information brought by technological tests and the genetic information brought by HMW and LMW glutenin subunits. Euphytica, 171, 87-109. http://dx.doi.org/10.1007/s10681-009-9997-1
  » http://dx.doi.org/10.1007/s10681-009-9997-1
• Pauly, A., Pareyt, B., Fierens, E. and Delcour, J. A. (2013). Wheat (Triticum aestivum L. and T. turgidum L. ssp. durum) kernel hardness: II. Implications for end-product quality and role of puroindolines there in. Comprehensive Reviews in Food Science and Food Safety, 12, 427-438. http://dx.doi.org/10.1111/1541-4337.12018
  » http://dx.doi.org/10.1111/1541-4337.12018
• Payne, P. I., Seekings, J. A., Worland, A. J., Jarvis, M. G. and Holt, L. M. (1987). Allelic variation of glutenin subunits and gliadins and its effect on breadmaking quality in wheat: analysis of F5 progeny from “Chinese Spring” X “Chinese Spring” (Hope 1A). Journal of Cereal Science, 6, 103-118. http://dx.doi.org/10.1016/S0733-5210(87)80047-4
  » http://dx.doi.org/10.1016/S0733-5210(87)80047-4
• Peña, E., Bernardo, A., Souler, C. and Jouve, N. (2005). Relationship between common wheat (Triticum aestivum L) gluten proteins and dough rheological properties. Euphytica, 143, 169-177. http://dx.doi.org/10.1007/s10681-005-3157-z
  » http://dx.doi.org/10.1007/s10681-005-3157-z
• Pomeranz, Y. and Williams, P. C. (1990). Wheat hardness: its genetic, structural, and biochemical background, measurements and significance. In: Y. Pomeranz (Ed.), Advances in cereal science and technology (v. 10, p. 471-544). St. Paul: American Association of Cereal Chemistry.
• Shewry, P. R., Halford, N. G., Tatham, A. S., Popineau, Y., Lafiandra, D. and Belton, P. S. (2003). The high molecular weight subunits of wheat glutenin and their role in determining wheat processing properties. Advances in Food and Nutrition Research, 45, 219-302. http://dx.doi.org/10.1016/S1043-4526(03)45006-7
  » http://dx.doi.org/10.1016/S1043-4526(03)45006-7
• Vázquez, D., Berger, A. G., Cuniberti, M., Bainotti, C., Miranda, M. Z., Scheeren, P. L., Jobet, C., Zúñiga, J., Cabrera, G., Verges, R. and Peña, R. J. (2012). Influence of cultivar and environment on quality of Latin American wheats. Journal of Cereal Science, 56, 196-203. http://dx.doi.org/10.1016/j.jcs.2012.03.004
  » http://dx.doi.org/10.1016/j.jcs.2012.03.004
• Williams, P., El-Haramein, K. R., Nakkoul, H. and Rihawi, S. (1988). Crop quality evaluation methods and guidelines. Aleppo: ICARDA.

Publication Dates

• Publication in this collection
  12 Jan 2017
• Date of issue
  Jan-Mar 2017

History

• Received
  15 Dec 2015
• Accepted
  28 Mar 2016