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Sponge and dough bread assessment in the northern grains region

D. Martin1,4, T. Lever2, A. Kelly2, J. De Faveri2, K.J. Quail3 and D. Miskelly4

1Department of Primary Industries and Fisheries, Leslie Research Centre, Toowoomba, Qld 4350, Australia
2
Department of Primary Industries and Fisheries, Toowoomba, Qld 4350, Australia
3
BRI Australia Ltd, North Ryde, NSW 1670, Australia
4
Value Added Wheat CRC Ltd, North Ryde, NSW 1670, Australia

Introduction

Sponge and dough bread manufacture accounts for the majority of western style bread products in Asia. This market requires high protein wheat and consequently is a potential major end use for high protein premium grade wheat from the northern grains region. A collaborative Value Added Wheat CRC project with BRI Australia Ltd and Queensland Department of Primary Industries and Fisheries investigated the quality requirements for sponge and dough bread in Asia in order to determine if Australia can produce wheats suitable for this bread type. As part of this work an investigation was undertaken to identify the key wheat quality characteristics required for bread manufacture by this process in Asia and in addition Australian wheat cultivars that have some or all of the necessary quality requirements required to produce good quality sponge and dough bread.

Materials and methods

A major part of the work based at the Leslie Research Centre was to investigate the relative importance of various quality measurements using a set of either 25 or 30 genotypes grown at up to three sites in 2000, 2001 and 2002. The trials grown in the winter of 2000 were conducted with 25 genotypes at Roma and Billa Billa in southwestern Queensland. These trial plots were arranged in two field replicates at each site. After harvest the field replicate samples were combined in order to produce sufficient quantities of sample for laboratory analysis. Due to the combination of replicate samples and the inadequacies of the experimental design used in the laboratory phase, the 2000 results were treated as an observational study. These samples also provided a very useful source of flour to facilitate the optimisation of the sponge and dough baking method.

Experimental design

In the 2001 and 2002 trials the set of genotypes was expanded to 30. The wheat quality data was obtained from a multi-phase process. The first phase involved the field trial where genotypes were grown in plots. The quality traits therefore contain variation for each of the field, milling and laboratory processes and at each phase of the experimental process replication was incorporated.

The 2001 trial was a 2-phase design. The experiment consisted of 30 genotypes grown at one location (Roma) in a replicated trial. Grain from each plot was divided into two duplicates and then processed through the mill and laboratory. Plots were allocated to positions within the milling process using an incomplete block design with blocks being test day. The same randomisation and level of duplication was carried forward from milling to the laboratory procedures. Through this field and laboratory duplication, the set of 30 genotypes was expanded to a total of 90 samples.

The 2002 trial was a three-phase design. The first involved growing the 30 genotypes at two locations, Roma and Biloela in a replicated design. Duplicate grain samples from each field plot were milled according to a specific design. Various grain measurements together with flour yield were measured at the second phase. Duplicate samples of flour were taken from these milled samples and allocated to the third phase of testing. Consequently the set of 30 genotypes at 2 sites was expanded to a total of 298 samples.

Measurement of quality traits

Grain protein was determined using a calibrated NIR 6500 spectrophotometer. Grain samples were milled through a Buhler laboratory mill according to AACC Method 26-21. Approved AACC Methods were used to determine particle size index (55-30), flour swelling volume (56-21) and mixograph properties (54-40A). Falling number was performed on samples according to ICC method 107/1 while farinograph and extensograph properties were determined using RACI methods 06-02 and 06-01 respectively.

Sponge and dough test baking

A water-jacketed GRL-200 pin mixer (Muzeen and Blythe Ltd, Manitoba, Canada) was used for all mixing operations. The sponge component consisted of: flour 140 g, yeast 4 g, water 84 mL, bread improvers (calcium hydrogen orthophosphate 0.5 g, ammonium sulphate 0.06 g, malt flour 0.5 g) 1.62 g, mixed for 2 min at 60 rpm. Added water and water bath temperatures were monitored and adjusted to achieve a finished sponge temperature of 26C +/- 0.5C. The sponge was fermented in a sealed container at 28C for 3 h and 55 min.

The dough was formed with; flour 60 g, sugar 10 g, fat 6 g, salt 4 g, water variable, sponge total, mixed at 60 rpm until optimal dough development was observed (usually after between 2 and 6 min). Water temperatures were adjusted to achieve a finished dough temperature of 28C +/- 0.5C. Water addition was calculated as total dough water (mL) = (Farinograph water absorption % - 6) x 2 – 84 (mL).

The mixed dough was rested for 20 min, divided into two 160 g dough pieces, moulded in a mono universal moulder (D. Ayres, Jones and Co., Ltd. Swansea, Great Britain), rested for 10 min, moulded again, placed in an oiled 550 cm3 loaf tin, then proofed at 39C and 80% rh for 60 min. Loaves were baked for 15min at 200C, removed from the tin, cooled at room temperature and the volume measured in a seed displacement volumeter.

Assessment and scoring for external appearance, oven spring and crumb texture, structure and colour was completed between 18 and 24 h following baking. Test baking results reported are the average loaf volume of two dough pieces, from a single batch of dough divided prior to moulding. For this work the scores were not included in the total analysis of results due to their qualitative nature and strong correlation with loaf volume.

This baking method was able to discriminate between flours of different quality used in Asian bread production (Figure 1). With assistance from AWB Ltd, three grades of flour, Premium, Standard and All-purpose, were obtained from Federal Flour Mill Berhad, Malaysia and evaluated using the above method.

Figure 1. Loaf volumes for Premium, Standard and All-Purpose grades of Asian milled flour (AMF) were 860cm3, 805cm3 and 680cm3 respectively.

Results

The genotypes provided a large range of quality test results for all the traits measured. Genetic correlations were adjusted for sources of variation in this study, namely site, genotype, field trial, milling process and laboratory variation. Genetic correlations of the test results with sponge and dough loaf volume are displayed in Table 1.

Table 1. Genetic correlations of quality traits with loaf volume for 2001 and 2002 harvests, Roma and Biloela.

 

Genetic correlation with loaf volume

Trait

Roma 2001

Roma 2002

Biloela 2002

NIR grain protein (%)

-

-0.176

0

1000 kernel weight (g)

-

0.618

-0.292

Milling yield (%)

-0.307

-0.200

0.480

Flour swelling volume (mL)

0.493

0.595

0.637

Extensograph extensibility (cm)

-0.026

-0.229

0.188

Extensograph resistance (BU)

0.381

-0.357

-0.075

Mixograph stability (min)

0.517

-0.297

-0.140

Farinograph water absorption (%)

-0.095

0.332

0.280

Farinograph DDT (min)

-0.208

-0.149

-0.141

Discussion

Contrary to inferences drawn from reviews of bread production methods, dough strength was not found to be a key factor for sponge and dough loaf volume. The most highly correlated quality trait was flour-swelling volume with a positive correlation that was consistent for each site and across both years. Therefore the robustness of this relationship indicates potential application as an indicator of sponge and dough loaf volume. The relative importance of flour swelling volume as an indicator of sponge and dough loaf volume is yet to be determined since the strength of the relationship found in this study could be limited by the sample set.

Among the cultivars evaluated consistent and large loaf volumes were achieved by a number of Batavia/Pelsart crossbreds in particular QT8753. The varieties Hartog and Kennedy also performed well. Overall this work has confirmed that Australia can produce wheats suitable for sponge and dough bread. A sample of Alsen, a US hard red spring wheat variety grown in Queensland from imported seed, was milled and baked with these samples. When grown in North America, Alsen demonstrated excellent sponge and dough bread quality. The sample of Alsen produced in Queensland, performed better than many genotypes in the project but produced a smaller loaf volume than the best performing genotype, QT8753 and very similar results to the premium grade Asian milled flour (Figure 2).

Figure 2. Loaf volumes for the genotype QT8753, Premium Asian milled flour (AMF) and the US spring wheat variety, Alsen, grown in Queensland, was 910 cm3, 845 cm3 and 830 cm3 respectively.

Conclusion

The results of this study have confirmed that Australia can produce wheats suitable for sponge and dough bread. In addition the test baking method developed as part of this project was found to discriminate between flours of different quality used in Asian bread manufacture and has been used to support this work and other projects including a northern region wheat molecular marker project which phenotyped samples from a Kukri/Janz double haploid population.

Acknowledgements

This work was funded by the Grains Research and Development Corporation through the Value Added Wheat CRC. The authors wish to thank John Sheppard and staff from the DPI&F wheat-breeding group for conducting the various field trials and providing samples for analysis. We are also grateful to Bruce Stewart, Lorelei Bartkowski, Janina Koltys, Linda Tredwell, and William Spence from the DPI&F Wheat Quality Laboratory for their expert technical assistance. William Hogan (BRI Australia Ltd.) also provided invaluable assistance in the development of the test baking method.

References

American Association of Cereal Chemists. Approved Methods, 10th Edition. (2000) Approved Methods 26-21; 54-40A; 55-30; 56-21.

International Association for Cereal Science and Technology (1997) ‘ICC Standards.’ Method 107/1. The Association, Vienna.

Royal Australian Chemical Institute (1995) The Official Testing Methods of the RACI Cereal Chemistry Division. Eds T Westcott, D Ross. Methods 06-01; 06-02.

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