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GrainGenes Reference Report: CCM-79-183

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Reference
CCM-79-183
Title
Swelling index of glutenin test. I. Method and comparison with sedimentation, gel-protein, and insoluble glutenin tests
Journal
Cereal Chemistry
Year
2002
Volume
79
Pages
183-189
Author
Wang C
Kovacs MIP
Abstract
Summary: Molecular weight distribution of wheat proteins is primarily responsible for the viscoelastic properties of flour dough. Furthermore, the amount of SDS insoluble proteins (mainly high molecular weight glutenin) plays the major role. We have developed a simple test to determine the swelling power of glutenin (swelling index of glutenin or SIG) for predicting dough properties and end-use quality. Flour samples (40 mg) were hydrated in distilled water and then allowed to swell in nonreducing solvents (SDS, lactic acid, or mixtures of the two) followed by low speed centrifugation. The SIG was calculated as the weight of the residue divided by the original sample weight. The SIG test was compared with the results from other small-scale tests for 20 flour samples. SIG tests showed highly significant correlations with the gel protein and insoluble glutenin test (r greater than or equal to 0.85, r greater than or equal to 0.93, P < 0.001, respectively) and significant correlations with SDS and Zeleny sedimentation tests (r greater than or equal to 0.74, r greater than or equal to 0.72, P < 0.001, respectively). The swelling capacity of glutenin depended on swelling time and mixing intensity in nonreducing solvents. Swelling curves obtained from SIG values versus different swelling time can be divided into three distinct stages: swelling, swollen, and breakdown. These stages may reflect soluble and insoluble glutenin contents and quality among different cultivars. SIG test values for short swelling time and low mixing intensity were significantly correlated to gel protein content and SDS-sedimentation values (r = 0.96, r = 0.90, P < 0.001, respectively). SIG test values for long swelling time and high mixing intensity were significantly correlated to insoluble glutenin content (r = 0.96, P < 0.001). The difference of swelling condition (time and mixing intensity) among these small-scale methods is the reason for their different correlations with insoluble glutenin content. Because large numbers of samples can be analyzed in a short time with excellent reproducibility, the SIG test may be a useful screening test in a breeding program, predicting the quantity and quality of insoluble glutenin
Keyword
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20
40
acid
breadmaking quality
breakdown
breeding
capacity
correlation
cultivar
dough
dough properties
dough property
end-use quality
flour
functional properties
glutenin
high molecular weight
high molecular weight glutenin
index
intensities
lactic acid
method
mixing
mixture
molecular weight
monomeric proteins
program
properties
protein
protein content
quality
quantities
reproducibility
residue
screening
screening-test
sds
sds sedimentation
sedimentation
sedimentation test
viscoelastic properties
water
wheat flour
wheat protein

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