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Title: Genetic and environmental factors controlling acrylamide formation in wheat and rye products
Author: Curtis, Tanya Yordanova
ISNI:       0000 0004 2724 2982
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2011
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Acrylamide formation in cooked food has become a significant problem for the food industry. This study concerned the accumulation of free asparagine, one of the precursors for acrylamide formation, in wheat and rye grain. Asparagine concentration was found to be greatly affected by environmental conditions (E), genetic factors (G) and the interaction between the two (G x E). One of the environmental conditions controlling free asparagine accumulation in wheat grain was sulphur deficiency, which caused an increase of up to thirty-fold in free asparagine concentration. Sulphur deficiency and free asparagine concentration were linearly related to the amount of acrylamide that formed when wheat flour was heated at 180°C. Asparagine concentration was also the main determinant of acrylamide formation in rye but, unlike in wheat, it was not affected by sulphur availability, at least under field conditions. Rye flour had lower acrylamide forming potential than wheat per unit of asparagine, possibly due to different concentrations of other free amino acids in the grain (proline). Quantitative trait loci (QTL) for free asparagine concentration and therefore acrylamide risk were found on chromosomes 18, 2A and 7A. QTL were also identified for alanine, glutamine, glycine, lysine, proline, serine, threonine, tryptophan and tyrosine possibly aided by the environmental factors. A cluster of these QTL was located on chromosome 3A in an area associated with the control of wheat yield. Matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI- TOF-MS) was used to show the distribution of asparagine in developing wheat grain fourteen days post anthesis. In grain from plants grown under normal conditions, most free asparagine was in the embryo and aleurone layer (bran fraction), while in grain from plants grown under sulphur deficient conditions there was great accumulation of free asparagine in the endosperm (white flour fraction). Reduction of acrylamide content could be achieved immediately by selection of low acrylamide risk varieties for cultivation and avoidance of sulphur deficiency in wheat. Further improvement could be made by breeding new, low asparagine varieties based on the QTL analyses.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available