The major components of wheat flour are keys to its functionality in processing and product quality. The major components, other than the lipids, are polymers: starch, protein, and non-starchy polysaccharides (NSP). In wheat NSP are primarily arabinoxylans (AX). These components are compartmentalized in the grain but are forced into close contact after the disruption caused by the milling process. These components further interact once water is added to the flour to create doughs and batters. It is these interactions and the water holding capacities of these polymeric components that are the unifying thread for most of this dissertation, other than the inclusion of nutritional traits in chapters 6 and 7. This dissertation consists of three independent studies, the last of which had two parts. Study one was "Effect of carbonate on co-extraction of arabinoxylans (AX) with glutenin macropolymer (GMP)". The aim of this study was to investigate if the level of AX in GMP increased under alkaline extraction conditions compared to extractions done in water. The amount of wet GMP obtained from alkaline extraction was greater than that from water extraction. Hard wheats had overall higher GMP wet weights than soft wheats. The level of AX in GMP extracted under alkaline conditions was greater than that in GMP extracted with water and the amount of increase was generally higher in soft wheats.
Study two was "Optimization of water addition to noodle doughs". The aim of this study was to determine if a lubricated squeezing flow (LSF) technique could be useful in determination of optimum water addition to noodle doughs. Comparing the LSF method with alternative methods (Mixograph and sieving test), optimum water additions predicted by LSF for both salted and alkaline soft-wheat derived noodle doughs were equivalent or slightly higher than those predicted by the Mixograph and sieving test. For both salted and alkaline hard-wheat derived noodle doughs, optimum water additions predicted by the LSF method were substantial higher than those predicted by the Mixograph but equivalent or slightly higher than those predicted by the sieving test. Relaxation time was the most useful parameter in determining optimum water addition for the soft-wheat noodle doughs. The LSF method in its current form was found to be not adequate for all noodle types. Additional work with LSF parameters altered to improve sensitivity and with more of samples should be performed.
Study three was "Determination of wheat quality and quantitative trait locus analysis". Part 1 was to measure a comprehensive set of quality phenotypes (including nutritional parameters) on a wheat population derived from the cross Tubbs [soft] x NSA98-0995 [hard]; (T x N). Part 2 was to identify if there were quantitative trait loci (QTL) associated with the traits determined in part 1. Considerable and transgressive segregation was observed for many of the studied traits. The transgressive segregation could useful, in that lines with superior soft-wheat quality can be identified that could be introduced quickly into the wheat breeding program from this elite x elite cross. Hardness index was significantly correlated with several important traits related to the solvent absorption capacity of the flour. Composite interval mapping detected a total of significant 28 QTLs on 10 wheat chromosomes for 15 end-use quality and nutrition traits in 2 harvest years. QTLs for total antioxidant activity (TAA) and total phenolic content (TPC) were identified for the first time. QTLs for TAA were on chromosomes 3B and 5BS, while the QTL for TPC was on chromosome 7AC. Hybridization between Tubbs and NSA surprisingly produced superior soft-wheat quality with potentially higher in nutritional values. The QTLs identified in this study could be useful in marker-assisted selection for future pre-selection of progeny from Tubbs or NSA. / Graduation date: 2012
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28583 |
| Date | 16 March 2012 |
| Creators | Kongraksawech, Teepakorn |
| Contributors | Ross, Andrew S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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