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Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Variation in quantity and quality of gluten proteins is largely responsible for the genotypic differences associated with the dough rheological parameters, maximum resistance (R[subscript]max) and extensibility (Ext.). In the context of bread making, doughs characteristic of good quality have moderate to high extensograph maximum resistance (R[subscript]max) and high extensibility (Ext.). The term usually applied to describe the balance between these two parameters is dough strength. Generally, weak doughs perform poorly in baking tests and as dough strength increases, bread making quality also increases. Important proteins that constitute the 'gluten complex' include high molecular weight glutenin subunits (HMW-GSs) and low molecular weight glutenin subunits (LMW-GSs). These proteins, which interact to produce large polymeric proteins, are coded at the Glu-1 and Glu-3 loci on group 1 chromosomes, respectively. Extensive allelic variation exists a1 each of the G/u-1 and Glu-3 loci. Field trials (4 years) and physical dough quality tests on harvested grain from a set of near-isogenic lines, differing in glutenin composition, were used to investigate the effect of numerous glutenin alleles on dough rheological parameters. Glutenin allele main effects were ranked as follows: Glu-A1 a = p = b > c for R[subscript]max and Glu-A1 a = b = p > C for Ext.; Glu-B1 i ≥ b = c > d = a for R[subscript]max and Glu-B1 a = i = c ≥ b ≥ d for Ext.; Glu-D1d > Glu-D1a = Glu-D1b ≥ Glu-D1f for R[subscript]max and Glu-D1 a = b = f ≥ d for Ext.; Glu-A3 d = b ≥ c = f ≥ a > e for R[subscript]max and Glu-A3 b = a = d = c = f ≥ e for Ext.; Glu-B3 g ≥ b = m ≥ d = i = h = f≥ a ≥ c for R[subscript]max and Glu-B3 i = d ≥ g = f = m ≥ b = c = h = a for Ext.; Glu-D3 a-Gli-D1 = f ≥ c = d = a ≥ b for R[subscript]max and Glu-D3 d ≥ a-Gli-D1 ≥ a ≥ b = c = f for Ext. The influence of protein content and two-way glutenin allele interactions are also discussed. Another aspect of this work investigated the relationship between HMW-GS expression levels and quality. RP-HPLC was used to quantify the proportion (% area) of individual HMW-GSs relative to total HMW-GSs. Except for Glu-BId (6+8*), the B-genome contributed the highest percentage of HMW-GSs and was significantly higher (P<O.OO1) in cultivars that contained the Glu-BIal allele. A high proportion of IBx subunits compared to IDx subunits (= 2.3, Glu-B1al) correlated with varieties reported to have extra strong dough properties, while a 1Bx:1Dx ratio of = 1.3 (Glu-B1 i, f, c, u and ak) was typical of varieties with moderate to high dough strength characteristics. In varieties which contain Glu-B1 alleles reported to produce weak: doughs the 1Bx:I1Dx value was = 1.0 (Glu-B1e) and = 0.6 (Gfu-B1). This suggests that the overall proportion of Glu-B1 subunits has a major influence on dough strength and that the proportion of 1Bx relative to 1Dx subunits, as determined by RP-HPLC, could be used to predict dough quality. RP-HPLC analysis also enabled the identification of varieties that contained the Glu-B1al allele and overexpressed subunit Glu-B1 7x, including the most likely source of this allele in bread wheat cultivars. Novel HMW-GS alleles in related wheat species with good quality potential were also identified. A simple small-scale screening assay was developed to efficiently assess the protein quality attributes associated with accessions of synthetic hexaploids, T tauschii and T dicoccoides. Development of the Turbidity assay is described and was used in conjunction with SE-HPLC and SDS-PAGE to conflrm and characterise previously undescribed HMW-GSs. The HMW-GS composition of T dicoccoides is discussed in detail where there were 49 HMW-GSs which combined to produce 54 different HMW-GS banding patterns. Accordingly, allelic designations were tentatively assigned to either individual or subunit pairs and these are also Teported in this manuscript. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277743 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Variation in quantity and quality of gluten proteins is largely responsible for the genotypic differences associated with the dough rheological parameters, maximum resistance (R[subscript]max) and extensibility (Ext.). In the context of bread making, doughs characteristic of good quality have moderate to high extensograph maximum resistance (R[subscript]max) and high extensibility (Ext.). The term usually applied to describe the balance between these two parameters is dough strength. Generally, weak doughs perform poorly in baking tests and as dough strength increases, bread making quality also increases. Important proteins that constitute the 'gluten complex' include high molecular weight glutenin subunits (HMW-GSs) and low molecular weight glutenin subunits (LMW-GSs). These proteins, which interact to produce large polymeric proteins, are coded at the Glu-1 and Glu-3 loci on group 1 chromosomes, respectively. Extensive allelic variation exists a1 each of the G/u-1 and Glu-3 loci. Field trials (4 years) and physical dough quality tests on harvested grain from a set of near-isogenic lines, differing in glutenin composition, were used to investigate the effect of numerous glutenin alleles on dough rheological parameters. Glutenin allele main effects were ranked as follows: Glu-A1 a = p = b > c for R[subscript]max and Glu-A1 a = b = p > C for Ext.; Glu-B1 i ≥ b = c > d = a for R[subscript]max and Glu-B1 a = i = c ≥ b ≥ d for Ext.; Glu-D1d > Glu-D1a = Glu-D1b ≥ Glu-D1f for R[subscript]max and Glu-D1 a = b = f ≥ d for Ext.; Glu-A3 d = b ≥ c = f ≥ a > e for R[subscript]max and Glu-A3 b = a = d = c = f ≥ e for Ext.; Glu-B3 g ≥ b = m ≥ d = i = h = f≥ a ≥ c for R[subscript]max and Glu-B3 i = d ≥ g = f = m ≥ b = c = h = a for Ext.; Glu-D3 a-Gli-D1 = f ≥ c = d = a ≥ b for R[subscript]max and Glu-D3 d ≥ a-Gli-D1 ≥ a ≥ b = c = f for Ext. The influence of protein content and two-way glutenin allele interactions are also discussed. Another aspect of this work investigated the relationship between HMW-GS expression levels and quality. RP-HPLC was used to quantify the proportion (% area) of individual HMW-GSs relative to total HMW-GSs. Except for Glu-BId (6+8*), the B-genome contributed the highest percentage of HMW-GSs and was significantly higher (P<O.OO1) in cultivars that contained the Glu-BIal allele. A high proportion of IBx subunits compared to IDx subunits (= 2.3, Glu-B1al) correlated with varieties reported to have extra strong dough properties, while a 1Bx:1Dx ratio of = 1.3 (Glu-B1 i, f, c, u and ak) was typical of varieties with moderate to high dough strength characteristics. In varieties which contain Glu-B1 alleles reported to produce weak: doughs the 1Bx:I1Dx value was = 1.0 (Glu-B1e) and = 0.6 (Gfu-B1). This suggests that the overall proportion of Glu-B1 subunits has a major influence on dough strength and that the proportion of 1Bx relative to 1Dx subunits, as determined by RP-HPLC, could be used to predict dough quality. RP-HPLC analysis also enabled the identification of varieties that contained the Glu-B1al allele and overexpressed subunit Glu-B1 7x, including the most likely source of this allele in bread wheat cultivars. Novel HMW-GS alleles in related wheat species with good quality potential were also identified. A simple small-scale screening assay was developed to efficiently assess the protein quality attributes associated with accessions of synthetic hexaploids, T tauschii and T dicoccoides. Development of the Turbidity assay is described and was used in conjunction with SE-HPLC and SDS-PAGE to conflrm and characterise previously undescribed HMW-GSs. The HMW-GS composition of T dicoccoides is discussed in detail where there were 49 HMW-GSs which combined to produce 54 different HMW-GS banding patterns. Accordingly, allelic designations were tentatively assigned to either individual or subunit pairs and these are also Teported in this manuscript. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1277743 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007

M.Tech. / Sorghum (Sorghum bicolour (L) Moench) and millets are drought resistant cereals (Kent and Evers, 1994) that can grow in areas with poor soils and inconsistent rainfall (Dendy, 1995) where other crops fail. They serve as staple food for many people in tropical sub- Saharan Africa and Asia (Klopfenstein and Hoseney, 1995). Traditionally, bread is made from wheat, which is a temperate cereal not able to grow well in these tropical regions. Leavened bread is seldom made from anything other than wheat (Alais and Linden, 1991) and this is because of the unique visco-elastic property of wheat flour (Hoseney, 1994). Unfortunately in tropical regions such as South Africa wheat is imported at a premium price. The aim of this study was to produce a wheat-finger millet composite flour which is suitable for bread making. Finger millet grain (FMV6) was milled with a laboratory hammer mill fitted with a 0.8 mm screen. The following wheat-finger millet composite doughs were made using standard bread making methods, 0:100 (Control); 90:10; 80:20; 70:30, respectively. Selected quality attributes of the composite dough and the bread thereof were analysed using standard methods. The formulation with 10% finger millet showed better results than other formulations. One formulation (80:20) was selected for improvement which included mixing ingredients at elevated temperatures (50°C and 93°C) and addition of 0.002% of a lipase enzyme, lipopan F; 0.3% vital wheat gluten and a combination of 0.002% lipopan F and 0.3% gluten. All formulations (including the basic formulation) contained Fungamyl Super MA (enzyme combination which contained fungal a-amylase and a xylanase). As the mixing temperatures were elevated, loaf volume decreased but when the industrial baking enzymes were introduced there was an improvement in peak time, dough stability and loaf volume. Image analysis showed that there was an improvement in crumb structure and bubble size distribution after the application of enzyme lipopan F. The crumb colour was lighter and softer when a combination of enzyme lipopan F and vital wheat gluten was applied. The bread made from formulation 80:20 with addition of a combination of enzyme lipopan F and vital wheat gluten (WFM2GL) was more acceptable than other formulations except the control bread. The bread had a high score in taste, crust appearance and mouth feel. The results suggest that there is a potential for producing a composite bread by substituting wheat flour with finger millet flour (up to 20%); mixing at 25°C with application of a combination of a lipase and vital wheat gluten. However, more work is needed to improve the quality of the bread to a greater extent.

Doctor of Philosophy / Genetics Interdepartmental Program / Allan K. Fritz / Globally, wheat (Triticum aestivum L.) is the second most widely grown cereal grain and is primarily used as a food crop. To meet the demands for human consumption, cultivars must possess suitable end-use quality for release and acceptability. However, breeding for quality traits is often considered a secondary goal, largely due to amount of seed needed and overall expense of such testing. Without testing and selection, many undesirable materials tend to be advanced. Here we demonstrate two methods, mega-genome-wide association mapping and genomic selection, to enhance selection accuracy for quality traits in the CIMMYT bread wheat breeding program. The methods were developed using high-density SNPs detected from genotyping-by-sequencing and processing and end-use quality evaluations from unbalanced yield trial entries (n = 4,095) during 2009 to 2014, at Ciudad Obregon, Sonora, Mexico. Genome-wide association mapping, with covariates for population structure and kinship, was applied for each trait to each site-year individually and results were combined across years in a mega-analysis using an inverse variance, fixed effect model in JMP-Genomics. This method presents a new way to detect genes of interest within a breeding program and develop markers for selection of these traits, which can then be used in earlier generations. Genomic selection prediction models were developed using ridge regression, Gaussian kernel, partial least squares, elastic net, and random forest models in R. With these predictions genomic selection (GS) can be applied at earlier stages and undesirable materials culled before implementing expensive yield and quality screenings. In general, prediction accuracy increased over time as more data was available to train the model. Based on these prediction accuracies, we conclude that genomic selection can be a useful tool to facilitate earlier generation selection for end-use quality in CIMMYT bread wheat breeding. Genomic selection was conducted for processing and end-use quality traits in the Kansas hard red winter wheat breeding unit. Genomic predictions demonstrate increases in accuracy with added data over time. These data demonstrate that current genomic selection models will need more data to continue improvement in prediction accuracy.

Ce travail consiste en l’étude de la faisabilité de l’application du chauffage ohmique aux opérations de fermentation et de cuisson de la pâte à pain, dans l’objectif d’une production de pain de mie sans croûte. Les caractéristiques de la pâte ont été étudiées, et principalement l’évolution de sa conductivité électrique – moteur de la génération de chaleur en chauffage ohmique. La conductivité électrique est très fortement dépendante des teneurs en sel et en eau de la pâte. Elle augmente également avec la température, mais diminue avec la porosité de la pâte et lors de la gélatinisation de l’amidon. Des équations simples ont pu être déterminées pour son calcul. Un premier modèle thermique a été développé afin de mieux comprendre la formation de gradients de température au sein du produit.Un prototype de four ohmique a été construit, permettant de réaliser à la fois la fermentation et la cuisson de pain de mie sans croûte. L’utilisation du chauffage ohmique permet une réduction significative de la phase de latence et donc du temps de fermentation. Une analyse d’images par tomographie rayons X a montré une porosité plusdéveloppée dans le produit fini, de même qu’une croissance des pores plus importante dans la partie supérieure du pain, contrairement à une cuisson conventionnelle.L’utilisation du chauffage ohmique en panification peut mener à des gains énergétiques potentiels d’un facteur 10. Les rendements énergétiques du procédé ont été évaluéssur gel de tylose, et sont comparables aux valeurs observées par de précédents auteurs. Enfin, un modèle numérique simplifié de transfert de chaleur et de matière a été développé, dans le but d’être employé comme outil prédictif lors d’une cuisson de pain par chauffage ohmique. / This work aims at studying the feasibility of applying ohmic heating to the proofing and baking steps of bread dough, for an objective of crustless bread production. The characteristics of the dough were studied, and mainly the evolution of its electrical conductivity – keyvariable of the heat generation in ohmic heating. The electrical conductivity is highly dependent on the salt and water contents of the dough. It also increases with the temperature, but decreases with the porosity of the dough and during the starch gelatinization step. Simple equations were used to calculate its evolution. A first thermal model was developed to understand better the formation of temperature gradients in the product.An ohmic oven prototype was built in order to realize proofing and baking of crustless bread in the same apparatus. The use of ohmic heating leads to a significant decrease of the lag time and therefore of the proofing time. An X-ray tomography image analysis showed a higher development of the porosity in the final product when using ohmic heating, as well as a more developed network in the upper part of the bread, contrary to a conventional baking.The use of ohmic heating may lead to potential energy savings of a factor of 10. The energy rates of the process were calculated using a gel of tylose, and were in the range of what could be observed by previous authors. Finally, a simplified numerical model of heat and mass transfer was developed, to be used as a predictive tool during the baking of bread by ohmic heating

Soy peroxidase enzyme obtained from isoelectic precipitation procedures was added to all-purpose flour (APF) to assess its effects on the rheological properties and consumer acceptability of yeast bread. A pH 4.8 isoelectrically precipitated fraction from soybeans was used because it produced the most precipitate and had about the same peroxidase activity as the other fractions. Gluten strength was determined using a farinograph for seven treatment groups: control (all-purpose flour), bread flour, all-purpose flour + soy flour, bread flour + soy flour, all purpose flour + pH 4.8 precipitate, all-purpose flour + 15 mg soybean peroxidase, and all-purpose flour + 25 mg soybean peroxidase. Four types of yeast bread were baked for loaf volume determination, texture analysis, and consumer acceptability: a control loaf using only all-purpose flour, a reference loaf using all bread flour, a loaf with all purpose flour + whole soy flour, and a loaf with all-purpose flour + pH 4.8 soy precipitate. The APF+soy flour, bread flour, bread flour + soy flour, and the APF + pH 4.8 precipitate produced an improvement in the gluten strength and mixing tolerance compared to the control (p<0.05). However, the improvement by the addition of the pH 4.8 precipitate cannot be attributed to the peroxidase enzyme because peroxidase needs hydrogen peroxide as a substrate and no hydrogen peroxidase could be added to the farinogragh; therefore, it was concluded that the increase in gluten strength produced by the pH 4.8 soy precipitate was due to an unknown component present in the pH 4.8 fraction. No significant differences (p<0.05) were found in crumb or crust texture for any of the treatment groups. The addition of pH 4.8 precipitate to APF significantly decreased (p<0.05) loaf volume compared to bread made from bread flour. The results from sensory analysis showed there was no difference in preference for any of the breads. This study showed no conclusive evidence that peroxidase enzyme improved gluten strength or loaf volume of yeast bread, but further research is warranted. / Master of Science

Content of free- (FPC) and bound- phenolics (BPC) significantly (p<0.05) increased during mixing, fermenting and baking. Bread crust and crumb contained the highest FPC and BPC, respectively. Antioxidant activities (AOA) followed the trends of their respective phenolic contents. HPLC analysis demonstrated that different phenolic acids showed various responses to the bread-making process. Total anthocyanin content (TAC) was significantly (p<0.05) reduced through mixing and baking, but fermentation elevated the levels. Anthocyanin extract of purple wheat exerted higher AOA than those of common wheat. Digested purple wheat extracts after in-vitro digestion demonstrated significantly (p<0.05) higher AOA than common wheat. During in-vitro testing, extracts exhibited concentration-dependent effects, while the use of different cell lines exhibited varying levels of cellular antioxidant and pro-oxidant properties. Purple wheat demonstrated higher cytoprotectivity and cellular AOA than those of common wheat. Our findings suggest that purple wheat has the potential to act as functional food in bakery products.