Sorghum (Sorghum bicolor (L). Moench) is used for human consumption in parts of Africa and Asia and as an animal feed mainly in the U.S. Though sorghum grain contains higher amounts of protein than other cereal grains such as wheat and corn, it is not as readily available for enzyme degradation in humans and animals. Protein body matrices called kafirins surround the starch granules in sorghum. Because the protein is less digestible, the starch is also less digestible for biofuel production. However variation for this trait exists and the line P850029 has a higher protein digestibility compared to other normal grain sorghum lines. This increase in digestibility of protein is due to the rearrangement of the kafirins in the prolamin protein bodies where, the γ-kafirins are rearranged in the seed endosperm and the amount of γ-kafirin in the grain is also reduced. The assay to phenotype the HD trait is time consuming and unpredictable. So identifying a quantitative trait loci (QTL) controlling the protein digestibility trait in sorghum would be beneficial in breeding. A recombinant inbred lines (RILs) population derived from P850029 x ‘Sureno’, were developed and used to map QTL regulating the protein digestibility trait. A single QTL was identified on chromosome 1 between Xtxp43 and Xtxp329. Validation of the identified QTL was done on heterogenous inbred families (HIFs). The results validate the same QTL identified on the RIL population on chromosome 1. Later the high digestibility trait (HD) was integrated with the Waxy trait in sorghum. The Waxy (WX) sorghums have starch completely in the form of amylopectin. The effect of endosperm type on ethanol yield and fermentation efficiencies was studied among HD, WX and HD-WX lines. The HD-WX lines fermented in a shorter time i.e. completed fermentation in 48 h and their fermentation efficiencies were also higher around 90%. The DDGS of the HD-WX lines also had lower residual starch content and 50% higher amino acid lysine content when compared to wildtype sorghum. Moreover, the relation between endosperm traits and grain yield in sorghum has not been fully explored. In this study, we compared the yield and yield components of four unique endosperm phenotypes, HD, WX, HD-WX and wildtype lines. A total of 100 F2:4 derived recombinant inbred lines population from a cross between Tx2907/P850029 were selected with 25 lines from each HD, WX, HD-WX and wild-type line were included in the study. These lines were grown in three replications in College Station and Halfway, Texas in a randomized complete block design. The results show that there are no significant differences in the grain yield.

Wheat grain quality and consumption is influenced by its constituents structure and concentrations. In the first part of the dissertation, six Canadian bread wheat cultivars; four (CDC Teal, AC Superb, AC Barrie, AC Splendor) belonging to the Canada Western Red Spring (CWRS), and two (AC Foremost, and AC Crystal) to the Canada Prairie Spring Red (CPSR) market classes were characterized for the relationship between their starch constituents and starch in vitro enzymatic hydrolysis. CPSR cultivars with relatively longer amylopectin chains of DP 37-45, reduced chain lengths of DP 15-18, and a low volume percent of small C-type starch granules, had reduced starch in vitro enzymatic hydrolysis rates. In the second part of the dissertation, near-isogenic wheat lines differing at the Waxy locus were analyzed for the influence of genome-specific granule-bound starch synthase I (GBSSI/Waxy; Wx-A, Wx-B, Wx-D) on starch composition, structure and starch in vitro enzymatic hydrolysis. Amylose concentration was more severely affected in genotypes with GBSSI missing from two genomes (double nulls) than from one genome (single nulls) of wheat, indicating dosage dependent amylose synthesis. Subtle differences in amylopectin chain length distribution were observed among non-waxy, partial and completely waxy starches, suggesting a non-limiting role of genome-specific GBSSI for amylopectin synthesis. A suppressive role of Wx-D on the short chain phenotype of wheat amylopectin was observed. In addition, Wx-D increased the volume percentage of large A-type starch granules and reduced starch hydrolysis index. Thus, among the waxy isoproteins, Wx-D might be the major contributor for reducing the rate of in vitro starch enzymatic hydrolysis in wheat. In the third part of the dissertation, endosperm starch’s physicochemical properties and structure during grain development in wheat waxy-null genotypes were analyzed. The study was conducted with pure starch isolated from wheat grains at 3-30 days post anthesis (DPA), at three day intervals. Changes in amylopectin structure were observed until 12 DPA, suggesting the formation of a basic amylopectin skeleton by this stage. A differential influence of waxy isoproteins on amylopectin structure formation has been suggested, with Wx-B and Wx-D affecting short glucan chains of DP 6-8 at 3 and 6 DPA, Wx-A being effective at 9 and 12 DPA, and Wx-D affecting DP 18-25 chains from 18-30 DPA.

Limited information exists regarding the effects of light pearling on the properties of physical grain characteristics, composition, and technological and sensory properties of selected varieties of Western Canadian barley especially hulless barley genotypes with modified starch characteristics. Nine barley genotypes with different hull (hulled and hulless) and starch characteristics (normal, waxy, and high amylose (HA)) were pearled to three differing levels. Scanning electron micrographs showed that the pericarp, testa, aleurone, and subaleurone layers were completely removed in heavily pearled barley whereas only a few outer layers were removed in minimally pearled barley. Waxy starch genotype Fibar and HA starch genotypes, SH99250 & SB94893 contained high levels of soluble β-glucan (9-11%). Waxy starch genotypes exhibited higher β-glucan solubility when cooked compared to normal and HA starch genotypes. However, HA starch genotypes had lower in vitro starch digestibility which may provide a lower glycemic response in humans.

Limited information exists regarding the effects of light pearling on the properties of physical grain characteristics, composition, and technological and sensory properties of selected varieties of Western Canadian barley especially hulless barley genotypes with modified starch characteristics. Nine barley genotypes with different hull (hulled and hulless) and starch characteristics (normal, waxy, and high amylose (HA)) were pearled to three differing levels. Scanning electron micrographs showed that the pericarp, testa, aleurone, and subaleurone layers were completely removed in heavily pearled barley whereas only a few outer layers were removed in minimally pearled barley. Waxy starch genotype Fibar and HA starch genotypes, SH99250 & SB94893 contained high levels of soluble β-glucan (9-11%). Waxy starch genotypes exhibited higher β-glucan solubility when cooked compared to normal and HA starch genotypes. However, HA starch genotypes had lower in vitro starch digestibility which may provide a lower glycemic response in humans.

This research study determines the potential to increase substantially the anisotropy of a coke from an aliphatic Waxy Oil produced by Sasol Synfuels at Secunda, South Africa. Experimental modifications included filtration, distillation and thermal treatment, followed by distillation with the aim of producing a carbonised product similar to needle coke. The substantial concentration of an iron oxide catalyst (up to 2%) in Waxy Oil is increased by an order of magnitude upon carbonisation and calcination due to low coke yield and reactivity factors. The catalyst also promotes oxidative polymerisation of the residue, acts as a barrier to mesophase formation and promotes multi-phase graphitisation. Filtration of Waxy Oil using a 0.5 ìm sintered metal filter reduces the ash content to 0.006% and increases the anisotropy of the carbonised product to 54% flow domains compared with 22% for the carbonised product of virgin Waxy Oil. Thermal treatment followed by distillation of Waxy Oil reduces the effect of organic reactivity promoters (mainly multi-alkylated aliphatics/aromatics and oxygenates), while increasing the concentration of thermally stable (C18 to C30) normal alkanes to 85% compared with 38% in the filtered Waxy Oil. Compared with the filtered Waxy Oil, thermally stabilised Waxy Oil reduces the amount of the pre-carbonisation residue (from 98.7 to 43.0%), while “static” carbonisation thereof increases the green coke yield (from 19.8 to 36.3%) and increases the anisotropicity (from 54 to 100% flow domains). The carbonisation mechanism of filtered and thermally treated Waxy Oil involves initial cracking of high molecular weight normal alkanes (C18 to C30), thus concentrating the molecular weight of normal alkanes (C18 to C22). This is followed by a slow cyclisation step involving both self condensation and cyclo addition reactions to form two- to six-ring cyclo-alkanes or hydro-aromatics. The hydro-aromatics are dehydrogenated rapidly to form methyl and di-methyl three- to six-ring substituted aromatics. Further thermal degradation dealkylates these molecules to form stable four- to six-ring “pre-mesogens”. The mesospheres are nucleated from the isotropic matrix and grow to more than 0.050 mm in diameter, with a volume of 2.61 x 10-3 mm3. Subsequent coalescence of the mesospheres produces mesospheres with diameters of over 0.200 mm and volumes of 41.82 x 10-3 mm3. The resultant microstructure of the solid carbon is composed of flow domains more than 400 ìm in length. Although needle cokes have historically been produced from aromatic residues, this research is the first to show that a coke with a similar microstructure can be produced from a totally aliphatic residue. The research thus provides potential for the development of a needle coke from a totally unique Waxy Oil residue with negligible sulphur (< 0.008%) and nitrogen (< 0.09%) contents. This is the first academic study of the chemistry of Waxy Oil. / Thesis (PhD)--University of Pretoria, 2011. / Chemical Engineering / unrestricted

Chenopodium L. is a relatively under-studied genus that includes the cultivated seed crop quinoa (Chenopodium quinoa Willd.). Quinoa is an allotetraploid (2n=4x=36, AABB genomes) that is cultivated by subsistence farmers and commercial growers in the Andean regions of South America. Approximately 60% of a quinoa seed is starch, a glucose polymer that is an important carbohydrate energy source in the human diet. Seed starch is normally comprised of amylose and amylopectin in a 1:3 ratio, but starches with different amylose:amylopectin ratios have different properties and potential uses. The accumulation of the amylose fraction of starch is controlled by a single dominant gene in quinoa, GBSSI. We report the sequencing and characterization of the GBSSI gene in 18 accessions of Chenopodium, including Andean quinoa and the related Mesoamerican chenopod grain species, C. berlandieri subsp. nuttalliae Saff. Two distinct homoeologs (GBSSIa and GBSSIb) were identified in the tetraploid accessions, and 19 different alleles were identified, including three null mutants – one in an accession of quinoa and two in a waxy landrace of C. berlandieri subsp. nuttalliae, referred to as ‘H02’. Expression analysis of the null mutants revealed that GBSSIa and GBSSIb were both strongly expressed late in quinoa and C. berlandieri subsp. nuttalliae seed development. Starch phenotyping indicated that ‘H02’ produced no amylose, likely due to its having two mutated copies of GBSSI. GBSSI sequences were used to analyze the phylogenetic relationships between quinoa and other members of the Chenopodium genus. This study and the discovery of Chenopodium GBSSI null-mutants will assist in the development of new Chenopodium crops with novel starches.

Yes / Waxy crude oils are pumped hot but upon power cut, pumping stops, the oil cools leading below the wax appearance temperature to precipitation of the wax and the formation of a gel throughout the pipe. In such a situation, what is the minimum pressure required to restart flow, not to merely deform the gel or break it? This paper provides a solution to this problem using microscopic observations under controlled cooling conditions and rheological data conducted in constant stress mode under controlled temperature and cooling conditions and restart experiments in laboratory pipelines replicating the rheometric conditions and deviations from them to inform large diameter operation in the field. Three important findings derive from the experimental data collected: (i) A fragmentation stress , rather than the static stress that precedes it, is found to be the more accurate predictor of flow re-start pressures; (ii) Waxy crude oils gels exhibit true yield stress and yielding process but also show flow on application of the slightest stress below yielding; (iii) This flow, in the elastic region, is jagged rather than continuous suggesting a consolidation process of the crystals and their agglomerates forming the gel. In the broader context of the existence of a yield stress, the data presented here show that there is such a thing as a yield stress and the concepts of a yield stress and that everything flows are not mutually exclusive.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-23T19:08:09Z No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-24T12:55:01Z (GMT) No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) / Made available in DSpace on 2017-03-24T12:55:01Z (GMT). No. of bitstreams: 1 fernandasampaio.pdf: 1013409 bytes, checksum: a971117fc3bdd9c19272fe04cac30974 (MD5) Previous issue date: 2009-02-13 / O gênero Lippia é um dos principais da família Verbenaceae e em sua maior parte está concentrado no Brasil, México, Paraguai e Argentina com poucas espécies endêmicas na África. O objetivo deste trabalho foi a construção de uma hipótese filogenética para 39 espécies do gênero Lippia ocorrentes no Brasil, Argentina, Bolívia, Paraguai e Uruguai com base em dados moleculares das regiões ITS, Waxy, TrnL-F e trnQ-rps16. As sequências foram amplificadas e purificadas para posterior seqüenciamento. As análises foram feitas utilizando-se Máxima Verossimilhança e Inferência Bayesiana. O presente trabalho revelou, pela primeira vez, aspectos filogenéticos de espécies do gênero Lippia com base em caracteres moleculares. De modo geral, as árvores filogenéticas baseadas nas diferentes regiões gênicas estudadas revelaram questões importantes como é o caso do monofiletismo da seção Goniostachyum. Outro ponto importante envolve a falta de resolução das seções Dipterocalix, Rhodolippia e Zapania. Dentre elas destaca-se a seção Zapania que constitui em vários aspectos estudados, a seção mais diversa. Embora o presente trabalho tenha mostrado aspectos inéditos com relação à organização filogenética de espécies e seções do gênero Lippia, a questão da especiação no gênero permanece em aberto. É possível que para resolver este problema sejam necessários estudos populacionais e filogeográficos, embasados por uma análise filogenética com maior número de genes e principalmente, envolvendo um maior número de espécies. / Lippia is one of the most important genus of the Verbenaceae family. It is mainly concentrated in Brazil, Mexico, Paraguay and Argentina with few endemic species in Africa. The present study was done in order to construct a phylogenetic hypothesis for 39 species of the genus Lippia from Brazil, Argentina, Bolivia, Paraguay and Uruguay based on molecular data of regions ITS, Waxy, TrnL-F and rps16-trnQ. The sequences were amplified and purified for subsequent sequencing. The phylogenetic analyses were done using the Maximum Likelihood and Bayesian Inference. It was possible to show for the first time, phylogenetic aspects of the genus Lippia based on molecular data. In general, the phylogenetic trees based on different gene regions revealed important points such as the monophyly of Goniostachyum section. Another important point involves the lack of resolution of the sections Dipterocalix, Rhodolippia and mainly Zapania which is the most diverse among them. Although this work has shown new aspects about the phylogenetic organization of sections and species of the genus Lippia, the speciation process of the genus remains an open question. To resolve this problem, additional studies using phylogeographic and population genetics approaches, based on a phylogenetic analysis with greater numbers of genes and mainly involving a great number of species should be necessary.

Doctor of Philosophy / Department of Grain Science and Industry / Yong Cheng Shi / To realize the full potential of waxy wheat flours in food applications, six advanced hard waxy wheat lines were studied. Pasting properties of waxy wheat flours as well as factors governing the pasting properties were investigated. Waxy wheat starch granules swelled more extensively and were more prone to α-amylase degradation than normal wheat starch. A combination of endogenous α-amylase activity and protein matrix contributed to a large variation of pasting properties of waxy wheat flours. Bi-axial extension properties classified dough from waxy wheat as in-elastic. Waxy wheat flour had higher water absorption and lower mixing time than normal wheat flour. Waxy wheat starch affected protein hydration but not protein extractability after optimum dough mixing. Presence of some non-protein free thiol contents and some gliadins acting as chain terminators could be the underlying reasons for waxy wheat flours producing slack dough. In an effort to improve functionality of waxy wheat flours, hydro-thermal processing was used. Two temperatures (140 and 160°C), three moisture contents (0, 12.4 and 20%), and four exposure times (0, 5, 15, 30 and 60 min) were employed. Hydrothermal processing resulted in non-cohesive waxy wheat flours with high viscosity and greater acid stability than native waxy wheat flour. A closer investigation revealed the possible role of endosperm proteins in improving pasting properties of waxy wheat flours. Upon thermal processing, waxy wheat flours demonstrated a long hydration time before forming dough. Heating decreased protein solubility while no changes in starch molecular weight distribution were observed. Our results indicate that hydro-thermal processing results in increased starch protein interaction. As part of application of waxy wheat, bread was baked by replacing normal wheat flour with two hard waxy wheat flours at 15, 30, and 45% levels. Substitution with waxy wheat flour resulted in higher loaf volume and softer loaves. However, substitution at > 30% resulted in excessive post-bake shrinkage and a ‘key-hole’ shape with an open crumb structure. Bread crumb microstructure indicated a loss of starch granule rigidity and fusing of starch granules. Soluble starch content was significantly higher in bread 1-day old crumb containing waxy wheat flour than in control bread.

Master of Science / Department of Grain Science and Industry / David L. Wetzel / Isogenic waxy wheat lines differ from their non waxy (normal) parents in functionality, end use, and chemical (i.e. amylopectin/amylose, lipid) contents. Other investigations of waxy and parent wheats involved the carbohydrate and protein fractions. The goal of this work is to apply chemical images to discriminate between the waxy and parent wheats and define the contribution of contrasting lipid profiles. Recent waxy topics include current interest in plant breeding activity to develop new lines that incorporate desirable traits with advantageous success in baking and milling, and the differences needed in milling techniques for waxy versus normal wheats that may be associated with lipids. From our empirical preliminary success in sorting parent wheat kernels from waxy wheat full null specimens by nearIR chemical imaging it was anticipated that using fundamental vibrational spectra in the mid infrared would provide the chemical basis of discrimination. FT-IR microspectroscopic in situ probing and imaging of kernel frozen sections was applied to genetically pure, well documented isogenic breeding lines. With the use of high spatial resolution, elucidation of fundamental vibrations of mid IR provides chemical manifestation of the genetic expression that differentiates waxy wheats from their parent wheats. Comparison between numerous contiguous pixels, typically 3,000 for each type, establishes a consensus and a mean spectrum with characteristic bands for waxy and parent. Extractions with solvents of differing polarity were employed to aid in lipid extraction in situ and kernel extracted endosperm. Differences between kernel sections of waxy and parent are observed using FT-IR microspectroscopic imaging. However, revealing lipid class contribution to the molecular bands required infrared analysis after selective extraction. Triple mass spectrometry of lipid molecule ions was used for compositional analyses to enhance lipid class profile distinction. A normal and waxy advanced breeding line wheat were also analyzed via the same methods. It was noted that digalactoslydyglyercides are the most abundant lipids in all samples, however the relative lipid profiles of normal wheat versus waxy wheat differ as well as tetraploid versus hexaploid. It is observed that in the endosperm of all parent wheat versus waxy wheat specimens analyzed, all waxy wheat specimens contained higher lipid content. Methods were also applied to partial waxy isogenic cultivars to determine detection limits that correspond to the degree of waxy genetic expression.