Thesis (Ph. D.)--Kansas State University, 2004. / Includes bibliographical references.

Thesis (Ph.D.)(Food Science)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references.

Dissertation (PhD)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (MSc (Genetics. Institute of Plant Biotechnology))--Stellenbosch University, 2008. / Sugarcane (Saccharum spp.) is an important crop which is cultivated worldwide for the high sucrose content in its stem. Conventional plant breeding has proven to be very successful over the years with regard to the enhancement of yield characteristics but due to the exhaustion of genetic potential in the commercial sugarcane germplasm recent progress has been slow. Genetic engineering seems to be a more attractive approach to enhance sucrose content and pest resistance in the stems but requires appropriate transgenes and suitable promoter. A promoter is essential to drive the transcription of a gene and is therefore critical to the success of transgenic approaches in sugarcane crop improvement. A negligible number of strong stem-specific promoters is available for use in sugarcane and this is one of the major limitations to genetic engineering. The goal of this project was to isolate a stemspecific promoter from maize and sorghum to drive stem-specific transgene expression in sugarcane. The approach used was to source promoters from non-sugarcane grass species with less complex genomes to simplify isolation and possibly counteract silencing. A cDNA sequence (SS) (EST clone, Accession number AW746904) from sugarcane was shown by Northern and Southern analysis to be stem-specific and to have an appropriately low copy number. The SS gene sequence was not expressed in the leaves of maize, sorghum or the sugarcane cultivars and prominent expression was observed only in the stems of the sugarcane hybrids N19 and 88H0019. The SS gene sequence was used to isolate its upstream regions from a Lambda genomic library of maize (Zea mays) and a sorghum (Sorghum bicolor) Bacterial Artificial Chromosome library (BAC). Of the four sorghum and six maize clones obtained in this study, a 4500 bp maize genomic DNA fragment (λ5) was sub-cloned in three fragments into separate pBluescript vectors using the ‘forced’ cloning approach for sequence and database (BLASTN) analysis. This revealed the complete SS gene sequence (975 bp), the promoter and a 300 bp intron region. A stretch of DNA sequence from nucleotides 664-3194 from the maize clone 5 sequence was designated the maize5-pro. Following sequence alignment of the maize and sugarcane promoter regions, significant sequence identity (68%) was observed between nucleotide 1675 and 3194 in maize and nucleotide 1506 and 2947 in sugarcane. The distance between the putative TATA-box and the TSS for this promoter (30 bp) was found to fall within the expected range of 32± 7 bp. The promoter region was analysed for possible cis-acting regulatory elements and revealed several promoter elements that are common in other plant promoters. The comparisons made between the putative transcription factors in maizepro-5 and the sugarcane promoter show that both promoter sequences are very similar as they share ten of the same transcription factors. However, the transcriptional factors WBOX, SRE and SP8BFIBSP8BIB are unique to the maize5-pro and the TAAG motif to the sugarcane promoter. Primers were designed with appropriate restriction sites and the promoter and intron (2850 bp) region was amplified by PCR (Polymerase chain reaction). The amplified fragment was fused inframe to the GUS reporter gene encoding β-glucuronidase to produce a transformation test vector. This will be used in future work to assess the functionality of the promoter through the production of stable transformants in which GUS activity can be measured in a range of tissues.

Orientador: Marcelo Andreotti / Resumo: O consórcio do sorgo com braquiária na entressafra, no Cerrado de baixa altitude, tem se mostrado como uma alternativa para a produção de grãos e forragem nesse período de condições climáticas adversas para outras culturas. Entretanto, são necessárias informações sobre a viabilidade do consórcio de ambas as culturas sob tais condições e se o uso de bactérias diazotróficas é uma alternativa na economia da adubação nitrogenada. Este estudo objetivou determinar o manejo mais adequado da adubação nitrogenada do sorgo granífero, inoculado ou não com Azospirillum brasilense, em cultivo solteiro ou em consórcio com capim, na safrinha, bem como acúmulo de macronutrientes na matéria seca da parte aérea de ambas as culturas em sistema plantio direto. O experimento foi conduzido em Selvíria-MS, num Latossolo Vermelho distrófico de textura argilosa, e o delineamento experimental foi em blocos casualizados com quatro repetições, em esquema fatorial 3x2x2, com o manejo do N (ureia) da seguinte forma: aplicação de 100% da dose na semeadura; 100% apenas em cobertura; e parcelada (30% na semeadura e 70% em cobertura), na dose de 120 kg ha-1 de N, no início do florescimento do sorgo; cultivo do sorgo solteiro ou em consórcio com capim; com as sementes de sorgo inoculadas ou não com A. brasilense. Foram avaliados os componentes morfológicos e produtividade de matéria seca da parte aérea do sorgo, sua produtividade de grãos e matéria seca da parte aérea do capim. Em geral, o manejo da adubação n... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Master of Science / Department of Grain Science and Industry / Yonghui Li / Antioxidants are widely used in food industries to delay lipid oxidation and prevent oxidative deterioration. In recent years, growing interests in developing safe and efficient antioxidants from natural sources due to the health-related risks associated with synthetic antioxidants. Recently, peptide antioxidants have drawn growing interests as since proteins are a macronutrient with various functionalities and high consumer acceptability. A lot of dietary proteins have been validated for their antioxidant potentials especially those obtained from animal proteins, nuts and pulses. Relatively less information is available on characterizing the antioxidant profile of cereal protein, and even less for sorghum protein. Sorghum is the fifth largest crop worldwide and is the third in United States. U.S. is leading in global sorghum production and distribution, and the state of Kansas is producing nearly half of U.S. sorghum. Currently, about one third of the U.S. sorghum is being used for ethanol production, resulting in more than 450 kilotons of by-products (e.g., DDGS) annually, which were often discarded or underutilized. DDGS is a premium protein source (~ 30% protein) that could be potentially modified into value-added products such as peptide antioxidants. In this study, relevant literatures detailing the extraction of cereal proteins, enzymatic hydrolysis of proteins, purification and characterization of hydrolysates, and evaluation of antioxidant profiles were extensively reviewed in Chapter 1. As preliminary experiments, sorghum kafirin protein was extracted from defatted sorghum white flour and hydrolyzed by 10 different types of enzymes from microbial, plant and animal sources. Hydrolysates prepared with Neutrase, Alcalase, and Papain displayed the most promising antioxidant activities as well as total protein recovery were primarily selected and investigated in depth described in Chapter 2, Chapter 3, and Chapter 4. The reaction conditions including substrate content, enzyme-to-substrate ratio, and hydrolysis time are critical parameters in producing peptides with desired activity and consistency, were therefore examined and optimized for each case of kafirin hydrolysates. The antioxidant capacity of the resulting hydrolysates was measured for antioxidant capacity through in vitro assays (DPPH, ABTS, ORAC, reducing power, and metal chelating) and then demonstrated in model systems (oil-in-water emulsion and ground meat). The fractions of hydrolysates possessing strongest activities were further fractionated by gel filtration and HPLC. Peaks representing the largest areas from HPLC were identified for major sequences by MALDI-TOF-MS. The experiment results indicated that all the three selected fractions of kafirin hydrolysates revealed excellent inhibition effects against oil and fat oxidations, which could be employed as tools to predict their performances in real food products. In addition, the structure studies showed that medium-sized hydrolysates of Neutrase (3 – 10 kDa) and Alcalase (5 – 10 kDa), and small-sized hydrolysates of Papain (1 – 3 kDa) exhibited relatively stronger activities. This study provided a workable processing method and critical reaction parameters for the production of peptide antioxidants from sorghum protein. The experiment results revealed that the sorghum peptide antioxidant could act through multiple mechanisms including free radical scavenging, metal ion chelation, hydrogen donating, and forming physical barriers to minimize the contact of oxidative agents to targets. These antioxidative peptides are a promising ingredient that can be potentially incorporated to food and feed products as alternatives to synthetic antioxidants or synergetic elements to nonpeptic antioxidants for protection of susceptible food ingredients. This study also made a positive impact to sorghum ethanol industry by guiding the conversion of sorghum protein-rich by-products into value-added antioxidant products as an additional revenue stream.

AN ABSTRACT OF THE THESIS OF Thara G. Siddaramu, for the Master of Science degree in Civil and Environmental Engineering, presented on February 5, 2011, at Southern Illinois University Carbondale. TITLE: EVALUATION OF DIFFERENT PRETREATMENT APPROACHES FOR DISRUPTING LIGNOCELLULOSIC STRUCTURES MAJOR PROFESSOR: Dr. Yanna Liang There are two major steps in biofuel production- pretreatment of lignocellulosic materials and enzymatic hydrolysis. The present study investigated the ability of two pretreatment methods, namely traditional oven and microwave oven treatments for disrupting lignocellulosic structures. The substrates tested were Jatropha seed cake and sweet sorghum bagasse. In recent years, Jatropha curcas also known as physic nut or purging nut has attracted extensive attention due to its several unique characteristics. Similarly, sweet sorghum has the potential to provide great value to energy sectors and food industries being that the entire plant is rich in various sugars and nutrients. Both crops can adapt to various climates, and can withstand extended drought conditions compared to other crops. Additionally, both Jatropha seed cakes and sweet sorghum bagasse are good sources of lignin and carbohydrates, which could be used for production of biofuels only if the sugars can be unlocked. Several treatment methods such as mechanical, physical, chemical and biological treatments have been reported to breakdown the cellulosic structure of biomass. However, other low cost and quicker methods, such as ovenpretreatment and microwave irradiation have not been evaluated for Jatropha seed cake and Sweet Sorghum Bagasse (SSB), respectively. Composition change of Jatropha seed cake samples was evaluated upon lime pretreatment at 100 oC with different parameters. With a lime dose of 0.2 g and a water content of 10 ml per gram of cake and a treatment period of 1 h, 38.2 ± 0.6% of lignin was removed. However, 65 ± 16% of hemicellulose was also lost under this condition. For all the treatments tested, cellulose content was not affected by lime supplementation. Through further examining total reducing sugar (TRS) release by enzymatic hydrolysis after lime pretreatment, results indicated that 0.1 g of lime and 9 ml of water per gram of cake and 3 h pretreatment produced the maximal 68.9% conversion of cellulose. Without lime pretreatment, the highest cellulose conversion was 33.3%. Finally, this study shows that Jatropha seed cake samples could be hydrolyzed by enzymes. Even though the cellulose content was not high for this Jatropha cake sample, the fractionation by lime presented in this study opened the door for other applications, such as removal of lignin and toxicity for use as animal feed and fertilizer. The microwave radiation pretreatment of SSB was evaluated with or without lime (0.1 g/g bagasse) at 10 ml water/g bagasse for 4 min. TRS release over 72-h enzymatic hydrolysis was different for samples treated differently and at different solid loadings. The TRS concentration was increased by 2 and 5-fold from 0 to 24 hours in non lime-pretreated and lime-pretreated samples, respectively. Further incubation of samples for 48 and 72 h did not result in increased TRS. Comparing different solid loadings of samples treated with or without lime, 1% solid content resulted in 1.4 times higher TRS increase than that of 5% solid concentration. Therefore, lime was effective in disintegrating lignocellulosic structures and making cellulose more accessible for saccharification. Higher solid loadings which can lead to higher sugar concentrations are desired for downstream biofuel production. But, as shown in this study, higher concentration of bagasse samples decreased rate of cellulose hydrolysis due to poorer mixing efficiency and hindrance to interactions between enzymes and solid materials. Thus, an optimal solid content needs to be determined for maximal cellulose hydrolysis and for preparing the hydrolysates for downstream processes, either bioethanol or lipid production.

Master of Science / Food Science Institute / Fadi M. Aramouni / Known for its antioxidant activity and other health benefits, tea is the second most consumed beverage in the world, following water. With up to 6% (w/w) of phenolic compounds, sorghum has the highest content compared to other cereals. The objective of this research was to develop and analyze a sorghum tisane using two different red sorghum hybrids. Tisanes are herbal infusions composed of anything other than the leaves from the Camellia sinensis plant. The sorghum kernel was cracked using an Allis experimental roll stand equipped with a Le Page cut mill. Samples were sifted at 180 RMP- 4” diameter throw for 2 min. The two hybrids were roasted in a Whirlpool convection oven at 212°C for 13 or 15 min. Three fruit and herbal combinations were tested to increase consumer acceptability. Samples was brewed for 4 min in 8fl.oz at 100°C. Oxygen Radical Absorbance Capacity(ORAC) and Total Phenolic Content (TPC) were used to analyze the beverage along with chemical, physical and sensory tests. TPC results showed sorghum tisane to have 38.5±6.91 mg gallic acid equivalence/ 8fl oz. and 433.7 ±7.11 μM Trolox equivalence/ 236.6 mL (8 fl.oz, 1 cup) for an ORAC value. Fruit and herbal combinations were also added to the sorghum to increase overall consumer acceptability. These combinations included strawberry mixed with lemon, blood orange mixed with pear, and pineapple mixed with orange. A consumer acceptance test was performed on the three different sorghum tisanes using a 9 point hedonic scale. Results showed an overall acceptability at 6.63±1.54 for the sorghum tisane infused with a strawberry and lemon combination while the sorghum tisane with pineapple orange scored 6.72 . These results demonstrate the potential for introducing a consumer acceptable sorghum tisane into the market.

Master of Science / Department of Agronomy / S.V. Krishna Jagadish / Low temperature is one of the most limiting stresses to crops that are adapted to tropical and subtropical regions, such as maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench], when introduced into temperate regions. However, no studies have compared the chilling tolerance of maize and sorghum grown together. Therefore, the objective of this research was to screen maize hybrids and sorghum genotypes for chilling tolerance at the germination and seedling stages. With the hypothesis that grain composition of maize and sorghum could lead to varying chilling tolerance, the seeds were analyzed for concentrations of protein, starch, and amylose. Five commercial hybrids of maize and 18 genotypes of sorghum were maintained in growth chambers for 31 days at two temperatures: a control temperature (25/20 °C, day/night) and at chilling temperatures (11/8 °C for 14 days; 12.5/9.5 °C for 14 days, and 14/11 °C for 3 days). Emergence and seedling height were measured during the experiment. At the end of the experiment, shoot dry weight, root dry weight, and leaf area were determined. Emergence of sorghum under the chilling temperature regime was low (18%). Average height of the emerged sorghum seedlings in the cold temperatures at the end of the experiment was 1.4 cm compared to 55.5 cm in the control treatment. All maize hybrids emerged, but emergence and growth were slowed by the cold temperatures, and average height at the end of the experiment was 4.6 cm compared to 96.1 cm in the control treatment. Shoot dry weight, root dry weight, and leaf area of the sorghum under the chilling temperatures were too small to measure, and, for maize, they were greatly reduced. The results showed that, for sorghum, temperatures should be above 14 °C for emergence, while maize could emerge at lower temperatures. The analyses of the sorghum seeds showed that Redbine 60 and RTx430 had the highest protein concentrations (15.71% and 15.35%, respectively), and Segaolane had the lowest protein concentration (9.83%). Segaolane had the highest starch concentration (72.71%), and RTx430 had the lowest starch concentration (65.31%). There was an inverse relationship between protein and starch concentrations in the sorghum seeds (R2 = 0.69). Amylose concentrations did not vary significantly among the sorghum seeds. The analyses of the maize seeds showed that Dekalb 51-20 and Pioneer 1151 had the highest protein concentrations (10.98% and 10.95%, respectively), and Pioneer 1105 had the lowest protein concentration (9.26%). Starch and amylose concentrations did not vary significantly among the maize seeds.

OLIVEIRA, Alexandre Bosco de. Envelhecimento artificial, osmocondicionamento e estresse osmótico em sementes de sorgo: parâmetros fisiológicos, bioquímicos e citoquímicos. 2010. 231f. Tese(Doutorado em Agronomia/Fototecnia)- Centro de Ciências Agrárias, Universidade Federal do Ceará, Fortaleza, 2010. / Submitted by Maria Naires Souza (marianaires@ufc.br) on 2011-12-13T20:20:37Z No. of bitstreams: 1 2010-tese-aboliveira.pdf: 7321006 bytes, checksum: d1680e4e160548270363c2cb4a032508 (MD5) / Approved for entry into archive by Aline Nascimento(vieiraaline@yahoo.com.br) on 2011-12-19T14:49:20Z (GMT) No. of bitstreams: 1 2010-tese-aboliveira.pdf: 7321006 bytes, checksum: d1680e4e160548270363c2cb4a032508 (MD5) / Made available in DSpace on 2011-12-19T14:49:20Z (GMT). No. of bitstreams: 1 2010-tese-aboliveira.pdf: 7321006 bytes, checksum: d1680e4e160548270363c2cb4a032508 (MD5) Previous issue date: 2010-03-22 / This research was carried out in order to obtain basic data that can help them understand the physiological, biochemical and cytochemical responsible for the deterioration of aged seeds, reinvigoration of those primed and inhibition of germination and seedling establishment of sorghum under salt stress and study some of the mechanisms of adaptation to stress. The first chapter studies the effects of water stress (0, -0.2, -0.4 and -0.8 MPa) and saline (0, 75, 150 and 300 mM NaCl) on germination and seed vigor two genotypes of sorghum (CSF 18 and CSF 20). In the second and third chapter, to assess the quality of the seeds in the laboratory and the establishment of sorghum seedlings in the field, respectively, used a completely randomized design with four replications and a 2 x 2, consisting of four treatments: 1. aged seeds, 2. aging seeds 3. aged seeds and osmotically conditioned and 4. aging seeds and osmotically conditioned. In the fourth study we evaluated the water uptake, germination and early growth of seedlings derived from seeds aged, primed and under salt stress (0, 100, 200 or 300 mM NaCl). In the fifth chapter cytochemical tests were performed on seeds of sorghum subjected to the treatments described in the fourth chapter, but under a salinity of only 100 mM. The same treatments were used in the sixth chapter to evaluate the effect of these factors on seedling establishment, absorption of ions, organic solutes accumulation, lipid peroxidation and changes in enzymatic antioxidant system in seedlings grown in hydroponics in the presence or absence of NaCl. The sorghum genotypes show differential tolerance to osmotic stress caused by PEG-6000 and by NaCl, and the sensitivity to them varies depending on the stage of plant development. The artificial aging and salt stress promote adverse effects on germination, vigor and stand establishment of sorghum, which can be partly alleviated by the technique of priming seeds. Salt stress leads to significant reductions in the quality of the seeds and early growth of sorghum seedlings, causing some cytochemical changes in the seeds and various biochemical and physiological changes in seedlings under hydroponic cultivation. / Esta pesquisa foi realizada visando a obtenção de dados básicos que possam auxiliar na compreensão dos mecanismos fisiológicos, bioquímicos e citoquímicos responsáveis pela deterioração de sementes envelhecidas, revigoração daquelas osmocondicionadas e inibição da germinação e estabelecimento de plântulas de sorgo sob condições de estresse salino, bem como estudar alguns dos mecanismos de adaptação ao estresse. No primeiro capítulo foram avaliados os efeitos dos estresses hídrico (0, -0,2, -0,4 e -0,8 MPa) e salino (0, 75, 150 e 300 mM de NaCl) na germinação e vigor de sementes de dois genótipos de sorgo forrageiro (CSF 18 e CSF 20). No segundo e terceiro capítulo, a fim de avaliar a qualidade fisiológica das sementes em laboratório e o estabelecimento de plântulas de sorgo no campo, respectivamente, utilizou-se um delineamento experimental inteiramente casualizado com quatro repetições, no esquema fatorial 2 x 2, constando de quatro tratamentos: 1. sementes envelhecidas; 2. sementes não envelhecidas; 3. sementes envelhecidas e condicionadas osmoticamente e 4. sementes não envelhecidas e condicionadas osmoticamente. No quarto trabalho foram avaliadas a absorção de água, germinação e crescimento inicial de plântulas oriundas de semente envelhecidas, osmocondicionadas e sob estresse salino (0, 100, 200 ou 300 mM de NaCl). No quinto capítulo foram realizadas análises citoquímicas em sementes de sorgo submetidas aos tratamentos descritos no quarto capítulo, contudo sob salinidade de apenas 100 mM. Os mesmos tratamentos foram utilizados no sexto capítulo para avaliar o efeito desses fatores sobre o estabelecimento das plântulas, absorção de íons, acúmulo de solutos orgânicos, peroxidação de lipídios e alterações no sistema enzimático antioxidativo em plântulas cultivadas sob hidroponia na presença ou ausência de NaCl. Os genótipos de sorgo apresentam tolerância diferencial aos estresses osmóticos provocados pelo PEG-6000 e pelo NaCl, sendo que a sensibilidade aos mesmos varia em função do estádio de desenvolvimento da planta. O envelhecimento artificial e o estresse salino promovem efeitos prejudiciais à germinação, vigor e estabelecimento de plântulas de sorgo, os quais podem ser parcialmente atenuados com a técnica do condicionamento osmótico de sementes. O estresse salino provoca reduções significativas na qualidade fisiológica das sementes e no crescimento inicial das plântulas de sorgo, provocando algumas alterações citoquímicas nas sementes e várias alterações fisiológicas e bioquímicas em plântulas sob cultivo hidropônico.