Digitized by Kansas Correctional Industries

Thesis (M.Sc. (Botany))-- University of Limpopo, 2013 / The aim of the study was to identify drought tolerant South African soybean cultivars for cultivation where water is a limited resource. Soybean [Glycine max. (L.) Merr] is one of the most important legumes in the world. A lot of attention has been focused on soybean cultivation in South Africa recently. Soybean production is mainly affected by several biotic and abiotic factors which reduce the yield and quality of the crop. Six South African soybean cultivars (LS 677, LS 678, Mopanie, Sonop, Knap and Pan 1564) and two American cultivars (R01 416 and R01 581) were carefully studied for morphological and physiological markers which contribute to drought tolerance. The study was conducted at the University of Limpopo (Turfloop campus). Soybean plants were grown in a glasshouse in a randomised block design given same amounts of nutrients and differing amounts of water (limited and overwatering). Data was collected at R3 growth stage by measuring several morphological (stem length, leaf surface area, flowers and seeds counts) and physiological (percentage chlorophyll, moisture content, total phenolics, total flavonoids, ureide content and antioxidant activity) parameters. An anatomical study was also carried out on the transverse sections of leaves, roots, leaf stalk and nodules. The different cultivars reacted differently to the three water treatments. LS 678 produced the tallest plants whereas those of Pan 1564 were the shortest. Water stress affected plants by reducing the number of flowers produced, the leaf surface area as well as the relative leaf water content. The moisture content of the growth medium was reduced faster as the plants matured and it was also lowered by the limited water availability. Percentage chlorophyll is another trait which was affected by water limitation. Cultivars with high phenolic and flavonoids content were associated with high antioxidant activity and slightly yielded higher than the others. The anatomical transverse sections of the roots and petioles have shown some secondary growth. The anatomy of the nodules of Mopani has shown some interesting differences in response to the three treatments. Limited water decreased xii the size of the vascular tissue and sclerenchyma as a result altering the functionality of the nodule. The anatomy of Sonop’s petiole had a thickened sclerenchymatous bundle sheath covering the phloem tissue. The sclerenchyma tissue is thought to guard against loss of water. The cross section of the leaf had a double layer of palisade mesophyll (upper surface) and only a single layer of spongy mesophyll (lower surface). In addition, the mesophyll and the epidermal cells of Mopani appeared much thicker. In terms of yield, there was no cultivar which yielded the highest but Mopani yielded the lowest. Since Mopani was low yielding, the main focus of the discussion was on the features (morphological, physiological and anatomical) of Mopani which can be associated with drought susceptibility. Some of these features include reduced stem length, large leaf surface area, low relative leaf water content, low growth medium moisture content and low antioxidant activity.

Thesis (M.Sc. Agriculture (Crop Science)) -- University of Limpopo, 2011 / The nature and magnitude of the genotype by environment interactions is important to identify superior and stable genotypes under the target environments. This will assist to maximize specific adaptation and to speed up the transfer of new cultivars to growers. The objective of this study was to determine the stability of selected soybean genotypes with regards to the agronomic traits, high yield and nodule formation. Field experiments were conducted under dryland conditions during the 2007/2008 and 2008/2009 growing seasons at the University of Limpopo’s experimental farm (Syferkuil) and at a farmer’s field at Gabaza community, Mopani District near Tzaneen. Ten selected soybean cultivars were evaluated under a randomised complete block design with three replications. Stability was assessed via joint regression and superiority analyses. Significant differences were found for genotypes, environments and genotype by environment interactions. Stability analysis after Eberhart and Russell’s model suggested that the genotypes showed marked differences to environmental changes. The cultivar superiority measure for seed yield indicated that variety Clark was the most stable genotype with an average yield of 5235 kg/ha, followed by L81-4858 and Barc-2 that provided average yield of 4839 kg/ha and 4582 kg/ha, respectively. In terms of number of nodules Magoye was observed to be stable with average of five nodules per plant. Cultivar Barc-2 was found stable for number of active nodules with an average of 3.17 active nodules per plant. Most of the genotypes performed better at Syferkuil than at Gabaza. In general Barc-2 was found stable for yield and other agronomic traits considered in this study. This variety could be suitable for large scale production in these or other similar environments in Limpopo Province.

No description available.

Doctor of Philosophy(PhD) / Soybeans contain around 40% of high quality protein and 20 % of oil. Soy protein has long been used as ingredients for its emulsification and texturizing properties in a variety of foods, soymilk and tofu being the most popular. Soymilk is essentially a water extract of soybeans and there are many variations on the basic soymilk processing steps. Tofu, or bean curd, is made by coagulating soy milk, and then pressing the resulting curds into blocks. This thesis was mainly devoted to thermal denaturation and coagulation of soy proteins and targeted several selected important factors as they relate to the functional properties. The effects of different chemical coagulants as well as proteases on yield and quality of tofu from soybeans were studied. Eight tested chemical coagulants were able to coagulate the soymilk and the results showed that the concentration of soymilk and type of coagulant had a great influence on the properties of the tofu gel. The results also confirmed that the use of a suitable concentration of the quick-acting coagulants is more critical than that of the slow-acting coagulants in tofu making. In general, the extent of soymilk gelation is not determined by a single characteristic but rather results from a combination of factors. The gelation ability of various most common commercially available proteases to coagulate non-defatted soymilk was surveyed and the thermal stabilities of selected protease systems were compared. The difference in the temperature where the enzyme shows its highest activity seemed to be the most significant indicator when choosing a suitable enzyme for a certain industrial application. The three most effective and versatile soymilk coagulants were identified. The presence of small amounts of ficin in the system increased the protein recovery when calcium chloride was used as a coagulant. The most commonly used techniques of analysis of degree of hydrolysis (TNBS, OPA and pH-stat) of soy protein were compared. It was concluded that the pH-stat technique was useful for evaluating the progress of an enzyme-catalyzed protein hydrolysis process on an industrial scale while the OPA method seemed to be the most suitable method to be used for determining DH during the proteolysis of soymilk in laboratory conditions. The roles of soybean proteins, protein fractions and subunits to differences in gelling properties of different soybean varieties were examined. The variability and the interrelationship between soybean seed traits were established and the seed characteristics related to soymilk yield and tofu quality were identified. The results suggested that it is useful to predict the quality of tofu from a combination of characteristics of the soybean seed. It was concluded that large differences exist in soybean seed characteristics and their contributions towards the properties of the final product and implications were made towards the relative importance of individual soybean seed traits to the functional and textural properties of soy products. The SDS gel capillary electrophoresis was applied to characterize soybean storage proteins. The lab-on-a-chip technology was compared with capillary electrophoresis and these two methods were used to quantify the relative amount of 7S and 11S fractions in various soybean cultivars. It was concluded that both lab-on-a-chip instrument and a traditional CGE were adequate for analysis of soy-based products. Both systems were able to reliably quantify the relative amount of protein fractions in samples and thus demonstrate their different genetic origin. The great advantage of the lab-on-a-chip technology is its time-efficiency while the traditional CGE is a preferred instrument for method development. The usefulness of the chemometrical analysis of electrophoretic profiles as a method for objective evaluation, data reduction and interpretation was shown. The possibility of improvement of the protein extraction from soybeans in order to provide a basis for the optimization of soymilk production was studied. The enzyme-assisted extraction using the hydrolytic enzyme treatment to disrupt the soybean cell wall components was expected to improve the protein extraction yield. The results confirmed that the right selection of operational variables led to an increased yield of soymilk as well as its protein concentration. It was also shown that the addition of selected enzyme preparations into the soymilk process design resulted in an increased extraction yield of proteins from seeds into soymilk. The protein quality did not deteriorate during the enzyme-assisted extraction process and a small amount of microbial transglutaminase added together with a coagulant produced tofu with a significantly increased yield while maintaing satisfactory textural properties.

Four different heating treatments with two different methods of cooking were applied to soybeans. The treatments were boiling 20 min, autoclaving 5 min, 10 min, or 20 min, after soaking the beans for 10 hr at 25°C. Vitamin B-6 and free folacin in cooking water were significantly (P<0.05) affected by the heat treatments. Treatments also significantly influenced vitamin B-6, free folacin, trypsin inhibitor activity, water absorption, moisture content; and blue, green, and amber values, in the cooked soybeans. Treatments decreased the definition of the soybean cell structures. Boiling method caused relatively more losses of vitamin B-6 into cooking water, inactivated trypsin inhibitor at the same level, and caused a lighter color of cooked soybean than autoclaving methods. Analysis of covariance showed relationships (P<0.05) between water absorption after cooking with total folacin in cooked soybeans, and water absorption after cooking with blue color value. Other relationships (P<0.05) were observed in cooked soybeans between texture and total folacin, moisture content and trypsin inhibitor activity and free folacin. / Graduation date: 1982

Prebiotic compounds comprise a group of dietary supplements defined as nonviable food ingredients that are selectively metabolized to favor beneficial intestinal bacteria. Such bacteria may confer various desirable effects including enhanced disease resistance and nutrient availability to the host. This study examined the effects of four prebiotics, GroBiotic®-A (a mixture of partially autolyzed brewers yeast, dairy ingredient components and dried fermentation products), mannanoligosaccharide (MOS), galactooligosaccharide (GOS), and the fructooligosaccharide (FOS) inulin on digestibility of soybean-meal-based diets by goldfish. A basal diet was formulated so that 50% of the protein was provided by soybean meal and the other 50% was from menhaden fishmeal. Each prebiotic was supplemented to the basal diet at 1% by weight. A diet containing all of its protein from menhaden fish meal also was prepared as a control diet. Chromic oxide was added to the diets at 1% as an inert marker. Each diet was fed to adult goldfish in duplicate 110-L iv aquaria for a total of 8 weeks. The dried fecal material from each aquarium was pooled over time and analyzed for protein, lipid, organic matter and chromium in order to compute coefficients of apparent digestibility. Genomic DNA of gut microbiota also was isolated from the fecal samples of goldfish fed the various diets and subjected to polymerase chain reaction (PCR) using bacteria-specific PCR primers to conserved regions flanking the variable V3 region of 16S rDNA. Then, denaturing gradient gel electrophoresis (DGGE) of the resulting amplicons was conducted as a means of assessing diversity of microbiota in the gastrointestinal (GI) tract. Results of the present study revealed that none of the prebiotics affected apparent digestibility coefficients of the soybean-meal-based diet compared to the basal diet, although the diet supplemented with MOS consistently yielded the lowest values. In addition, goldfish digested the soybean-meal-based diets as well as the control diet. DGGE analysis revealed no differences in microbiota of goldfish fed the various prebiotics. These results are in contrast to those obtained with carnivorous fish species such as the red drum (Sciaenops ocellatus) in which the prebiotics increased digestibility coefficients of soybean-meal-based diets and altered GI tract microbiota.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--Mississippi State University. Department of Agricultural and Biological Engineering. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.