Fertilizer studies were carried out with guar in the field and greenhouse over two seasons. Response to N was found in terms of plant growth and bean yield. With very low available soil P, fertilizer P increased the P concentration in guar plants but not bean yields. Zinc increased yields in the greenhouse only on the soil with the lowest available Zn.

Plants with greater drought tolerance will increase crop production in many areas of the world. The purpose of this study was to examine the physiological responses of guar, a drought tolerant plant, under water stress. The dry treatment received only one irrigation and yielded respectably. This treatment maintained turgor and metabolic functions throughout the study by decreasing transpiration rate and increasing diffusive resistance.

No description available.

No description available.

Mayonnaise is a mixture of egg yolk, vinegar, water, spices and 70-80% oil forming a semi-solid oil-in-water emulsion. When preparing a low-fat mayonnaise with an increased water content, thickening agents are required for increased viscosity and emulsion stability. The hydrocolloids xanthan gum and guar gum are sometimes used for this purpose and they act synergistically creating a viscosity increase. However, guar gum has poor acid stability, and because mayonnaise is an acidic product guar gum will eventually start to degrade causing a viscosity decrease and subsequent emulsion separation. Despite this fact, guar gum and xanthan gum are extensively used in mayonnaises today. The aim of this degree project was to explore how the synergy between guar gum and xanthan gum influences the viscosity of a low fat mayonnaise and whether high acidity will have an impact on the viscosity over a 4-week period. This was to examine if and if so, how a mayonnaise recipe can be modified to maintain a cost efficient product with the desired rheological properties in times of hydrocolloid price fluctuations. The study was conducted by preparing 15 mayonnaises with 50% fat, either at pH 3,5; 4 or 5 and a total of 0,6 % hydrocolloids with varying proportions of guar gum and xanthan gum. The mayonnaise samples were studied by measurements of viscosity, color changes and a visual comparison of their mayonnaise-like flow-properties compared to Hellmann’s Real Mayonnaise used as reference. The viscosity of the mayonnaises increased with increasing ratio of guar gum. On the other side, there were greater viscosity losses in mayonnaises with increasing ratio of guar gum 4 weeks after preparation compared to 4 days, with no apparent signs of correlation between higher acidity and hydrocolloid degradation. Mayonnaises with 20% xanthan gum and 80% guar gum had the texture most similar to the reference. In these low-fat mayonnaises, the use of more xanthan gum led to an undesired “slimy” texture and a lower viscosity – an important aspect if adjusting a low-fat mayonnaise recipe by increasing the ratio of xanthan gum. Because a commercial mayonnaise sometimes is consumed several months after manufacturing, that time frame is most likely required in order to fully measure how much the high acidity in mayonnaise will affect its viscosity. This project has shown a pattern where viscosity in the assessed mayonnaises starts to decrease a few weeks after preparation. However to find out exactly to what extent and how this would affect the overall product, and ultimately: if guar gum/xanthan gum combinations are suitable for long-term mayonnaise applications, further studies are required. / Viskositet och syrastabilitet i majonnäs med låg fetthalt och olika proportioner av xantan och guarkärnmjöl Majonnäs är en blandning av äggula, vinäger, vatten, kryddor och 70-80% olja som bildar en semi-solid olja-i-vatten-emulsion. För att tillverka en lågfettsmajonnäs med högre vatteninnehåll behöver förtjockningsmedel tillsättas för viskositet och emulsionsstabilitet. Hydrokolloiderna xantangummi och guarkärnmjöl används ibland i detta syfte och de utövar en synergi som ger ökad viskositet. Dock har guarkärnmjöl dålig syrastabilitet och eftersom majonnäs är en sur produkt kommer guarkärnmjölet efter ett tag att brytas ned vilket leder till en viskositetsminskning och emulsionsseparation. Trots detta används guarkärnmjöl och xantangummi i stor utsträckning i majonnäser idag. Syftet med examensarbetet var att undersöka hur synergin mellan guarkärnmjöl och xantangummi påverkar viskositeten i en lågfettsmajonnäs och huruvida en hög syrahalt kommer att påverka viskositeten under en 4-veckorsperiod. Detta för att se om och i så fall hur ett majonnäsrecept kan modifieras för att erhålla en kostnadseffektiv produkt om priset på hydrokolloider växlar. För arbetet bereddes 15 majonnäser med 50% fetthalt, antingen med pH 3,5; 4 eller 5 och totalt 0,6% hydrokolloider med olika proportioner av guarkärnmjöl och xantangummi. Majonnäserna undersöktes genom mätning av viskositet, färgförändringar och en visuell jämförelse av deras majonnäsliknande flytegenskaper i förhållande till Hellmann’s Real Mayonnaise som användes som referens. Viskositeten i majonnäserna ökade med ökande halt guarkärnmjöl. Å andra sidan minskade viskositeten i högre grad med ökande halt guarkärnmjöl 4 veckor efter tillverkning jämfört med 4 dagar, men inga tydliga samband mellan högre syrahalt och nedbrytning av hydrokolloider syntes. Majonnäser med en blandning av 20% xantangummi och 80% guarkärnmjöl hade den konsistens som var mest lik referensen. I dessa försök med lågfettsmajonnäser ledde användandet av högre halt xantangummi till en oönskad ”slimig” textur och en lägre viskositet – en viktig aspekt om ett recept på lågfettsmajonnäs ska modifieras genom att öka halten xantangummi. Eftersom en kommersiell majonnäs ibland konsumeras flera månader efter tillverkning så är det troligtvis den tidsramen som krävs för att helt kunna mäta hur mycket den höga syrahalten i majonnäs kommer att påverka dess viskositet. Detta projekt har påvisat ett mönster där viskositeten i de analyserade majonnäserna börjar minska några veckor efter tillverkningen. Men för att få reda på exakt i vilken utsträckning och hur detta skulle påverka produkten i sin helhet, och i slutändan: om kombinationen med guarkärnmjöl och xantangummi är lämplig för majonnäser med lång hållbarhet krävs ytterligare studier.

The reactions of carboxylic acids with organoaluminium reagents were studied, which led to the formation of novel aluminium compounds. The reactions of orthofunctionalised derivatives of benzoic acid with trivalent aluminium organyls AlR3, led to the formation of different Al-based molecular clusters, depending on the nature of R, the reaction stoichiometry and the character of the benzoic acid derivative. The obtained compounds were characterised in the solid state by X-ray diffraction methods and two main motifs were observed. When the acid and AlR3 reacted in a one-to-two stoichiometry the obtained products, [iBu4Al2(μ-O2CC6H4-2-μ- O)]2, [(Me2Al)2(μ-O2CC6H4-2-μ-NH)]2, [(iBu2Al)2(μ-O2CC6H4-2-μ-NH)]2, [(Me2Al)2(μ- O2CC6H4-2-μ-NMe)]2 and [(iBu2Al)2(μ-O2CC6H4-2-μ-NMe)]2, consisted of a central distorted 12-membered macrocycle, formed by two [Al-O-C-O-Al-X] units (X= O,N) and was found to be dimeric. The reaction between anthranilic acid derivatives and AlR3 could also take place in a one-to-one ratio. For anthranilic acid and Nmethylanthranilic acid the obtained crystals only allowed a qualitative analysis and showed the structure of the products, [MeAl(μ-O2CC6H4-2-μ-NH)]4, [iBuAl(μ-O2CC6H4- 2-μ-NMe)]4 to be tetrameric and each consisting of a distorted 16-membered ring formed by four [O-C-O-Al] units. With the reaction of N-phenylanthranilic acid it was possible to isolate a structural analogous product [iBuAl(μ-O2CC6H4-2-μ-NPh)]4 which could be fully characterised by x-ray crystallography and NMR spectroscopy. Where the quantity and quality of the obtained product was sufficient, the solution behaviour of the compounds was elucidated by multinuclear and multidimensional NMR spectroscopic techniques. The 27Al NMR showed that the aforementioned aggregates are maintained in solution, which for the 12-membered [Al-O-C-O-Al-N] macrocycle of [(iBu2Al)2(μ-O2CC6H4-2-μ-NH)]2 was confirmed by a NOESY spectrum. The second part of this project focused on the preliminary studies towards the application of aluminium compounds in the crosslinking of guar and carboxymethyl hydroxypropyl guar, which are common additives in hydraulic fracturing. Different commercially available aluminium compounds were tested for their general ability to crosslink the aforementioned polysaccharides, yielding promising results for aluminium lactate, aluminium acetylacetonate and aluminium isopropoxide. For the system comprising aluminium lactate in combination with CMHPG, rheological studies were carried out to determine the viscosity, the viscoelasticity, the shear recovery and the stability towards high temperatures. These sought to evaluate the crosslinking properties of the aluminium additive and to optimise the required conditions of the different system components. Finally, it was possible to obtain first proof-of-concept data suggesting that synthetically obtained aluminium compounds such as [Me2Al(μ- O2CPh)]2 and Al[MeC(CH2O)3]2(AlMe2)3 can be employed for the crosslinking of guar and CMHPG.

Four experiments were conducted to evaluate guar meal as a source of prebiotic galactomannans for laying hens. In the 1st experiment, late phase laying hens were fed diets with 0, 5, 10% guar meal (GM) for 56 days or 15% GM for 28 days then switched to the 0% GM diet for the final 28 days. In the 2nd experiment, young pullets were fed guar germ (GG) or GM at 0, 2.5 or 5% for 20 weeks. In the 1st and 2nd experiments, egg production and feed consumption were not affected by feeding up to 5% guar by-products whereas feed efficiency was decreased by guar feeding. Feeding of GG or GM did not affect egg weight or shell quality, but decreased the egg yolk color and Haugh units. Guar increased absolute and relative liver weight, but did not affect the weights of the pancreas, spleen, or the incidence of fatty liver or liver hemorrhage. Feeding 10% GM depressed feed consumption and increased body weight loss. Feeding 15% GM severely depressed egg production followed by a recovery of production after returning to 0% GM feeding. In the 3rd and 4th experiments, late phase laying hens were induced to molt by feed withdrawal (FW) or feeding 15 or 20% GM with or without β-mannanase (Hemicell??). All hens except those fed 15% GM with enzyme obtained a complete cessation of lay in 10 days. Compared to FW birds, hens fed GM had lower body weight reduction and mortality, while hens fed 20% GM with enzyme had higher post-molt egg production. Salmonella enteritidis (SE) present in 6 organs (crop, liver, spleen, ovary, oviduct and cecum), and SE in cecal contents were significantly reduced by 20% GM feeding with and without enzyme. The results showed that GG or GM can be safely fed to laying hens up to 5% without adverse effects on performance. An alternative molting method employing 20% GM with or without β-mannanase is preferable to FW because GM feeding results in a complete molt and decreases mortality, as well as enhances the resistance to SE of molted hens.

A series of four experiments were conducted to evaluate whether a preconditioning period, in which adult leghorn cockerels are allowed 3 weeks to adapt to diets containing relatively high levels of guar meal (GM) resulted in changes in digestive tract morphology and ecology. It was expected that these changes would result in increased utilization of GM as birds became acclimated to consuming it at high levels. In the 1st experiment, 28 birds were fed diets containing 0, 6, 12, or 24% GM. Consuming the 24% GM diet resulted in decreased body weight, increased small intestine, liver, and pancreas weight, increased ceca and villus length, and increased severity of injury to the intestinal mucosa (P < 0.05). In the 2nd experiment, 28 cockerels were subjected to a partial cross-over experiment. Preconditioning to the 24% GM diet resulted in decreased TMEn of GM, decreased body weight, and decreased absorptive capacity of the GI tract as evidenced by increased energy lost via the excreta (P < 0.05). The 3rd experiment evaluated how differences in endogenous energy losses (EEL) from 30 cockerels affected the TMEn content of GM in birds consuming 0, 6, or 12% GM. Decreased EEL was observed in birds conditioned to 6 and 12% GM relative to the control group (P < 0.05). Further, decreased TMEn of GM was observed in birds consuming 6% GM relative to those consuming the control diet (P < 0.05). In the 4th experiment, changes in cecal microbiota were evaluated in 24 cockerels consuming 0, 6, or 12% dietary GM using denaturing gradient gel electrophoresis of amplified bacterial DNA sequences. Cecal microbiota of birds consuming 12% GM was considerably different from the control group (similarity coefficient = 84%) with an apparent decrease in the complexity of microbial communities. Results of these studies show that consuming 12% dietary GM results in changes in the cecal microbial community which may be responsible for modest increases in the TMEn of GM when compared to 6% dietary GM, which consistently resulted in decreased TMEn values of GM. Further, determining the TMEn value of GM appears to be highly dependent upon factors such as preconditioning diet and timeframe and innate physiological "thresholds" which seem to initiate or limit the maximum physiological response to preconditioning that the bird is capable of.

Unbroken gel and residue from guar-based fracturing gels can be a cause for formation damage. The effectiveness of a fracturing treatment depends on better achieveing desired fracture geometry, proper proppant placement and after that, a good clean-up. The clean-up is achieved by reducing the fluid viscosity using chemical additives called "Breakers". There are many different types of breakers used in the industry, but they can be broadly divided into two categories: oxidizers and enzymes. Breaker perfromance depends on bottomhole temperature, breaker concentration and polymer loading. Different kind of breakers, used at different concentrations and temperatures, give different kind of "break" results. Therefore, the amount of unbroken gel and residue generated is also different. This project was aimed at studying basic guar-breaker interactions using some of the most common breakers used in the industry. The breakers studied cover a working temperature range of 75 degrees F to 300 degrees F. The effectiveness of each breaker was studied and also the amount of damage that it causes. Viscosity profiles were developed for various field concentrations of breakers. The concentrations were tested over temperature ranges corresponding to the temperatures at which each breaker is used in the field. The majority of these viscosity tests were 6 hours long, with a few exceptions. Early time viscosity data, for the intial 10 minutes of the test, was also plotted from these tests for fracturing applications where the breaker is required to degrade the fluid by the time it reached downhole. This was needed to prevent the damage to the pumping equipment at the surface yet still have almost water-like fluid entering into the formation. The study provides a better understanding of different breaker systems, which can be used in the industry, while designing fracturing fluid systems in order to optimize the breaker performance and achieve a better, cleaner break to minimize the formation damage caused by polymer degradation.

Four experiments were conducted to evaluate guar meal as a source of prebiotic galactomannans for laying hens. In the 1st experiment, late phase laying hens were fed diets with 0, 5, 10% guar meal (GM) for 56 days or 15% GM for 28 days then switched to the 0% GM diet for the final 28 days. In the 2nd experiment, young pullets were fed guar germ (GG) or GM at 0, 2.5 or 5% for 20 weeks. In the 1st and 2nd experiments, egg production and feed consumption were not affected by feeding up to 5% guar by-products whereas feed efficiency was decreased by guar feeding. Feeding of GG or GM did not affect egg weight or shell quality, but decreased the egg yolk color and Haugh units. Guar increased absolute and relative liver weight, but did not affect the weights of the pancreas, spleen, or the incidence of fatty liver or liver hemorrhage. Feeding 10% GM depressed feed consumption and increased body weight loss. Feeding 15% GM severely depressed egg production followed by a recovery of production after returning to 0% GM feeding. In the 3rd and 4th experiments, late phase laying hens were induced to molt by feed withdrawal (FW) or feeding 15 or 20% GM with or without &#946;-mannanase (Hemicell??). All hens except those fed 15% GM with enzyme obtained a complete cessation of lay in 10 days. Compared to FW birds, hens fed GM had lower body weight reduction and mortality, while hens fed 20% GM with enzyme had higher post-molt egg production. Salmonella enteritidis (SE) present in 6 organs (crop, liver, spleen, ovary, oviduct and cecum), and SE in cecal contents were significantly reduced by 20% GM feeding with and without enzyme. The results showed that GG or GM can be safely fed to laying hens up to 5% without adverse effects on performance. An alternative molting method employing 20% GM with or without &#946;-mannanase is preferable to FW because GM feeding results in a complete molt and decreases mortality, as well as enhances the resistance to SE of molted hens.