2011 Annual Report
Pectin is a major component of citrus peel with extensive functionality and the degree of methylesterification has a very strong influence on functionality. Techniques to reliably produce novel, non-random patterns of methylesterification in pectin molecules and accurately characterize their distribution will be investigated. Fractions containing pectin or other polysaccharides from citrus processing waste will be characterized for macromolecular and nanostructural properties. They will then be treated with pectin modifying enzymes at varying pH, temperature, and salt concentrations and the resulting changes in functionality and nanostructure determined. Chemical modifications will be performed using nucleophilic reagents to modify functionality alone or in combination with enzymatic treatments. Materials generated will be tested for biosorption properties as amorphous powdered materials and after conversion via chemical crosslinking. In addition, water holding capacity, viscosity, and other rheological functional properties such as yield point will be determined along with changes in fragmentation size, molecular weight distribution, degree of polymerization, degree of substitution of added groups, as well as thermal and pH tolerance. Materials with appropriate properties will then be tested in applications such as drilling fluids, dry strength additives for paper, cement additives, and absorbents for spill applications.
The economics of producing newly developed by-products will be evaluated and compared with those products currently utilized for targeted applications. Economic information will include raw materials, consumable, and energy costs, fixed capitol investment cost, and a breakdown of operating and capital cost estimates.
Multiple pressings of citrus processing waste with minimal water addition showed that greater than 80% of the soluble sugars could be removed from the nonsoluble residues, yielding a 5-6% sugar wash and residue that is suitable for pectin extraction. Non-thermal concentration of the water sugar wash is being pursued to overcome fouling issues in order to produce a 20-25% fermentable sugar substrate for improved ethanol production for use as a biofuel.
A method for rapid pectin analysis for determining free acid groups based on conductivity. Determination of these functional groups is important for development of suspension aid products.
Analyzed fractions from high temperature extraction of citrus peel for molecular weight and other important properties, which is important for understanding separation pectin fraction before peel fermentation takes place.
It has been found that not all pectin is involved in the formation of gels. Preliminary testing and data suggests that only a subfraction of the pectin molecules are modified by enzymatic deesterification and that the potential properties of pectin may not be fully realized without further improvements to the enzymatic the modification procedure.
This project replaced project 6621-41000-013-00D which was a bridging project for project 6621-41000-011-00D.
Widmer, W., Zhou, W., Grohmann, K. 2010. Pretreatment effects on orange processing waste for making ethanol by simultaneous saccharification and fermentation. Bioresource Technology. 101:5242-5249.
Hanley, M.J., Cancalon, P., Widmer, W.W., Greenblatt, D.J. 2011. The effect of grapefruit juice on drug disposition. Expert Opinion on Drug Metabolism & Toxicology. 7(3):267-286.