Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2011
Publication Date: 6/22/2011
Citation: Shogren, R.L., Peterson, S.C., Evans, K.O., Kenar, J.A. 2011. Preparation and characterization of cellulose gels from corn cobs. Carbohydrate Polymers. 86(3):1351-1357. DOI: 10.1016/j.carbpol.2011.06.035.
Interpretive Summary: This research found that corn cobs can be modified to form cellulose gels and that such gels have potential for use as thickeners, suspending agents and dietary fiber. There is little current commercial utilization of corn cobs so new value added uses would add to farm income. It was found that corn cobs extracted with sodium hydroxide and bleach and then homogenized formed a clear gel in water. The gel was made up of tiny interlocking cellulose microfibrils. The strength of the gel was much higher than cellulose gels prepared in the past from other agricultural materials and other methods. This information will benefit scientists in academia, food and biomaterials industries who may be interested in insoluble dietary fiber, thickeners and biobased composite materials.
Technical Abstract: Aqueous cellulose gels were prepared by extraction of ground corn cobs with hot aqueous sodium hydroxide/sodium hypochlorite and shearing. Initial shearing in a blender broke up cob tissue structure into individual cells and resulted in a gel. Subsequent shearing in a high pressure homogenizer increased viscosity by 50-100x. Rheological studies showed all samples were gel-like from 0.5-2.0% and that G’ increased following a power law with exponents of 3.7 and 3.2 for blended and homogenized samples, respectively. G’ and G” were maximal after two passes through the homogenizer and were about ten times larger than typical literature values for microfibrillar cellulose suspensions. SEM and AFM of two-pass sample showed networks of microfibrils and larger expanded fibrillar aggregates while bundles of more separate microfibrils were observed after eight passes. These results should improve understanding of the relationships between processing, morphology and properties of cellulose from corn stover and lead to new applications.