Location: Cotton Structure and Quality ResearchTitle: Upland cotton surface amino acid and carbohydrate contents vs. color measurements Author
|Rodgers, Iii, James - Retired ARS Employee|
|Knowlton, James - Agricultural Marketing Service (AMS, USDA)|
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2018
Publication Date: 9/20/2018
Citation: Peralta, D.V., Rodgers, J.E., Knowlton, J.L., Fortier, C.A. 2018. Upland cotton surface amino acid and carbohydrate contents vs. color measurements. Journal of Cotton Science. 22(2):142-152.
Interpretive Summary: Cotton color is a vital part of pricing the commodity. Color development after harvesting and initial +b rating has been known to cause economic losses; as yellowness during storage and shipping is a problem. Yellowness has historically been thought to indicate fiber processing issues. It is still debated as to what exactly causes the increases in cotton yellowness during growth and over time, however reactions between amino acids and carbohydrates on the surface of the cotton may play a role. If it can be determined that the color change is solely due to surface reaction, and is not immediately effecting the quality of the fibers, stakeholders in the industry will be able to better assess cotton quality and economic value.
Technical Abstract: Upland cotton is naturally white, with its yellowness (+b) rating influencing its economic value. Field conditions, microorganisms and growth problems can cause cotton to become discolored, potentially indicating a decrease in quality. Some reactions between amino acids and carbohydrates on the surface of cotton fibers may lead to color development, and initial amounts of those constituents on the fiber surface after harvest may indicate potential future changes in +b ratings. This study used HVI, a portable spectrophotometer, ion chromatography and a ninhydrin test to compare amino acid and carbohydrate content of 45 Upland cotton samples with their color measurements: +b, Rd, and L*a*b*. A correlational statistical analysis found a quadratic relationship between amino acid content and +b; and highly positive correlations between amino acids and +b ratings: 0.8607; and b* values: 0.820 (p<0.05).