Comparisons of Minicard ratings with ion chromatography sugar profiles of water extracts of cotton fibers and those of Minicard sticky spot materials

Abstract

Specific levels of the carbohydrates melezitose and trehalulose deposited on the surface of cotton fibers are indicators of whitefly or aphid contamination. These deposits could cause stickiness problems during cotton ginning and textile processing. Cotton stickiness is highly complex, but surface carbohydrates may play the largest role in manifesting an issue. We utilized ion chromatography (IC) to identify and quantify nine sugars of interest present in the water extracts of 25 cotton samples to create sugar profiles for each sample: inositol, trehalose, glucose, fructose, trehalulose, sucrose, melezitose, raffinose and maltose. We compared the sugar profiles to the respective Minicard ratings of either NONE, LIGHT, MODERATE or HEAVY to draw correlations between the IC data and the rating. Trehalulose and melezitose in water extracts highly and positively correlate to Minicard ratings, confirming past researchers' attribution of cotton stickiness to insect sugars. Trehalose and maltose also highly correlated, possibly due to their marker content in honeydew. Glucose and fructose moderately correlated to the ratings. IC studies of the collected Minicard sticky spot material found trehalulose and melezitose were the most prevalent sugars in HEAVY rated samples. Glucose and fructose were present in larger amounts in the MODERATE versus HEAVY rated samples. This result may indicate that the Benedict Test, which attributes these reducing sugars to stickiness, may not be sufficient for conjecturing a stickiness issue. When comparing the averages of the nine sugars present in water extracts versus those sugars contained in Minicard sticky spots, the overall distributions were very similar.Over the years, the production rates and efficiency of cotton fiber processing technologies have changed and their performance has improved, thereby changing the requirements for a higher quality cotton fiber. The spinning of yarn performance is affected by the fiber characteristics, such as fiber morphology (convolutions), geometric features (length, fineness), static electrical forces, waxes, salts and sugars. 1 The sugars present on the fiber are usually a combination of plant metabolic sugars and entomological sugars. If the cotton is over contaminated with insect sugars, they should be detected prior to the beginning of the cotton fiber processing. 2,3 This is because cotton stickiness if a very serious problem in textile areas, including the growing, ginning and spinning sectors, and can cause major problems during opening, carding and through to spinning, many times resulting in financial losses. 4 Silverleaf Whitefly (Bemisia tabaci) and Cotton Aphid (Aphis gossypii) honeydew deposits have been