Determination of pectin content on cotton fabric sized with starch

The wetting property of pretreated cotton fabrics is obviously affected by the pectin on cotton fiber.To measure the property of the pretreated cotton fabric in quantity,the content of pectin is usually determined.For cotton fabric sized with starch,the starch has significant impact on the determination of pectin with the traditional test method.In this paper,a new method was proposed on the basis of DNS-spectrophotometer-method.The effects of absorption wavelength,quantity of DNS,reflux time of starch solution with sulfuric acid,and reflux time of pectin solution with sulfuric acid were investigated.The content of pectin can be determined precisely by this method,avoiding the influence of starch.It has practical significance for investigating the pretreatment with compound enzyme and the effect of pectin on wetting property of cotton fabric.