The first characterization usually provided when distinguishing between amylose and amylopectin is the linear nature of amylose as opposed to the branched nature of amylopectin. Amylopectin has relatively high molecular weight, amylose is low molecular weight molecule. Amylose is water soluble, but does not form a starch gel or paste. Amylopectin is insoluble in water. Amylose gives a dark-blue color when an iodine solution is added. Amylopectin gives a reddish-brown color when an iodine solution is added. Amylose provides strength, amylopectin prevents rapid gelling of starches. The proportion of amylose and amylopectin differs depending on the source of starch.