PHYSICOCHEMICAL PROPERTIES OF STARCH FROM AROIDS OF NORTH EAST INDIA

Starch from the corms of local aroid cultivars (cv.) Colocasia esculenta (cv. Mukhia Kochu), Xanthosoma caracu (cv. Boga Dohi Kochu), Xanthosama sagittifolium (cv. Kola Dohi Kochu), and Amorphophallus paeonifolius (cv. Ool Kochu) were isolated and their morphology, composition, structure, and physicochemical properties were studied. The yield of starch was in the range of 10.23-14.81% (A. paeonifolius-C. esculenta) of fresh weight corm (peeled off). The scanning electron microscopy of isolated starch of Colocasia esculenta revealed its round polygonal shape with a diameter of 0.71-1.25 mu m. The shape of the starch of Xanthosoma caracu and Xanthosama sagittifolium were found to be polygonal with a diameter of 1.25-2.21 and 2.1-2.84 mu m, respectively. There was considerable variation among the four aroids with respect to total amylose content, amylose leaching, phosphorus and carbon content, susceptibility towards enzymes, and acid hydrolysis and crystalline nature. The smallest sized starch of Colocasia esculenta, with a yield of 13.81 +/- 3.86% (fresh weight), showed great potential to be a source for baby food, fine printing paper, plastic sheets, carrier material for cosmetics, laundry stiffening agent, and other applications.