Effect of Slice Thickness and Blanching Methods on Physical and Functional Properties of Elephant Foot Yam [Amorphophallus paeoniifolius (Dennst.) Nicolson], Powder during Storage

Abstract

Elephant foot yam [Amorphophallus paeoniifolius (Dennst.) Nicolson] is a perishable tropical tuber with potential for value addition through dehydration and powder production. The present study evaluated the effects of slice thickness and blanching method on selected physical and functional properties of elephant foot yam powder during ambient storage. Fresh, mature tubers of cv. Gajendra were sliced into three thicknesses, namely 2, 4 and 6 mm, and subjected to six blanching treatments: no blanching, water blanching for 3 min, water blanching for 5 min, microwave blanching for 30 s, microwave blanching for 60 s and microwave blanching for 90 s. The treated slices were dried in a cabinet dryer at 60°C for 6-7 h, pulverised, sieved through a 500 µm mesh, packed in 400-gauge polypropylene pouches and stored for six months. The experiment was conducted using a factorial completely randomised design with three replications. Powder recovery was highest in 2 mm unblanched slices, whereas moisture content increased with slice thickness, water blanching and storage duration. Water absorption capacity and swelling capacity were greater in water-blanched samples, particularly after 5 min of blanching, whereas bulk density was highest in powder prepared from 6 mm slices. Storage was associated with a gradual increase in moisture content and a decline in water absorption capacity, swelling capacity and bulk density. The results indicate that slice thickness and blanching method influence the quality characteristics of elephant foot yam powder, and that pre-treatment selection should be based on the desired functional property of the final product.