Effect of pretreatments and drying techniques on functional and physicochemical properties of aerial yam (Dioscorea Bulbifera) powder

Abstract:

This research was conducted to study the effect of pretreatments and drying techniques on functional and physicochemical properties of aerial yam (Dioscorea bulbifera) powder. In the present study, four pre-treatments (Untreated, Cold water, Lukewarm water, Hot water blanching) were combined with three drying methods (Sun drying, Tray drying, Pyramid solar drying). The prepared aerial yam powders were evaluated for functional and physico-chemical properties. Among pretreatments hot water blanching showed superior results for bulk density (0.724 g/ cm 3 ), oil absorption capacity (1.168 g/g), moisture (9.233%), fat (0.506%) and carbohydrate content (80.858%), while lukewarm water treatment was superior for water absorption capacity (2.630 g/g), starch content (28.733%) and fiber content (2.383 g/g). Control treatment showed higher values for ash content (3.392%), protein content (6.423%), total flavonoid content (4.403%QE), total phenol content (3.433%GAE) and total tannin content (1.529%TAE). Among the drying methods, tray drying showed superior performance for the studied parameters. Tray drying recorded minimum moisture content (9.088%) and fat content (0.533%). Tray drying recorded maximum bulk density (0.727 g/ cm 3 ), oil absorption capacity (1.196 g/g), and water absorption capacity (2.527 g/g), ash content (3.188%), protein content (6.458%), fiber content (2.196%), carbohydrate content (80.743%), starch content (27.884%), total flavonoid content (3.549%QE), total phenol content (2.923%GAE) and total tannin content (1.328%TAE). In a combination treatments lukewarm water treatment with tray drying was found to be the most suitable treatment.