Thermal and Physicochemical Properties of Some Starchy Foods: Yam (Dioscorea rotundata), Cocoyam (Xanthosoma sagittifolium) and Plantain (Musa paradisiaca)

摘要

The thermal and physicochemical characteristics of yam species (Dioscorea rotundata), plantain species (Musa paradisiaca) and cocoyam species (Xanthosoma sagittifolium) were studied. Yam, cocoyam tubers and fingers of plantains were processed into flour for the determination of quality characteristics. The moisture content of the samples ranged from 5.6 - 8.4% with the plantain flour having the lowest value. The protein content of yam was the highest (3.2%) while the plantain flour was the lowest (2.07%) although with the highest carbohydrate content of about 88.34%. Values for ash content ranged between 1.93% and 2.82% with the lowest value obtained for plantain and the highest for cocoyam. The wettability values ranged from 40.67- 106.67secs being highest in the plantain flour. Angle of repose was highest for plantain (35.67~(o)). The amylose content was highest in yam (35.92%) while plantain gave the least (25.53%). Cocoyam has the highest solubility at 45℃ and the highest also at 90℃, the same thing was observed in its swelling power. Yam gave the least value for solubility. Pasting temperature ranged from 48.01 - 49.51℃ with highest in cocoyam flour. Peak time ranged from 4.97 min to 5.15 min while plantain had the highest value. Peak viscosity ranged between 272.47 and 373.87 RVU being lowest for cocoyam and highest for yam flour. The relatively higher pasting temperatures required, and the lower pasting viscosities make cocoyam suitable for producing weaning foods and other products that require low viscosity. Pasting properties of cocoyam revealed relatively higher thermal and mechanical stability which will make it a good ingredient for processed foods, especially those that require thermal sterilization.