The Food Potential Of Potato Yam (Dioscorea bulbifera)

Abstract

A study was undertaken to determine the Food potential of “Potato yam,” (Discorea bulbifera) an underexploited tuber by determining the proximate analysis of the fresh tuber, functional properties of the flour and sensory evaluation of it's “amala” product. These were compared with those of two other yam species - yellow (D. cayenensis) and white yams (D. rotundata). Proximate analysis of potato yam showed moisture 63.13%, carbohydrate 34.35%, protein 1.20%, fat 0.49% and ash 0.87%. Functional properties of its flour showed a water absorption 10.20ml/g, moisture 9.50%. Swelling index 5.09ml/g, reconstitution index 10.20ml/g, least gelation concentration 4.00%, while bulk and loose pack densities of 0.53 and 0.60g/ml respectively. All values compared favourably with those of yellow and white yams. “Amala” prepared from potato yam also compare favourably with yellow and white yam in respect to colour, texture, flavour and general acceptability. There was no significant difference at P ≤ 0.05 using ANOVA between the “amala” products of the three yam species. The study indicates that potato yam is a good energy food source and a good substitute for white yam, especially considering the high cost of white yam.

Key words: Yam species, Discorea bulbifera, proximate composition, functional properties and sensory evaluation.

Nigerian Food Journal Vol.22 2004: 209-215