Abstract

Starch was extracted from aerial yam (Dioscorea bulbifera) using water, sodium hydroxide, ammonium oxalate, and oxalic acid as extraction solvents, oven-dried at 45°C for 24 h, and milled to flour. The starch obtained was evaluated for yield, chemical and functional properties using standard procedures. The sensory attributes of the starch cooked pastes were also determined. Aerial yam extracted with oxalate gave the highest yield of 20.20% and high amylose content was observed in the water extracted aerial yam samples. A higher purity of 90.45% was observed in the aerial yam starches extracted with oxalate. Water extracted aerial yam starch had the highest swelling power and solubility index of 48.44% and 25.75 g/g with the least gelation capacity of 4% with high pasting viscosities and also low pasting temperature and time. The cooked paste of the starch extracted with oxalic acid was the most acceptable in terms of appearance (8.60) and overall acceptability (8.16). The starch extracted with water had higher swelling power and a solubility index than other starches extracted. Extraction of aerial yam starch with different solvents resulted in variations in the characteristics of the starch, which can find wide applications in both food and non-food industries.

Key words: Aerial yam starch, extraction solvents, yield, chemical, functional, sensory properties.