Flour composition and physicochemical properties of white and yellow bitter yam (Dioscorea dumetorum) starches
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Date
2018-04
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Publisher
Industrial Crops and Products (Elsevier Journal)
Abstract
Bitter yam (Dioscorea dumetorum) is an underutilized tuber crop that is rich in starch and may be potentially used
as a starch source by the industry. In this study, the composition and physicochemical properties of flour and
starch from white and yellow bitter yams were studied. Bitter yam showed significant variations in their
proximate composition, but mineral contents were very similar. The amylose content (approx. 15%) of white
bitter yam starch was slightly lower than the yellow variety (approx. 17%). Bitter yam starch granules were very
small (average 5 μm) and polygonal in shape. Starch extracts displayed the A-type crystallinity pattern with
varying relative crystallinity: 22.1–28.0%. The peak gelatinisation temperature (approx. 83 °C) and pasting
temperature (approx. 87 °C) were fairly high and similar for both starches. Starch peak viscosity of the white
bitter yam was significantly higher than the yellow variety, which could be associated with its slightly lower
amylose content. Bitter yam starch may find application in the industry where fairly high temperatures (> 80 °C)
are frequently encountered.
Description
Research work on properties of white and yellow bitter yam starches.