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EFFECT OF DRYING METHOD AND VARIETY ON QUALITY OF CASSAVA STARCH EXTRACTS
Akintunde, B. O. & Tunde-Akintunde, T. Y.
Abstract
Cassava tubers are main sources of calories and dietary fibre for Nigerians. Cassava
tubers are highly perishable and need to be processed immediately after harvest.
Cassava can be used for human consumption, livestock feed or industrial purposes.
Cassava starch is one of the main industrial products of cassava processing. The long
drying times for cassava starch production during sun drying have necessitated the
need for alternative drying methods. However, the quality of the starch obtained from
these alternative drying methods needs to be investigated. Starch was produced from
four different varieties (TME 1, TMS 30572, TMS 01/1235 and TMS 01/1181) of
cassava using two drying methods (sun and oven drying at 40oC). The physical (yield
and moisture content), functional (water binding capacity, swelling power and
solubility) and pasting properties of the starch produced were investigated. The
moisture content varied from 9.24 to 10.48%, with oven dried TME 1 having the
lowest values and sun dried TMS 01/1181 having the highest value. The yield of
starch obtained from drying the four varieties using the two drying methods increased
from 458.5 to 687.2g per kg of cassava tuber. The water binding capacity, swelling
power and solubility increased from 97.97 to 99.83 g water/g sample, 11.69–14.19
g/ml and 10.20 – 12.96% (g soluble solids/ g DM of whole starch sample)
respectively, for the different varieties dried using the two drying methods. Peak
viscosity, trough, break down, final viscosity, peak time and pasting temperature
values for the four cassava varieties were in the range of 335.76–619.89 RVU,
135.67–192.35 RVU, 199.38–433.99 RVU, 196.01–257.72 RVU, 3.23–3.91 min and
70.05–72.95oC, respectively for the two drying methods. The values obtained from
the cassava varieties considered were generally significantly different (except colour)
which shows significant effect of cassava variety used on starch properties. Also,
cassava starch samples dried at lower temperature have better functional and pasting
properties. This indicates that alternative drying methods should be used at
temperatures lower than 40oC in order to obtain products of high quality.
Keywords
Physico-chemical properties; Drying; Cassava; variety
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