Influence of Baking Time and Temperature on the Quality of Kocho Biscuit Enriched with Faba Bean and Wheat
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Date
2010-06
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Addis Ababa University
Abstract
The production of nutritious biscuit from Kocho of low protein and high carbohydrate, mineral
and crude fiber; fortified with faba bean of high protein and moderate fat content; and wheat of
good glutenin and gliadin; were the bases for enriched biscuit production. The proximate
analysis of enriched Kocho biscuit was done using the AOAC, 2003 analytical procedure. The
enriched Kocho biscuit showed an upgrade in protein content from 0.96 of whole Kocho
biscuit processed at 1700C for 10min to 9.7% of KFWB2 at 1700C for 10min. This also implies
that the consumption of 2 pack of 250g each (one pack contain 21 biscuit of each weighing
12g) of enriched Kocho biscuit of blend KFWB2 processed at 1700C for 10min accommodates
the daily protein requirement of 39g/day and 50g/day for the age of 1-3 and 4-10; respectively.
The mineral content of enriched Kocho biscuit is improved by the presence of Kocho and faba
bean. The time and temperature effect of baking the enriched biscuit shows a major change in
protein content due to an increase in the faba bean concentration. With increasing temperature
and time the value of the protein decreased due to protein denaturation by heat. As can be seen
in KFWB3 processed at 1700C when the time increases from 7 to 8, 8 to 9, and 9 to 10min the
protein decreases from 9.94%-9.51%, 9.51%-9.08%, and 9.08%-8.99% respectively.
Correspondingly, at a fixed time of 10min in KFWB3, an increase in temperature from 1600C
to 1700C, and 1700C to 1800C resulted in decrease from 9.56%-9.08%, and 9.08%-8.98%
respectively. The result obtained from the SPSS analysis revealed that biscuit KFWB2
processed at 1700C for 10 min. gave best result for protein content of 9.7% on dry basis. This
implies that the enriched Koch biscuit is a good source of protein and can support problem
solving in protein malnutrition in the country. The farinograph data for various blends of flour
revealed that faba bean has 206 FQN which is better than that of wheat of 108FQN.
Combination of this faba bean with Kocho flour improves its farinograph quality number from
7 to 200 of KFWF3 and makes it more suitable for biscuit production. The flour property like
water and oil adsorption for whole Kocho flour (KF) were 2.29ml/g and 0.93ml/g; respectively
which improved to KFWF2 of 2.05 ml/g and 1.15ml/g; respectively which is not significantly
different form wheat flour of 2.2ml/g and 1.18ml/g. This makes the enriched Kocho biscuit
comparable in terms of farinograph quality number and dough consistency with the standard
whole wheat flour biscuit. The water activities of the whole blended flours were in between
0.47% and 0.55% indicating below the minimum water content required by microorganisms.
The water activity for the biscuit is also in the range of 3.7% and 6.5%. The moderately high
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amount of water activity in whole wheat flour biscuit (KFWB5) results in damage by
microorganisms. The recommended water activity for the biscuit is in the range of 0.3% and
0.5%.
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Keywords
Process Engineering