Production and characterization of Protein isolates from locally produced mustard meal for the development of biscuit
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Date
2009-12
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Addis Ababa University
Abstract
A process for the preparation of Holetta 1 mustard protein isolate, comprising steps such as
ground the seed, removal of oil with hexane, followed by extraction at alkaline pH 10, 11 and
12. The protein was subjected to separation by centrifugation, neutralization, washing and
freeze-drying. The parameters evaluated were protein yield, purity and presence of some
antinutritional factors. The protein yield was 56-80%.The purity of the protein isolate was
73.29%, 75.40% and 68.225 at pH value of 10, 11 and 12 respectively. The antinutritional
factors levels of defatted meal was as follows, glucosinolates represents 5.1%, phytate was
3.19% and tannins was 0.35% but after processing its value was 0.013%, 0.035 and 0.65% at
pH10, 0.012%, 0.03% and 0.75% at pH11 and 0.02%, 0.215% and 1.45% at pH12
respectively. The lowest protein solubility was achieved at pH 5.some functional properties
such as water adsorption(WA), fat adsorption (FA), emulsifying activiy (EA) and foaming
capacity (FC) were evaluated.Holetta1 mustard defatted meal were compared with soybean
meal in terms of functional properties. The tested result showed a high water absorbtion and
was superior to soybean meal in FA, EA and foaming properties
The chemical composition results of mustard variety of Holleta 1 defatted meal was 38.42%
of protein, 5.03% of ash, 7.10% of moisture, 31.15% of fiber, 7.79% of crude fat and 10.53%
of carbohydrate but after processing, the mustard precipitated protein isolate contained
75.40% of protein, 2.64% of ash, 7.97% of moisture, 0.08% of fiber, 12.61% of crude fat and
1.31% of carbohydrate.
In addition to the above, this study evaluated the effectiveness of substituting different
concentrations of mustard protein isolated (MPI) on the physicochemical and sensory
properties of biscuits. Proximate chemical analysis results of biscuits showed that
fortification increased protein contents from 9.67% to 12.77% as well as increased moisture
and fat content from 4.18% and 8.26% to 9.46% and 8.49% respectively but carbohydrate
content was decrease from 76.79% to 68.16%. Fortification processes were conducted by
substituting specified concentrations (3%, 6%, and 9%) MPI from the total percent of wheat
flour (100%). Results indicated that fortification decreased spread factor compared with the
control (100% wheat flour). Sensory results showed that as the fortified MPI ratios increased
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most of liking attributes decreased. Sensory analysis also showed that 3% of fortified MPI
provided the best quality ratios within each type of fortification. Fortification of MPI could
be used in production of high-protein biscuits.
The result obtained for fortification of biscuit with mustard protein isolate, the incorporation
of MPI ratio increase with the decrease of hardness (strength) from 20.2N, 20N, 17.2N and
15.7N for control (100% wheat flour), 3% MPI, 6%MPI and 9% MPI fortified biscuit
respectively.
Regarding to profitability, gross earning will be 46,200,000birr, ROI = 26.84%, pay back
period = 3.2 year and break even point = 17.54%
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Keywords
Centrifugation, Neutralization