Enrichment of a Cassava Meal (Gari) with Soyabean Protein Extract

Text-only Preview

60
Advances in Natural and Applied Sciences, 2(2): 60-62, 2008
ISSN 1995-0748
© 2008, American Eurasian Network for Scientific Information
This is a refereed journal and all articles are professionally screened and review ed
ORIGINAL ARTICLE
Enrichment of a Cassava Meal (Gari) with Soyabean Protein Extract
Uche B. Eke, Samson O. Owalude and Lamidi A. Usman
Department of Chemistry, University of Ilorin, P.M.B. 1515, Ilorin, Kwara State, Nigeria.
Uche B. Eke, Samson O. Owalude and Lamidi A. Usman: Enrichment of a Cassava M eal (Gari) with
Soyabean Protein Extract: Adv. in Nat. Appl. Sci., 2(2): 60-62, 2008
ABSTRACT
A low protein cassava meal, (gari), has been fortified with protein extract from soyabean seeds. The enriched
gari was found to contain 9.63% protein which was adjudged as capable of reducing the level of poor feeding culture
among the poor of in the developing countries of the world especially W est Africans where gari is a staple. The
process of gari production did not significantly denature the protein content and no visible change in characteristic
flavour, physical appearance and taste was noticed. The stability of the protein extract under the gari processing
conditions of wet fermentation and high temperature were also examined.
Key words: Gari, protein extract, soyabean flour, fermentation, frying, food fortification.
Introduction
In the continuous search for solution to the problem of malnutrition in its various forms, mainly among the
people of the developing countries, views have been expressed of the need to improve the nutritive quality of our
local food through better processing and enrichment. Gari (processed cassava meal) is one of such basic foods
worthy of attention. It is widely eaten in the west and central Africa and forms a staple food for majority of the
people in the southern part of Nigeria. An estimate of about ten million tones is produced in Nigeria alone per annum
(Okafor, 1992). High protein foods of animal origin such as meat, fish milk and eggs are very expensive especially
to the low income earners who are the majority in the population of W est African sub region. Although efforts to
increase the local production of these animal protein sources at affordable prices are still ongoing (Akerele, 1967),
fortification of gari with non-animal protein will be another alternative. Gari is never eaten alone as a full meal but
rather taken with vegetable stew to satisfy the other nutrient requirements and this also depends on the animal protein
content of the stew. Consequently, several studies have examined the fortification of cassava meal with vegetable
protein (Akerele, 1967; Obadina et al., 2006; M orse and Uriah, 1975). A recipe consisting of 70% full fat soybean
flour, 20% whole fat sesame flour, 5% defatted groundnut flour and 5% dried yeast powder as an appropriate
supplement for gari related diet has been identified.5 The biological value of gari has been found to be raised from
47 to 68 with this blend. Also laboratory rats were fed with cassava marsh fortified with defatted soybean flour
and it was observed that the nutritive quality of the staple cassava meal was greatly improved (Akerele, 1967). These
studies however recommend that investigation of texture, flavour and palatability of cooked mixtures be carried out
before human trials of the diet are attempted. The present study is concerned mainly with the extraction of soybean
protein and its fortification with gari in other to convert it to a good basic food that is affordable and that can supply
the minimal protein requirement of a balanced diet (Boen et al., 2008). The incorporation of the protein extract into
gari gave a good blend with high protein and quality organoleptic parameters. Other parameters examined include
colour, flavour, texture and adhesibility of the food blend when made into morsels. The stability of the protein
extract under the gari processing conditions of wet fermentation and high temperature were also examined.
Corresponding Author: Uche B. Eke, Department of Chemistry, University of Ilorin, P.M.B. 1515, Ilorin, Kwara State, Nigeria.
E. M ail: ekeub@ yahoo.co.uk and owalude1412@ yahoo.com

Adv. in Nat. Appl. Sci., 2(2): 60-62, 2008
61
M aterials and methods
Materials
The soyabean seeds were bought in a local market in Ilorin metropolis. Cassava tubers were collected from the
Gari Processing Industry in Ilorin, Kwara State, Nigeria.
Preparation of Soyabean Seed cake
Soyabean Flour (SBF)

The soyabean seeds were steam heated for one hour and dehulled after cooling. The soyabean seeds
were pre-heated to remove trypsin which is a proven protein inhibitor in soyabean (Friedman et al. 1982).
The dehulled seeds were blended into fine particles using magnetic Blender (SHB- 515 model made by Sorex
Company Limited, Seoul, Korea) to obtain the seed cake. SBF samples were defatted using the standard official and
tentative procedure of the American Oil Chemists Society (AOCS, 1979). The resultant defatted seed cake
was air dried and kept for analysis.
Extraction of Proteins
The method described by Usman et al was adopted (Usman et al., 2006). The extractant employed was 0.1M
Na SO solution. Extraction was carried out at ambient temperature (29oC) using a mechanical shaker. All
2

4
suspensions were centrifuged at 4000 rpm for 1 hour. The supernatant liquid obtained was dialyzed against distilled
water for 48 hours.
Processing of Fortified Gari
Cassava tubers were peeled, washed and grated. The grated cassava was pressed inside a cloth bag and allowed
to ferment for 3 days. After fermentation, the mash was filtered through a mesh to remove the undegradable roots
(Asiedu, 1989). A mixture of cassava and the protein extract in the ratio 2:1 was stirred continuously for 1 hour and
transferred into a clean white cloth. The mixture is dehydrated by pressing and left for 24 hours. The cassava
containing the extract was fried at a moderate temperature with constant stirring. The enriched gari was then allowed
to cool and packaged thereafter.
Chemical analysis
Fortified and the unfortified gari were analyzed for crude protein using the micro-Kjeldhal (N x 6.25) method.
Results and Discussion
The percentage fat content of the soyabean seeds was calculated by the weight loss of the samples after solvent
extraction to be 16.2%. The protein content of the defatted soyabean seeds was 31.2%, a value slightly lower than
the literature reports of between 32 and 39.3% (Ajewole and Onasanya, 1996). This variation may be attributed to
the geographical and climatic conditions of the source of the seeds (Hildebrand et al., 1981). The fortified gari was
found to be 9.63% protein rich which showed that at the end, gari processing may not have significantly denatured
the protein content. A panel of tasters was composed to evaluate the organoleptic properties of the food blends
prepared from the fortified gari and the non-fortified one. The panel found that in terms of taste, texture and flavour
there was no significant difference between the two blends.
Conclusion
Our results show that during gari processing, the protein content was not significantly denatured and that the
fortified gari is 9.63% protein rich which is a considerable improvement on the 1.2% reported for the non-fortified
gari (Stevenson and Graham, 1983). This makes soyabean protein a good option in the food supplementation efforts
of food scientists. However a further work must be carried out to evaluate its nutritive value when consumed by
humans.

Adv. in Nat. Appl. Sci., 2(2): 60-62, 2008
62
References
Ajewole, K. and L.O. Onasanya, 1996. M ineral elements, proteins and fatty acid composition of some improved
soyabean varieties in Nigeria. Journal of the Chemical Society of Nigeria, 21: 52-56.
Akerele, I.A., 1967. Nutrient enrichment of gari. W est African Journal of Biological and Applied Chemistry,
10: 19-22.
Asiedu, J.J., 1989. Processing Tropical Crops, A technological Approach, John W iley Press Incorporation.
Boen, T.R., B.T. Soeiro, E.R. Pereira-Filho and J.A. Lima-Pallone, 2008. Folic acid and iron evaluation in Brazilian
enriched corn and wheat flours. Journal of the Brazilian Chemical Society, 19: 53-59.
Friedman, M ., K. Grosjean and J.C. Zahnlry, 1982. Inactivation of soyabean’s trypsin inhibitors by thiols. Journal
of the Science, Food and Agriculture, 33: 165-172.
Hildebrand, D.F., N.S. Hehiarachchy, T. Hymowtz and J.W . Erdman, 1981. Electrophoretic separation and
properties of winged bean seed trypsin inhibitor. Journal of the Science Food and Agriculture, 32: 443-450.
M orse, R.E. and N. Uriah, 1975. Fortification of gari. Nutrition Reports International, 16: 29.
Obadina, A.O., O.B. Oyewole, L.O. Sanni and S.S. Abiola, 2006. Fungal enrichment of cassava peels proteins.
African Journal of Biotechnology, 5: 302-304.
Okafor, N., 1992. Commercialization of fermented foods in sub-Saharan Africa” in Application of bacteriology to
Traditional Ferment Foods, National Academic Press, USA. Official and Tentative methods of the American
Oil Chemical Society 1, AOCS, Champaign, 1L (1979).
Stevenson, M .H. and W .H. Graham, 1983. The chemical composition and true metabolisable energy content of
cassava root meal imported into Northern Ireland. Journal of the Science, Food and Agriculture, 34: 1105-1106.
Usman, L.A., O.M . Ameen, S.A. Ibiyemi and N.O. M ohammed, 2005. The extraction of proteins from the Neem
seed (Azadirachta indica A. Juss). African Journal of Biotechnology, 4: 1142-1144.