Pupuru (a fermented cassava product) is one of the major
staple foods amongst the Yoruba, Ilaje and Ijaw speaking people in the south-south
and south-western region of Nigeria, which had its source from the Ikale tribe
of Ondo state. The traditional method of processing cassava tubers into pupuru
involve, cassava tuber harvesting, peeling, washing, soaking, dewatering,
moulding and smoking. The pressed and mashed cassava tubers are then rolled or
molded into a ball shape and dried by smoking: it was observed that the pupuru
produced by this method is infested with unpleasant odour, drudgery, poor
packaging and cannot be stored for a long period. Hence, this project
investigates in detail an improved method that will eliminate the deficiencies
associated with the traditional method of pupuru production. The proximate
composition, sensory evaluation, PH, hydrocyanide content, density and water
absorption capacity of the resulted pupuru from the improved method were
determined. The moisture content (10.21%) was lower than the moisture content
of the traditionally produced pupuru which is 24.01%. Also, the HCN content
which is 0.81mg/kg was found to be lower to the traditionally produced pupuru
which was 1.45mg/kg. With the introduction of improved techniques and modern
equipment, this study has led to the production of improved pupuru with better
organoleptic qualities such as colour, odour, mouldability, stickiness and
texture. The improved method involves harvesting, peeling, washing, soaking,
dewatering, pressing, sundrying, milling, sieving, remilling and packaging.
with the use of machines and methods that reduces the problem of traditional
1.2 BACKGROUND OF THE STUDY
Cassava (Manihot Esculenta Crantz) is a dicotyledonous plant
belonging to the botanical family Euphorbiacea. Cassava is primarily a source
of carbohydrates and contains very little protein or fat. It is a staple food
for over 500 million people in the developing world, (FAO, 2005).
Cassava tubers are highly perishable and cannot be kept in
fresh condition for more than a few days after harvest without serious
deterioration in quality. In order to extend its shelf life, cassava is being
processed into dried products in a variety of ways in different parts of the
world to meet the local needs, taste and storage.
The major process and form of cassava tuber fall into four
general categories: meal, flour, chips and starch. (FAO, 2005). Traditionally,
cassava roots are processed by various methods into numerous products, such as,
Garri, fufu, lafun, abacha, pupuru e.t.c.
Cassava is widely used for both human consumption, livestock
feed and various forms of Industrial uses, (FAO, 2006). It can be prepared by
boiling, baking, frying and roasting. The young leaves of sweet cassava are
used as vegetable greens and they are more wholesome than the roots since they
contain high amount of protein, the leaves are also valuable food for
particular goats, (Ihekoronye and Ngoddy, 1995). Also, there is an increase in
the use of cassava in industrial fermentation for alcohol production and for
microbial protein production for animal feed (FAO, 2005).
About 19% of the world production of cassava is used in the
manufacture of industrial starch products (such as in laundry, gums and
adhesive). And in the preparation of pharmaceuticals and in production of
alcoholics, (Agbo-Egbe and Mbome, 2006). The demand for these products is on
the increase and Governments interest in cassava research is also increasing
with strong emphasis on mechanization. This is because cassava processing is
labour intensive and the quality of the locally processed items are below acceptable
standards. Lack of mechanization is responsible for the long time required for
processing a given product.
Major importance of cassava processing according to………
Traditional processing methods produce shelf stable products
e.g. gari, kokonte.
Grating, fermentation and other unit operations reduce the
level of cyanide in cassava.
Cassava fermentation by lactic acid bacteria e.g. in gari,
agbelima, akyeke, improves safety of the product against pathogens, reduce
cyanide content, improves nutritional value.
New cassava products can be developed to expand market for
cassava including downstream processing of cassava flour and cassava starch.
Cassava is one of the most drought tolerant crops and can be
successfully grown on marginal soils, giving reasonable yields where many other
crops do not grow well. One of the advantages of cassava over other starchy
crops is the variety of uses to which the roots can be subjected to (Olatidoye
et al., 2010).
Cassava is a perennial woody shrub, grown as an annual and
is a tropical root crop, requiring at least 8 months of warm weather to produce
a crop. It is traditionally grown in a savanna climate, but can be grown in
extremes of rainfall. Cassava is a major source of low cost carbohydrate for populations
in the humid tropics (Onwueme, 1978). The largest producer of cassava is
Brazil, followed by Thailand, Nigeria, Zaire and Indonesia.
In Nigeria, many traditional foods are processed from
cassava roots among which are “Pupuru”, lafun, fufu and gari amala and eaten
with soup depending on the family income. Cassava may be supplemented with
legumes in this zone, many people cannot afford the supplementation which in
most cases are in form of expensive animal proteins (Olatidoye et al., 2010).
The cassava used for the “pupuru” is the bitter variety. The
use of cassava as a food is limited by its perishability, protein content and
potential toxicity. Processing methods have been devised to reduce their
toxicity and at the same time convert the highly perishable roots to more
stable products. These processes include, soaking, fermentation, drying and
roasting. The toxicity is due to the cyanogenic glycoside. Fermentation is one
method by which cyanogenic glycoside in “pupuru” can be reduced and also result
in the production of volatile compounds that give “pupuru” its unique flavor
and colour. Most of the juice from the cassava pulp is expressed during this
Pupuru” is commonly consumed by the people living in the
riverine areas of the western, southern, eastern and the middle belts of
Nigeria, where it is also known as “Ikwurikwu” [Aboaba, et al,1988; Shittu,
2001]. It is a traditional fermented, smoked-dried cassava food consumed in
Southwestern Nigeria. The technology of “pupuru” processing originated from the
Ikale people of the Riverine area of Ondo State, Nigeria [Shittu, 2005].
The time allowed for fermentation is critical, if too short,
detoxication process will be incomplete, resulting in a potential toxic product
and if it is too long, the product will have a strong sour taste and the
texture will be coarse (Azam Ali, Judge, Fellows and Battcock, 2003).
Pupuru is probably the most important staple food in
riverine area of Nigeria (Ihekoronye and Ngoddy, 1995) and development of any
real significance in cassava processing has been concentrated on its
production. (Akinrele, 1964).
According to Olowoyo et al., (2000) and Ikujenlola and
Lawson (2005), process modifications and the use of modern technology (machine)
led to the production of improved Pupuru of better organoleptic qualities. The
production technique involves the use of simple machines such as; fermentation
tank, conditioned water for soaking, hydraulic pressing, kiln oven, rotary
dryer and better packaging practices. These helped reduce the production and
reconstitution time by 45 and 65% respectively (Ikujenlola and Lawson, 2005).
The improved Pupuru will have a longer shelf life.
The fresh cassava tuber is peeled, washed, sliced and packed
into sack and soaked in a flowing stream from 3–4 days to soften the root. The
softened cassava tubers are then defibered followed by de-watering process
which is achieved by placing a heavy stone or concrete slab on the bag
containing the defibered cassava pulp. The de-watered cassava pulps are moulded
into a ball shape and placed on a wooden platform called “aka” and smoked for
three days. The smoked pupuru can be further processed to make pupuru flour.
(Olaoluwa et al 2012).
The disadvantages of traditional methods of pupuru
production include poor shelf-life and the offensive odour which is caused by
the fermentation process used. The local farmers in the rural areas may
sometimes soak the cassava tubers with the peels in the stream inside a
traditional pot for a good number of days. These local methods do not promote
ease of production and at the same time large scale production is hindered.
(Olaoluwa et al 2012).
Other disadvantages of traditional processing which tends to
pose problems to quality pupuru flours as stated by…………….. includes:
High labour input – manual operations and low efficiency.
Scattered and uneconomical nature of operations.
Time consuming nature of the processes.
Lack of quality assurance and Poor product packaging.
Highly perishable – short storage life
Low levels of protein
Some varieties of cassava contain high levels of Cyanogenic
glucosides which impart toxicity to the plant
However, because of the problems associated with the
traditional method of pupuru production, the objective of this study is aimed
improving method of pupuru production that will reduce to
minimum the problems associated with the local method as stated above.
examine the stages that products undergo and the time spent
To help reduce the odour and increase the shelf life sof
traditional cassava flour.