Garri is the most popular form in which cassava is consumed in Nigeria. This research studied the effect of fermentation period on cyanide reduction in garri flour (white and yellow garri samples) and comparison with some selected samples marketed in Aba, Nigeria. The cyanide content of the various garri samples were estimated by alkaline picrate paper spectrophotometric method. The results showed that the cyanide contents decreased significantly (p<0.05)>0.05). Cyanide concentrations of the market purchased garri samples had 14.37±0.05 to 36.32±0.1 mg/kg and 18.37±0.05 to 29. 68±0.05 mg/kg in the white and yellow garri samples respectively. These values indicated that about 50% of the market purchased garri samples showed varying cyanide concentrations of 1st to 2nd day’s fermentation. This study has revealed the need to educate the public on the imminent danger of inadequate fermentation of garri flour and it will subsequently strengthen the moral norms of the producers to adapt to normal period of 5 to 6 days. Article Citation: Ukpabi Chibueze F, Emeghebo Ngozi, Ukpabi Emmanuel and Emole Eke Chukwu. Effect of fermentation period on cyanide reduction in garri flour and comparison with some selected samples marketed in aba, Nigeria. Journal of Research in Agriculture (2013) 2(1): 152-156. Full Text: http://www.jagri.info/documents/AG0033.pdf

1. Effect of fermentation period on cyanide reduction in garri flour and
comparison with some selected samples marketed in aba, Nigeria.
Keywords:
Cassava, Cyanide, Garri, Fermentation.
ABSTRACT:
Garri is the most popular form in which cassava is consumed in Nigeria. This
research studied the effect of fermentation period on cyanide reduction in garri flour
(white and yellow garri samples) and comparison with some selected samples
marketed in Aba, Nigeria. The cyanide content of the various garri samples were
estimated by alkaline picrate paper spectrophotometric method. The results showed
that the cyanide contents decreased significantly (p<0.05) with the length of
fermentation period of the grated cassava mash from 1st
to 4th
days. Though there
was a decrease in cyanide concentrations between the 4th
and 5th
days, they were not
significant (p>0.05). Cyanide concentrations of the market purchased garri samples
had 14.37±0.05 to 36.32±0.1 mg/kg and 18.37±0.05 to 29. 68±0.05 mg/kg in the white
and yellow garri samples respectively. These values indicated that about 50% of the
market purchased garri samples showed varying cyanide concentrations of 1st
to 2nd
day’s fermentation. This study has revealed the need to educate the public on the
imminent danger of inadequate fermentation of garri flour and it will subsequently
strengthen the moral norms of the producers to adapt to normal period of 5 to 6
days.
152-156 | JRA | 2013 | Vol 2 | No 1
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www.jagri.info
Journal of Research in
Agriculture
An International
Scientific Research Journal
Authors:
Ukpabi Chibueze F1
,
Emeghebo Ngozi1
Ukpabi
Emmanuel2
and Emole Eke
Chukwu2
.
Institution:
1. Department of
Biochemistry, Abia State
Polytechnic, Aba.
2. Department of Chemistry,
Abia State Polytechnic, Aba.
Corresponding author:
Ukpabi Chibueze F.
Email:
ukpabichibueze@yahoo.com
Phone No:
0806670705.
Web Address:
http://www.jagri.info
documents/AG0033.pdf.
Dates:
Received: 03 Dec 2012 Accepted: 05 Dec 2012 Published: 05 Apr 2013
Article Citation:
Ukpabi Chibueze F, Emeghebo Ngozi, Ukpabi Emmanuel and Emole Eke Chukwu.
Effect of fermentation period on cyanide reduction in garri flour and comparison with
some selected samples marketed in aba, Nigeria.
Journal of Research in Agriculture (2013) 2(1): 152-156
An International Scientific Research Journal
Original Research
Journal of Research in Agriculture
JournalofResearchinAgriculture

2. INTRODUCTION
Food products prepared from cassava (Manihot
species) are the staple diet consumed in tropical Africa.
Products such as garri, fufu and tapioca are very popular
in Nigeria. These food products play major roles in
efforts to alleviate food crisis because of their efficient
production of food energy, year- round availability and
food systems in Africa. In recent times changes have
raised to increase cassava productivity, new varieties, use
modern irrigation methods, chemical fertilizers and
herbicides. It is estimated that the crop production is
about 40% of all calories consumed in Africa (Roa et al.,
1997).
Garri flour is the most popular processed food
from cassava in Nigeria. In garri production, fresh roots
are peeled and grated. The grated pulp is put in jute and
the jute are placed under heavy stones or pressed with a
hydraulic lock between wooden platforms for 5 to 6 days
to express excess liquid from the pulp while it is
fermenting. The dewatered and fermented lumps of pulp
are sieved and roasted. Palm oil may be added to give a
light yellow colour to the garri. When palm oil is not
added a white garri is produced. Nowadays, the
processing techniques of garri has moved from simple
processing to complicated procedures which involve
semi-mechanised and intergrated accelerated methods
(Odoemelam, 2005).
Recent studies have shown that garri is widely
consumed as food in several parts of Nigeria (Harbor and
Ogundu, 2009; Odoemelam, 2005). Garri can be eaten
dry or soaked in water as “Eba” and consumed with
soups. “Eba” is a very popular food in Nigeria and is
gaining popularity in many African countries because of
its fast and easy reconstitution into a convenient food.
The major factor that limits the use of cassava as food is
that it is a significant source as cyanogenic glucosides
(Enidiok et al., 2008). These cyanogenic glucosides are
widely distributed in the plant, with higher
concentrations in the leaves and root peel and lower
concentrations in the root parenchyma (inside the root)
(Cardoso, 2005). The major traditional method of
reducing cyanide in garri is by fermentation over periods
of about 5 to 6 days (FIIRO, 2006). Although, other steps
such as peeling, washing, grating, drying, dewatering,
milling and roasting can also influence the level of
residual cyanide in cassava products (Omoike and
Adediran, 1991).
Due to the imminent danger and high toxicity of
several cassava varieties, the Codex Alimentarius
Commission has set the limits of 10 mg/kg hydrocyanic
acid for cassava flour and cassava starch (FAO/WHO,
1991).The expansion of food markets has forced some
countries such as Indonesia to introduce a sanitary
control to regulate the entry of food products (Djazuli
and Bradbury, 1999). Other countries such as Colombia
have set a regulation for cyanogenic glycosides levels in
animal feed (ICONTEC, 2002). Few comparative studies
have been carried out on the effect of fermentation
period on cyanide reduction in cassava products, with the
assumption that the commercially sold cassava products
have a high level of residual cyanide due to the reduced
length of fermentation period of the cassava pulp by the
producers in a bid to increase turnover and hence,
maximize profit (Odoemelam, 2005). This assumption
represents a health risk because cassava consumption has
been associated with several types of pathological
disorders (Enidiok et al., 2008). Health risks whether at
the global, national or local level is a result of multiple
major human-related factors (Moghaddam et al., 2012).
Data on hydrogen cyanide levels in garri will help in
formulating public health policies and strengthen the
moral norms of the processors.
This work has two objectives: the first is to
evaluate the effect of fermentation period on cyanide
reduction in garri flour. The second objective consists in
comparing the results obtained after analyzing the above
samples with some selected garri samples marketed in
Aba Nigeria.
153 Journal of Research in Agriculture (2013) 2(1): 152-156
Chibueze et al.,2013

3. MATERIALS AND METHODS
Plant material
Cassava tubers were obtained from National
Root Crop Research Institute Umudike (NRCRI) and
were identified as NR8082.
Sample preparation
10.0 kg of fresh tubers were peeled, washed with
water and grated in an engine-power machine made for
that purpose. The mashed cassava pulp was divided into
two portions A and B. The portion B was mixed with
palm oil while the other portion left as such. The two
samples were separately packed into two different jute
bags for dewatering using local fabricated mechanical
press.
Each sample was further divide into 5 portions
and was fermented at the interval of 1, 2, 3, 4 and 5 days
respectively. The fermented and semi-drying cassava
pulp was sieved and subsequently roasted in a circular
frying pan with continuous stirring until the meal
become light and crisp. In addition, 20 garri samples
(10 white and 10 yellow) were bought from the major
markets in Aba, Abia State Nigeria. The garri samples
were randomly selected from these markets over a period
of three days.
Analysis
Cyanide content of the garri samples were
determined by alkaline picrate paper spectrophotometric
method as described by Balagopalan et al., (1988) and
Onwuka (2005).
Each garri sample (1.0 g) was homogenized at
room temperature in 50ml of distilled water for 60 mins
in a 100 ml beaker. An alkaline picrate paper
(whatman No1 strip) was hung over the test sample in
the conical flask for 18 h at room temperature. The
alkaline picrate paper was removed and eluted with
60 ml distilled water into a 100 ml beaker. The
absorbance of the eluted sample solution was measured
spectrophotometrically at 540 nm against the reagent
blank.
A standard solution of potassium cyanide was
treated as the test sample and the absorbance was
measured at the same wavelength. The cyanide
concentration was subsequently calculated.
RESULTS AND DISCUSSION
The hydrogen cyanide contents of white and
yellow garri and effect of length of fermentation
are presented in Table 1. Cyanide contents of the white
and yellow garri samples on the 1st day recorded
the highest concentration values of 31.44±0.03 and
35.25±0.05 mg/kg respectively. Similarly, on the 5th
day,
the results also indicated significant reduction (p<0.05)
of 13.78±0.05 and 11.23±0.05 mg/kg respectively. The
level of cyanide reduction in both garri samples were
significantly different (p<0.05) between the 1st
and 4th
days of fermentation. However there was no significant
difference (p>0.05) observed between the 4th
and 5th
days
of the fermentation. It can be deduced from the result
that, the longer the fermentation period less the residual
cyanide. The reduction may be attributed to the
breakdown of the cyanogenic glycosides in the cassava
pulp during the various steps involved in the production
especially fermentation. Therefore, cassava must be
processed adequately in order to reduce cyanide
contents. This supports the earlier findings by
Odoemelam (2005) that significant reduction (p<0.5) in
cyanide level was observed over period of 3 days of
fermentation.
Journal of Research in Agriculture (2013) 2(1) : 152-156 154
Chibueze et al.,2013
Table 1 The HCN contents of white and yellow garri
Samples and effect of length on fermentation
Fermentation
period
Level of HCN
White garri
(mg/kg)
Yellow garri
(mg/kg)
1 day 31.44± 0.03 35.25±0.05
2 days 22.88± 0.05 20.66± 0.03
3 days 16.46± 0.03 14.29± 0.00
4 days 13.81± 0.05 12.0.6±0.05
5 days 13.78±0.05 11.23± 0.05
Results are expressed as means of triplicate
determination ±S.E

4. Table 2 shows the cyanide contents of market
purchased garri samples, obtained from different
locations in Aba, Abia State Nigeria. These market
purchased garri samples were reported fermented for 3 to
4 days by the sellers and the cyanide levels ranged from
14.37±0.05 to 36.32±0.10 mg/kg on dry matter basis.
The wide variation in the cyanide contents of the market-
purchased garri samples showed that 4, 2, 2 and 2 white
garri samples fall within the 1st
, 2nd
, 3rd
and 4th
days of
fermentation respectively while 0, 5 and 5 yellow garri
samples fall within the 1st
, 2nd
and 3rd
days respectively.
These values indicated that about 50% of the market
purchased garri samples showed varying cyanide
concentrations of 1st
to 2nd
day’s fermentation of the
reference garri samples as shown in Table 1. The present
finding supports the earlier observation that the cyanide
levels in the market purchased garri samples had higher
levels than the residual cyanide levels in the 3 days
fermented reference garri samples (Odoemelam, 2005).
This situation could probably arise from the
reduced lengths of fermentation periods therefore, it is
necessary to discourage the practice of reducing
fermentation period in attempt to increase sales. The
result represents a health risk because cassava
consumption with high concentrations of cyanigenic
glycosides causes tropical ataxic polyneuropathy in
individuals over 40 years old and also exacerbates the
conditions of goiter and cretinism in women and children
with a low iodine intake (Delenge et al., 1994; Haque
and Bradbury, 2004).
CONCLUSION
This result indicated that about 50% of the
market purchased garri samples showed varying cyanide
concentrations indicating fermentation period of 1 to 2
days. The work agrees with Odoemelam, (2005) that
campaign to educate the public on the danger of this
unwholesome practice is paramount.
ACKNOWLEDGMENT
The authors are grateful to the management of
National Root Crops Research Institute, Umudike for the
assistance rendered in the running of the analysis.
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155 Journal of Research in Agriculture (2013) 2(1) : 152-156
Chibueze et al.,2013
Table 2 The HCN contents of market purchased
garri samples
Samples
Level of HCN
White garri
(mg/kg)
Yellow garri
(mg/kg)
Sample A 16.32±0.03 29.30± 0.03
Sample B 32.27±0.08 18.67± 0.03
Sample C 33.20±0.05 18.37± 0.05
Sample D 14.37±0.05 29.69± 0.05
Sample E 36.32± 0.1 19.97±0.09
Sample F 18.04±0.05 19.28± 0.04
Sample G 19.12±0.04 20.05± 0.06
Sample H 23.08±0.06 22.37± 0.08
Sample I 28.88±0.05 24.01± 1.02
Sample J 34.58±0.12 27.36± 8.05
Results are expressed as means of triplicate
determination ±S.E

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Journal of Research in Agriculture (2013) 2(1) : 152-156 156
Chibueze et al.,2013
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