1. Expanding cassava production and
commercialization
June 12 15.00 – 15.40
Chair: Prof. Lennart Salomonsson
Cassava commercialization
– adding value through product development -
The SLU Global Food Security Research Symposium
Results of a Swedish Government Initiative
June 12-13
By
Leon Brimer , Emmanuel Ohene Afoakwa , Drinah Banda Nyrienda & Linley Chiwona-Karltun

2. Right now there is much emphasis on Africa’s growth
• food is in this respect a factor of great importance , because:
• Growing populations means growing demands in general
• Growing wealth means growing wishes for a higher food diversity
• Growing towns means growing needs for food with a long shelf life
• Changed life styles means growing markets for “convenience food”
• Food products developed need to fulfill these demands at
the same time this means:
• possibilities of adding value to the products
• whether sold locally
• nationally
• or exported

3. Plant crops – which and why those?
• Out of the estimated more than 300.000 green plant species
• Mankind basically depends on very few staple crops
• In a modern African context maize and cassava are among the most
important ; especially with regard to energy (starch crops)
• Both were brought to the continent from the Americas
• Cassava is estimated to be the major calorie providing crop for
at least 500 million people
However:
• The starch containing root after harvest is highly perishable
• Out of the major staple crops worldwide cassava is , however, the only one
domesticated as landraces/cultivars containing acutely poisonous
concentrations of naturally occurring plant toxins (so-called cyanogens)

4. HO OH R2 R2
R3 - C - C - CN = HO - C - CN C = O + HCN
R2 R1 R3 R3
+
R1 - OH
O R2
R3 - C - C - CN R1 - O - C - CN
R2 R1 R3
Cyanohydrin Cyanohydrin
Hydroxynitrile
lyase or
OH-
Hydrogen-
cyanide
H3O+
2,3-Epoxynitrile
H2O
Hydrolases
Cyanogenic glycoside/lipid
CN- +H2O
OH-
H+
Cyanide
Reactions to form cyanide: Cyanogens = cyanogenic compounds

5. In the case of Cassava

6. Both due to perishability and to the potential toxicity!
• cassava roots in general must be processed soon after
harvest

7. The reactions to the new varieties – 1.
• In West Africa (notably Nigeria and Ghana) an established
industrial production of stable fermented food products -
such as Gari.

8. Standards for cassava
• 1993 JECFA – max. 10 mg HCN/kg flour
• 2003 Codex – max. 50 mg HCN/kg fresh (sweet) root
• 2010 Codex – fresh bitter roots (over 50 mg HCN/kg)
must be labled to be processed to detoxify
• 2010 EAC – bitter roots contain more than 50 mg
HCN/kg f.w. However,sweet roots when analysed
must contain up to 200 mg HCN/kg
• 2000 – Indonesia ”food” must not contain more than
40 mg HCN/kg f.w.

9. However
• Imported fresh roots for sale in retail shops as sweet cassava
in Europe have been shown to often have a higher content:
(Kolind-Hansen and Brimer, 2010)
• As has frozen peeled large pieces imported to Australia (Burns
et al., 2012).
• And cassava chips imported to Australia
Kolind-Hansen, L. & Brimer, L. (2010). The retail market for fresh cassava root tubers in the
European Union (EU); the case of Copenhagen, Denmark. A chemical food safety issue? J.
Sci. Food Agric. 90, 252-256.
Burns, A. E., Bradbury, J. H., Cavagnaro, T. R. & Gleadow, R. M. (2012). Total cyanide content of
cassava food products in Australia. J. Food Comp. Anal. 25, 79-82.
So – quality assurance must be in place for food safety – AND to ensure export!

10. The reactions to the new varieties – 2.
A few small and medium-scale traders and processors have
emerged to experiment with cassava-processing ventures

11. Towards
effective production, product diversification, quality assurance
1 – Basic survey to disclose the following
a – what is grown?
b – what is generally known about the grown landraces/cultivars?
c – which cultivars are used for which products?
d – how are the products produced (description of processing)?
e – what are the general characteristics of each product?
f – what is known (can be shown through analysis) about product food safety?
g - what is the situation concerning commercial production and marketing?

12. Nyirenda, D.B., Chiwona-Karltun, L., Chitundu, M.,
Haggblade, S. and Brimer, L. (2011). Chemical food safety of
cassava products in regions adopting cassava production
and processing – experience from Southern Africa. Food
and Chemical Toxicology 49, 607-612
Haggblade, S., Andersson Djurfeldt, A., Banda Nyrendah, D.,
Bergman-Lodin, J., Brimer, L., Chitundu, M., Chiwona-
Karltun, L., Cuambe, C., Dolislager, M., Donovan, C.,
Droppelmann, K., Jirström, M., Mudema, J., Kambwea, E.,
Kambewa, P., Nielson, H., Nyembe, M., Salegua, V.A., Tomo,
A. and Weber, M. (2012). Cassava Commercialization in
Southeastern Africa. Journal of Agribusiness in Developing
and Emerging Economies. 2(1), 4-40.
On the basis of the information gathered a
new more detailed survey of cassava cultivars
was performed
First study period of CATISA and its results

13. The purpose of a second survey was:
• To investigate the dynamics (changes) in landraces/cultivars used
• To disclose the reasoning for keeping cultivars or to skip them, respectively
• To disclose changes in products and product processing if any
• To thereby get a solid background for further product and processing development

14. INFORMATION OBTAINED ON THE CASSAVA VARIETIES
1. Information on the source and description of the cassava varieties
CASSAVA
VARIETIES
PART A: INFORMATION ON THE SOURCE PART B: INFORMATION ON THE DESCRIPTION
Source Local/Hybrid Institution which
introduced the
variety
Characteristics of
the leaves and
stalks/stems
Characteristics
of the tubers
outer covers
Resistance to
disease and
drought tolerance
Kampolombo
MST
Varieties –
Kasama
Roots and
Tubers Res
Center
Hybrid and
sweet variety
FODIS Large brown
leaves
Large light
brown tubers
Become less disease
resistant after
growing for a longer
period (4Years). Less
drought tolerant
Bangweulu Same as
above
Hybrid and
bitter variety
FODIS Purplish leaves Brown tubers Less disease
resistant and less
drought tolerant
Chila
Same as
above
Hybrid and a
slightly bitter
variety
FODIS Green leaves Light brown
tubers
Disease tolerant but
attacked by ants, a
bit drought tolerant
Mweru Same as
above
Hybrid and
sweet variety
FODIS Brown stem Medium
brownish tubers
Disease tolerant and
not drought tolerant
Mweulu Tanzania Local and
sweet variety
Chinsali District Green thin leaves,
reddish stalks
Brown outer
cover but
reddish tubers
Disease resistant
and drought tolerant
Tanganyika Tanzania Local and
sweet variety
Chinsali District Light green leaves,
whitish stalks
Whitish tubers Disease resistant
and drought tolerant
Nalumino
MST
Varieties –
Kasama
Roots and
Hybrid FODIS Light brownish
leaves, brown
stalks
Large brown
tubers
Disease resistant
and attacked by ants
during drought.

15. 1. Information on the preference and use of the cassava varieties
CASSAVA
VARIETY
PART C: INFORMATION ON THE PREFERENCE AND USE
PREFERENCE USE
Liking of the
variety
Reason(s) for liking the variety How the variety is used
Kampolombo Yes
The leaves are nice for relish), the
tubers can be cooked fresh because
they are sweet and milled dried
tuber make a nice cassava mealie
meal for Nshima.
The fresh tuber can be eaten raw, cooked or
roasted. The fresh leaves can be pound and
cooked as relish. The dried tubers can be
stored up to six months and milled into
cassava mealie-meal and flour.
Bangweulu
Yes
The tubers are bigger and more
starchy but bitter
The dried tubers can be milled into cassava
mealie-meal and flour. The tubers cannot be
eaten raw but can be roasted after soaking.
Chila
Yes High yield but is bitter
The dried tubers can be milled into mealie-
meal and flour. The tubers cannot be eaten
raw but can be cooked or roasted after
soaking. The fresh leaves can be pound and
cooked as relish.
Mweru Yes Tubers are starchy and high yielding
and sweet
The fresh tuber can be eaten raw, cooked or
roasted. The fresh leaves can be pound
and cooked as relish. The dried tubers can
be milled into mealie-meal and flour.
Mweulu- local Yes Gives high yields and it’s not bitter
The fresh tuber can be eaten raw, cooked or
roasted. The fresh leaves can be pound
and cooked as relish. The dried tubers can
be milled into mealie-meal and flour.
Tanganyika Yes Tubers can be cooked fresh, are
sweet
Can be eaten raw, cooked or roasted. Milled
into mealie meal and flour.
Nalumino Yes The tubers grow bigger (After 2
years) and give a high yield and are
The fresh tuber can be eaten raw, cooked or
roasted. The fresh leaves can be pound and
cooked as relish. The dried tubers can be

16. CASSAVA VARIETY PART C: INFORMATION ON THE PROCESSING METHODS AND STORAGE
PROCESSING METHODS STORAGE
Method(s) Used Reason(s) for using
this/these method(s)
Storage of flour and dried
cassava products
Shelf life of flour and
dried cassava products
Kampolombo Chipping, Grating or
Soaking
Soaking method; people
just like it.
Dried cassava products are
stored in sacks, store for
longer. The flour is stored in
plastic packages – store for
shorter period.
Dried products can stay for
a longer time without being
attacked by weevils while
flour can be stored for 6-10
months.
Bangweulu
Soaking. To increase the
yield, Bangweulu after
soaking, can be mixed with
pounded chips of any sweet
variety prior to drying.
To remove cyanides and
give fermented flavour
Chila Soaking method; for mealie
meal. Chipping; for flour.
Mweru Chipping, Grating or
Soaking
Soaking for fermented taste
Mweulu
Chipping, Soaking Nshima prepared chipped
mealie meal is thick just like
maize. Nshima form soaked
cassava is slippery and
hold the stomach for a
longer time.
Tanganyika Chipping. However, the
chips can soaked for a day(
If they taste bitter) prior to
drying
Nshima prepared from this
cassava mealie-meal tastes
like maize meal.
Nalumino Chipping, Soaking For fermented taste
Manyokola
•Information on the processing methods and storage of the varieties

17. To choose cultivars for
optimal product development
physiochemical properties must be known
So the following investiations has been undertaken:
• Proximate analysis (crude protein etc)
• Minerals
• Total cyanogens (toxins)
• Viscoelastic
Of different cultivars

18. And since cassava roots
and their products do not
show any significant levels
of the mycotoxins
aflatoxins
– in contrast to maize -
Figure 1. Chemical structure of sterigmatocystin (A) and aflatoxin B1 (B).

19. Now we are ready and so are farmers for further
product development
industrialisation of production
Thank you!

20. Leon Brimer - M.Sc., Ph.D. and D.Sc. (pharm) –
Associate Professor of Chemical Food Safety,
University of Copenhagen,
Faculty of Health and Medical Sciences,
Department of Veterinary Disease Biology
Appointed Panel member (by the EFSA’s Management Board) of :
•the “EU Scientific Panel on Food contact materials, flavourings, enzymes
and processing aids ” (CEF), under the European Food Safety Authority
(EFSA), Parma, Italy.
♦Under CEF member of the two workgroups (WG’s):
♦ (1) Flavourings WG and
♦(2) Processing Aids WG
Additional: member of the “Work Group on alkaloids in food” under the Panel of Contaminants
in the Food Chain (CONTAM) under (EFSA).