Presentation at the RTB Annual Review and Planning Meeting (Entebbe, Uganda, 29 Sep-3 Oct 2014)

1. Enhancing the Role of Yam in Food
Diversification and Income Generation
Bussie Maziya-Dixon, Antonio
Montes-Lopez, Oladeji Alamu, Ibironke Popoola and
Robert Asiedu

2. Introduction
 As much as 97 percent of the increase in world
population from 2000 to 2050 will occur in today’s
developing countries.
 The developed countries’ share of population is
expected to fall from 20 percent in 2000 to only 13
percent in 2050.
 Africa will undergo the most rapid growth, increasing
from 784 million in 2000 to nearly 1.8 billion in 2050.

3. The food industry in West and Central Africa
 Globally, urban areas are currently
growing at a rate of 2.2 percent
 Rural to urban migration is the most
significant and relevant trend from the
point of view of the food processing
industry.
 Therefore, there is a strong local demand
for transformed products which would
meet the rising standards in terms of
quality, sanitary and nutritional
requirements.

4. Importance of Yams
 More than 54 million tons of yams
are produced in Sub-Saharan Africa
annually
 Over 95% of this production lies in
a five-country “yam belt” that
includes Nigeria, Benin, Togo,
Ghana, and Côte d'Ivoire, with
Nigeria as the leading producer.

5. Importance of Yams
Plays a key role in food security based on
the range of species, maturity periods of
cultivars, superior shelf life of fresh
tubers compared to other root and tuber
crops
Yam is consumed in different ways, such
as boiled, fried, or baked.
Tubers are often dried and milled into
flour for reconstituting into a stiff paste,
which is eaten with soup.

6. Importance of Yams
 Yam is suggested to have
nutritional superiority when compared
with other tropical root crops
 It contains some amount of proteins,
lipids, vitamins and minerals
 Modern researches have shown
that yam extracts can
-reduce blood sugar
-show antioxidative activity

7. Quality Characteristics (Food quality/end-user attributes)
Quality is a combination of product
properties or attributes which can play a
crucial role in defining end user
acceptability
Properties considered:
a) Organoleptic and sensory attributes
b) Safety
c) Nutritional value
d) Functional properties
e) Stability during storage

8. Importance of Quality Characteristics
 Functional properties are important food quality
characteristics that have impact on consumer product
acceptability.
 They can also be used as indicators or determinants of food
quality for yam-based food products.
 Varieties with good eating qualities are characterized by high
dry matter; starch and amylose content.
 To stimulate demand, research for development must
understand and encourage the demand for yam products.

9. Proximate composition of selected white yam
varieties grown in riverine areas( N=12)
%Protein 2.91
%Ash 1.98
%Dry matter 36.3
%Fat 1.2
%Sugar 3.36
%Starch 56.7
%Carbohydrate 30.2
%Amylose 29.3
Others 116.2

10. Vitamin C, anti-nutritional factors and
Functional properties of selected white yam
varieties grown in riverine areas(N=12)
Swelling
Power 8.09
Solubility(%
) 6.83
Water
Binding
Capacity
(%) 129
Vitamin C
(mg/100g)
6.49
Phytate(mg/
100g)
18.2
Tannin(mg/
100g) 7.1

11. Comparative analysis of nutritional qualities of white
yam varieties from Nigeria and Ghana
9.12
2.72
0.54
7.18
1.05
33.7
18.59
5.41
1.98
0.6
5.6
0.63
31.78
20.3
Percent
Proximate Composition (%)( N=40)
Ghana
Nigeria

12. Vitamin C and anti-nutritional factors of white yam
varieties grown in Ghana and Nigeria
Phytate
(%)
Tannin
(%)
Vit C
(mg/100g)
Location Ghana Nigeria Ghana Nigeria Ghana Nigeria
Mean 2.11 2.63* 0.12 0.22* 7.48* 5.13
Minimum 1.38 2.04 0.04 0.07 4.90 2.89
Maximum 3.71 3.30 0.18 0.32 10.00 6.68
Std.
Deviation 0.68 0.30 0.04 0.08 1.64 1.32
* Difference significant at 0.05

13. Objective: Delivering highly consumer accepted
varieties and linking farmers to markets and food
industry.
Selection of D. rotundata varieties to produce yam flour (IITA-DELUXE)
Methodology
1. Elite varieties from AYT and were
selected released varieties .
2. Testing varieties with yam
processors
3. Determining processing
parameters
4. Selection by processors, assisted
by quantitative data elicited during
the processing in their factory.
Parameters measured:
1. Fresh weight
2. Weight after peeling
3. Conversion rate
Fresh/Flour
4. Cooking time
5. Sensory attributes

14. Results
4.5
Dioscorea rotundata varieties selected for yam flour-instant poundo yam
4
3.5
3
2.5
2
1.5
1
0.5
0
Kg FRESH : 1 Kg FLOUR
Threshold 2(4varieties )
Threshold 1 (4varieties)

15. Selection of D. rotundata and D. alata varieties
to produce yam fries: (IITA, PRIMLAKS-SIMPLI)
Methodology
Materials and methods
1. Elite and released
varieties selected
2. Testing varieties with
yam processors
3. Measuring processing
parameters
4. Selection by processors,
assisted by quantitative
data elicited during the
processing in their
factory.
Parameters measured
1. Fresh weight
2.Weight after peeling
3. Oxidation
4. Blanching
5. Freezing
6. Frying
7. Sensory attributes
8. Selection Index

16. Result
Selection index: Processors+Breeder+Consumer
Selection Index (SI)
4
3.5
3
2.5
2
1.5
1
0.5
0
CH 1
CH 1
CH 2
Threshold of selection
6 7 9 10 13 15 17 18 19 20 21 22 33 44 55
Variety
Variety 6,10,13,17,20,22 and also 9 and 15 were selected
CH 1 : Commercial yam fries CH 2: Commercial Potato French fries

17. Diversification of yam utilization through
product development using D. Alata

18. Capacity building and technology dissemination
through training
- Degree and
non degree
training
- Training of
Trainers
- Demand-driven
processing
workshops

19. Summary
• Yam plays a key role in food security
• Selection and identification of varieties with good eating qualities
with high dry matter; starch and amylose content are being
selected ( Nigeria and Ghana)
• Selection and identification of varieties that are good for instant
poundo- yam and yam fries
• Diversification of yam utilization through product development –
yam cake, yam fritters, yam flakes, yam bread etc
• Dissemination of technology through training ( Train the trainers,
processing workshops etc)

20. Next Steps:
 Product Development and
characterization
 Technology dissemination
through training
 Sensory Evaluation
 GIS-Areas to produce each
variety
 Linking Farmers

21. Acknowledgement

22. THANK YOU