ASSESSMENT OF GLYCEMIC INDEX OF COCOYAM, COWPEA
AND PLANTAIN COMPOSITE FLOUR MEAL FOR
APPARENTLY HEALTHY NIGERIANS
1J.
1Nutrition
V Akinlotan, 2I.O Olayiwola, 3A Ladokun and 4S.A Sanni
and Dietetics Department, Moshood Abiola Polytechnic Abeokuta
2,4Nutrition and Dietetics Department, Federal University of Agriculture Abeokuta
3Department of Animal Physiology Federal University of Agriculture Abeokuta
INTRODUCTION





Consumption of high and easily digestible carbohydrate foods may
result in higher glycemic index (GI) leading to higher risk of diabetes
and other nutritional diseases.
The upsurge in the incidence and prevalence of diabetic worldwide
and in Nigeria in particular is a challenge for urgent action in the
adoption of appropriate dietary management (WHO 2010).
Careful combination of slowly digestible starchy food staples such as
cocoyam, plantain combined with cowpea could give appreciable low
GI and nutritional value of the meals.
Lowering the glycemic index of meals can improve the control of
diabetics and other nutritional diseases.
Hence, this study was carried out to determine the glycemic index of
meals produced from cocoyam, plantain and cowpea flour blends.
COCOYAM
is an excellent source of carbohydrate which
gives energy.
 commonly called ‘taro’ in Nigeria, West Africa.
 It is a common name for several plants in the
Araceae family which are used for their corm.

PLANTAIN
It is from the genus Musa and species
paradisiaca.
 The matured unripe plantain contains more
starch and less sugar than bananas.

COWPEA


Known as Vigna unguiculata.
They are the most important plant food legume.
GLYCEMIC INDEX
It measures how quickly a particular food can
raise blood sugar.
 A high carbohydrate food (high glycemic index)
raises blood glucose after consumption.

FOOD STARCH



Food starch are classified into rapidly digestible starch,
slowly digestible starch and resistant starch.
Starch from plantain and cowpea is known to belong to
the SDS (Slowly Digestible Starch).
A food with high glycemic index (rapidly digestible
starch) raises the blood glucose which can result in
obesity over time.
FOOD STARCH





CONTINUES
In Nigeria, West Africa, majority of the staple or core meal is
from carbohydrate source.
In order to create varieties of meal, people tend to mix their
diet.
This mixing became apparent because of emergence of some
nutritional diseases.
Mixed diet is known to show reduced overall GI of the meal
(Wolever and Mehling, 2003).
Terminal diseases especially Type 2 diabetes can be
delayed/reduced by increasing the frequency of consumption
of low glycemic food.
OBJECTIVE

The overall objective is to produce mixed meal from
cocoyam substituted with plantain and cowpea at various
level to determine the glycemic index of the composite
flour.
METHODOLOGY
Cocoyam flour production
 Cowpea flour production
 Plantain flour production

PRODUCT FORMULATION
Cocoyam + plantain flour (10 blends) - ‘‘amala’’
paste
 Cocoyam +cowpea flour (10 blends) – cookies

PRODUCT ANALYSIS

The flour and the meal were analysed for starch
and sugar.
GLYCEMIC INDEX DETERMINATION




Ten apparently healthy volunteers (5 males and 5
females) aged 19 – 30 years were also fed with the meals
(‘‘amala’’ and cookies).
Postprandial blood glucose was determined at thirty
minutes interval for two hours using glucometer.
Fasting blood sugar (FBS)
Postprandial glucose level
DATA ANALYSIS
The statistical design was a randomized design.
 Starch and sugar were analyzed using Analysis of Variance.
 The incremental area under the blood glucose response curve
IUAC was calculated according to (Bronus et al., 2005)
The data obtained was used to calculate GI of the meals.
 Means were separated using Duncan’s multiple range tests.
 Level of significance were determined at 5%.

RESULTS
Table 1.0: Starch, and sugar content of oven dried cocoyam/plantain flour.










BLENDS
95:5
90:10
85:15
80:20
75:25
70:30
65:35
60:40
55:45
50:50
STARCH %
71.82 + 0.06a
71.72 + 0.01a
71.61 ± 0.25a
71.52 ± 0.19a
71.49 ± 0.10a
71.32 ± 0.04ab
71.28 ± 0.06ab
71.14 ± 0.08ab
71.02 ± 0.11c
69.88 ± 0.63c
SUGAR%
9.37 + 0.18a
9.33 + 0.013a
9.30 + 0.13a.
9.24 ± 0.05b
9.21 ± 0.08b
9.20 ± 0.09b
9.17± 0.17b
9.17 ± 0.04c
9.10 ± 0.10c
9.08 ± 0.05c

Mean values with different superscript along the column were significantly different (p<0.005)
Table 2.0: Starch, and sugar content of oven dried cocoyam/cowpea flour.
BLENDS
 95:5
 90:10
 85:15
 80:20
 75:25
 70:30
 65:35
 60:40
 55:45
 50:50
STARCH %
72.59 + 0.09a
70.78 + 0.18a
69.64 ± 0.16a
68.71 ± 0.04a
67.21 ± 0.60a
65.52 ± 0.13a
64.78 ± 1.33a
62.37 ± 0.40b
60.71 ± 0.02b
58.45 ± 0.75b
SUGAR%
7.54 + 0.33a
7.20 + 0.09a
6.81+ 0.04a
6.70 ± 0.25a
6.57 ± 0.27a
5.81 ± 0.04b
5.78 ± 0.13b
5.33 ± 0.08c
5.20± 0.02c
5.12 ± 0.16c
Mean values with different superscript along the column were significantly different (p<0.005)
TABLE 3.0: MEAN EFFECT OF STARCH CONTENT OF MEAL PRODUCED FROM
COCOYAM/PLANTAIN AND COCOYAM/COWPEA.
Cocoyam/plantain
Cocoyam/cowpea
Ratio
‘‘Amala’’ paste
Cookies
95:5
70.32 + 0.04a
49.50 + 0.32a
75:25
56.20 + 0.06b
42.50 + 0.25b
50:50
48.43 + 0.29c
34.10 + 0.02c
Mean values with different superscript along the column were significantly different (p<0.005)
TABLE 4.0: MEAN EFFECT OF SUGAR CONTENT OF MEAL PRODUCED FROM
COCOYAM/PLANTAIN AND COCOYAM/COWPEA.
cocoyam/plantain
cocoyam/cowpea
Ratio
Amala paste
Cookies
95:5
7.34 + 0.04a
4.92 + 0.1a
75:25
7.26 + 0.02b
4.46 + 0.06b
50:50
6.29 + 0.01c
4.37 + 0.01c
Mean values with different superscript along the column were significantly different (p<0.005)
TABLE 5.0: MEAN EFFECT OF GLUCOSE CONTENT OF DIFFERENT MEALS
PRODUCED FROM COCOYAM/PLANTAIN AND COCOYAM/COWPEA.
cocoyam/plantain
Cocoyam/cowpea
Ratio
Amala paste
Cookies
95:5
64.92 + 0.37a
59.09 + 0.20a
75:25
61.61 + 0.91b
54.24 + 0.29b
50:50
54.60 + 0.28c
51.64 + 0.24c
Mean values with different superscript along the column were significantly different (p<0.005)
TABLE 6.0: AVAILABLE CARBOHYDRATE AND GLYCEMIC LOADS OF
COCOYAM-PLANTAIN AND COCOYAM-COWPEA.
%
starch
%
sugar
TAC
per
100g
Weight supply
50g
AC(g)
A C per
serving
Glycemic
index
70.32
56.50
48.43
7.34
7.26
6.26
77.66
63.76
54.72
64.38
78.42
91.37
388
319
274
67
63
58
49.50
42.50
34.10
4.92
4.46
4.37
54.42
46.96
38.47
91.88
106.47
129.97
272
235
192
70
64
58
‘‘Amala’’ paste
95:5
75:25
50:50
Cookies
95:5
75:25
50:50
(Serving size 500g)
TABLE 7.0: GLYCEMIC INDEX OF COCOYAM-PLANTAIN AND
COCOYAM-COWPEA
Test diet
i AUC of food
i AUC of glucose
Glycemic index
of the food
Classification
‘’Amala’’ paste
95:5
75:25
50:50
867 + 38
913 + 48
992 + 49
578 + 33
578 + 33
578 + 33
67
63
58
High
Medium
low
Cookies
95:5
75:25
50:50
830 + 31
897 + 42
994 + 48
578 + 33
578 + 33
578 + 33
70
64
58
High
Medium
Low
CONCLUSION



The study showed that the meals elicited different G.I (P
< 0.05).
Cocoyam-plantain and cocoyam-cowpea blends (50:50)
produced low glycemic index in the blood
It could be recommended as diet for both healthy and
diabetic patients.
SELECTED REFERENCE



Brown F., Bjorck L., Frayn K.N., Gibbs A. L., Lang V., Slana G.
And Wolever T.M.S. 2005. Glycemic index methodology.
Nutrition Research Review 18: 145 – 171
Ojinnaka M.C., Akobundu, E.N.T. and Iwe M.O. 2009. Cocoyam
starch modification effect on functional sensory and cookies
qualities. Pakistan Journal of Nutrition 8(6): 558-567
Wolever, T.M.S and Menling, C. 2003. Long-term effect of
varying the source or amount of dietary carbohydrate on
postprandial plasma glucose, insulin, triaclylglycerol and free fatty
acid. Concentrations in subjects with impaired glucose tolerance.
American journal of clinical nutrition 77 (3): 612-621.
THANK YOU