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American Journal of Food and Nutrition, 2019, Vol. 7, No. 2, 43-48
Available online at http://pubs.sciepub.com/ajfn/7/2/2
Published by Science and Education Publishing
DOI:10.12691/ajfn-7-2-2
Quality Evaluation of a Ready-To-Eat Breakfast Cereal
(Muesli) Made from Selected Nigerian Indigenous
Food Crops
Adeoye B. K.*, Ezelibe M. C., Akinlade A. R., Ani I.F, Ngozi E.O., Ajuzie N.C.
Department of Nutrition and Dietetics, Babcock University, Nigeria. P.M.B. 21244, Ikeja Lagos
*Corresponding author: adeoyeb@babcock.edu.ng
Received May 04, 2019; Revised June 06, 2019; Accepted June 15, 2019
Abstract Production of high quality and well packaged multi-cereal product is lacking in Nigerian and muesli
which is mostly imported is scantly circulated. Thus, this study aimed at producing and assessing the qualities of
muesli made from Nigerian food crops. Muesli was produced from two different combinations of separately
processed food crops (i.e cereal, tuber, nuts, fruit) and a commercially produced muesli served as the control. The
muesli samples were assessed for their functional properties, nutritional composition, sensory qualities and cost of
production. The samples were stored for eight weeks (28°C ±2) during which total bacterial and fungal counts were
determined at two weeks interval. All analyses were done in triplicate and data was subjected to Analysis of variance
(P< 0.05) and means were separated by Duncan Multiple Range Tests. Results showed that the muesli samples had
the same bulk density (0.63 ±0.00 g/ml) which was not significantly different from the control (0.61 ±0.00 g/ml)
while the swelling capacity (113.33±23.09 % and 106.67±32.32 %) of the two muesli samples was significantly
different from the control. The control was significantly different in moisture content (7.21%) and carbohydrate
(62.51%) content while the muesli samples were significantly different in crude protein (9.93 %), crude fat (14.
67 %), crude fibre (7.05 %), ash content (6.13 %), and energy (394.03 Kcal). At the end of the storage period the
total bacteria count was 3.0 x 10-1 and total fungal count was 2 x 10-1 for the muesli samples while there was no
growth in the control. The muesli samples were not significantly different from the commercial muesli in colour but
were significantly different in other sensory attributes. The cost analysis showed the retail price of commercial
muesli to be 192 % to 203 % of the production cost of the muesli samples.
Keywords: grains, tuber, nuts, fruits, breakfast, muesli
Cite This Article: Adeoye B. K., Ezelibe M. C., Akinlade A. R., Ani I.F, Ngozi E.O., and Ajuzie N.C.,
“Quality Evaluation of a Ready-To-Eat Breakfast Cereal (Muesli) Made from Selected Nigerian Indigenous Food
Crops.” American Journal of Food and Nutrition, vol. 7, no. 2 (2019): 43-48. doi: 10.12691/ajfn-7-2-2.
1. Introduction
The ready to eat breakfast cereal belong to the category
of foods that are inherently stable and have a long shelf
life [1]. The advantage of ready-to-serve or ready-to-eat
breakfast food is not only that it is time saving, but it also
exclude all the demands of food preparation and these
advantages, supplemented by the attractive flavour and
crispiness of the products are responsible for its popularity.
Breakfast cereals are very numerous in the market, some
are sweetened to a level appropriate for use without
further addition of sugar [2] and examples of ready-to-eat
breakfast cereal include granola, rice krispies, corn flakes,
cheerios, muesli etc.
The current Nigerian market for cereals is largely
dominated by single grain products (mostly corn flakes).
Modern business providing high quality well packaged
African multi-cereal whole-grain product is lacking in
Nigerian despite the important health benefits of such
products. Thus, there is a need for food businesses with
the objective to develop, produce and package novel food
products from local raw materials that are native to
Nigeria. Over the past years, Nigerians preference is
changing towards more quality and well-packaged food.
Consumption patterns are changing in line with the strong
growth of the middle class. Cereals are standard staple
items in daily Nigerians diet and it is convenient for many
Nigerians. Hence factors like cultural attachments, health
and nutritional advantages indicate a strong potential
market for a well packaged fortified multi-cereal whole-
grain meal. However, processing of these traditional
African grains for food is getting too little innovation and
investment at a commercial level, especially in the area of
convenience-type foods aimed at the rapidly growing
middle-class urban population [3].
Muesli was developed around 1900 by Swiss physician
Maximilian Bircher-Benner for patients in his hospital,
where a diet rich in fresh fruit and vegetables was an
essential part of therapy. Muesli in its modern form
became popular in western countries starting in the 1960s
American Journal of Food and Nutrition 44
as part of increased interest in healthy food and vegetarian
diets. Muesli is a breakfast and brunch dish based on raw
rolled oats and other grains, fresh or dried fruits, seeds and
nuts and it contain all of the basic nutrients: carbohydrates,
protein, fat, minerals, vitamins and fibre [4,5]. Muesli may
be mixed with cow milk, soy milk, almond milk, other
plant milk, and yoghurt or fruit juice. It is not doused in
any sweeteners or oils to aid in the baking process because
there is no baking process. So it tends to be a lighter,
healthier option than granola in that it is cool, it is quick,
and it is healthy [6].
Muesli is not among the list of products produced by
leading breakfast cereal industries in Nigeria though there
is possibility of small scale industries to be producing the
product however, it is not widely circulated. In a survey
conducted in an urban area prior to this research it was
found that 80 % of the respondents were not aware of the
product. Hence, this research aimed at producing muesli
from multi grains and other crops that are indigenous to
Nigeria which will perhaps help our cereal companies
to give a thought to utilization of our crops in this
manner. There will also be firsthand information on the
nutritional and sensory qualities of muesli produced from
combination of different Nigerian indigenous crops
2. Materials and Methods
2.1. Materials
The raw materials were obtained from Babcock University
Superstore and Ilishan- Remo market, Ogun State. The
materials used were divided into three (3) groups; Grains/
tuber, Nuts, and Fruit. Grains and tuber group include;
maize (Zea mays), wheat (Triticum aestivum), sorghum
(Sorghum bicolour), tiger nut (Cyperus esculentus). While
the nuts were groundnut (Arachis hypogaea) and coconut
(Cocos nucifera) and the fruits were banana (Musa acuminata),
paw-paw (Carica papaya) and dates (Phoenix dactylifera).
2.2. Processing of the Grains/Tuber
The method used for the muesli production was
developed from information obtained from MacEacheran
[3], Australian Food History Timeline [4] and Troughton
[6] about production of muesli. Before processing, the
cereal grains and tigernut were properly cleaned and
sorted to remove stones, dirt, chaff, bad seeds and other
extraneous matter. Wheat and sorghum (350 g each) were
boiled with 2.5 L of water separately while 350 g of maize
was boiled with 4.5 L of water and 2 g of salt was added
to each of them. The density of the water left after boiling
was determined in order to know if there was any loss
from the grains during boiling. The boiled grains were
weighed and combined in ratio 2:1: 2:1 for wheat, maize,
sorghum and tigernut before being blended with 1 L of
water. This was later dried at 80 °C for 24 h. The process
is as described in Figure 1.
2.3. Processing of the Nuts
The brown skin of the coconut was peeled after
de- shelling, grated, immersed in sugar syrup, drained and
dried at 80°C for 6 h (Figure 2) while the already processed
cashew nut was merely crushed into smaller sizes.
2.4. Processing of the Fruits
The banana was peeled and then cut into small cubes
after which it was immersed in sugar syrup (to prevent
browning) and then drained. The banana was then dried in
the oven at 80°C for 24 h. The date and pawpaw fruits
were washed, after which the seeds were removed. Then
they were cut into small pieces, immersed in sugar syrup,
drained and dried at 80 °C for 24 h (Figure 3).
Figure 1. Processing of the cereals (Wheat, Sorghum, Maize, Tigernut)
Figure 2. Processing of the coconut
Figure 3. Processing of the fruits
45 American Journal of Food and Nutrition
2.5. Production of Muesli
The processed ingredients were stored in clean air-tight
containers until required for mixing.
The composition of the muesli was as follows:
Sample 1
Composition
Ratio
60 % grains
(wheat: maize: sorghum : tigernut)
2:1: 2:1
30 % fruits
(banana : paw-paw : dates)
1:1:1
10 % nuts (coconut :cashew nut)
1:1
Sample 2
Composition
Ratio
60 % grains
(wheat: maize: sorghum : tigernut)
2:1: 2:1
20 % fruits
(banana : paw-paw : dates)
1:1:1
20 % nuts (coconut :cashew nut)
1:1
2.6. Determination of Specific Gravity
of the Water Left after Boiling
Fifty millilitre specific gravity bottle was thoroughly
cleaned with distilled water, dried in an oven at 50°C and
allowed to cool. The weight of the cooled dried bottle (W1)
was recorded. The dried bottle was filled with distil water
and surface of the bottle was cleaned with a cotton wool
and weighed as (W2). The bottle was emptied and rinsed
twice before it was filled with 10 ml of the water that was
left after boiling of the grains separately. The bottle was
cleaned with cotton wool and weighed as (W3) and
specific gravity (S.G) was calculated as follows;
31
21
..
WW
SG WW
−
−
=
[7]
2.7. Determination of Bulk Density
Bulk density was determined by a modified method of
Nwanekezi et.al, [8]. Each experimental cereal (muesli)
was slowly filled into 100 ml measuring cylinder. The
bottom of the cylinder was gently tapped on a laboratory
bench until there was no further diminution of the sample
after filling to 100 ml mark. Bulk density was estimated as
mass per unit volume of the sample (g/ml). The mean of
triplicate measurements of each treatment was taken as the
estimate of bulk density.
2.8. Water Swelling Capacity
The water swelling capacity was determined by the
method described by Okaka and Potter [9]. 50 ml
graduated cylinder was filled with the sample to the 5 ml
mark and distilled water was added to give a total volume
of 35 ml. The top of the graduated cylinder was tightly
covered and mixed by inverting the cylinder. The
suspension was inverted again after 2 minutes and left to
stand for further 8 minutes and the volume occupied by
the sample was taken after the eighth minute.
2.9. Determination of Nutritional
Composition of the Muesli Cereal
The moisture content, ash content, crude protein,
carbohydrate content, crude fibre, crude fat of the muesli
cereal with commercial muesli cereal were determined.
Samples were analyzed chemically according to the
official method of analysis described by the Association of
Official Analytical Chemist [10]. All analyses were
carried out in triplicate.
2.10. Energy Content
Energy content was determined according to Atwater
and Woods [11]. It uses a single factor for each
of the energy-yielding substrates (protein, fats and
carbohydrates), regardless of the food in which it is found.
The energy values are 17kJ/g (4.0 kcal/g) for protein,
37kJ/g (9.0kcal/g) for fat and 17kJ/g (4.0 kcal/g) for
carbohydrate.
2.11. Determination of Storage Stability
One hundred grams with four replicates of the
respective muesli samples was sealed in polythene bags
and stored under ambient condition of 28 ± 2°C for eight
weeks. The total viable and fungal count was determined
using pour plate method [12] at the beginning and at two
weeks interval.
2.12. Sensory Evaluation
Muesli samples were compared with the commercially
produced muesli by a ten-membered, untrained panel
which consists of lecturers and students of Nutrition and
Dietetics. The muesli samples produced were soaked in
milk for 30 minutes before presenting to the panelists this
was because the muesli products were very hard compared
to the commercial muesli. The samples were analyzed for
odour, colour, taste, texture and overall acceptability. The
score was based on a hedonic scale ranging from 1
representing dislike extremely to 9 representing like
extremely [13].
2.13. Statistical Analysis
Data obtained were subjected to analysis of variance
(ANOVA) and means were separated using the Duncan
multiple range tests (SPPS 20.0)
3. Results and Discussion
3.1. Specific Gravity of the Water Left
after Boiling the Grains
Specific gravity of the water left after boiling of wheat,
sorghum and maize was 0.99, 0.99 and 0.96 respectively.
With specific gravity of less than 1, the implication is that
food materials were not likely to have been lost in the
water.
American Journal of Food and Nutrition 46
3.2. Functional Properties of the Muesli
Sample
The results (Table 1) of the functional properties of the
muesli samples showed that the muesli samples produced
from Nigerian food crops were not significantly different
in bulk density (0.63g/ml) from the commercial product
(0.61g/ml) but differ significantly from the commercial
sample in swelling capacity. The swelling capacity of the
commercial sample being 73.33 % while the muesli
samples had 106.67 and 113.335 % swelling capacity.
High swelling capacity of the muesli samples was not
desirable in that it may result in the reduction of the
nutritional content [14] of the muesli products. The bulk
density of the samples were higher than what was reported
by Eke- ejiofor et al. [15] for granola, a similar product
that is multi-grain.
Table 1. Functional properties of the muesli samples
Samples Bulk density(g/ml) Water swelling capacity (%)
A 0.61a ±0.00 73.33b±41.63
B 0.63a±0.00 113.33a±23.09
C 0.63a±0.00 106.67a±32.32
Means with the same superscript along the column are not significantly
different (p<0.05)
A: Commercial Muesli
B: Muesli sample with 60% grains/tuber, 10% nuts and 30% fruits
C: Muesli sample with 60% grains/tuber, 20% nuts and 20% fruits.
3.3. Nutrient Content of the Muesli Samples
Nutrient composition of the muesli samples containing
different quantities of fruits and nuts made from
indigenous food crops was the same. However when
compared with the commercially produced muesli, it was
found that the test samples were significantly different
in protein content (6.78 – 9.93%), Crude fat
(11.87 – 14.67%), Crude fibre (6.39 – 7.05%), Ash
content (5.25 – 6.13%), and Energy (383.99 –
394.03Kcal). However, the nutrient composition of the
muesli samples from indigenous crops could be compared
with what was reported by Germline [16] for nutrient
composition of commercial muesli. When the nutrient
composition was compared with nutritional composition
of granola reported by Eke- ejiofor et al. [15], it was found
that the carbohydrate and protein content of the muesli test
samples was comparable to that of granola while the
muesli samples had higher ash and fibre content, granola
was higher in fat and energy content. Also, when
compared with the report of Agbaje et al. [17] for granola
bar it was found that the samples were higher in protein,
fat, fibre, ash and energy.
3.4. Storage Stability of the Muesli Samples
The result of the microbial quality of the muesli
samples on storage and the commercial muesli showed
that there was no microbial growth in the commercial
product [18] which was produced seventeen months
before the analysis. However, growth ranging from
1.0 × 101 - 3.0 × 101 (cfu/ml) was recorded in the muesli
from indigenous crops. The total bacterial and fungal
count recorded for the samples were still within the limit
(<103) for ready to eat foods [19]. The results are as
presented in Table 3.
3.5. Sensory Quality of the Muesli Sample
The results of sensory evaluation of the muesli samples
are as represented in Table 4. The muesli products from
Nigerian indigenous crops were significantly different (P<
0.05) from the commercial muesli in taste, odour, texture
and overall acceptability while there was no significant
difference in the colour. However, the panelists generally
commented on the rancid odour of the commercial product.
The overall acceptability of the muesli produced using
Nigerian indigenous crops had values of 7.80 ±1.03 and
7.30 ±1.50 while the commercially produced muesli was
4.20±2.25. It is necessary to mention that commercial
muesli was scarce and only the one that has been produced
few months back was available for this research.
3.6. Cost Analysis of the Muesli Sample
Cost analysis of the muesli samples is as presented in
Table 5. The cost of production for sample B (760 g)
was 748 Naira while 760g of sample C cost 791 Naira.
However the retail price of a pack of commercial sample
which is 375 g is 750 Naira thus, 375g of sample B cost
370 Naira while 375g of sample C cost 390 Naira.
Table 2. Nutrient content of the muesli samples
Variables
A
Samples
B
C
Moisture content (%) 7.21
a
±0.03 6.65
b
±0.07 6.65
b
±0.07
Crude protein (%)
6.78b±0.11
9.93a±0.06
9.93a±0.06
Crude fat (%) 11.87
b
±0.02 14.67
a
±0.02 14.67
a
±0.02
Crude fiber (%) 6.39 b±0.03 7.05 a±0.02 7.05 a±0.02
Ash content (%) 5.25
b
±0.02 6.13
a
±0.02 6.13
a
±0.02
Carbohydrate (%) 62.51 a±0.12 55.57 b±0.09 55.57 b±0.09
Energy (kcal/g) 383.99
b
±0.00 394.03
a
±0.00 394.03
a
±0.00
Means with the same superscript across the row are not significantly
different (p<0.05)
A: Commercial Muesli
B: Muesli sample with 60% grains/tuber, 10% nuts and 30% fruits
C: Muesli sample with 60% grains/tuber, 20% nuts and 20% fruits.
Table 3. Microbiological quality of the muesli samples
Weeks
A
Samples
B
C
Total bacteria 0 - - -
(cfu/ml) 2 - 1.0 x 10-1 1.0 x 10-1
4 - 1.0 x 10
-1
2.0 x 10
-1
6 - 1.0 x 10
-1
2.0 x 10
-1
8 - 3.0 x 10-1 2.0 x 10-1
Total fungal
(cfu/ml) 0 - 2.0 x 10
-1
-
2 - 1.0 x 10
-1
2-0 x 10
-1
4 - 1.0 x 10-1 2.0 x 10-1
6 - 2.0 x 10-1 2.0 x 10-1
8 - 2.0 x 10
-1
2.0 x 10
-1
A: Commercial Muesli
B: Muesli sample with 60% grains/tuber, 10% nuts and 30% fruits
C: Muesli sample with 60% grains/tuber, 20% nuts and 20% fruits.
47 American Journal of Food and Nutrition
Table 4. Sensory quality of the muesli samples
Samples
Taste
Odour
Colour
Texture
Overall acceptability
A
3.70b±2.67
5.60 b±2.01
6.40 a±2.50
5.60 b±2.12
4.20 b±2.25
B
7.80a±1.03
7.90 a±0.99
7.40 a±0.70
7.40 a±1.43
7.80 a±1.03
C
7.70 a±1.16
7.80 a±0.92
7.60 a±0.84
7.20 a±1.75
7.30 a±1.50
Means with the same superscript along the column are not significantly different (p<0.05)
A: Commercial Muesli
B: Muesli sample with 60% grains/tuber, 10% nuts and 30% fruits
C: Muesli sample with 60% grains/tuber, 20% nuts and 20% fruits.
Table 5. Cost analysis of muesli from indigenous crops
Food Materials
Sample B Quantity (g)
Price (Naira)
Sample C Quantity
Price (Naira)
Wheat 200 45 200 45
Sorghum 200 40 200 40
Maize 100 40 100 40
Tigernut
100 130 100 130
Banana 40 66 26.7 40
Paw-paw
40
50
26.7
40
Dates 40 38 26.7 40
Coconut
20
34
40
210
Cashew nut 20 105 40 68
Power
100
100
Labour 100 100
Total 760g 748 760g 791
B: Muesli sample with 60% grains/tuber, 10% nuts and 30% fruits
C: Muesli sample with 60% grains/tuber, 20% nuts and 20% fruits.
The cost analysis showed a difference of 360 to 380
naira in the production cost of the muesli samples and the
retail price of commercial muesli. The retail cost of the
commercial sample was 192 % and 203 % of the
production cost of the muesli from Nigerian indigenous
crops. The wide margin between the production cost of the
muesli samples and the retail price of commercial sample
may be more than enough to take care of other expenses in
the distribution chain. However, the present cost of muesli
in the country is high for many to afford and only those in
high class and very few in middle class are likely to be
able to afford it. Production of muesli at very low cost by
making use of indigenous food crops will be advantageous
to its popularity and wide distribution in the country
which is in accordance with the production concept [20].
4. Conclusion
The study showed that muesli produced from Nigerian
indigenous crops had high swelling capacity, high content
of crude protein, crude fat, crude fibre, ash content and
energy content with low moisture and carbohydrate
content. In addition, it was found that muesli from
indigenous crops was more acceptable in taste, odour,
texture and in overall acceptability. The cost of production
was reasonable when compared to the retail price of the
commercial muesli. Production of muesli in the country
using indigenous food crops will go a long way in making
muesli available at reduced price.
Statement of Competing Interests
The authors have no competing interests.
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The Author(s) 2019. This article is an open access article distributed under the terms and conditions of the Creative Commons
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