INTRODUCTION
The growth in diet-related illnesses such as obesity,
cardiovascular diseases, and some types of cancer led
the World Health Organization (WHO) and other related
organizations to encourage the consumption of fortified
food [1]. Fortification is a deliberate addition of essential
nutrients to a product to conserve its nutritional quality,
enhance its added value, provide it with some functions,
as well as to prevent or correct a particular nutritional
deficiency in the population [2, 3]. However, one of the
essential requirements of fortification is an appropriate
food vehicle. Food vehicles should be widely consumed
by a large proportion of the population to be able to meet
the nutritional needs of the target group [4].
Baked food products are good potential vehicles
of micronutrients and bioactive compounds because
they are consumed all over the world by children and
adults. Muffin is one of the most common bakery
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
products appreciated by people due to its taste and soft
texture. Muffins are ready-to-eat snack food, similar
to cupcakes, which are usually eaten at breakfast, as
evening snacks, for tea, or at other meals. Muffins are
also served as snacks during many celebrations. A
special feature of muffins is their porous structure that
leads to high volume and spongy texture [5, 6].
In response to the increasing demand for healthy,
natural, and functional products, scientists are doing
tremendous work in collaboration with industries to
improve the nutritional quality of food products. Since
fruits and vegetables are rich in natural nutrients,
phytochemicals, and phenolic compounds with
biological properties, incorporating them in muffins
is a good way to fulfill the desires of consumers [7].
Furthermore, natural antioxidants from fruits and
vegetables may inhibit lipid peroxidation in food and
improve food quality and safety [5].
Dacryodes macrophylla L. is a fruit tree belonging to
the Buseraceae family that is widespread in Cameroon,
Equatorial Guinea, and Gabon. The fruits are commonly
consumed directly or used to make natural juices and
jelly [8]. D. macrophylla L. has red color that indicates
the presence of phenolic compounds (e.g., anthocyanin)
and some minerals (e.g., iron).
To the best of our knowledge, there are no available
published data on D. macrophylla L. fruits as a potential
value-added ingredient of muffins. Nevertheless,
in our previous work, we studied the dyeability and
bacterial resistance of these fruits on woolen fabric [9].
Ngondi et al. also showed that hydroethanolic extract
of D. macrophylla L. fruits could have anti-obesity and
antioxidant properties [10].
Therefore, we aimed to develop value-added
muffins fortified with D. macrophylla L. fruits and to
study the impact of that incorporation on the quality
and acceptability of muffins. To achieve this aim, we
fortified muffins with 1% of D. macrophylla L. fruit.
Then, we evaluated their physicochemical properties,
rheological parameters, and sensory characteristics. In
addition, we determined the antioxidant properties of
fortified muffins to assess their functionality.
STUDY OBJECTS AND METHODS
Study objects. We studied two groups of muffins:
with egg and without egg. Each group contained a
control and experimental samples with 0.5 and 1% of
Dacryodes macrophylla L. extract instead of wheat
flour.
Materials. Wheat flour (maida), sugar, baking
soda, baking powder, egg, vegetal oil (soybean), and
liquid milk (green packet Verka) were purchased from
a local supermarket (Amritsar, India). 2,2-diphenyl-
1-picrylhydrazyl (DPPH), 6-hydroxy-2,5,7,8-tetramethylchronan-
2-carboxylic acid (Trolox), and ascorbic
acid were obtained from Sigma-Aldrich Company
Ltd. (St Louis, MO, USA). Analytical grade methanol,
NaOH, NaCl, HNO3, H2SO4, and HClO4 were provided
by Sisco Research Laboratories Ltd. (Mumbai, India).
We used such equipment as an orbital shaker (Remi,
Mumbai, India), a rotary evaporator (IKA Werke GmbH
and Co. KG, Staufen, Germany), and a freeze dryer
(Christ Beta 2-8 LD plus, Germany). Freeze-dried
D. macrophylla L. was used to enhance the antioxidants
and color of muffins.
Preparation of D. macrophylla L. extract. The
seeds of fresh D. macrophylla L. fruit were discarded
and the rest of the pulp was dried in a freeze dryer,
followed by an extraction with 70% ethanol in an orbital
shaker for 2 h at 200 rpm. It was then centrifuged
at 4000 g for 10 min at 25°C and the supernatant
was collected. The residue was re-extracted and
the supernatant was collected and concentrated in a
rotary evaporator under reduced pressure at 45°C. The
remaining water was eliminated in the freeze dryer and
the DME was kept in a fridge at –70°C in sealed plastic
containers for the following experiments.
Preparation of muffins. Sugar was first powdered
with a mixer and eggs were manually beaten in a bowl
with a spoon (just for mixing purposes) for 1 min before
weighing. All the ingredients were then weighed to
prepare six different muffins (Table 1). Preliminary
baking was done to standardize the formulation
of muffins and to find the sensorily acceptable
concentration of D. macrophylla L. extract.
Then, the required number of eggs was mixed
with sugar using an electric hand mixer until creamy.
Sunflower oil was added to the creamy mixture, which
was continuously mixing, followed by the required
amount of liquid milk. After about 4 min of mixing,
wheat flour was gradually added to the emulsified
gel during continuous stirring in the same direction.
Baking powder was the last ingredient to be added to
the formulation. The dough was then introduced into
greased muffin molds and baked in the preheated oven
at 210°C for 8 min. The muffins were allowed to stand
for 2 min in the oven and then taken out to cool down for
about 30 min at room temperature.
The samples were then kept in sealed plastic foodgrade
bags at room temperature for further analysis. For
eggless muffins, the first step was to mix sugar with oil
and the last step was to add baking soda after baking
powder. For fortified muffins, D. macrophylla L. extract
was dissolved in liquid milk before being added to the
mixture (with egg and without egg).
Rheology of dough. Rheological tests of muffin
dough were performed with a rheometer (MCR-102,
Anton Paar Austria) as reported by Jantider et al. [11].
The dough sample was loaded between two parallel
plate geometric probes of 40 mm in diameter (PP40) and
kept for 5 min (for equilibration). The gap between the
plates was 1 mm and the sample was run at 25°C. Stress
was set at 0.1 Pa and frequency at 1 rad/s according to
the linear viscoelastic region. The measurements of
storage modulus (G’, solid component) and loss modulus
(G’’, liquid component) were recorded.
Specific gravity of dough. The specific gravity
of each type of muffin dough was determined
gravimetrically by dividing the weight of a known
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
volume of dough by the weight of an equal volume of
water. A standard container was used for measurements
[12].
Moisture content. The gravimetric method was used
to determine the moisture content in muffin crumb. For
this, 2 g of a sample was dried in an air oven at 105°C
until no further weight change, using a clean, dry, and
pre-weighed aluminum moisture dish. The moisture
content was calculated as follows:
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
=
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
where W1 is the weight of samples before drying; W2 is
the weight of samples after drying (in grams).
Weight loss. The baking loss of muffins was
determined in percentage based on the weight of muffin
after baking and the weight of muffin dough by using the
following formula [13]:
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Where Wd is the weight of dough; Wm is the weight of
muffin.
Muffin height and diameter. A digital caliper was
used to measure the height of muffins (from the highest
to the lowest point) and their diameters (mm).
Water activity. The water activity of the samples
was measured by placing about 2 g of muffin crumb on
a plastic dish of a water activity meter (AquaLab TE,
series 3B, version 3.4, Decagon). After calibration with
water, values were recorded at 25°C in triplicate.
Muffin volume. The volume of muffins was
determined by the millet-seed displacement method as
described by Rashida et al., with slight modification [5].
An empty baker was filled with millet seeds and then the
seeds were transferred into a container. Then, a muffin
was placed in the center of an empty baker and the seeds
were loaded back from the container. The remaining
seeds were put in a measuring cylinder and their volume
(in mL) represented the volume of the muffin. The
specific volume was then calculated by dividing the
volume recorded by the weight of the muffin (mL/g).
Crude fat. Crude fat of the muffins was estimated
gravimetrically on the Soxhlet apparatus [13]. The
samples were weighed (W1) and lipid was extracted with
hexane for 6 h at 65°C. The lipid extract was then dried
in the oven at 102°C till constant weight. Crude fat was
expressed in percentage and calculated as follows:
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
Ash (%) =
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Where W1 is the weight of a sample in grams before
lipid extraction; W2 is the weight of the dried lipid
extract.
Ash content. Total ash was determined by the
incineration method in a muffle furnace. The samples
were weighed in porcelain crucibles and incinerated for
1 h at 550 ± 10°C. White ash was cooled and weighed.
Ash content was expressed in percentage by using the
following formula:
Mg =
( 
 Vs
Y X
Moisture content (%) = 100 –
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Ash (%) =
W2
W1
× 100 Calcium Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat Ash (%) =
W2
W1
× 100 Calcium content =
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
Weight loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
Ash (%) =
W2
W1
× 100 Calcium content =
Volume Where W1 is the weight of a sample in grams before
incineration; W2 is the weight of the sample after
incineration.
Mineral content. Preparation of samples. The
defatted muffins and extracts were digested using a
mixture of tri-acid [14]. Three milliliters (3 mL) of triacid
(HNO3:H2SO4:HClO4 = 5:1:1) was added to 0.5 g
of a sample and the mixture was heated at 80°C. After
about 2 min, two milliliters (2 mL) of tri-acid was
added again under continuous heating until the fume of
the mixture became transparent. The digested samples
were then cooled at room temperature and the volume
was made up to 20 mL with double distilled water.
After filtration with Whatman filter paper, the solution
was diluted to 100 mL with double distilled water and
stored at room temperature as a stock sample solution for
mineral estimation.
Calcium. To quantify calcium content, 5 mL of
the stock sample solution was diluted to 50 mL with
double distilled water. 2 mL of NaOH 1N was added and
then a pinch (about 100 mg) of the murexide indicator
(a mixture of grind 0.2 g of ammonium purpurate with
100 g of NaCl) to turn the solution pink.
The pink sample solution was then titrated with
EDTA solution, 0.01 M (3.723 g of EDTA dissolved in
1000 mL of water) until the pink color turned dark
purple. The endpoint of titration was determined by
comparing the endpoint color of the sample to the one
Table 1 Formulation of muffins
Ingredients, g Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
Wheat flour 149 148.5 149.25 150 148.5 149.25
Sugar 85 85 85 85 85 85
Vegetal oil 75 75 75 75 75 75
Milk 75 75 75 75 75 75
Baking powder 5.1 5.1 5.1 5.1 5.1 5.1
Eggs 0 0 0 75 75 75
Baking soda 1 1 1 0 0 0
D.M. extract 0 1.5 0.75 0 1.5 0.75
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
obtained with the blank (titration with 50 mL of water).
The calcium content (mg/g) was calculated as follows:
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
content (%) = 100 –
(W1 – W2)
W1
× 100
– Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Mg =
1,645
( ) 400.8

 
Vs
Y X
content (%) = 100 –
(W1 – W2)
W1
× 100
Wm)
× 100 Crude fat (%) =
W2
W1
× 100
100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Magnesium. To determine the magnesium content,
we first estimated the hardness (Ca + Mg) of the
samples. For this, 5 mL of the stock solution was diluted
to 50 mL with water in a conical flask, followed by the
addition of 1 mL of the buffer solution and about 100 mg
of the EBT indicator (a mixture of grind 0.40 g of
Erichrome with 100 g of NaCl). The wine red color
developed and the titration was done with 0.01 M of
EDTA. The endpoint was reached by comparing the
blue color of the sample solution with the one obtained
with the blank (water). Then, magnesium was measured
in mg/ml by subtracting the volume of EDTA used to
determine hardness to the one used to quantify calcium:
Mg =
1,645
( ) 400.8

 
Vs
Y X
Moisture content (%) = 100 –
(W1 – W2)
W1
× 100
loss (%) =
(Wd – Wm)
Wd
× 100 Crude fat (%) =
W2
W1
× 100
=
W2
W1
× 100 Calcium content =
Volume of EDTA used
Volume of sample used
× 100
Where Y is the volume of EDTA used to estimate
hardness, mL; X is the volume of EDTA used to quantify
calcium, mL; and Vs is the volume of a sample, mL. The
result was expressed in mg/g of the sample.
Phosphate. The phosphate content was determined
spectrophotometrically at 625 nm. Five milliliters (5 mL)
of the stock solution was diluted to 50 mL with water
and then mixed with 2 mL of ammonium molybdate
reagent (prepared by mixing 25 g ammonium molybdate
dissolved in 175 mL water and 280 mL H2SO4 diluted
with 400 mL of water and making the final volume up
to 1000 mLwith distilled water) and 0.5 Ml of stannous
chloride (2.5 g SnCl2 dissolved in 100 mL water). The
mixture was kept for 15 min and then used to record
optical density against the blank on a microplate reader.
Potassium, Sodium and Zinc. These elements
were analyzed by atomic absorption spectrometry [15].
KCl, NaCl, and ZnSO4 were used as a standard to
quantify K, Na, and Zn, respectively. A serial dilution
of each standard was performed to make a calibration
curve for each element. Subsequently, the filtrated
liquor from mineralization of each sample was diluted
with double distilled water and the content of minerals
was determined at 766.5 nm for K, 330.2 nm for Na,
and 213.9 nm for Zn with an AA 6300 spectrometer
(Shimadzu, Tokyo, Japan) against the blank by
extrapolation of absorbance on the calibration curve of
each element. The final amount (dry weight) was then
calculated in mg/g of the sample.
Muffin color. The color of the muffins was
determined the next day after preparation by recording
the L*, a*, and b* values of crust and crumb. A
spectrophotometer with spectra match software was
used according to the CIE Lab color scales, where L
goes in a range of 0 to 100 from dark to light, a* from
green to red, and b* from blue to yellow. Color values
were measured three times at three different points on
each muffin and then averaged.
Texture analysis. The texture profile of crumb
cubes (12.5 mm3) from the middle of the muffins was
determined using a texture analyzer (Model EZ-SX,
Stable microsystems, Shimadzu, UK) equipped
with a 5-kg load cell [16]. A double compression test
was performed by putting a crumb cube sample in
the center of a heavy-duty platform (HD P/90) and
subjecting it to compression (50%) with an aluminum
75-mm cylindrical probe (P/75) at 1 mm/s. The texture
parameters (firmness, cohesiveness, gumminess,
chewiness, and springiness) were calculated based on
the texture profile graphic [17].
Antiradical activity. Preparation of extract. To
prepare the extract, 100 mg of a defatted powdered
muffin (muffins defatted with hexane were dried in the
oven at 40°C and powdered in a porcelain container)
was mixed with 1 mL of 80% methanol in an Eppendorf
tube. The extraction was performed in the orbital shaker
for 2 h at 25°C followed by centrifugation at 500×g
for 15 min. Supernatants were pooled in an empty
Eppendorf tube for antiradical analysis.
DPPH assay. Free radical scavenging of the muffin
samples was determined according to the method
described by Uswa and Rabia, with slight modification
[18]. 100 μL of a muffin extract was added to
3.9 mL of the DPPH solution (2.4 mg of DPPH in 100 ml
of 80% methanol) and vortexed thoroughly. The
mixture was then incubated for 30 min in the dark
and the absorbance was read at 515 nm by using a
spectrophotometer against 80% methanol as the blank.
The control was 3.9 ml of DPPH + 100 μL of the solvent.
A calibration curve of trolox was plotted, with the result
expressed in μM trolox equivalent/mg of the sample.
Sensory evaluation. The overall acceptability of the
fortified muffins was evaluated on the 9-point hedonic
scale [19]. Muffin samples were given randomly to a
panel of 100 untrained volunteers from Guru Nanak Dev
University, Amritsar (India). They were requested to
score their appreciation from extremely unpleasant (1)
to extremely pleasant (9) based on color, odor, texture,
taste, and overall assessment. The panelists were also
asked to rinse their mouths with water before tasting
each sample.
Data management and statistics. The results were
analyzed with Statgraphics Plus program Version 2.1.
Data were presented as mean values of triplicate
reading ± standard deviation subjected to one-way
analysis of variance (ANOVA). Tukey test was used to
compare the means, and a significant difference was
determined at P ˂ 0.05.
RESULTS AND DISCUSSION
Table 2 shows the physical properties of the muffins
fortified with Dacryodes macrophylla L. We observed
that the baking loss in the eggless muffins (9.00–9.56%)
was statistically the same but significantly (P ˂ 0.05)
lower than in the muffins with eggs (11.22–11.67%).
Similarly, the moisture content in the muffins with
eggs was higher than in the eggless samples. This
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
might be related to the weaker dough consistency of the
muffins with eggs, leading to higher viscosity. When the
viscoelasticity of dough is high, air bubbles incorporated
during the creaming step of preparation tend to increase
and rise to the surface of the muffin, getting lost at the
beginning of baking. Moreover, carbon dioxide and
vapor pressure produced during baking might escape
and increase the baking loss and moisture content.
Larger cells also increase baking loss and usually
quicken moisture migration during baking [20].
Specific gravity gives general information about
air bubbles that are incorporated in the dough during
mixing and have a direct effect on the muffin height.
Higher specific gravity means less incorporation of
air and a lower muffin height. We found the specific
gravity values for the eggless muffins (1.12–1.14) to
be higher than that for the muffins with eggs (1.03–
1.07). Therefore, the height of the eggless muffins was
lower (33.97–34.37 mm) that that of the muffins with
eggs (41.00–41.40 mm). Table 2 also shows a slightly
higher specific gravity, and therefore a lower height,
in the samples fortified with the D. macrophylla L.
fruit extract. These results might be explained by the
presence of eggs which provide the dough with water
and protein (an egg contains 74% of water and 12.8% of
protein), thereby increasing its viscoelasticity.
Another reason might be the amount of air
incorporated in the egg-containing dough compared
to the eggless dough. Potential fibers present in
D. macrophylla L. fruits might have increased the
dough viscosity and consequently decreased air bubbles.
Similar results were reported by Rashida et al. and
Manuel et al. who found that using fibers in bakery
increased the specific gravity and viscosity of the dough,
which might further lead to a lower height and volume
of muffins by obstructing air incorporation during
mixing [5, 17].
At the same wavelength, the specific volume of the
eggless muffins (1.66–1.70 mL/g) was significantly lower
than that of the muffins with eggs (2.18–2.36 mL/g).
Specific volume indicates the number of air bubbles
retained in the final product after baking. The higher
specific volume of the muffins with eggs could be
explained by higher dough viscoelasticity (due to protein
and water from eggs) which might have enhanced the
expansion of air bubbles by carbon dioxide and vapor
pressure during baking.
Besides, Shevkani and Singh reported that
higher dough viscoelasticity ensured air bubbles
stability during baking [21]. They also found that the
incorporation of proteins in muffin dough increased the
specific volume and height of the final products. In our
study, however, the specific volume of the muffins with
eggs was slightly lower due to the D. macrophylla L.
fruits extract.
Similar results were found by Singh et al. and Prerna
et al. who fortified muffins with Jambolan fruit pulp
and red capsicum pomace powder, respectively [12, 16].
Our results might be justified by the presence of fibers
in D. macrophylla L. fruits which might have inhibited
the expansion of muffin by weakening the ability
of the gluten matrix to retain carbon dioxide during
baking [13].
Water activity (Aw) is an important parameter that
enhances the shelf life of dry foods when their value
is low. It represents free water in the food and can be
defined as a ratio of vapor pressure of the food to the
vapor pressure of pure water. The water activity of the
eggless muffins (0.81–0.83) was lower than that of the
muffins with eggs (0.87–0.90). Consequently, the shelf
life of the former samples was higher.
In contrast, Table 2 shows a slight decrease in water
activity of the egg-containing muffins fortified with the
D. macrophylla L. fruit extract. It might be attributed to
fibers in D. macrophylla L. fruits absorbing more water
and thereby reducing unbound water in muffins.
Moisture, fat, and ash contents (Table 2) in the
control muffins with eggs (25.33, 18.61, and 1.27) were
significantly higher than those in the control eggless
samples (19.17, 16.82 and 1.07). Higher moisture might
be attributed to egg yolk phospholipids acting as
emulsifiers and thereby holding moisture in emulsified
form.
Similarly, the increment of fat and ash in the control
muffins with eggs may be due to the inherent presence
of fat and minerals in the egg. The incorporation of
Table 2 Physical properties of muffins with Dacryodes macrophylla L. extract
Physical properties Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
Baking loss, % 9.00 ± 0.33a 9.56 ± 0.48a 9.11 ± 0.11a 11.67 ± 0.19b 11.22 ± 0.11b 11.56 ± 0.29b
Specific gravity 1.12 ± 0.00c 1.14 ± 0.00d 1.13 ± 0.00d 1.03 ± 0.00a 1.07 ± 0.00b 1.06 ± 0.00b
Specific volume, mL/g 1.70 ± 0.03a 1.66 ± 0.01a 1.69 ± 0.02a 2.36 ± 0.01d 2.18 ± 0.01b 2.27 ± 0.01c
Water activity, Aw 0.83 ± 0.00a 0.81 ± 0.00a 0.82 ± 0.00a 0.90 ± 0.00c 0.87 ± 0.00b 0.89 ± 0.00c
Moisture, % 19.17 ± 1.64a 19.67 ± 0.73a 19.33 ± 0.88a 25.33 ± 0.44b 26.00 ± 1.04b 25.50 ± 0.76b
Crude fat, % 16.82 ± 0.13a 16.84 ± 0.46a 16.82 ± 0.22a 18.61 ± 0.34b 18.63 ± 0.24b 18.63 ± 0.31b
Height, mm 34.37 ± 0.50a 33.97 ± 0.30a 34.23 ± 0.27a 41.40 ± 0.35b 41.00 ± 0.21b 41.33 ± 0.33b
Values are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant
(P ≥ 0.05)
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D. macrophylla L. did not have any significant effect
on moisture or fat, although it slightly increased the ash
content. These results might be due to lower fat and ash
contents in D. macrophylla L.
Furthermore, the mineral content (Table 3) in the
control muffins with eggs was higher than that in
the control eggless muffins, particularly phosphorus,
sodium, potassium, and zinc, which showed a significant
difference. This result was expected because of the
inherent presence of minerals in the egg. Also, both
samples clearly illustrated the enhancement of minerals
in the muffin fortified with the D. macrophylla L.
extract, thereby showing this extract as a rich source of
minerals.
Our results were in line with those found by Sheetal
et al., who reported increased mineral contents in
muffins fortified with dried Moringa Oleifera [1].
The rheology parameters of muffin dough s are
presented in Table 4 as G’, G’’, and tan δ, where G’
(storage modulus) represents dough elasticity meaning a
solid-like behavior, G’’ (loss modulus) represents dough
viscosity meaning a liquid-like behavior, and tan δ (ratio
of G’’ over G’) tends to zero for solids and to infinity for
liquids.
We observed that the storage modulus of all doughs
was greater than the loss modulus, indicating a typical
elastic dough behavior required for good quality
muffins. Besides, Nazanin and Mostafa reported that
the viscosity of cake dough should be optimum to hold
air bubbles in the final product, since too low dough
viscosity inhibits air incorporation and too high dough
viscosity inhibits expansion of air bubbles [22].
In our study, the control muffin with egg exhibited
the highest tang δ, indicating very soft gel dough. As
can be seen in Table 4, the moduli of the eggless doughs
were lower than the moduli of the doughs made with
eggs. This was due to the functional role of an egg as a
good emulsifier increasing dough viscoelasticity.
The moduli G’ and G” increased both for the
eggless and egg-containing muffins fortified with 1%
D. macrophylla L. This might be attributed to the
capacity of potential fibers in D. macrophylla L. to
absorb water in the dough, thereby lowering the free
water level available to facilitate the movement of
particles in the matrix. The direct consequence of this
process was higher dough viscoelasticity. This finding
was also supported by Jantinder et al. and Felicidad
et al. who found that adding proteins and Jambolan
fruit pulp increased muffin dough viscosity and
viscoelasticity, respectively [16, 23].
The color of bakery products is one of the most
important parameters that influences consumers’
purchasing choices. Crumb color highly depends on
the formulation ingredients, as well as the duration and
temperature of baking, whereas crust color depends on
caramelization and Maillard reactions.
The color data for our muffins are given in Table 5
as L*, a*, b* and DE corresponding to lightness,
redness, yellowness, and different color. We observed
that the L* and a* values of crumb and crust color for
the control muffins with egg were slightly lower than
those for the control eggless muffins but the difference
was not significant (P ≥ 0.05). However, the b* value of
the control muffins with egg was higher than that of the
Table 3 Mineral and ash contents of muffins fortified with Dacryodes macrophylla L. extract
Component Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
Ca, mg/g 3.58 ± 0.53a 5.18 ± 0.53ab 4.38 ± 0.27a 4.11 ± 0.53a 6.79 ± 0.53b 5.72 ± 0.27ab
Mg, mg/g 2.27 ± 0.32a 2.92 ± 0.56a 2.76 ± 0.32a 2.60 ± 0.32a 3.90 ± 0.56a 3.73 ± 0.43a
P, mg/g 0.66 ± 0.13a 0.87 ± 0.01abc 0.83 ± 0.02ab 1.00 ± 0.02bc 1.11 ± 0.02c 1.05 ± 0.02bc
Na, mg/g 5.03 ± 0.03a 7.19 ± 0.01d 5.82 ± 0.02b 5.93 ± 0.06b 7.75 ± 0.01e 6.75 ± 0.02c
K, mg/g 1.52 ± 0.02a 3.61 ± 0.01d 2.40 ± 003b 2.88 ± 0.11c 5.36 ± 0.03f 3.87 ± 0.05e
Zn, ×102
mg/g 0.39 ± 0.03a 1.53 ± 0.08bc 1.13 ± 0.09b 1.67 ± 0.31c 3.36 ± 0.06e 2.45 ± 0.21d
Ash, % 1.07 ± 0.07a 1.12 ± 0.06ab 1.11 ± 0.06ab 1.27 ± 0.03ab 1.34 ± 0.03b 1.29 ± 0.05ab
Values are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant
(P ≥ 0.05)
Table 4 Rheology parameters of muffins with 1% of Dacryodes macrophylla L. extract
Rheology parameters Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
G’ 103.90 ± 9.38a 120.90 ± 9.39a – 664.00 ± 22.62b 804.00 ± 23.13c –
G’’ 41.00 ± 3.56a 42.29 ± 3.13a – 286.11 ± 7.47b 299.9 ± 8.02b –
Tang delta 0.39 ±0.03a 0.35± 0.031a – 0.43± 0.01b 0.37± 0.01a –
Values are mean ± standard deviation of triplicate experiments
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
control eggless muffins. This result could be due to egg
protein enhancing the Maillard reaction by providing
amino acid which may have reacted with sugars to
generate dark-brown substances, thereby reducing the
lightness of the final product, as well as redness [21, 22].
However, high yellowness might be attributed to the
yellow part of the egg which might have impaired the
color of the muffin dough. Moreover, incorporating the
D. macrophylla L. extract decreased the L*, a*, b* and
DE values of the muffins (crumb and crust). This might
be due to the pigments and polyphenol interacting with
other constituents of the dough to impart greenness,
thereby darkening the muffin’s color. These results were
in line with those reported by Rashida et al. and Marina
et al. who noticed a reduction in the L*, a*, and b* values
with increased amounts of wheatgrass powder and
avocado puree in muffin dough, respectively [5, 24].
Since the eggless and egg-containing muffins with
0.5% DME were heterogeneous, they were not included
in the color analyses.
The textural parameters of the muffins are presented
in Table 6. We found that the eggless muffin (4.68)
was firmer than the muffin with egg (3.65). This was
expected because an egg is a good emulsifier that acts
as a plasticizer by increasing dough viscoelasticity and
thereby reducing muffin firmness.
We also noticed that muffin firmness showed an
opposite trend to the specific volume. This was in line
with Nazaninet and Mostafa who concluded that softness
was improved by both a higher cake volume and the
anti-firming effect of the emulsifiers [22]. Furthermore,
we found that firmness decreased with the incorporation
of D. macrophylla L. This result was consistent with
Prerna et al. who reported a decrease in muffin hardness
with an increase in capsicum pomace [12]. Chewiness
corresponds to the amount of energy required to
disintegrate food for swallowing. Chewiness and
gumminess of muffins follow the same trend as hardness
since both parameters are dependent on firmness [17].
Springiness is a desirable property indicative of muffin
elasticity, since it measures the extent of recovery
between the first and the second compression. In our
study, the springiness values were generally higher
(0.68–1.97) than those obtained by Shevkani and
Singh who added different protein isolates to muffins
(0.64–0.85) [21].
The higher springiness of the control muffin with egg
(1.97), compared to the control eggless sample (1.27),
might be due to egg protein aggregation that improved
the quality of muffins. However, this textural parameter
decreased with the incorporation of D. macrophylla L.
Prerna et al. also reported a decrease in springiness with
the incorporation of capsicum pomace [12].
Cohesiveness is the ability of a material to stick
to itself. It measures the internal resistance of food
structure under some compression. We found the
cohesiveness value of the control muffin with egg to be
significantly higher (0.29) than that of the control eggless
Table 5 Color parameters of muffins with 1% of Dacryodes macrophylla L. extract
Color data Color
parameters
Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
Crust L* 47.67 ± 0.58b 38.17 ± 1.43a – 46.85 ± 0.40b 34.74 ± 1.32a –
a* 3.80 ± 0.27d 2.16 ± 0.09c – 0.95 ± 0.03b –0.17 ± 0.03a –
b* 22.38 ± 0.15b 19.01 ± 0.49a – 28.55 ± 0.25c 21.76 ± 0.32b –
DE 46.56 ± 1.18a 52.24 ± 0.13b – 47.70 ± 1.50a 50.70 ± 0.63b –
Crumb L* 69.31 ± 1.13c 46.70 ± 0.30b – 52.36 ± 1.75b 36.21 ± 2.59a –
a* 10.33 ± 0.51c 6.73 ± 0.58b – 6.16 ± 0.27b 0.90 ± 0.13a –
b* 29.52 ± 0.21c 23.49 ± 0.49b – 38.51 ± 0.16d 18.03 ± 0.89a –
DE 40.40 ± 2.72a 57.40 ± 1.80c – 46.22 ± 0.07b 69.62 ± 0.97d –
Values are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant
(P ≥ 0.05)
Table 6 Texture parameters of muffins under study
Texture parameters Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
Hardness 4.68 ± 1.57c 2.96 ± 0.55a 3.03 ± 0.14a 3.65 ± 0.32b 2.61 ± 0.20a 3.01 ± 0.05a
Adhesiveness, mJ 0.007 ±0.003a 0.008 ± 0.002a 0.006 ±0.002a 0.022 ± 0.002b 0.031 ± 0.004bc 0.023 ± 0.005b
Cohesiveness 0.17 ± 0.011a 0.16 ± 0.01a 0.17 ± 0.01a 0.29 ± 0.04b 0.23 ± 0.01ab 0.24 ± 0.01ab
Springiness, mm 1.27 ± 0.11ab 0.68 ± 0.04a 0.75 ± 0.24a 1.97 ± 0.45b 1.02 ± 0.14ab 0.84 ± 0.14a
Gumminess, N 1.35 ± 0.33b 0.63 ± 0.06ab 0.71 ± 0.06ab 1.05 ± 0.21ab 0.48 ± 0.09a 0.52 ± 0.03a
Chewiness, mJ 3.02 ± 1.14b 0.54 ± 0.15a 0.74 ± 0.15ab 1.38 ± 0.40ab 0.35 ± 0.01a 0.40 ± 0.17a
Values are mean ± standard deviation of triplicate experiments
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Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39
muffin (0.17). This result might be attributed to the egg
protein network along with starch gel that might have
impacted the muffin crumb texture [21].
Nevertheless, there was no significant difference
in cohesiveness and adhesiveness values in the muffins
fortified with D. macrophylla L. Our results were in
agreement with those found by Maria et al. who reported
no significant differences in cohesiveness values among
fiber-enriched bake products (squash seed flour) [20].
Overall, hardness, chewiness, gumminess, and
springiness decreased with the incorporation of
D. macrophylla L., whereas cohesiveness and
adhesiveness did not show any significant difference.
However, the muffins with egg had lower hardness,
chewiness, and gumminess and higher springiness,
cohesiveness, and adhesiveness compared to the eggless
muffins.
The total phenolic content assay determines both
bound and unbound phenolics, while the radical
scavenging activity assay measures free antioxidants.
Thus, the latter is more efficient at preventing the
reactive oxygen species from attacking lipoproteins,
polyunsaturated fatty acids, DNA, amino acids, and
sugars because it describes the capacity of an antioxidant
in both food and biological systems [25].
Therefore, we used DPPH, a stable free radical, to
evaluate the antioxidant capacity of our fortified muffins
(Table 7). We found that the DPPH inhibition values
for both eggless muffins and those with eggs increased
significantly with the incorporation of D. macrophylla
fruit. This result may be attributed to antioxidant
compounds in D. macrophylla fruit increasing the
DPPH activity.
Our results were consistent with those found by
other authors who reported better DPPH activity with
higher levels of Jambolan fruit pulp in the gluten-free
muffins [11, 16].
The results of sensory evaluation of the muffin
samples are presented in Table 8. The overall
acceptability ranged from 5.3 to 7.9, meaning that the
muffins were considered slightly or moderately pleasant
according to the 9-point scale, except for the sample
scoring 5.3 (neither unpleasant, nor pleasant).
The egg-containing muffins with 1% of DME
recorded the lowest score (5.3) and was considered not
acceptable because its acceptance index (59%) was lower
than 70% (Table 9). This low score resulted from the
sample’s taste, which also had the lowest score. Most
panelists considered its taste unpleasant, indicating
bitterness after swallowing.
In contrast, the control egg-containing muffins
received the highest overall acceptability score (7.9) and
the highest acceptance index (87.88%). However, we
found no significant difference with the control eggless
muffin or the egg-containing muffin with 0.5% DME.
The highest score of the control egg-containing muffin
might be attributed to its texture, which was rated
Table 7 DPPH assay: Antiradical activity of muffins with Dacryodes macrophylla L. extract
Radical Scavenging Activity Eggless muffins Egg-containing muffins
Control 1% DME 0.5% DME Control 1% DME 0.5% DME
DPPH, μM troloxeq/mg 3.90 ± 0.52a 6.84 ± 0.93bc 5.06 ± 0.19abc 4.57 ± 0.26ab 7.85 ± 0.96c 6.22 ±0.30abc
Values are mean ± standard deviation of triplicate experiments
Table 8 Sensory indicators of muffins under study
Sample Color Odor Texture Taste Overall acceptability
Eggless muffins
Control 7.9 ± 0.1cd 7.7 ± 0.1c 7.4 ± 0.1c 7.7 ± 0.1cd 7.7 ± 0.1c
1% DME 6.6 ± 0.1b 7.1 ± 0.1b 6.6 ± 0.1a 7.2 ± 0.1c 6.9 ± 0.1b
0.5% DME 7.1 ± 0.1c 6.9 ± 1.0b 6.8 ± 0.1ab 6.4 ± 0.1b 6.6 ± 0.1b
Egg-containing muffins
Control 7.9 ± 0.1cd 7.6 ± 0.1c 8.2 ± 0.1d 7.8 ± 0.1d 7.9 ± 0.1c
1% DME 6.1 ± 0.1a 6.3 ± 0.1a 7.1 ± 0.1bc 4.6 ± 0.2a 5.3 ± 0.1a
0.5% DME 7.5 ± 0.1c 7.6 ± 0.1c 8.0 ± 0.1d 7.8 ± 0.1d 7.7 ± 0.1c
Values are mean ± standard deviation of triplicate experiments. Values carrying the same letter in the same column are not statistically significant
(P ≥ 0.05)
Table 9 Acceptance index and acceptability among muffin
samples
Sample Acceptance
index, %
Acceptability, %
Like Dislike
Eggless muffins
Control 86.00 101 (100.0) 0 (0.0)
1% DME 77.11 89 (88.12) 12 (11.88)
0.5% DME 73.33 83 (82.18) 18 (17.82)
Egg-containing muffins
Control 87.88 101 (100.0) 0 (0.0)
1% DME 59.22 44 (43.56) 57 (56.44)
0.5% DME 85.55 98 (97.03) 3 (2.97)
A product is acceptable when its acceptance index is greater than 70%
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highest (8.2). Its appreciation by the panelists was in
agreement with its springiness and specific volume (1.97
and 2.36, respectively), also scored highest.
The incorporation of D. macrophylla L. fruits
tended to lower the average acceptance scores both
for the eggless muffins and for those with eggs. The
same trends were observed by Abdessalem et al. who
introduced date fiber concentrate in muffins [13]. In
our work, the egg-containing muffins with 0.5% DME
had the best rank among the samples and received the
same rank as the controls (both with and without egg).
This means that the panelists preferred the muffins with
D. macrophylla L. extract to the eggless control muffins.
CONCLUSION
Our results revealed that the incorporation of
Dacryodes macrophylla L. fruit decreased water
activity, the L*, a*, and b* values, as well as the firmness
of the muffins, whereas no prominent difference was
observed in their baking loss, height, moisture, fat,
cohesiveness, springiness, gumminess, or chewiness.
In contrast, D. macrophylla L. increased specific
gravity, changed rheology, and tended to increase
adhesiveness, antioxidant activity, and mineral contents
(particularly Na and K) of the muffins. Another
interesting result was that the panelists statistically
accepted the muffins with 0.5% of DME, scoring them
in the same range as the control ones.
Therefore, D. macrophylla L. fruit is a good potential
ingredient to develop new bakery products rich in
minerals and antioxidants but further investigations
need to be done to improve the color acceptance of
muffins and to determine the optimal concentration of
D. macrophylla L.
CONTRIBUTION
A.S. Ndinchout, V. Kaur, and N. Singh conceived,
designed, and performed the study, collected the
data, and wrote the manuscript. D.P. Chattopadhyay,
M.A. Nyegue, and F.P. Moundipa contributed to the data
analysis and proofread the manuscript.
CONFLICTS OF INTEREST
The authors declare that there is no conflict of
interest regarding the publication of this paper.
ACKNOWLEDGMENTS
We thankfully acknowledge the financial support in
the form of fellowship and cooperation in each step of
this doctoral research provided by the Organization for
Women in Science for Developing World (OWSD), Italy
and the Swedish International Development Corporation
Agency, which helped us to complete the work. We are
also thankful to the staff and students at Guru Nanak
Dev University, Amritsar (India) and Dr. Saha Foudjo
Brice, University of Bamenda, Cameroun for their help
and cooperation during sensory evaluation

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