INTRODUCTION
Plants are generally considered an important source
of nutrients and food supplements since they are rich in
nutritive components essential for humans and animals.
Growing scientific evidence that supports their health
benefits has led to an increase in plant-based foods and
diets [1]. Seeds, which are key components of several
plant-based diets, are recognized as having a wide range
of potential health benefits. Replacing energy-dense
foods with high protein seeds has been shown to have
beneficial effects on the prevention and management
of obesity and related disorders, such as cardiovascular
disease, diabetes and the metabolic syndrome. A great
number of people in the world depend on conventional
plants to obtain remedies as pharmaceuticals. Medicinal
plants are not only used as an alternative to traditional
treatment if it does not exist, but they also provide an
excellent source of bioactive natural products [2].
Acanthaceae is a tropical and subtropical
family of dicotyledonous flowering plants rich in
nutritional and medicinal components. It includes 346
genera and around 4300 species distributed across
temperate regions, mostly in Indonesia, Malaysia,
Africa, Brazil, and Central America. Some species
have colorful flower petals and are used as a source
of natural dyes. Chemically, Acanthaceae plants
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Foods and Raw Materials, 2022, vol. 10, no. 1
E-ISSN 2310-9599
ISSN 2308-4057
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Mariod A.A. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 67–75
contain important secondary metabolites such as
glycosides, flavonoids, alkaloids, triterpenoids, fatty
acid methyl esters, and fatty acids. These compounds
play an important role in many biological reactions
and work against many lethal diseases [3]. Most
of the Acanthaceae species have high therapeutic
applications due to their alkaloid contents [4].
Their leaves and seeds are used to treat bronchial
diseases, flu, and ulcers, as well as to relieve poisonous
insect and snake bites, dry cough, and diarrhea [5].
Monechma Hochst., closely related to Justicia L., is
an Acanthaceae genus that contains about 60 species
mostly found in tropical and sub-tropical regions,
particularly in South Africa. Monechma plants are
well adapted to harsh environments. As reported by
Darbyshire and Goyder, twelve species are recorded
in Angola, two of which have recently been added
to Monechma [6]. Although these two species are
morphologically similar, especially in flower and fruit
morphology, there is some morphological evidence to
support their separation. In particular, there are notable
differences in inflorescence form.
Monechma ciliatum is a species with unique
biochemicals and phytochemicals that make it
traditionally useful for many African communities,
especially in rural areas. It shows significant
antibacterial activity against Bacillus subtilis, Staphylococcus
aereus, Escherichia coli, and Pseudomonas
aeraginosa, compared to well-known antibiotics,
as well as antifungal activity against Cladosporium
cucumerinum and Candida albicans [7]. Studies on
their seed extracts, seedcakes, and leaves reveal great
contents of nutrients with antioxidant, antimicrobial and
medicinal properties [8].
M. ciliatum mainly grows in tropical regions. It is
found in the west and southwest of Sudan where it is
well known and traditionally used. Owing to its small
brownish black seeds, this species is referred to as black
mahlab, or El-Mahlab El-Aswad, in Sudan. In one of
our earlier works, we reported its richness in fat and
other essential nutrients, as well as many benefits in
traditional treatments and cosmetic uses [9]. According
to that study, the protein content of the M. ciliatum
seed was 21%, with 783.3 mg/g N as total amino acid.
The main fatty acids in M. ciliatum fat were oleic
(47.3%), linoleic (31.4%), stearic (16.0%), and palmitic
(4.5%). The content of tocopherols was 45.2 mg/100 g.
Boiling, roasting, and germination are traditional
methods generally used to improve the nutritional
properties of seeds. Studies of the impact of cooking on
the nutrient contents in several seeds revealed changes in
their chemical composition and nutritional components.
In another work, we studied the effect of introducing
мahlab seed flour as a vegetarian food supplement on
kisra (Sudanese bread made of sorghum flour) [10].
Mahlab seeds were subjected to three industrial
treatments, namely boiling, roasting, and germination.
The processed mahlab seed flour was added to sorghum
flour and after the necessary fermentation, four samples
of supplemented kisra were made. We performed
proximal chemical analysis and evaluated the sensory
parameters of the samples against those of conventional
sorghum kisra. The results showed that the use of
M. ciliatum seed flour as a supplement to sorghum kisra
significantly improved its nutritional value. We also
found that all the panelists gave 10% higher scores to
sorghum kisra supplemented with roasted M. ciliatum
seed flour, compared to the other samples.
Mbah et al. reported an increase in protein, fiber,
iron, and zinc contents in Morenga seeds as a result
of boiling and roasting. In another study, processing
techniques such as boiling, roasting, soaking, and
blanching significantly (P < 0.05) reduced tyrosine
and cystine contents in black gram (Vigna mungo), but
increased histidine [11, 12]. We also reported that boiling
and roasting increased fat and protein contents and decreased
moisture, carbohydrate, and fiber contents in
safflower seeds [13]. We found that these processing
methods had an insignificant effect on fatty acids, while
Ghazzawi and Ismail showed that roasting and frying
of nuts had a positive effect on the fatty acids profile and
antioxidant activity [14].
Roasted watermelon seeds have fewer benefits and
a lower nutritional value compared to raw seeds. They
are heated at about 160 degrees Celsius for only 15 min
in order to give them a delicious roasting flavor
without causing them to burn and lose their nutritional
value [15]. A study published in 2014 indicated that
roasting sesame seeds and their subsequent fermentation
enhanced their nutrient content after they were ground
to a fine powder [16]. Sesame roasting and peeling
decreased the content of phytates and oxalate, the
compounds that affect digestion and reduce protein
absorption in the intestine. Therefore, it is preferable to
eat peeled and roasted sesame.
Muangrat et al. studied the effect of heat and time
of roasting and microwave treatment on the contents
of acids, free fatty acids, and iodine, as well as the
saponification and peroxide number of black sesame
seed oil [17]. They found that the microwave-roasted
oil samples showed higher antioxidant activity due to a
greater content of total phenols, sesamol, and sesamolin.
This indicates that both roasting and microwave
treatment are suitable methods to achieve better quality
for black sesame oil products [17].
Germination is an effective technique used to
improve the nutritional content of legume seeds. It
decreases their fat content and increases minerals
and fatty acids, thus producing healthy nutrients
with bioactive components [18]. Ren et al. found that
germination provided brown rice with considerable
amounts of beneficial nutrients and bioactive
compounds [19]. Due to the high cost of animal protein,
researchers conduct studies on plants as an affordable
source of protein. Including plant protein in the daily
diet can prevent malnutrition among poor people,
especially in developing countries. Sranacharoenpong
et al. reported increasing numbers of stunted children
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Mariod A.A. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 67–75
in Africa. Stunting, or impaired growth, is caused by
poor nutrition [20]. Since M. ciliatum seeds are rich in
protein, fat, minerals, and other nutrients, they could
be used to prevent this condition. These seeds are very
hard to mill so they are traditionally soaked in water
before milling. We aimed to study the impact of boiling,
roasting, and germination processes on the composition
and nutritional contents of M. ciliatum seeds.
STUDY OBJECTS AND METHODS
Monechma ciliatum seeds (7 kg) were purchased
from a local market. The seeds were hand-sorted to
remove broken seeds and foreign materials. Then,
they were well cleaned with running tap water twice
and stored in white/clear reclosable self-seal zip lock
polyethylene bags (2.36”×3.94”, 4 Mil thick) at 25°C.
Boiling of M. ciliatum seeds. 600 g of M. ciliatum
seeds was put into three 1.0 L beakers, 200 g in each.
Water was added at a ratio of 1:4 and boiled to 100°C
for 40 min on a magnetic stirrer hot plate until the
seeds were cooked. The seeds were drained and dried
in a 50°C vacuum oven and then ground to 0.5–0.8 mm
particles in a grinder (Moulinex, Japan). Finally, they
were put into white/clear reclosable self-seal zip lock
polyethylene bags (2.36”×3.94”, 4 Mil thick) and stored
in a refrigerator at 0–5°C at a relative humidity of
55–65% for analysis.
Roasting of M. ciliatum seeds. 500 g of washed and
dried M. ciliatum seeds were arranged in 3 aluminum
foil dishes and then put in an electric air oven, as
described by Chirinos et al. with some modifications
[21]. The seeds were roasted at 180°C for 20 min.
The roasted seeds were left to cool to 25°C and then
were ground to 0.5–0.8 mm particles in an electric
grinder (Moulinex, Japan). They were stored in a
refrigerator at 0–5°C at a relative humidity of 55–65%
for analysis.
Germination of M. ciliatum seeds. In line with the
method described by de Jesus et al., 500 g of M. ciliatum
seeds were soaked in 2500 mL of 0.7 g/L sodium
hypochlorite solution for 30 min at 25°C [22]. Then, the
seeds were well washed with running tap water twice,
drained, and soaked in deionized water for 5 h. After
that, they were kept between two layers of cotton cloth
for 72 h at room temperature (25°C). The germinated
seeds were dried in an air oven at 60°C till constant
weight. Then, they were ground to 0.5–0.8 mm particles
in an electric grinder (Moulinex, Japan) and stored in a
refrigerator at 0–5°C at a relative humidity of 55–65%
for further use. The control samples were only ground to
0.5–0.8 mm particles in an electric grinder (Moulinex,
Japan) and stored in the same conditions.
Proximate chemical analysis. Moisture, crude fat,
crude fiber, and ash were analyzed using the methods
of the Association of Official Analytical Chemists [23].
Total nitrogen was analyzed by the micro-Kjeldahl
method, with nitrogen converted to protein using the
factor of 6.25. The carbohydrate content was calculated
by subtracting the sum of fat, protein moisture, fiber, and
ash from 100.
Mineral determination. 0.03 Ag ground sample
was put in a microwave vessel containing 5.0 mL
of HNO3 and 2 mL of H2O2 (Suprapur, Merck).
Then, it was heated to 205°C for 15 min to obtain
a finely digested mixture. The mixture was left to
cool to 25°C and a colorless solution was obtained.
The solution was analyzed by inductively coupled
plasma-mass spectrometry (ICP-MS) according to the
method described by Ngigi and Muraguri with some
modifications [24].
Fatty acid composition. Test seeds (15.0 g) were
ground and their oil was separated in a Soxhlet extractor
(Gerhardt), as indicated by the American Oil Chemists
Society [25]. The removed oil was methylated and
changed over to fatty acid methyl esters. Then, it was
analyzed on a Shimadzu GC-2010 gas chromatograph
with a DB-23 column (60 m×0.25 mm ID, 0.25 μm
film thickness). The injector, column, and indicator
temperatures were 230, 190, and 240°C, respectively.
The split proportion was 80:1. Helium (1.0 mL/min) was
used as a transporter gas.
Determination of tocopherols. A solution of 250 mg
of black mahlab seeds oil in 25 mL n-heptane was
used for the high performance liquid chromatography
(HPLC). The HPLC analysis was conducted using a lowpressure
gradient system fitted with an L-6000 pump,
an F-1000 fluorescence spectrophotometer (detector
wavelengths of 295 nm and 330 nm for excitation and
emission, respectively), and a D-2500 integration system
(Merck-Hitachi). 20 μL samples were injected by a
655-A40 autosampler onto a 25 cm×4.6 mm ID Diol
phase HPLC column (Merck, Darmstadt, Germany)
at a flow rate of 1.3 mL/min. The mobile phase was
n-heptane/tert, butyl methyl ether (99+1, v/v) [26].
Amino acid composition. A 200 mg sample was
digested with 5.0 mL 6N HCL in a hydrolysis tube.
The solution was incubated at 11°C for 24 h and filtered
through filter paper. Then, 200 mL of the filtered
solution was evaporated at 140°C for about an hour
and 1.0 mL of a diluted buffer was added to the dried
sample. The amino acid composition of the hydrolyzed
sample was determined on an S 433 automatic amino
acid analyzer (Sykam, Germany) [9].
Statistical analysis. The analyses were performed
in triplicate. The mean values and standard deviation
(mean ± SD) were determined by Duncan’s test
(P < 0.05). The measurable analysis of variance
(ANOVA) was applied on all the values using a
Statgrafics® Statistical Graphics System (version
18.1.12).
RESULTS AND DISCUSSION
The weight of a hundred or thousand seeds is an
important characteristic of the seeds’ fullness and
maturity. It also indicates the amount of flour from
the seeds [27]. In our study, the average length of
Monechma ciliatum seeds was about 4.0 mm and 100
seeds weighed about 3.0 g.
Proximate chemical composition of boiled,
roasted, and germinated M. ciliatum seeds. The
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seeds’ chemical composition is very important because
they contain many nutrients and growth materials that
affect germination. Seeds are considered a basic source
of food. For example, Chia (Salvia hispanica) seeds are
used as ingredients or supplements in many foodstuffs
such as baked products, muesli, dairy drinks, fruit
smoothies, or salads. They are also used as thickeners
in soups and sauces [28]. The proximate compositions
of untreated black mahlab (UM), boiled black mahlab
(BM), roasted black mahlab (RM), and germinated
black mahlab (GM) seeds are presented in Table l.
Moisture content. The seed’s moisture, which is
usually expressed as a percentage on a wet weight basis,
is an important indicator that affects the seed’s quality
and shelf-life. In our study, the moisture content of
untreated black mahlab seeds was 9.43%, while boiling,
roasting, and germination decreased it to 6.91, 6.41, and
9.41%, respectively. This finding was consistent with
the one we made in our earlier study, namely a decrease
in the moisture of crude safflower seeds after roasting
and boiling [29]. Hatamian et al., who studied chia
seeds, also found a diminished moisture content after
roasting [30].
Fat content. The fat contents of untreated and
treated black mahlab seeds are shown in Table 1. The
UM seed flour had a fat content of 11.65%, which was
lower than 14.66% for BM and 12.39% for RM, but
higher than 11.30% for GM. As we can see, boiling and
roasting increased the fat content, while germination
had an insignificant effect on this indicator. This result
disagreed with Onyeike and Oguike, who showed that
crude fat was highest in raw groundnut seeds and lowest
in boiled groundnut seeds [31].
Protein content. Proteins are essential nutrients for
the human body. They are the basic units of body tissue
and can also serve as an energy source. Proteins provide
as much energy density as sugars. Most importantly
for nutrition is that protein contains amino acids [32].
The protein contents of untreated and treated black
mahlab seeds are shown in Table 1. We found that all
the processing methods increased the protein content.
Amounting to 22.29% in UM, it increased to 23.89,
22.90, and 24.34% in BM, RM, and GM, respectively.
Thus, boiling and germination contributed to a higher
protein content, unlike roasting. This finding was
consistent with that in our earlier study, where the
germination of black cumin increased both the oil and
the protein contents, while other constituents decreased
[29]. In a study by Olanipekun et al., the flour from
processed kidney bean seeds had a significantly higher
protein content than that of the raw seeds [33]. Cargo-
Froom et al. reported that boiling and roasting enhanced
the pulses’ protein content, availability, and digestibility,
as well as the content of essential amino acids [34].
Similarly, Mbah et al. showed that boiling and roasting
increased the protein content in Moringa seeds [11].
The higher protein content in the processed seeds might
be due to the increase of proteolytic enzymes activity
which hydrolyzed proteins to their amino acids during
processing.
Fiber content. Dietary fiber includes parts of plant
food that the body cannot digest or absorb. Unlike other
food components (fats, proteins, or carbohydrates),
which the body breaks down and absorbs, fiber passes
relatively well through the stomach, small intestine, and
colon, and then out of the body [35]. The fiber content
in untreated and treated black mahlab seeds is shown in
Table 1. As we can see, it reached 9.2, 10.1, 9.0, and 9.9%
in UM, BM, RM, and RM, respectively. It was slightly
affected by roasting and germination and increased
by boiling. This result agreed with Mbah et al. who
reported that boiling and roasting increased the fiber
content in Moringa seeds [11]. However, it was opposed
to our earlier finding that roasting and boiling decreased
the fiber content in safflower [13].
Carbohydrate content. Carbohydrates are a group
of organic compounds that include sugars, starches,
and fibers that provide the body with energy. During
digestion, carbohydrates are converted into glucose
sugar. The pancreas secretes insulin to help glucose
sugar enter the cells in the brain and muscles and
provide them with the energy needed to perform
various functions. The excess of glucose sugar is stored
in the liver in the form of glycogen to be used when
needed [36]. The carbohydrate contents of untreated
and treated black mahlab seeds are shown in Table 1.
As we can see, the total available carbohydrates in UM,
BM, RM, and GM amounted to 43.60, 40.89, 45.62,
and 41.39%, respectively. The carbohydrate content
was the highest in RM followed by UM, GM, and BM.
Our findings agreed with those of Onyeike and Oguike,
who reported that boiling and frying increased the total
carbohydrate content in groundnuts [31]. This indicates
that M. ciliatuim flour is a good source of energy for
consumers.
Ash content. The ash contents in untreated and
treated black mahlab seeds are shown in Table 1. The
Table 1 Approximate chemical analysis of raw, boiled, roasted, and germinated Monechma ciliatuim seeds, %
Sample Moisture Fat, % Carbohydrate, % Protein, % Fiber, % Ash, %
Untreated mahlab 9.43 ± 0.03b 11.56 ± 0.37 a 43.60 ± 0.70 a 22.29 ± 0.23a 9.20 ± 0.22 a 3.92 ± 0.10a
Boiled mahlab 6.91 ± 0.01a 14.66 ± 0.31c 40.89 ± 0.50 b 23.89 ± 0.29b 10.11 ± 0.14b 3.54 ± 0.10 a
Roasted mahlab 6.14 ± 0.11a 12.39 ± 0.25b 45.62 ± 0.70c 22.90 ± 0.13 a 9.00 ± 0.23 a 3.95 ± 0.20 a
Germinated mahlab 9.41 ± 0.30b 11.30 ± 0.08 a 41.39 ± 0.20d 24.34 ± 0.17b 9.90 ± 0.29 a 3.66 ± 0.10 a
Values are means of triplicate determinations. a,b,c,d Means in the same column followed by the same superscript are not significantly different at
P < 0.05
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ash content in UM was 3.92%. Insignificantly affected
by all processing techniques, it amounted to 3.95, 3.66,
and 3.45% in RM, GM, and BM, respectively.
Mineral content in boiled, roasted, and germinated
M. ciliatum seeds. The mineral compositions of
untreated, boiled, roasted, and germinated black mahlab
seeds are presented in Table 2. The concentrations of
major and trace elements in the untreated seeds were
significantly (P < 0.05) higher than in the processed
seeds. Table 2 shows how boiling, roasting, and
germination affected sodium, calcium, potassium,
copper, iron, zinc, magnesium, manganese, selenium,
and phosphorus contents in M. ciliatum seeds. As we
can see, the three processing treatments varied in their
effects on the mineral contents.
The sodium (Na) content in UM was 264.1 mg/kg.
This value insignificantly decreased to 251.6 mg/kg in
BM, significantly decreased to 227.4 mg/kg in RM, and
insignificantly increased to 270.7 mg/kg in GM.
The calcium (Ca) content in UM was 4911 mg/kg.
After treatment, it significantly decreased to 4158.5,
4666.3, and 3880.3 mg/kg in BM, RM, and GM,
respectively. The roasted sample had the highest content
of calcium.
The potassium (K) content in UM was 7812.7 mg/kg.
After treatment, it decreased significantly to
4787.6 mg/kg in BM and insignificantly to 7702.6 and
7140.0 mg/kg in RM and GM, respectively. The roasted
M. ciliatum seeds had the highest content of potassium.
The copper (Cu) content in UM was 12.40 mg/kg.
It did not change significantly after the treatments,
amounting to 12.11, 11.53, and 11.73 mg/kg in BM, RM,
and GM, respectively.
The iron (Fe) content in UM was 166.5 mg/kg.
After treatment, it significantly decreased to 59.2 and
89.6 mg/kg in BM and RM, respectively, and
insignificantly decreased to 162.2 mg/kg in GM.
The zinc (Zn) content in UM was 23.66 mg/kg.
After treatment, it significantly decreased to 19.67 and
21.36 mg/kg in BM and RM, respectively, and
insignificantly decreased to 22.88 mg/kg in GM. The
germinated sample was the richest in zinc.
The magnesium (Mg) content in UM was
4747.2 mg/kg. After treatment, it significantly decreased
to 4387.6 and 4367.3 mg/kg in BM and GM, respectively.
However, roasting had no significant effect on the
magnesium content, which amounted to 4747.6 mg/kg
in RM.
The manganese (Mn) content in UM was
93.19 mg/kg. This value significantly decreased after
treatment, amounting to 66.02, 84.79, and 67.36 mg/kg
in BM, RM, and GM, respectively. The roasted sample
was the richest in manganese.
The selenium (Se) content in UM was 0.56 mg/kg. It
did not change significantly after boiling, amounting to
0.54 mg/kg in BM. However, it significantly decreased
to 0.26 and 0.41 mg/kg in RM and GM, respectively.
The phosphorus (P) content in UM was
3059.5 mg/kg. It did not change significantly after
germination, amounting to 3002.7 mg/kg in GM.
However, it significantly increased to 3118.8 and
3205.8 mg/kg in BM and RM, respectively. The roasted
sample had the highest content of phosphorus.
Thus, the three processing treatments generally
decreased the contents of minerals in the raw seeds.
Sodium was decreased by boiling and roasting,
but increased by germination. Iron and zinc were
insignificantly affected by boiling and roasting.
Magnesium was not affected by roasting but it was
decreased by boiling and germination. Selenium slightly
diminished with boiling but significantly diminished
after roasting and germination. However, the roasting
technique contributed most to the minerals retention,
followed by germination and then boiling. This might be
due to the fact that minerals leached from the seeds into
distilled water at different rates during cooking. This
result agreed with Kinge et al., who reported that boiling
and roasting of Djansang (Ricinondron heudelotii) seeds
significantly increased the amount of phosphorous, iron,
calcium, and magnesium [37]. Boiling retained those
minerals better than roasting. However, the amounts
of potassium and sodium were significantly lower in
the boiled samples compared to the roasted ones. Their
study concluded that the roasting process preserved
minerals better than boiling. Our findings were also
consistent with the ones we made earlier, namely that
the contents of major elements in raw safflower seeds
were higher than in the roasted and boiled seeds [13].
According to Table 2, only sodium and phosphorus were
significantly increased by germination and roasting,
respectively.
Fatty acid composition of the oil from boiled,
roasted, and germinated M. ciliatum seeds. The
human body uses essential fatty acids (EFAs) to
produce healthy cell membranes and benefit from their
Table 2 Effects of boiling, roasting, and germination on the mineral contents (g/kg) in Monechma ciliatum seeds
Sample Na Ca K Cu Fe Zn Mg Mn Se P
Untreated mahlab 264.1a 4911.2a 7812.7a 12.40a 166.5a 23.66a 4747.2a 93.19a 0.56a 3059.5a
Boiled mahlab 251.6b 4158.5b 4787.6b 12.11a 59.2d 19.67b 4387.6b 66.02b 0.54a 3118.9b
Roasted mahlab 227.4c 4666.3c 7702.6c 11.53b 89.6c 21.36a 4747.6a 84.79c 0.26b 3205.8c
Germinated mahlab 270.7d 3880.3d 7140.0d 11.73b 162.5b 22.88a 4367.2b 67.36d 0.41c 3002.7d
Values are means of triplicate determinations ± S.D. a,b,c,d Means in the same column followed by the same superscript are not significantly
different at P < 0.05
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multiple biological roles. In particular, they influence
the inflammatory cascade, reduce the oxidative stress,
and provide neural and cardiovascular protection.
A significant factor in various illnesses, fatty acid
levels are used to distinguish potential biomarkers
for a few pathologies, for example, polycystic ovary
condition [38]. Some treatments, such as progressive
heating, can influence the arrangement of fatty acids in
food [39].
The compositions of fatty acids in untreated and
treated M. ciliatum seed oils (UM, BM, RM, and GM)
determined by gas chromatography are presented in
Table 3. As we can see, oleic and linoleic were the
major fatty acids. The untreated sample had 68.15% of
unsaturated fatty acids and 31.40% of saturated fatty
acids. Boiling slightly changed the composition of
unsaturated fatty acids and decreased the content of
saturated fatty acids to 22.82%. Palmitic acid increased
from 6.11% in UM to 31.80 and 21.80% in RM and GM,
respectively. Myristic acid increased from 0.14% in
the untreated seeds to 4.46 and 8.43% in RM and GM,
respectively. Oleic and linoleic acids decreased from
44.87 and 16.84% in the untreated samples to 39.21
and 10.26% in RM and to 29.40 and 9.16% in GM,
respectively. It was clear that roasting and germination
increased the content of saturated fatty acids and
decreased that of unsaturated fatty acids. These results
disagreed with our previous study, where fatty acids
of black cumin seeds did not change with roasting and
boiling [29]. Ali et al. found that the relative content
of polyunsaturated fatty acids decreased while that
of saturated fatty acids increased in groundnut seed
oil exposed to microwave heating [35]. However, the
roasting process slowed down the oxidative deterioration
of polyunsaturated fatty acids.
Tocopherol composition of the oil from boiled,
roasted, and germinated M. ciliatum seeds.
Tocopherols are fat-soluble compounds with vitamin E.
This is a term for eight different molecules, namely α-,
β-, γ-, δ-tocopherol, and the corresponding tocotrienols.
The activity of vitamin E in humans is related to
its antioxidant properties. It is synthesized only in
photosynthetic organisms and acts as a protective
component. Tocopherol has also been found to be crucial
for seed storage and germination [40]. The nutritional
benefits of vitamin E (α-tocopherol) and its importance
in the daily diet have been well documented. The
contents of total tocopherols in treated and untreated
M. ciliatum seeds oil are shown in Table 3. As we can
see, the total tocopherol concentration decreased during
boiling and roasting as a result of heating. However,
it was significantly increased by germination. In
particular, the content of tocopherols in the untreated oil
was 0.11 mg/100 g. This amount was affected equally
by boiling and roasting, decreasing to 0.10 mg/100 g in
both BM and RM. Germination, however, increased it to
0.18 mg/100 g. Our results agreed with Junmin et al.,
who reported that the roasting of sesame seeds at 160°C
for 30 min led to a steady decrease in total tocopherols
and sesamolin [41].
Amino acid composition in boiled, roasted, and
germinated M. ciliatum seeds. Table 4 shows the
amino acid composition in the treated and untreated
M. ciliatum seeds. Generally, amino acids increased
with boiling, roasting, and germination, except for
methionine acid which was decreased by all the
treatments. Aspartic acid and lysine were decreased
by roasting. Total amino acids in the untreated black
mahlab seeds amounted to 22.291 g/100 g. They
increased to 23.894, 22.899, and 24.336 g/100 g in the
boiled, roasted, and germinated samples, respectively.
The roasted sample had the lowest content of total
amino acids due to the decrease in aspartic acid and
lysine. These results were in agreement with those
Table 3 Boiling, roasting, and germination effects on fatty acids (%) and tocopherols (mg/100 g) in Monechma ciliatum seed oil
Fatty acids Untreated mahlab Boiled mahlab Roasted mahlab Germinated mahlab
C12 Lauric 0.859a 1.807b 2.258c 20.427d
C14 Myristic 0.140a 0.124a 4.462b 8.433c
C16 Palmitic 6.116a 6.495a 31.804b 21.806c
C18 Stearic 3.238a 3.236a 6.135b 3.806a
C20 Archidic 9.183a 9.020a – –
C22 Behenic 0.839a 0.829a – –
C23 Tricosanoic 7.033a 6.626b – –
C24 Lignoceric 3.994a 3.709a – –
C16:1 Pamitoleic 0.251a 0.270a 4.083b 2.177c
C18:1 Oleic 44.878a 44.420a 39.216b 29.408c
C18:2 Linoleic 16.480a 16.734a 10.264b 9.159c
C20:1 Eicosenoic 6.545a 6.453a 1.378b 0.73c
Saturated 31.402a 22.826b 45.059c 54.203d
Unsaturated 68.154a 67.881b 54.941c 41.475d
Tocopherol 0.11a 0.10a 0.10a 0.18b
a,b,c,d Means in the same row followed by the same superscript are not significantly different at P < 0.05
Table 4 Boiling, roasting, and germination effects on amino acids in Monechma ciliatum seeds, g/100 g
Amino acid Untreated mahlab Boiled mahlab Roasted mahlab Germinated mahlab
Aspartic acid 2.294 2.349 2.285 2.514
Serine 1.555 1.665 1.576 1.676
Glumatic acid 2.485 3.679 3.386 3.824
Glycine 1.165 1.224 1.243 1.229
Histidine 0.525 0.559 0.586 0.525
Arginine 2.532 2.930 2.889 2.889
Therionine 1.014 1.111 1.092 1.096
Alanine 1.130 1.207 1.170 1.213
Proline 1.157 1.276 1.198 1.306
Threonine 0.695 0.744 0.743 0.750
Valine 1.215 1.318 1.262 1.354
Methionine 0.300 0.000 0.023 0.000
Lysine 1.386 1.453 1.246 1.462
Isoleucine 1.009 1.123 1.061 1.124
Leucine 1.912 2.130 2.003 2.112
Phenylalanine 1.017 1.124 1.134 1.164
Total 22.291 23.894 22.899 24.336
Values are means ± SD
in our earlier work, where we observed extremely
high contents of amino acids in the boiled and roasted
safflower seeds, compared to the fresh samples [13].
This finding was also consistent with that of ELSuhaibani
et al., who found that germination and
cooking of goat pea (Securigera securidaca L.) seeds
increased the proportion of essential amino acids [42].
They also reported that soaking and cooking processes
increased valine, phenylalanine, isoleucine, and leucine,
but reduced methionine and lysine. Our results disagreed
with those reported by Nwosu et al., who found that
boiling black gram (Vigna mungo) seeds for 120 min
generally decreased the concentration of leucine, lysine,
and arginine [12]. Blanching and soaking improved
the concentrations of lysine, isoleucine, and histidine,
compared to the control samples.
CONCLUSION
Generally, most of the nutritional factors were
enhanced by processing treatments. All the treatments
increased protein and amino acids. Boiling and roasting
increased the fat content, while boiling and germination
increased the fiber content. Saturated fatty acids were
higher and unsaturated fatty acids were lower in
the roasted and germinated samples. Minerals were
decreased by all the treatments, except for sodium
which increased in the germinated sample. Our results
can be applied in large-scale research experiments
with Monechma ciliatum seeds used as a food product,
supplement, or ingredient in new products.
CONTRIBUTION
Abdalbasit Adam Mariod conceived and designed
the analysis, contributed data and analysis tools, and
wrote the paper. Eshraga Mustafa Abdalrahman Mustafa
collected the data, performed the analysis, and wrote
the paper. Mahdi Abbas Shakak contributed data and
analysis tools and wrote the paper.
CONFLICT OF INTEREST
The authors declare that there is no conflict of
interest related to this article.
ACKNOWLEDGEMENTS
The first author thanks the Dean of Scientific
Research, University of Jeddah, KSA for the financial
support. The present study was supported by the grant
number UJ-24-18-DR University of Jeddah, KSA.

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