Kamranga (Carambola—Aver-
rhoacarambola), Datashak (Stem amaranth—Amaranth-
uslividus), Korolla (Bitter gourd—Momordica charantia).
2.3. Sample Preparation
Raw and fresh fruits and vegetables were collected from
local market, weighted and then dehydrated by freezing
(BUCHI Rotavapor R-114, Switzerland). Each of 300
gram of these fruits and vegetables were also taken and
were extracted using Ethanol, n-Hexane, Chloroform,
and Water. These extracts were then converted to powder
form for further analysis.
2.4. Analysis Performed
2.4.1. Determinat ion of F at Binding Capacity (FBC),
Sugar Binding Capacity (SBC)
FBC of was measured using a modified method of Wang
and Kinsella [12]. In brief, Ethanolic food extracts were
at first mixed with soyabean oil and mixed with the help
of a vortex machine (VM-2000, Digisystem Laboratory
Instruments Inc., Taiwan) to disperse the sample. After
centrifugation the supernatant was decanted, the tube was
weighed to identify amount of fat bound to the extract.
SBC was measured by incubating ethanolic food ex-
tract with glucose sample as previously described [13].
2.4.2. Determina tion of Cytotoxic Property and
Vitamin C, Protein and Iron Content
In vitro Cytotoxicity Test was performed using Brine
Shrimp Lethality Bioassay method as described previ-
ously [14]. Previous method for Raw and fresh samples
was also used to determine Vitamin C by HPLC [15].
Food protein content was determined by method de-
scribed by Pellett and Young [16,17]. Iron contents of the
samples were determined by Flame Atomic Absorption
Spectrophotometer with previously described method
[18].
2.4.3. Determination of Lipid Peroxidation
Male Long Evans rats (6 weeks of age) were purchased
from Bangladesh Council of Scientific and Industrial
Research (BCSIR), Dhaka. All the rats were housed in
plastic cages (bedding was wood chips) and acclimatized
to the laboratory conditions (12 h light/dark cycle) for 7
days prior to the commencement of the treatment. The
rats in this study were cared for and sacrificed in accor-
dance with the ethical norms approved by Bangladesh
Association for Laboratory Animal Science. After treat-
ment, the animals were sacrificed and livers were re-
moved. Then livers were perfused with ice-cold saline to
remove blood. These tissues were homogenized in phos-
phate buffer (50 mM, pH 7.4) using Dounce glass ho-
mogenizer (the USA). Lipid peroxidation was determined
by estimating the thiobarbituric acid reactive substances
(TBARs) according to the method of Ohkawa [19].
2.4.4. Determinat ion of Total Phenolics Content
To measure total phenolics contents of the extracts, pre-
viously described method was used without modification
[20].
2.5. Data Analysis
All analysis for samples were carried out in triplicate and
expressed as mean value with their standard error. Graphs
were generated using Microsoft Excel 2007 (Microsoft
Corporation). For statistical analysis, Statistical Package
for Social Science (SPSS, version 17.0, IBM Company)
was used.
3. Results
3.1. Fat Binding Capacity
The Fat binding capacities (FBC) of the samples are
shown in a Bar diagram. Pineapple, Stem amaranth, and
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Food Functionality of Popular and Commonly Consumed Indigenous Vegetables and Fruits from Bangladesh 743
Water spinach samples had high fat binding capacity. But
in Hog Plum and Red amaranth, the capacity was ob-
served in much lower amount (Figure 1).
3.2. Sugar Binding Capacity
Pineapple, Stem amaranth, Pomelo and Carambola pos-
sessed high level of Sugar Binding Capacities. And the
SBC of Water spinach was lowest among all (Figure 2).
3.3. In Vitro Cytotoxicity Test
In the first figure Mortality rate (%) of the Brine shrimp
nauplii in the presence of 0.01 mg/ml dose of sample
extracts. Vincristine sulfate was used as positive control
at 0.5 mg/ml dose, whereas artificial saline water was
served as Negative control. In this experiment Pomelo
showed very high cytotoxic property as 100% mortality
rate was achieved by it. Other extracts showed a mortal-
ity rate 30%. The third Figure shows the Mortality rate
(%) of the Brine shrimp nauplii in the presence of 0.1
mg/ml dose of sample extracts. Again Pomelo showed
very high cytotoxicity as indicated by 100% mortality
rate. But other extracts showed a mortality rate 60%
(Figures 3(a) and (b)).
3.4. Vitamin C Content
Pomelo contains the highest amount of Vitamin C among
all samples and Water spinach contains the lowest amount
Figure 1. Fat Binding Capacity of the samples (%).
Figure 2. Sugar (glucose) binding capacity (%) of the sam-
ples.
(Figure 4).
3.5. Protein Content
The figure represents the protein contents of the samples
using a Bar diagram. Here, Red amaranth contains the
highest amount of protein among all and Pomelo con-
tains the lowest (Figure 5).
3.6. Iron Content
High amount of Iron was found in Stem amaranth, Water
spinach, Red amaranth and Bitter gourd. But Pomelo,
Carambola, Hog Plum and Pineapple possess low amount
of Iron (Figure 6).
(a)
(b)
Figure 3. (a) Mortality rate (%) of brine shrimp nauplii at
0.01 mg/ml dose; (b) Mortality rate of (%) brine shrimp
nauplii at 0.1 mg/ml dose.
Figure 4. Vitamin C contents of the samples (mg/100g).
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Food Functionality of Popular and Commonly Consumed Indigenous Vegetables and Fruits from Bangladesh
744
Figure 5. Protein contents of the samples (g/100g).
Figure 6. Iron contents of the samples (mg/kg).
3.7. Antioxidant Property
In the following figure, the LPO levels of different liver
tissue homogenate were given. In the OS sample, only
oxidative stress was present in the tissue homogenate, so
that high level of Lipid peroxide (LPO) was found. And
in the test samples, food extracts were given in the tissue
homogenate with induced oxidative stress. It was found
that Red amaranth, Pineapple and Pomelo extracts are
capable of lowering the LPO level significantly (Figure
7).
3.8. Total Phenolics Content
The figure showed total phenolics contents of the sam-
ples in a Bar diagram (Figure 8).
Here, Water spinach and Stem amaranth contain high
amount of total phenolics. The amount of total phenolics
in Red amaranth, Bitter gourd, Pomelo and Carambola
were also higher. Pineapple contains the lowest amount
of total phenolics among all the samples.
4. Discussion
Bangladeshi indigenous fruits, grains, vegetables etc. had
been reported to have immense therapeutic and medicinal
values [21,22], but no systematic approach had been
made to generate a functional food database so far. Thus
as a first step some commonly used parameters, to judge
food functionality, were analyzed, like Moisture content,
Fat and Glucose binding capacity of foods, Cytotoxicity
Figure 7. LPO concentrations (nMol/100µl/mg protein).
Figure 8. Total ph enolics contents o f the s amples (mg GAE/g).
of that food, Antioxidant content, Micro and Macro nu-
trient content.
Optimum moisture content is necessary for a food’s
freshness and nutritional balance. Also, food industries
require a minimum or maximum percentage of moisture
on certain foods in order to pack and/or label [23]. In this
study it was found that the moisture content of Hog Plum
was the lowest (84.5%). And the moisture content of
Bitter gourd was the highest (92.25%) (data not shown).
This means that by eating these foods, one can feel fuller
on a smaller amount of calories than foods with less wa-
ter content. Therefore, these are excellent foods for los-
ing weight or maintaining current weight. Another health
benefit is that they help to keep skin hydrated, which
leads to healthy, glowing skin.
Determination of FBC is essential for the discovery of
anti obesity property in food. In this study it was found
that the FBC of Pineapple was the highest (500%) among
all the samples under study. The FBC of Stem amaranth
was also found high (361.9%). And the FBC of Hog
Plum was the lowest (96.3%). It was found that fat bind-
ing capacity of patented fibre complex from Opuntiafi-
cusindica was only 72%, which is much lower than these
indigenous Bangladeshi foods (www.proactol.com). So it
can be stated that Pineapple and Stem amaranth have
huge potentials against obesity (Figure 1).
Sugar Binding Capacity determines the sugar removal
ability of a food from a system and can be used against
high blood sugar level of a diabetic patient [24]. In this
study, it was found that Pineapple, Stem amaranth and
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Food Functionality of Popular and Commonly Consumed Indigenous Vegetables and Fruits from Bangladesh 745
Pomelo have potential sugar binding capacity: 270.891%,
237.6237% and 221.7821% respectively. And the lowest
SBC was found in Water spinach (51.49%). As in Bang-
ladesh there is a high prevalence of Diabetics, so these
samples can be considered as new dimension to control
high blood sugar level at a low cost for developing coun-
tries (Figure 2).
Cytotoxicity determination helps to detect the ability
of a sample to destroy cells. This functionality helps to
determine anti tumor and chemotherapeutic agents [14].
In the study, it was found that, Pomelo has a very strong
cytotoxic property with 100% mortality rate. And the
lowest activity was found in Red amaranth (0%). It indi-
cates the presence of cytotoxically active compounds in
Pomelo at a significant quantity. In future it will be fur-
ther investigated to see whether these are more cytotoxic
to the abnormal cells than to the normal cells or not
(Figure 3).
Ascorbate is a vital nutrient and acts as cofactor of en-
zymes or antioxidant against oxidative stress [25]. In the
study, it was found that, Pomelo had a very high level of
Vitamin C (155 mg/100g). Also this was true for Bitter
gourd (90 mg/100g). Lowest amount was found in Water
spinach (20 mg/100g). Among them Red and Green Hot
Chili Peppers contained highest Vitamin C (242 mg/100g).
As these study foods contain high amount of Vitamin C
(the recommended daily allowance of Vitamin C is 75 -
90 mg), they may be used to cure arthritis and other joint-
related diseases or pain, fight against age-related memory
loss, macular degeneration, cataracts and other eyesight
problems—complications very much common among the
people aged 65 or over in Bangladesh (Figure 4).
Protein is an important macronutrient. Among all the
vegetables and fruits Bracken (20 g/100g) and Apricot
(9.2 g/100g) contain highest amount of proteins
(http://www.wholefoodcatalog.info). In the study, it was
found that, Red amaranth has the highest level of protein
among all other samples (4.31 g/100g). And the lowest
amount of protein was found in Pomelo (0.57 g/100g).
As proteins are necessary in animals' diets, it is specu-
lated that these available country foods may help to ful-
fill the protein requirements of Bangladeshi poor people,
to whom it is very difficult to buy costly protein rich
foods (Figure 5).
Iron is an essential micronutrient and key component
of many proteins in the study, it was found that, Stem
amaranth contains very high level of Iron (1855.67 mg/
kg). Also Water spinach, Red amaranth and Bitter gourd
have significant levels of iron content: 998.41 mg/kg,
838.46 mg/kg and 733.68 mg/kg respectively. The lowest
amount of Iron was found in Pomelo (159.09 mg/kg). It
is estimated that, Men need around 8 mg of iron in their
daily diet and women need up to 18 mg (or 27 mg if
pregnant) (www.betterhealth.vic.gov.au). Even though
these low requirements iron deficiency Anemia is very
much prevalent in Bangladesh. So, these high iron con-
taining study foods can play a vital role against iron defi-
ciency anemia (Figure 6).
Lipid peroxidation refers to the oxidative degradation
of lipids and may cause hemolysis by rupturing red blood
cell membranes [26]. In addition, end-products of lipid
peroxidation may be mutagenic and carcinogenic [27]. It
was found that, Glutathione peroxidase 4 (GPX4) knock-
out mice do not survive past embryonic day 8, indicating
that the removal of lipid hydroperoxides is essential for
mammalian life [28]. In this research it was studied that
whether the food extracts under study inhibite lipid per-
oxidation or not. On basis of the results of thiobarbituric
acid reactive substance (TBARS) assay, this study clearly
indicates that all the food extracts under study decreased
the level of LPO. Among them, Red amaranth, Pineapple
and Pomelo decreased the LPO level noticeably. The
LPO level of the oxidative stress induced sample was
7.064 nMol/100µl/mg protein. But the levels of LPO in
the samples containing the extracts of Red amaranth,
Pineapple and Pomelo were 0.383, 0.599, and 0.674
nMol/100µl/mg protein respectively. So these food ex-
tracts have strong anti oxidative properties and are capa-
ble of lowering LPO level considerably and thus can be
used to minimize stress and oxidative radical mediated
injuries in a cost effective way (Figure 7).
Natural phenols are small molecules containing one or
more phenolic group. Most are known to have an antioxi-
dant activity and give protection against heart disease
and cancer. That’s why foods containing natural phenols
are generally considered as health food. In the study, it
was found that, Water spinach and Stem amaranth had a
high level of total phenolics contents: 59.339 and 55.728
mg GAE/gm extract respectively. And Pineapple had the
lowest phenolics content among all: 11.006 mg GAE/gm
extract. These data suggests that Water spinach and Stem
amaranth can be consider as health food (Figure 8).
From this study it was observed that the most promis-
ing functional foods are Red amaranth, Pomelo and Pine-
apple. When we statistically analyze these data, it was
found that there were significant correlation between Iron
content with protein content (p = 0.04) and with phenol-
lics content (p = 0.02). We also found that a significant
negative correlation between LPO content and sugar
binding capacity to each other (p = 0.007).These results
suggests that indigenous foods of Bangladesh can be act
as potential functional food and there functionality may
depends on other property of that food also. We will plan
to test these foods in vivo for further analysis (like to
identify their anti-diabetic, anti-carcinogenic, anti hyper-
tensive properties).
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Food Functionality of Popular and Commonly Consumed Indigenous Vegetables and Fruits from Bangladesh
746
5. Acknowledgements
This work had been funded by follow up research grant
of the United Nation University (UNU)-Kirin for fellows
of session-2010-11. The Authors expressed their sincere
gratitude to the authorities of the National Food Research
Institute (NFRI),2-1-12 Kannondai, Tsukuba, Ibaraki
305-8642, Japan for their all out support.
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