1. The study analyzed levels of minerals and trace elements in seeds, pulp, and skin of pumpkins from three regions in Guyana. Atomic absorption spectrophotometry was used to determine the concentration of elements in the samples. 2. Higher quantities of important minerals like iron, copper, zinc, and phosphorus were found in the seeds compared to the pulp and skin. The seed samples provided over 20% of the daily value for some of these minerals. 3. Concentrations of elements varied between the different pumpkin parts and growing regions, likely due to differences in soil composition and environmental conditions. However, the seeds were consistently shown to be a good source of several essential nutrients.

1. APCBEE Procedia 2 (2012) 135 – 140
2212-6708 © 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of Asia-Pacific Chemical,
Biological & Environmental Engineering Society
doi:10.1016/j.apcbee.2012.06.025
b
D
Abst
The
Atom
were
Ther
the m
skin
a sig
samp
in th
found
meta
since
pollu
preve
© 20
Chem
Keyw
1. In
∗
C
E
Applic
a
Department of Ch
tract
study of this re
mic Absorption
e determined in
re was a signific
means of each e
samples. In ter
nificant differe
ples, respectivel
e seeds of the p
d in the skin sa
als cadmium an
e lead is toxic a
ution of the soil
ent growth of p
012 Published
mical, Biolog
words: AAS, Cucu
ntroduction
Corresponding au
-mail address :pr
ICBF
cation of
Science
V
a
Chemistry Divis
hemistry, Faculty
search is based
Spectrophotom
n the seed, pulp
cant difference
element in the s
rm of the distri
nce in the mean
ly. The results
pumpkins, impl
mples, justifyin
nd lead were pre
at even small le
ls and water ar
prostate cancer c
d by Elsevier B
ical & Enviro
urbita Maxima, M
uthor, Tel: +592
rofessorverma@y
FS 2012: Ap
f Atomic
es: (A St
Vishal Mah
ion, University of
y of Natural Scien
d on the determi
metry. The elem
p and skin (pee
in the means fo
seed for the Be
bution of the el
ns for each elem
show some ele
lying that the n
ng some of the u
esent with the l
evels. The Cad
round the areas
cells in human b
B.V. Selection
onmental Engi
Metals Analysis
2-2226690, Fax
ymail.com
pril 7-8, 20
c Absorp
tudy on
habira
and V
f Guyana, Berbic
nces, University o
Guyana, South
ination of multi
ments, K, Ca, M
el) of three pum
or each of the e
erbice, Essequib
lements in the d
ment. They wer
ements essentia
nutritive value o
use of pumpkin
latter only bein
dmium levels w
of production
beings.
n and/or peer r
ineering Socie
x: +592-222669
12, Bangko
ption Spe
Cucurbi
Vishwa Ve
ce Campus,Berbic
of Guyana,Turkey
America
i-trace elements
Mg, P, Zn, Cu,
mpkins, one fr
lements of inter
bo and the Dem
different parts o
re in higher qua
al to the human
of pumpkin see
n skin, such as,
ng found in the
were the more si
of the crop. H
review under
ety
91
k, Thailand
ectrosco
ita Maxi
ermab
∗
ce, Guyana, South
yen Campus, Pin
s in cucurbita m
, Ni, Fe, Co, an
rom each of the
rest. There wa
merara pumpkin
of the pumpkin
antities in the se
diet such as K
ds is high. Tra
as an ingredien
skin samples,
ignificant of the
However, at lev
responsibility
d
opy in Fo
ma)
h America
Code 101110, G
maxima (pumpk
nd heavy metal
e three countie
s no significant
ns, likewise for
n, it was found t
eed than in the
K, Cu, Zn, P, Fe
aces of all the e
nt in skin cream
making it harm
e two, suggestin
vels below 0.50
y of Asia-Pacif
ood
eorgetown,
kin) by Flame
ls, Pb and Cd
es of Guyana.
t difference in
r the pulp and
that there was
skin and pulp
are abundant
elements were
ms. The heavy
mful as a food
ng significant
0 ppm it helps
fic
Available online at www.sciencedirect.com
© 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of Asia-Pacific
Chemical, Biological & Environmental Engineering Society Open access under CC BY-NC-ND license.
Open access under CC BY-NC-ND license.

2. 136 Vishal Mahabir and Vishwa Verma / APCBEE Procedia 2 (2012) 135 – 140
Cucurbita maxima var. maxima Duchesne, commonly called pumpkin is an orange fruit from the Cucurbita
genus that belongs to the Cucurbitaceae family; which also includes squash and cucumbers. The pumpkin
consists of many parts out of which three are basic; the skin, pulp and the seeds. The pumpkin pulp and seeds
are known sources of treatment for various health problems such as: decreasing cancer risks, anti-
inflammatory, improve bone density and prostate health in elderly men, anti oxidative, prevent kidney stones,
combating depression, and to deter intestinal parasites such as tapeworms etc. [1].
Minerals play an important role in chemical, biological, biochemical, metabolic, catabolic and enzymatic
reactions in the living cells of plants, animals and human beings and they have great significance due to their
tendency to accumulate in the vital human organs over prolonged periods of time. Apart from hydrogen,
carbon, oxygen, nitrogen and sulphur which are the bulk of living matter, there are essential minerals which
are vital in the functioning of the human body. A mineral is an element which is needed in an amount of
more than 100 mg per day like sodium, potassium, magnesium, phosphorous, chlorine, sulphur and calcium
and they are referred to as macro minerals. Those elements which are essential but are needed in amounts less
than 100 mg per day are known as trace elements which include: iodine, iron, copper, manganese, zinc, cobalt,
molybdenum, selenium and chromium [2, 5]. An element is essential when a deficient intake consistently
results in an impairment of a function from optimal to suboptimal and when supplementation with
physiological levels of this element, but not of others, prevents or cures this impairment [3].
Among the trace elements include the heavy metals like lead, mercury, cadmium, which may disturb the
normal functions of the central nervous system, liver, lungs, heart, kidney; resulting in conditions such as
hypertension, abdominal pain, skin eruptions, intestinal ulcer and different types of cancer, if they enter the
body.
The main aim of this study is to investigate the levels of some macro minerals and trace elements in the
seeds, pulp and skin of pumpkin. A study was done by Durdana Rais Hashmi, Shahnaz Ismail and G.H.
Shaikhto assess the level of Fe, Cu, Mn, Zn, and Cr in 18 varieties of vegetables. [4]. However, the research
did not indicate the part of the vegetable which was analysed.
2. Experimental Details:
An Atomic Absorption Spectrophotometry (AAS) was used for the determination of K, Ca, Mg, Cu, Fe, Zn,
Co, Ni, Cd and Pb. This technique is based on digesting the sample by oxidising the organic matter
composition and aspirating (converting the digested sample into a liquid/gas aerosol) the treated sample into a
characteristic flame. Atomic Absorption Spectrophotometer (Perkin Elmer-3030B), equipped with a graphite
furnace was used [3].
3. Open Vessel Wet Digestion
The aim of the digestion was to solubilise the elements of interest in the pumpkin samples. The digestion
process is a combination of oxidation/destruction of organic matter and dissolution of the mineral phase to a
certain extent to bring the elements into solution. In the procedure, samples were treated with a mixture of
concentrated nitric acid and hydrochloric acid. This formed nitrohydrochloric acid (NOCl), according to
equation 1, which had a strong oxidizing effect and gave almost complete dissolution of organic samples.
The NOCl destroyed the organic matter to give carbon dioxide and water.
3 HCl + HNO3 2 H2O + NOCl + Cl2 (1)
Also, as part of the digestion hydrogen peroxide was used. Under acidic conditions hydrogen peroxide
undergoes an equilibrium reaction to give hydroxyl radical (equation 2) which aided in oxidation of organic
matter.

3. 137Vishal Mahabir and Vishwa Verma / APCBEE Procedia 2 (2012) 135 – 140
H2O2 + H+
H2
+
OOH H2O + .
OH (2)
The hydrogen peroxide was also added to remove any NOCl that was present.
In this technique the liquid sample was aspirated, i.e. aerosolized and mixed with combustible gases such
as air acetylene and nitrous oxide acetylene (used for Ca analysis). The mixture was ignited in a flame whose
temperature reached from 2100 to 2800 C. In the combustion process the atoms of the elements of interest in
the sample were reduced to free unexcited ground state atoms which absorbed light at a characteristic
wavelength as illustrated in fig. 1 below. The characteristic wavelength of the elements is specific and
accurate to 0.01 to 0.10 nm. To provide the element with specific wavelengths, a light beam from a lamp
whose cathode is made of the element being determined, was passed through the flame. In addition, the slit
widths for each element were set. Then a device such as a photomultiplier would have detected the reduction
in the intensity of light due to absorption by the analyte, and this would have been directly related to the
concentration of the element in the sample.
4. Determination of Phosphorous in the samples by UV-VIS Spectrophotometry
Phosphates themselves are colourless. Due to the reactive nature of phosphates, they are easily converted
to a coloured compound through chemical reaction which can then be directly detected. This ammonium -
vanadomolybdate reagent will react with phosphates to produce a yellow heteropoly acid compound with an
uncertain formula (though it is thought to be (NH4)3PO4·NH4VO3·16MoO3.). This compound will absorb UV
light at 410nm. Absorbance is directly proportional to concentration of phosphorous.
The values of the detected elements are given the following Tables.
Table 1. showing mg of each element in 100 Grams of fresh seed from the three counties (Berbice, Essequibo and Demerara refer to three
counties in all the places)
Element
mg per 100g Fresh Seed and % DV
Berbice % DV Essequibo % DV Demerara % DV
Calcium 3.778 0.38 2.339 0.23 3.183 0.32
Iron 3.621 20.12 3.652 20.29 5.639 31.33
Magnesium 1.022 0.26 0.613 0.15 0.979 0.25
Copper 0.428 21.40 0.200 10.00 0.297 14.85
Cadmium 1.737 0.00 1.267 0.00 2.272 0.00
Zinc 3.188 21.25 1.822 12.15 2.778 18.52
Cobalt 0.419 0.00 0.634 0.00 1.744 0.00
Nickel 6.676 0.00 5.168 0.00 5.062 0.00
Phosphorous 52.175 5.22 20.440 2.04 26.459 2.65
Potassium 4.469 0.13 4.657 0.13 4.062 0.12
Lead 0.000 0.00 0.000 0.00 0.000 0.00

4. 138 Vishal Mahabir and Vishwa Verma / APCBEE Procedia 2 (2012) 135 – 140
Table 2. showing milligrams of each element in 100 grams of fresh pulp from the three counties
Element
mg per 100g Fresh Pulp and % DV
Berbice % DV Essequibo % DV Demerara % DV
Calcium 5.738 0.57 0.430 0.04 0.519 0.05
Iron 7.077 39.32 0.693 3.85 1.112 6.18
Magnesium 1.483 0.37 0.120 0.03 0.125 0.03
Copper 0.085 4.25 0.006 0.30 0.007 0.35
Cadmium 1.018 0.00 0.178 0.00 0.280 0.00
Zinc 0.217 1.45 0.022 0.15 0.019 0.13
Cobalt 0.000 0.00 0.000 0.00 0.005 0.00
Nickel 5.201 0.00 0.681 0.00 1.273 0.00
Phosphorous 22.954 2.29 2.241 0.22 2.210 0.22
Potassium 24.594 0.70 2.213 0.06 2.235 0.06
Lead 0.000 0.00 0.000 0.00 0.000 0.00
Table 3. showing milligrams of each element in 100 grams of skin from the three counties
Element
mg per 100g Fresh Skin and % DV
Berbice % DV Essequibo % DV Demerara % DV
Calcium 1.060 0.11 1.034 0.10 0.760 0.08
Iron 3.070 17.06 2.871 15.95 3.234 17.97
Magnesium 0.508 0.13 0.513 0.13 0.513 0.13
Copper 0.007 0.35 0.011 0.55 0.004 0.20
Cadmium 1.414 0.00 1.459 0.00 1.593 0.00
Zinc 0.020 0.13 0.017 0.11 0.029 0.19
Cobalt 1.242 0.00 1.535 0.00 1.616 0.00
Nickel 3.081 0.00 2.192 0.00 2.182 0.00
Phosphorous 4.999 0.50 5.375 0.54 4.194 0.42
Potassium 4.654 0.13 4.272 0.12 4.530 0.13
Lead 0.136 0.00 0.260 0.00 0.021 0.00

5. 139Vishal Mahabir and Vishwa Verma / APCBEE Procedia 2 (2012) 135 – 140
Fig. 1. illustrating the distribution of Zinc in the seed, pulp and skin samples of the three pumpkins
5. Discussion
The results obtained in this research showed lower quantities of each element per 100 grams of fresh seed
and pulp samples than in literature. For instance, the average amount of Ca in the pulp of the pumpkins
studied was found to be 0.475 mg per 100g of fresh pulp, whereas, previous research found 21 mg of Ca per
100 grams of fresh pulp. This was so because of the different types of soil conditions under which the crop
was cultivated and the various climatic and weather conditions of the different geographic locations of study
from those of literature. However, the results obtained still showed significant levels of iron, copper, zinc and
phosphorous in the seed samples (high % DV) and can be compared over the three different geographical
areas studied, and with respect to the three different parts of the pumpkin, the seed, pulp and skin. Iron,
copper, zinc, phosphorous and potassium were all important elements which were found in quantities that is
considered high in term of the % DV of each that the pumpkin seeds can provide.It was found that the
elements which are known mineral nutrients, that is, all of the elements analysed for except Cd and Pb, were
in larger amounts in the seed than in the skin and pulp, respectively, of each of the pumpkins.
The level of cadmium seemed to be threatening since the seed samples contained about 1.27 to 2.27 mg Cd
per 100 grams of fresh seed. The pulp contained 0.10 to 0.28 mg Cd per 100 grams of fresh pulp and the skin
had about 1.40 to 1.60 mg Cd per 100 grams of fresh skin. However, cadmium is helpful in preventing the
growth of prostate cancer cells and a level of < 0.50 ppm is safe for human consumption.
Lead was the other heavy metal detected. However, it was found only in the skin samples, but in all three
of the pumpkins.
0
5
10
15
20
25
Seed Pulp Skin
%DailyValue
Part of Pumpkin
Distribution of Zinc in the Seed, Pulp and Skin
Berbice
Essequibo
Demerara

6. 140 Vishal Mahabir and Vishwa Verma / APCBEE Procedia 2 (2012) 135 – 140
Acknowledge
The initial research work was done in the Department of Chemistry, University of Guyana. However,
assistance was provided by other laboratories in the country.
Thanks to Ms. Sandrene Abrams and staff at GGMC for their assistance. Special thanks to Randy Sanichar
and the staff of the Quality Assurance lab at DDL for accommodating me on their AAS instrument. Thanks
also to Kevin and Mr.G. Jafar of GUYSUCO, LBI, and Ms. A. Hinds, Senior Analyst of Food and Drugs Lab,
for use of the UV-Vis Spectrophotometer.
References
[1] http://sennyong.blogspot.com/2010/02/dont-throw-away-pumpkin-skin-and-seeds.html-
[2] Aggett P. J. Trace Elements in Human Nutrition, Journal of Tropical Paediatrics, April 1980, 61-64.
[3] http://www.sciencemag.org/content/213/4514/1332.pdf, pg. 1332.
[4] Raish Hashmid D, Ismail S, Shaikh G.H.Assessment of the level of trace metals in commonly edible vegetable locally available
in the markets of Karachi City, Centre for environmental studies,PCSIR Laboratories Complex, Pakistan, 2007.
[5] Mertz, W. The Essential Trace Elements, AAAS 1981;213:1332-1338.