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Chemical evaluation of the de-seeded oil pumpkin (Cucurbita pepo L. var. Styriaca) biomass


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Oil pumpkin (Cucurbita pepo L. var. Styriaca) is an economically important horticultural plant cultivated for oil production. After harvesting seeds, the residual biomass has a limited application and is usually left in the field. An experimental study was performed to evaluate the chemical composition of the seeded fruit oil pumpkin biomass (OP) dried by solvent-exchange using ethanol. The sugar composition of polysaccharides obtained by sequential extraction with water and dilute alkali indicated the prevalence of pectic polysaccharides. Hemicelulloses were released in higher amounts in the alkaline step. The chemical composition of OP and its individual tissues (peel, flesh and hairy flesh) was investigated and compared to the corresponding preparations of standard pumpkin (SP, Cucurbita pepo L.). The content of components (on oven-dry basis), calculated from the analysis data of the individual tissues, was estimated for OP: 7.9 % ash, 7.6 % Klason lignin, 19.3 % pectin (as uronic acids), 34.1 % neutral carbohydrates, and 27.4 % α-cellulose and for SP: 6.4 % ash, 4.0 % Klason lignin, 20.9% pectin (as uronic acids), 38.1% neutral carbohydrates, and 29.2 % α-cellulose, respectively. The OP biomass showed a higher proportion of hemicelluloses.
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Chemical Papers 63 (4) 406–413 (2009)
DOI: 10.2478/s11696-009-0035-5
Chemical evaluation of seeded fruit biomass of oil pumpkin
( L. var. )
Zuzana Košťálová, Zdenka Hromádková*, Anna Ebringero
Institute of Chemistry, Center for Glycomics, Slovak Academy of Sciences, Dúbr a vská cesta 9, 845 38 Br atislava, Slovakia
Received 18 September 2008; Revised 7 November 2008; Accepted 11 November 2008
Oil pumpkin (Cucurbita pepo L. var. Styriaca) is an economically important horticultural plant
cultivated for oil production. After harvesting seeds, the residual biomass has a limited application
and is usually left in the field. An experimental study was performed to ev aluate the chemical
composition of the seeded fruit oil pumpkin biomass (OP) dried by solven t-exchange using ethanol.
The sugar composition of polysaccharides obtained by sequential extraction with water and dilute
alkali indicated the prevalence of pectic polysaccharides. Hemicelulloses were released in higher
amounts in the alkaline step. The chemical composition of OP and its individual tissues (peel,
flesh and hairy flesh) was in vestigated and compared to the corresponding preparations of standard
pumpkin (SP, Cucurbita pepo L.). The content of components (on ov en-dry basis), calculated from
the analysis data of the individual tissues, was estimated for OP: 7.9 % ash, 7.6 % Klason lignin,
19.3 % pectin (as uronic acids), 34.1 % neutral carbohydrates, and 27.4 % α-cellulose and for SP:
6.4 % ash, 4.0 % Klason lignin, 20.9% pectin (as uronic acids), 38.1% neutral carbohydrates, and
29.2 % α-cellulose, respectively. The OP biomass showed a higher proportion of hemicelluloses.
2008 Institute of Chemistry, Slov a k Academy of Sciences
Keywords: Cucurbita pepo L. var. Styriaca, seeded pumpkin fruit, polysaccharides, pectin
During the last decades, great attention has been
given to the concept of sustainable economic systems
including the valorization of local biomass. Agricul-
tural byproducts are cheap and abundant lignocellu-
losic feedstocks for the production of polysaccharide-
based materials as well as of antioxidants and other
compounds used in food, medicine and other areas.
Pumpkin (Cucurbita pepo L. var. Styriaca) is an eco-
nomically important horticultural plant cultivated for
oil production in Slovakia. This hull-less seed pumpkin
variety discovered in the late 19th Century (Teppner,
2000) is a spontaneous mutant of standard pumpkin
(Cucurbita pepo L.). After harvesting seeds, the resid-
ual biomass has a limited application and is usually
left in the field.
Pumpkin has been cultivated throughout the world
as vegetable as well as for medical purposes. Its phar-
macological activities comprising antidiabetic, antihy-
pertensive, antitumor, antimutagenic, immunomodu-
lating, antibacterial, antihypercholesterolemic, intesti-
nal antiparasitic, antalgic, and antiinflammation ef-
fects, and utilization possibilities of various pumpkin
species have been reported (Fu et al., 2006; Esuoso et
al., 1998). Important physiological effects of pump-
kin fruit and seeds are connected with the present
proteins, oil and antioxidants (Fahim et al., 1995;
Murkovic et al., 2002), and the cell wall polymers con-
stituting the dietary fiber components (Essien et al.,
1992; Ratnayake et al., 1999; Li et al., 2005; Fu et
al., 2007; de Escalada Pla et al., 2007). Recent studies
werefocusedontheextraction and characterization
of pectin-rich fiber products isolated from pumpkin
(Curcubita moschata) (de Escalada Pla et al., 2007),
and of pectins from other pumpkin species (Fu et al.,
2007; Shkodina et al., 1998; Jun et al., 2006). Their
biological activity (Jun et al., 2006), viscosity and
gelling properties (Evangeliou et al., 2005; Ptitchkina
et al., 1994), and applicability as bread making addi-
*Corresponding author, e-mail:
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Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009) 407
tive (Ptitchkina et al., 1998) were also explored. The
studies on pumpkin fruits are non-systematic as the
concerned texture changes during storage and cook-
ing of C. maxima (Ratnayake et al., 1999), and chem-
ical and biochemical changes of C. moschata affected
by osmotic stress (de Escalada Pla et al., 2005). The
bioactive materials of pumpkins were suggested to be
polysaccharides, including protein-bound polysaccha-
rides (Fu et al., 2006, 2007). In addition, pumpkin
polysaccharides were reported to have significant an-
tioxidant potential (Fu et al., 2006). From this point of
view, phenolic substances such as phenolic acids and
lignin, which might be covalently linked to cell wall
pectins and hemicelluloses, are of great importance
(Oosterveld et al., 2000).
Among the various Cucurbita species, there are
only a few reports on C. pepo and its hull-less seed mu-
tants dealing with their history, histology, and genet-
ics of the whole plants (Teppner, 2000) and their seed
coat (Stuart & Loy, 1983; Zraidi et al., 2003). Chemi-
cal composition has only been reported for their seed
coats (Stuart & Loy, 1983), and the phenolics and cell
wall polysaccharides from pumpkins (Cucurbita sp.)
were studied to evaluate the fruit product authenticity
(Kurz et al., 2008). In continuation of our studies con-
cerning the exploitation of lesser-known and underuti-
lized agricultural plants, the aim of the present work
was to create a sound basis for future technological ap-
plications of the fruit biomass from oil pumpkin, par-
ticularly the non-cellulosic polysaccharides. For this
purpose, chemical composition of the seeded oil pump-
kin biomass and of its different tissues was studied and
compared to those that of the standard pumpkin tis-
sues. Emphasis has been put on the pectic polysaccha-
rides and hemicelluloses as well as on the associated
phenolic components.
Standard pumpkin (Cucurbita pepo L.) and hull-
less seed oil pumpkin (Cucurbita pepo L. var.Styri-
aca) were harvested in September 2005 at the local
fields belonging to the scholar enterprise Kolíňany in
Kolíňany (Slovakia). Gallic acid and d-galacturonic
acid were obtained from Fluka (Germany). All other
chemicals used in this study were of analytical grade.
The citrus pectate and methyl esterified citrus pectin
(DE 20 %) used as standards were prepared and do-
nated by Dr. A. Malovíko (Institute of Chemistry,
Slovak Academy of Sciences, Bratislava, Slovakia).
Fresh fruits of standard pumpkin (SP) and oil
pumpkin (OP) were cleaned with tap water and then
rinsed with distilled water. After halving the fruits,
the seeds were carefully removed and the resulting
biomass of SP and OP were grated into small pieces
(0.6–0.8 mm). The grated OP was dewatered by: (i)
drying on air at 24
C for 2 days yielding air-dried
biomass (DOP) and (ii) the solvent exchange method
using ethanol to remove water from OP. To the OP
biomass, containing 90 % of water, 95 % ethanol was
added and after 2.5 h, the ethanol–water extract was
decanted. To the residue, another portion of 95 %
ethanol was added and after 3 h, the suspension was
decanted again. The insoluble fiber residue and solu-
tions from decantation were filtrated. After the last
treatment, the insoluble fiber mass was dried on air
yielding ethanol-dried biomass (EOP). The filtrate
and decanted solutions were collected and evaporated
under vacuum at 40
C yielding the ethanol-soluble
fraction which was further dialyzed in cellulose tubing
(MWCO 12.4 kg mol
, Sigma–Aldrich). The reten-
tate was lyophilized yielding fraction of EsOPD. This
fraction was further separated into water-soluble (ws-
EsOPD) and insoluble parts (wis-EsOPD) by a disso-
lution of EsOPD (0.2 g) in 10 mL of distilled water at
C for 3 h and a following centrifugation at 12000
for 7 min. Both fractions were lyophilized.
Distilled water (35 mL) was added to EOP (0.5 g)
and left to soak overnight at 24
C followed by stir-
ring for 1 h at 35
C. The suspension was subjected
to centrifugation at 12000 min
for 7 min. The su-
pernatant was dialyzed using a cellulose membrane
(MWCO of 12.4 kg mol
, Sigma–Aldrich) against
distilled water to a constant conductivity value of the
diffusate which was lyophilized yielding the water-
soluble fraction EOP-W. The water-insoluble pump-
kin residue was further extracted with 1 % NaOH (31
mL) for 1 h at 60
C under stirring. The alkali-insoluble
residue (EOP-R), separated from the extract by cen-
trifugation, was acidified with acetic acid extensively
washed with distilled water and oven-dried at 105
for 3 h. The alkaline soluble extract was neutralized
with acetic acid to pH approximately 7.3, subjected
to dialysis, and the retentate was lyophilized yielding
the alkali-soluble fraction EOP-A.
From the seeded pumpkin halves of both fruits, the
peel (P) was manually cut off. Then, the mesocarp
tissue flesh (F) was separated from the endocarp
tissue hair-like flesh (HF), where the seeds had been
located. The obtained pumpkin tissues were grated
and dried according to procedure (ii). The residual
moisture content of all dried samples was taken as
weight loss after heating at 105
Sugar composition analysis of the pumpkin sam-
ples was performed by the two-step acid hydrolysis
(72 % H
at ambient temperature for 2 h and after
dilution to 4 % H
for 4 h under reflux). The acid-
insoluble residue obtained by filtration was quantified
gravimetrically as Klason lignin. The polysaccharide
fractions were hydrolyzed with 2 M trifluoroacetic acid
under reflux for 2 h. The sugars released by both
hydrolytic procedures were qualitatively analyzed by
paper chromatography (PC) using systems S
acetate–pyridine–water (ϕ
acetate–acetic acid–formic acid–water (ϕ
4). The neutral sugar composition of hydrolyzates was
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408 Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009)
determined by GC of their alditol trifluoroacetates us-
ing a Hewlett–Packard Model 5890. The above men-
tioned methods were described in more details in a
previous paper (Hromádková & Ebringerová, 2003).
The total carbohydrate content (TC) was deter-
mined by a modified version of the phenol–sulfuric
acid method (Rao & Pattabiraman, 1989), which com-
prises also treatment of the aqueous suspension of the
sample with concentrated sulfuric acid. A part of the
hydrolyzate was diluted with distilled water and then
sulfuric acid and phenol were added. Glucose was used
as a standard.
The uronic acid content (UA) was determined us-
ing 3-hydroxybiphenyl as a reagent (Ahmed & Labav-
itch, 2007) and galacturonic acid as a standard.
The content of extractive substances (ES) was de-
termined gravimetrically by Soxhlet extraction with
chloroform–ethanol (ϕ
= 2 : 1) for 6 h. The nitro-
gen content was determined using an elemental an-
alyzer Fisons instrument EA1108, and the ash con-
tent was determined gravimetrically by combustion at
C. The total phenolics content (TP) was de-
termined by the Folin–Ciocalteau assay (Thaipong et
al., 2006) using gallic acid as a calibration standard.
The α-cellulose content was determined by modifica-
tion of the novel hydrolytic technique based on hydrol-
ysis with an acetic acid–nitric acid mixture (Brendel et
al., 2000). This modification introduced a new extrac-
tion step with diluted acetic acid adjusting pH to 2.5
in order to enhance the release of pectic polymers as
well as the centrifugation speed (12000 min
). Spec-
trophotometric measurements were carried out on a
Spectronic 20 Genesis (Rochester, USA) spectrome-
ter. Fourier transform infrared (FTIR) spectra were
obtained on a NICOLET Magna 750 spectrophotome-
ter with a DTGS detector and OMNIC 3.2 software
using 128 scans at the resolution of 4 cm
ples (2.0 mg) were pressed into KBr pellets (200 mg).
Results and discussion
Effect of the drying method
The effect of drying on the composition of grated
OP biomass was tested using (i) drying on air at
ambient temperature and (ii) solvent exchange with
ethanol (Fig. 1). Analytical data of the obtained sam-
ples are summarized in Table 1. In comparison to the
air-dried biomass (DOP), the ethanol-dried biomass
(EOP) showed a significantly higher content of Kla-
son lignin and higher proportion of glucose, whereas
the content of extractive substances (ES) was similar
and protein content was slightly lower. Glucose repre-
sents mainly cellulose, some amounts might however
originate from the hemicellulose cell wall components
(xyloglucan, glucomannan) (Ebringero et al., 2005)
as well as from starch found in pumpkins (de Escalada
Pla et al., 2005). It has to be noted that the Klason
Fig. 1. Scheme of drying and isolation of easy extractable non-
cellulosic polysaccharides from the seeded fruit biomass
of oil pumkin (OP).
lignin values are overestimated because proteins, ash
and some phenolics forming acid-insoluble substances
during the hydrolytic step contribute to these values.
As expected, with respect to other reports on pump-
kin fruits (de Escalada Pla et al., 2005, 2007), EOP
is rich in pectic polysaccharides indicated by the high
content of uronic acids consisting predominantly of
galacturonic acid (detected by PC in system S
arabinose and galactose, both constituting the neutral
polysaccharide side chains of the pectin molecule (Vor-
agen et al., 1995). High proportion of xylose in DOP
indicates the presence of xyloglucan, xylan, and/or the
xylogalacturonan component of pectic polymers found
in watermelone (Mort et al., 2002).
Differences in composition of DOP and EOP can
be explained by the removal of aqueous-ethanol sol-
uble compounds (EsOPD) during the ethanol treat-
ment and the following dialysis step. This fraction con-
tained uronic acids (10 %), arabinose, and galactose
as dominating neutral sugars, and minor amounts of
mannose, rhamnose, glucose, and xylose. Its protein
content, estimated from the nitrogen content w(N) =
(6.25 %), was more than three times higher than that
in both DOP and EOP (Table 1). A part of nitro-
gen might belong to polyamines found in the fruit of
normal and a hull-less seed varieties of pumpkin (Be-
zold et al., 2003). The sugar composition indicated
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Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009) 409
Tabl e 1 . Effect of drying on the oil pumpkin biomass (OP) dried on air (DOP) and by solvent exchange with ethanol (EOP)
Content, w
Neutral sugars, x
/mole %
Ash Protein ES
Rha Ara Xyl Man Glc Gal
DOP 2.0 7.9 11.3 6.6 14.4 tr 6.3 28.6 3.3 46.5 15.3
EOP 6.8 6.1 8.8 6.9 20.4 tr 4.4 10.9 4.4 75.0 5.3
0 nd 35.0 3.6
10.1 4.2 37.9 4.1 12.4 5.2 36.2
Analytical data are means of at least three experiments. a)Calculatedonair-drybasis;b) Klason lignin as acid-resistant portion
after hydrolysis; c) substances isolated by chloroform–ethanol extraction; d) uronic acids determined by the 3-hydroxybiphenyl
assay; e) ethanol-soluble fraction from the ethanol drying process after removal of dialyzable substances; f ) total phenolics (TP)
determined by the Folin–Ciocalteau assay; tr traces detectable by PC, nd not determined.
Fig. 2. FTIR spectra of (a) oil pumpkin biomass dried on air
(DOP) and by (b) ethanol exchange (EOP), (c) aqueous
ethanol-soluble material after dialysis (EsOPD), (d)
wis-fraction of EsOPD and (e) ws-fraction of EsOPD;
) amide II band; AG typical spectral pattern of
that EsOPD comprised fragments formed through
metabolic pathways from various pectic polysaccha-
ride components (homogalacturonan, rhamnogalac-
turonan RG-I, xylogalacturonan, arabinan, galactan,
and arabinogalactan) and glycoproteins rich in ara-
binose and mannose (Fu et al., 2007). These were
present in the water phase of the grated pumpkin
biomass comprising up to 95 % of the fresh pump-
kin tissues (Mc Cance & Widdowson, 1991) and they
were not precipitated by an addition of ethanol during
the solvent-exchange drying process.
FTIR spectrum of the ws-EsOPD fraction (Fig. 2)
confirmed this suggestion showing absorption bands
of carboxylate (1604 cm
) and ester (1740 cm
groups and bands in the mid-infrared region typical
of pectic arabinogalactans at 1074 cm
, 1045 cm
and 864 cm
(Kačuráková et al., 2000). The small ab-
sorption band at 1510 cm
in the spectrum of EOP
is related to aromatic ring vibrations, confirming the
presence of lignin and other phenolics. The band at
1546 cm
corresponds to N—H deformation (amide
II) vibration of protein and/or polyamine (amide I vi-
bration of protein might be overlapped by the car-
bonyl stretching) and those at 2958–2854 cm
methyl and methylene stretching vibrations of lipids,
respectively. As can be seen, proteins and lipids are
accumulated in the insoluble fraction (wis-EsOPD).
This is in accordance with the, only slightly, increased
level of extractives in EOP in comparison to DOP (Ta-
ble 1), caused by partial removal of extractives during
the ethanol-drying treatment. In accordance with the
aim of this study, drying by solvent exchange has the
advantage of alcohol-insoluble residue (EOP) contain-
ing the bulk cell wall polymers, which is of importance
for the characterization of non-cellulosic polysaccha-
ride components of the oil pumpkin biomass.
Fractional extraction of seeded oil pumpkin
fruit biomass (EOP)
In order to isolate easily extractable non-cellulosic
polysaccharides, EOP was subjected to a simple two-
step extraction procedure using water in the first and
1 % NaOH at elevated temperature in the second step
(Fig. 1). The yield and analytical data of the released
cell wall polysaccharide fractions EOP-W and EOP-
A, respectively, and of the extraction residue (EOP-
R)aresummarizedinTable2. Extracted polysaccha-
rides contained about 2–3 % of total phenolics (TP),
however, no Klason lignin was determined. This lignin
(20.9 %) remained in the extraction residue EOP-R.
The sugar composition of both fractions unequivocally
indicated the prevalence of pectic polymers with a
high proportion of arabinose and galactose represent-
ing neutral side chains in both fractions. These agrees
with the results of Ptitchkina et al. (1994), who found
a high level of neutral sugar side chains in pumpkin
pectin. Xylose-containing hemicelluloses (xyloglucan
and xylan) were released in somewhat higher amounts
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410 Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009)
Tabl e 2 . Yield and analytical data of non-cellulosic water-extractable (EOP-W) and alkali-extractable (EOP-A) polysaccharide
fractions of oil pumpkin biomass (EOP) and its extraction residue (EOP-R)
/% Neutral sugars, x
/mole %
Rha Fuc Ara Xyl Man Glc Gal
EOP-W 2.1 2.5 2.1 27.9 3 2 34 11 6 11 33
EOP-A 12.9 3.5 3.3 36.1 5 2 41 18 0 13 20
EOP-R 53.2 nd 20.9
nd 0 0 0 3 5 88 4
Analytical data are means of at least two experiments. a) Related to oven-dried EOP; b) calculated on air-dry basis; c) phenolics
determined as Klason lignin. TP total phenolics content, nd not determined. See footnote in Table 1.
Tabl e 3 . Analytical data of peel (P), flesh (F), and hair-like flesh (HF) of standard pumpkin (SP) and oil pumpkin (OP) biomasses
Content, w
Neutral sugars, x
/mole %
UA Rha Fuc Ara Xyl Man Glc Gal
SP/P 8.4 20.2 7.8 33.8 2.8 1.6 26.2 8.8 7.7 33.0 19.9
SP/F 5.5 20.7 4.6 62.4 1.6 0.7 9.2 7.3 6.5 58.1 16.6
SP/HF 9.0 23.8 7.9 45.8 4.5 1.0 9.1 12.3 5.4 53.5 14.2
OP/P 11.0 20.1 9.2 31.8 10.0 Tr 13.4 13.0 8.1 43.9 11.6
OP/F 6.6 18.9 4.7 67.7 1.9 0.9 4.3 5.8 10.3 68.0 8.8
OP/HF 10.0 21.8 6.0 50.2 4.2 1.7 13.3 17.5 6.4 39.4 17.5
Values are means of at least two experiments. a) Calculated on oven-dry basis; b) determined by the modified phenol–sulfuric acid
assay. See footnote in Table 1.
Fig. 3. FTIR spectra of (a) water-extracted (EOP-W) and (b)
alkali-extracted (EOP-A) polysaccharides of oil pump-
kin biomass, (c) citrus pectate, and (d) 20 % methyl
esterified citrus pectin; (
) amide II band; P typical
pectin bands.
in the alkaline step. Fucose is indicative of xyloglu-
can which is the predominating hemicellulose compo-
nent in pumpkin primary cell walls (Ratnayake et al.,
FTIR spectra of the EOP-W and EOP-A frac-
tions (Fig. 3) confirmed the prevalence of pectin by
intense bands at 1144 cm
, 1100 cm
, 1070 cm
1047 cm
, 1017 cm
, and 956 cm
et al., 2000). Supported by the spectral pattern of
standards (methyl esterified pectin and pectate), data
in Fig. 3 indicate that the pectin polysaccharides in
EOP-W are partially methylated (νC
1740 cm
), while those in the EOP-A fraction ap-
pear to be in the carboxylate form (ν
1604 cm
). The typical bands of xylan (1043 cm
1082 cm
, 1162 cm
), xyloglucan (1153 cm
, 1118
, 1078 cm
, 1041 cm
), and arabinogalactan
(1139 cm
, 1074 cm
, 1045 cm
) (Kačuráková et
al., 1999, Kačuráko et al., 2000) are overlapped by
pectin bands. Sugar composition of EOP-R with pre-
vailing glucose and high lignin content corresponds to
the crude lignin-containing cellulose.
Composition of the main pumpkin tissues
In the further part of the study, the fresh seeded
fruit biomasses of SP and OP were separated into
three tissues peel (P), flesh (F), and inner hair-like
flesh (HF), with the aim to characterize their contri-
bution to the composition of the whole biomass. The
separated tissues were dried by the ethanol method
described above for OP and were, therefore, accom-
panied by the mass loss caused by dissolution and
decantation of low-molar mass, ethanol-soluble com-
Relative proportions of the isolated tissues and
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Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009) 411
Tabl e 4 . Comparison of SP and OP composition data derived from the proportions and compositions of the P, F, and HF tissues
Content, w
SP 6.4 4.0 20.9 34.1 27.4
OP 7.9 7.6 19.3 38.1 29.2
Composition data (in % on oven-dry basis) are calculated from analysis data of the P, F, and HF tissues (Table 3); a) expressed
as uronic acid content; b) neutral carbohydrates (NC) content was calculated as a difference between total carbohydrates content
and the content of pectin.
Fig. 4. Content (% of oven-dried sample) of lignin (full)
and polysaccharide components pectin, expressed as
uronic acids content (dotted), neutral carbohydrates
(empty), and α-cellulose (dashed) in the peel (P), flesh
(F), and hair-like flesh (HF) of standard pumpkin (SP)
and oil pumpkin (OP). The relative proportions of the
tissues are expressed in percentage.
their main components are illustrated in Fig. 4 and
summarized in Table 3. In comparison to SP, OP
showed a higher proportion of P (27 % vs. 20 %),
about the same proportion of F (69 % vs. 70 %) and
a lower proportion of HF (4 % vs. 10 %). As shown in
Fig. 4, the distribution patterns of lignin, pectin (as
UA content), and α-cellulose components, when com-
paring the corresponding P, F, and HF tissues of OP
and SP, are very similar, but there are differences in
the content of the components.
Differences in the lignin content between SP and
OP were observed in all tissues. The peel of both, SP
and OP, was rich in lignin; its content was by about
amounts of lignin, but its amount in OP was twice that
in SP. On the contrary, HF of the oil cultivar (mutant)
showed a very low content of lignin (2.2 % vs. 5.3 %
in SP) and a higher content of extractives (7.9 % vs.
6.0 % in SP, Table 3). The differences observed in
the lignin content between HF of SP and OP are in
correlation with the lignin content reported for the
seed coat (testa) of standard pumpkin and its hull-
less mutant (Stuart & Loy, 1983; Bezold et al., 2003),
which was lower in the seed coat of the mutant.
In case of peel tissues from OP and SP, there is
a discrepancy between the contents of neutral carbo-
hydrates and α-cellulose. This can be explained by
the different analytical methods used. Determination
of the total carbohydrate content by colorimetry is
strongly affected by the presence of phenolics, pro-
teins, etc., which might contribute to the color change
in the phenol–sulfuric acid test (Wang et al., 2008).
However, during the analysis of α-cellulose, these com-
ponents were removed from the fiber residue.
The flesh of OP and SP represents 69–70 % of their
biomass. For this tissue, OP and SP showed a similar
pectin content (18.9 % and 20.7 %), but the amount
of neutral carbohydrates and their sugar composition
in OP (Table 3) indicated a higher content of hemi-
cellulosic polysaccharides. However, the pectin compo-
nent had a lower degree of branching by arabinose and
galactose-containing polysaccharides. The higher pro-
portion of non-cellulosic polysaccharides in the flesh
of OP is evident from larger differences between the
neutral carbohydrates content (NC) and α-cellulose.
In addition, the HF of OP showed a greater difference
between the neutral polysaccharides and the pectin
contents in comparison to those of SP.
The most distinct differences were observed with
the HF fractions of OP and SP not only considering
the lignin but also the polysaccharide components. In
comparison to OP, SP showed higher content of glu-
cose and uronic acid. The content of hemicelluloses,
estimated as the sum of xylose and manose, was higher
in OP. It can be presumed that the mutation process
affected not only the composition of seed coat (Stu-
art & Loy, 1983; Bezold et al., 2003) but also of the
endocarp flesh tissue, where the seeds are located.
In comparison with SP, larger amounts of extrac-
tives were present in the peel of OP (Table 3). How-
ever, their amount was considerably lower in the HF
tissue of the hull-less mutant (OP), showing a similar
relation as that of the above mentioned lignin content.
Based on the total carbohydrate content and the
sugar composition (Table 3), the distribution of non-
cellulose cell wall polysaccharides of the P, F, and HF
tissues was very roughly estimated. The uronic acids
content, attributed to pectin, varied from 20.2 % to
23.8 % and 18.9 % to 21.8 % of the SP and OP tissues,
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412 Z. Košťálová et al./Chemical Papers 63 (4) 406–413 (2009)
respectively, and was the highest in the HF tissues.
Due to low proportion of HF in both OP and SP cul-
tivars (4 % and 10 %, respectively); it has no marked
effect on the composition of the whole biomasses.
From the differences between the contents of total
carbohydrates and uronic acids (Fig. 4), higher pro-
portions of neutral polysaccharides belonging to pec-
tic polysaccharides and hemicelluloses were observed
with the OP tissues, varying from 11.7 % to 48.8 %,
whereas the contents varied from 13.6 % to 41.7 %
in the SP tissues. In contrast, the proportions of α-
cellulose in OP and SP tissues were similar (18.8–
32.4 %) and (14.4–31.4 %), respectively. In addition,
the sugar analysis data (Fig. 4, Table 3) indicated a
higher proportion of hemicellulosic polymers in the
OP tissues.
Based on the analytical data of the P, F and HF
tissues in Fig. 4, the proximate content of the main
components of both SP and OP biomasses was calcu-
lated and illustrated in Table 4. When compared to
the SP biomass, OP displayed a much higher content
of lignin, similar content of pectin and a larger propor-
tion of hemicelluloses, whereas the α-cellulose content
was slightly higher.
The presented results suggest that the oil pumpkin
biomass represents a potential source of non-cellulosic
polysaccharides (hemicelluloses and pectic polysac-
charides). Although the content of pectin is some-
what lower in OP, the advantage of this polysac-
charide component is in its low degree of branching
by arabinose- and galactose-containing polysaccharide
side chains. This is of particular importance for the po-
tential production of pectin for the food industry. Non-
cellulosic polysaccharides are associated with pheno-
lics and other extractive compounds. Such phenolics-
rich polysaccharides might exert antioxidant activities
which have been reported for preparations obtained
from other plant sources, such as wheat bran (Yuan
et al., 2005), spruce wood (Ebringerová et al., 2008a),
and almond shells (Ebringero et al., 2008b). How-
ever, diversity of the hemicellulose and pectic com-
ponents of the oil pumpkin biomass and their asso-
ciation with phenolics needs further investigations in
order to develop possible isolation and potential ap-
plications for these polysaccharides. Currently, inves-
tigations dealing with the selection and optimization
of convenient extraction methods are in progress.
Acknowledgements. This work was financially supported by
the Slovak Grant Agency VEGA, grant No. 2/0062/09 and by
the EEA grant No. SAV-FM-EHP-2008-03-05. The authors are
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... Antidiabetic, immunomodulation, antitussive, and antioxidant activities have been reported for pectin fractions extracted from different species of pumpkin [33][34][35]. Variations in the extraction methods influence the physicochemical properties and bioactivity of pumpkin pectin [29,32,36].Therefore, new extraction methods enable the acquisition of pectins with different functional properties. ...
... Xylose was also found in the apple pectins, and fucose was foundin the pumpkin pectin. The presence of fucose was observed by other researchers in the composition of pumpkin pectin, obtained by different extraction methods [29,36] and in the composition of apple pectin obtained using ultrasonic treatment [52]. Two types of polysaccharide regions were observed in the pectin samples: smooth region (homogalacturonan) and hairy region (rhamnogalacturonan). ...
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The physicochemical characteristics and functional properties of pumpkin (Cucurbita maxima D. var. Cabello de Ángel) pectin obtained by cavitation facilitated extraction from pumpkin pulp have been evaluated and compared with commercial citrus and apple pectins. C. maxima pectin had an Mw value of 90 kDa and a high degree (72%) of esterification. The cytoprotective and antioxidant effects of citrus, apple and pumpkin pectin samples with different concentrations were studied in vitro in cell lines HT-29 (human colon adenocarcinoma) and MDCK1 (canine kidney epithelium). All pectin samples exhibited cytoprotective effect in HT-29 and MDCK1 cells after incubation with toxic concentrations of cadmium and mercury for 4 h. Pumpkin pectin increased the proliferation of cadmium-treated MDCK1 cells by 210%. The studied pectins also inhibited oxidative stress induced by 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH) in cell cultures, as determined by measuring the production of intracellular reactive species using dihydrochlorofluorescein diacetate (DCFH-DA). Pectin from pumpkin pomace had the highest (p < 0.05) protective effect against reactive oxygen species generation in MDCK1 cells induced by AAPH. Distinctive features of pumpkin pectin were highly branched RG-I regions, the presence of RG-II regions and the highest galacturonic acid content among the studied samples of pectins. This correlates with a considerable protective effect of C. maxima pectin against oxidative stress and cytotoxicity induced by heavy metal ions. Thus, C. maxima pectin can be considered as a source of new functional foods of agricultural origin.
... In Europe and Asia, it appear to be a wild plant [21]. reduces pressure of human blood by obstructing angiotensin converting enzyme thereby downregulate diabetes [22,23]. ...
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Diabetes mellitus remains one of the dreaded diseases that affect both man and woman. It also causes a disorder which incapacitates human body from producing and exhausting insulin. In this work, in silico method was used to explore the anti-angiotensin converting enzyme activities of selected phytochemicals obtained from Cucurbita pepo L. The optimization of the phytochemicals obtained from Cucurbita pepo L. resulted to series of descriptors which exactly describe anti-angiotensin converting enzyme activities of Cucurbita pepo L.. Also, 3-[(Z)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy-1,4,5-trihydroxycyclohexane-1-carboxylic acid (Compound 3) with -7.7 kcal/mol proved to have better tendency to inhibit angiotensin converting enzyme than compound 1,2,4-8 as well as the referenced drug (Metformin) thereby dowregulating diabetes. The ADMET (absorption, distribution, metabolism excretion and toxicity) were examined and reported.
... Pumpkin seed cake flour (PSCF) was mixed with wheat flour to produce a special bread (Mansour et al., 1999) and for improving sausage quality (Mansour et al., 1996). Košťálová et al. (2009) and his coworkers suggested that the oil pumpkin biomass could be a potential source for non-cellulosic polysaccharides (hemicelluloses and pectic polysaccharides). The advantage of this polysaccharide is its low degree of branching of the side chains of sugar moieties of arabinose and galactose, which is promising for production of pectin used in the food industry. ...
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A large amount of wastes and by-products are generated during the vegetables and fruits production and food industry. These wastes create increasing disposal and severe environmental problems or discarded with a loss of valuable biomass and nutrients. However, these wastes contain bioactive compounds of great potential and value-added compounds. These wastes or by-products can be incorporated as food additives and/or used as nutraceuticals. Therefore, the valorization of agro wastes or by-products from the food industry significantly contributing to a sustainable food chain from an environmental and economic point of view. Pumpkin is a gourd-like fruit of the genus Cucurbita (family Cucurbitaceae), indigenous to the tropical and sub-tropical countries. Worldwide, three common pumpkin species are grown, namely Cucurbita pepo, Cucurbita maxima, and Cucurbita moschata, which economically represent the most important species. Globally, China, India, Ukraine, Egypt, and the United States are the major pumpkin-producing countries. Pumpkins are a rich source of important natural bioactive compounds such as carotenoids, tocopherols, phytosterols, phenolics, antidiabetic polysaccharides, minerals, vitamins, antifungal proteins, essential and nonessential amino acids, pectin, and fibers. Besides, the pumpkin seed oil is rich in unsaturated fatty acids (omega-6 and omega-9). The bioactive compounds found in pumpkin exhibit a wide range of biological activities such as antioxidant, anti-inflammatory, cardio protective, antiaging, antimicrobial anticancer, and prebiotic activities. The wastes from pumpkin fruits and biomass from seed oil production retained great amounts of these bioactive compounds, representing a potential for their use as a nutraceutical or dietary supplement. The present chapter describes the economic values, chemical composition, bioactive compounds, health benefits, and pumpkin fruits’ biological activity. In addition, the current status of the use, recovery, food, and non-food applications of pumpkin processing by-products, including peels, pulp, and seeds. The technologies employed to obtain and isolate the highly value-added components from these by-products will also be discussed.Keywords Cucurbita SeedSeed cakePeelPulpNutritional valueBio-wastesValorization
... Squash is also low in calories and contains a high amount of fibre [10]. The vegetable has also been reported to possess various medicinal properties, such antidiabetic, antitumor, antimutagenic, antibacterial and anti-inflammatory effects [11,12]. The impressive health benefits of squash are attributed to organic compounds, nutrients, vitamin C, potassium, manganese, copper, phosphorus, calcium, iron and other antioxidant compounds. ...
The neonicotinoid insecticide sulfoxaflor is widely used in Egypt. This work assessed the safety of using sulfoxaflor in squash to consumers, along with the residue behaviour. Supervised field trials were conducted to investigate the dynamics and terminal residues of sulfoxaflor in squash under Egyptian field conditions for several agricultural practices, including worst-case scenarios. A QuEChERS-based protocol coupled with LC-MS/MS was employed to measure residues in squash fruits; the limit of quantitation was successfully validated at 0.01 mg/kg. Sulfoxaflor residues reduce in squash fruits via a first-order decay process, with a calculated half–life (t1/2) of 6.13 days and significant degradation (88.5%) after 14 days. During harvest, the terminal residues of sulfoxaflor were ranged from 0.365 to 1.611 mg/kg and from 0.576 to 1.865 mg/kg on sampling days of 3, 7 and 14 days when applied 2-3 times at single or double recommended dose, respectively. A consumer risk assessment was performed employing the FAO/WHO approach; the risk quotients (RQs) were ≤0.0102, and hence; no significant health risks associated with consumption of squash treated with sulfoxaflor were identified.
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... The leaves of C. pepo contain 43.8% protein (Oloyede, 2012), the fruits are characterized by low fat content (2.3%), high carbohydrates (66%) and low proteins (3%) and very high carotenoids contents (171.9 to 461.9 µg/g) (Adedayo et al., 2013). Seeds are used as an antidiabetic, antihypertensive, antitumor, antimutagenic, immunomodulatory, antibacterial, anti-hypercholesterolemic, intestinal antiparasitic, antalgic, and anti-inflammatory agent (Kostalova et al., 2009) C. pepo has high agricultural properties and it is included in the fruit-eaten vegetables class. Its fruits can be used in food and cosmetic industry while seeds are used as snack foods (Sağlam & Çetin, 2018). ...
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... Zucchini is an economically important plant and is cultivated throughout the world for oil and medical purposes. Pharmacological effects comprising antidiabetic, antihypertensive, antitumor, antimutagenic, immunomodulating, antibacterial, antihypercholesterolemic, intestinal antiparasitic, antalgic, antiinflammation effects and utilization possibilities of various Zuchini species have been reported (Kostalova et al., 2009). All summer squash are a rich source of nutrients, especially the natural antioxidants beta-carotene, folic acid, and vitamins C and E. They contain healthful minerals including potassium, iron, calcium, magnesium, phosphate, copper, and zinc. ...
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The aim of the presented work was to evaluate polar and non-polar extracts and fatty oil, isolated from pumpkin fruit (Cucurbita pepo L.), as a potential food supplements or raw material for cosmetic and pharmaceutical preparations. The extracts were isolated from the pumpkin peel, mesocarp and pulp and fatty oil from the seeds. The highest yield of total extractive matter and highest β-carotene content was determined in peel extracts at concentrations of 5.45 g/100gf.p.m and 136.22 μgg−1f.p.m, respectively. The presence of phenolic acids, flavonoids and carotenoids in polar and non-polar extracts was confirmed by UHPLC-DAD-ESI-MS and HPLC-DAD analysis, respectively. The yield of fatty oil in the seeds was 34.53%, while TLC and HPLC analysis showed the highest percentage of triglycerides (99.3%) and methyl esters (99.7%) in fatty oil and fatty acids methyl esters, respectively. Non-polar extracts of peel showed the highest antioxidant activity estimated by DPPH test (EC50 = 0.041 mgcm−3), fully comparable to activity of synthetic BHT antioxidant (EC50 = 0.021 mgcm−3). High linear correlation factor (0.9969) of EC50 values on β-carotene concentration suggests that β-carotene is the most responsible for significant antioxidant activity of non-polar extracts. Investigated isolates showed no antimicrobial activity against Lt. monocytogenes, St. aureus, E. coli, P. vulgaris, C. albicans, P. aeruginosa, B. cereus, K. pneumoniae and B. luteus under the examined conditions. Bearing in mind the results presented, the C. pepo isolates can be used as an alternative to synthetic antioxidants and a rich source of phytochemicals in food and pharmaceutical industry.
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Microbial lipase (triacyl glycerol acyl hydrolase) is a very important enzyme in many industrial applications. The production of enzyme from different microorganisms was semi- quantatively screened by producing clear zone around microbial colonies on agar plates which were compatible with the results of quantitative screening for specific activity of lipase produced by most strains. The significant and higher productive lipase strains were only 3 from 42 strains of Lactobacillus spp.(L. plantarum, L. acidophilus and L. casei), 1 from 2 strains of Bacillus subtilis, 1 from 4 strains of B. cereus, 1 from 5 strains of Pseudomonas aeruginosa, 1 from 3 strains of Serratia marcescens, 1 from 2 strains of Aeromonas spp. 1 from 5 strains of Aspergillus niger, 1 from Candida albicans and 1 from 2 strains of Saccharomyces cerreviseae, all these strains have been selected for further experiments
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Texture of buttercup squash ‘Delica’ (Cucurbita maxima D.) during storage, and the effect of cooking on the texture, have been investigated using a penetrometer and an Instron Universal Testing Machine. Firmness (measured by penetrometer) of uncooked and cooked squash increased during the first 2 months of storage (P < 0.001). The Texture Profile parameters of hardness, fracturability, and gumminess tended to decrease during storage, whereas cohesiveness, chewiness, and springiness remained unchanged. A procedure for isolating cell walls in tissues containing high levels of starch has been developed. An initial extraction of the tissues with HEPES buffer‐containing mercaptoethanol was followed by grinding the residue in a ball mill and a second HEPES buffer extraction. Any remaining starch was gelatinised and then removed by α‐amy‐lase treatment. Sequential fractionation of the cell wall polysaccharides was done. The cell walls of buttercup squash at harvest were composed of 34% pectin, 26% hemicelluloses, and 39% cellulose by dry weight.
TEPPNER H. 2000. Cucurbita pepo (Cucurbitaceae) - History, seed coat types, thin coated seeds and their genetics. - Phyton (Horn, Austria) 40 (1): 1-42, 46 figures. - English with German summary. The pecularity of flowering shoots of Cucurbitoideae with male inflorescence, female flower, next order shoot and tendril in and beside the leaf axil are interpreted as primary axillary shoot with two basal lateral shoots, whose lowermost internodes are reduced. Cucurbita pepo L. subsp. gumala TEPPNER subsp. nova, C. pepo subsp. pepo var. georgica TEPPNER van nova and C. pepo subsp. pepo var. flogra TEPPNER var. nova are described as new taxa. C. pepo subsp. gumala is regarded as one of the possible progenitors of C. pepo subsp. pepo. With the help of the herbals from the 16(th) century it is shown, that the horticultural groups pumpkin, vegetable marrow, scallop, acorn and ornamental gourds were already present during this time in Europe. The testa consists of the five layers epidermis (1), hypodermis (2), sclerenchyma (3), aerenchyma (4) and chlorenchyma (5). 0 is the sign for the outer walls of placenta epidermis, () around the number mean that this layer need not be obligatorily present in the ripe dry seed; bold numbers indicate lignification. According to these symbols the four main testa types in the ripe seeds may be characterised as follows: thick coated (most C. pepo types) semi-thick coated (in the F2 from a thin x semi-thin cross) (0).2.4.5. semi-thin coated (C. pepo var. georgica) (0).4.5. thin coated (C. pepo var. styriaca, var. oleifera and var. flogra) 1.4.5. From the testa structure of the phenotypes in the F2 from the cross thin x semi-thin it is estimated, that 6-12(-15) genes should be responsible for the studied characters and, consequently, an allele constellation as in var. styriaca must be very rare, which is the reason for the uniqueness of this variety. The first evidence of oil production from thick coated seeds in Styria dates back to 1735. The thin coated mutant must have segregated from the normal C. pepo around 1870-1880 in Styria.
Due to the increasing interest in the supply with antioxidants and especially carotenoids in foods, pumpkins were analysed for their content of α -carotene, β -carotene, and lutein. A wide range of varieties of pumpkins that are commercially available in Austria was analysed. For this study the pumpkins were grown in Austria to obtain data that are relevant for local nutrition. The varieties analysed derived from three species i.e. Cucurbita pepo,C. maxima and C. moschata. Additionally, a cross breed of C. maxima and C. moschata was tested. The content of the carotenoids ranged from 0.06 to 7.4 mg/100 g for β -carotene, from 0 to 7.5 mg/100 g forα -carotene and from 0 to 17mg/100g for lutein.
The selective release of soluble oligomeric structures from corn cobs (CC) by autohydrolysis was optimized using the severity factor (logR0), and a maximum xylo-oligosaccharides (XOS) production was obtained at logR0=3.75. Gel filtration chromatography was employed to separate oligosaccharides (OS) from the crude hydrolysate and two fractions with average degrees of polymerization (DP) of 3–4 and 5–6 were compared with commercial XOS in their ability to promote the growth of Bifidobacterium adolescentis, B. longum, Lactobacillus brevis and L. fermentum as carbon and energy sources. Among the tested strains, B. adolescentis and L. brevis displayed the highest growth and XOS consumption, in contrast to B. longum and L. fermentum whose overall growth on XOS was low. XOS mixtures from CC autohydrolysis, mainly constituted by xylotriose and xylotetraose, were fermented by B. adolescentis as well as commercial XOS containing essentially xylobiose, whereas L. brevis preferred XOS with an average DP of 2. However, an increase in XOS chain length to DP 5–6 clearly reduced the extension to which B. adolescentis utilized these OS. This study showed that XOS of low molecular weight from CC autohydrolysis exhibit a potential bifidogenic capability similar to commercial XOS.
The pod and pulp of fluted pumpkin (Telfairia occidentalis), which are discarded after seed removal, and which together constitute about 64% of the whole fruit weight, were analysed for their proximate chemical and mineral element composition. The effects of fermentation on the crude protein, crude fibre and ether extract contents of the pod and pulp were also investigated. The moisture, crude protein, crude fibre, ether extract, ash, and nitrogen-free extract contents of the fresh pod were: 91.30%, 1.40%, 0.85%, 0.50%, 0.40% and 5.60%, respectively, and for the pulp: 92.80%, 1.30%, 0.46%, 0.30%, 0.30% and 4.84%, respectively. Fermentation (0–120 h) increased the per cent crude protein and generally decreased the crude fibre and ether extract contents of the pod and pulp samples.Analyses of the fruit pod and pulp, respectively, for mineral elements revealed the following in mg/100 g dry matter: sodium (10.50; 27.50), potassium (1584; 2320), magnesium (665.90; 147.20), calcium (196.7; 162.10), phosphorus (30.00; 260.00), iron (16.76; 13.86), zinc (5.31; 4.30), copper (1.26; 1.13) and manganese (0.07; 0.06). The results of this study show the potentials of these fruit parts as livestock feedstuffs.
Pumpkin powder, introduced initially as a nutritional supplement, has been found to give very large, unexpected, increases in the loaf volume and organoleptic acceptability of wheat bread produced using flour samples with comparatively poor breadmaking properties. Maximum effectiveness occurs at low levels of addition, where the nutritional benefit would be marginal, but the improvement in quality is massive, suggesting a possible role for pumpkin powder as a functional ingredient in breadmaking. Two hard wheat red Winter flours (denoted as samples F1 and F2) were used. The gluten networks formed by these samples were found to be respectively weaker and stronger than the optimum range for breadmaking, giving breads with relatively low specific volumes (∼3.8ml/g for F1 and ∼3.2ml/g for F2) and with low hedonic ratings from a sensory panel. Progressive addition of pumpkin powder gave an initial rise and subsequent decrease in loaf volume. The maximum values attained were higher for F1 than for F2 (∼5.6 and 4.2ml/g, respectively), but in both cases occurred at levels of addition between 5 and 10g/kg flour. Panel scores for organoleptic acceptability increased systematically with increasing loaf volume, reaching a value close to the maximum of the 5-point hedonic scale used at specific volumes above ∼4.3ml/g. The increase in aeration is tentatively attributed to surface activity of the highly acetylated pectin present as a major component (∼30% of the total dry-matter content) of pumpkin tissue.