Quality analysis of different cultivars oil pumpkin (Cucurbita pepo L. var. styriaca) fruits pulp, seeds, oil and oil cake ; Skirtingų veislių aliejinio moliūgo (Cucurbita pepo L. var. styriaca) vaisų minkštimos, sėklų, aliejaus ir išspaudų kokybės analizė
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ALEKSANDRO STULGINSKIO UNIVERSITETAS
SKIRTINGŲ VEISLIŲ ALIEJINIO MOLIŪGO
(Cucurbita pepo L. var. styriaca) VAISIŲ
MINKŠTIMO, SĖKLŲ, ALIEJAUS IR IŠSPAUDŲ
Daktaro disertacijos santrauka
Biomedicinos mokslų sritis, agronomijos mokslo kryptis (06 B)
Akademija, 2011 Disertacija rengta 2007–2011 metais Lietuvos žemės ūkio universitete (nuo
2011 08 Aleksandro Stulginskio universitetas).
prof. dr. Honorata Danilčenko (Aleksandro Stulginskio universitetas, žemės
ūkio mokslai, agronomija, 01 A).
doc. dr. Elvyra Jarienė (Aleksandro Stulginskio universitetas, žemės ūkio
mokslai, agronomija, 01 A)
Disertacija ginama Aleksandro Stulginskio universiteto Agronomijos
mokslo krypties taryboje:
prof. habil. dr. Rimantas Velička (Aleksandro Stulginskio universitetas, žemės
ūkio mokslai, agronomija, 01 A).
prof. habil. dr. Romas Gružauskas (Lietuvos sveikatos mokslų universitetas,
žemės ūkio mokslai, zootechnika, 02 A)
doc. dr. Jolanta Sereikaitė (Vilniaus Gedimino technikos universitetas,
technologijos mokslai, chemijos inžinierija, 05 T).
dr. Alvyra Šlepetienė (Lietuvos agrarinių ir miškų mokslų centras, žemės ūkio
mokslai, agronomija, 01 A).
doc. dr. Pranas Viškelis (Lietuvos agrarinių ir miškų mokslų centras, žemės
ūkio mokslai, agronomija, 01 A).
doc. dr. Virginija Dulskienė (Sveikatos mokslų universitetas, biomedicinos
mokslai, medicina, 06 B)
doc. dr. Rita Pupalienė (Aleksandro Stulginskio universitetas, žemės ūkio
mokslai, agronomija, 01 A).
Disertacija bus ginama viešame Agronomijos mokslo krypties tarybos posėdyje
2011 m. gruodžio mėn. 16 d. 11 val. Aleksandro Stulginskio universitete
centrinių rūmų 261 auditorijoje.
Aleksandro Stulginskio universitetas
Studentų g. 11, Akademija, LT – 53361, Kauno r., Lietuva
Disertacijos santrauka išsiuntinėta 2011 m. lapkričio mėn. 16 d.
Disertaciją galima peržiūrėti Aleksandro Stulginskio universiteto ir Lietuvos
agrarinių ir miškų mokslų centro bibliotekose.
In the course of mankind development raw materials and food have been
the most important bioenergetical resourse describing both regional and national
culture. Development of even and relatively safe system of human supply with
food products is an important field of state activity. At present cultivar of raw
materials is increasing, however, the percentage of naturally grown and
minimally processed products is decreasing. Attention to food safety, its
nutritious and biological value is increasing in our country, which is also
conditioned by new consumer attitude to food quality as well as increasing
concern about environmental pollution and its influence of health.
Demand for and volumes of alternative production are increasing,
assortment of food products is growing. The by-products that remain after
processing of food raw materials are usually utilized or used as alternative fuel,
fertilizers, fodder, etc. Possibilities to use the by-products of this production for
the improvement of nutritious value, in production of functional food products or
in chemistry industry are under investigation.
Nutritious value of great (Cucurbita maxima) and musky (Cucurbita
moschata) pumpkin pulp has been widely investigated, but chemical and qualitative
analysis of pulp and other parts of oil pumpkin fruits has been superficial so far. For
example, seed cake of oil-bearing plants is used not only as fodder for animals but
also as valuable raw material for creation of new products. Pulp, seeds and seed oil
cake of oil pumpkins can be not an exception because of high content of valuable
proteins and their energetical value (Ramachandran et al., 2007). Innovative
products made from seeds of oil pumpkins can be offered to the consumers with
special needs (children, sportsmen, patients of cardiovascular diseases, etc.).
Scientific literature presents numerous articles about use of sunflower and
rape seed oil cake, about qualities of soya proteins. However, data about chemical
composition and use of oil pumpkin pulp and seed cake is insufficient. Usually,
only seeds of oil pumpkin are used, while the remaining pulp is spread in field as
an organic fertilizer. This work presents a research based argument that pulp,
seeds and cake of oil pumpkins are of high nutritious value.
Chemical composition of fruit pulp, seeds and oil depends on the
genotipe of oil pumpkins. Pulp, oil and seed cake of oil pumpkins are rich in
biologically valuable materials.
Aim of the research:
To investigate and evaluate quality of pulp, seeds, oil and cake of
different cultivars oil pumpkins.
3 Tasks of the research:
1. To investigate and compare chemical composition of pulp, seeds, oil and
seed oil cake of different cultivar oil pumpkin fruits.
2. To evaluate oxidative stability, number of peroxides and free fatty acids,
colour of pumpkin oil.
3. To conduct sense evaluation of seed quality of oil pumpkins.
Biochemical composition and nutritious value of not only seeds but also
of oil, seed oil cake and fruit pulp of oil pumpkins have been established for the
Practical importance of the work:
Having evaluated biochemical composition and nutritious value, fruit
pulp, seeds, oil and cake of oil pumpkins can be a valuable raw material for
creation of innovative products.
The defended propositions of the thesis:
Chemical composition of oil pumpkin fruit pulp and seeds depends on the
pumpkin genotype and meteorological conditions.
Chemical composition and oxidation stability of pumpkin seed oil depend
on the genetic characteristics of the cultivar.
Quality of oil pumpkin seed cake depends on the characteristics of the
Approval of the dissertation work:
Results of the dissertation work have been presented at the following
scientific conferences: Respublican scientific conference „Optimization of
assortment, technologies and environment of ornamental and garden plants“
(Mastaičiai, 2008); International scientific-practical conference „Human and
nature safety“ (Akademija, 2009); 4th international conference on quality and
safety in food production chain, (Wrocław, 2009); Respublican scientific
conference „Optimization of assortment, technologies and environment of
ornamental and garden plants“ (Mastaičiai, 2011).
Publisher works. The main research data are present in 8 publication,
where of 1 in ISI publications with citation index, 1 – in ISI publications, 2
publications approved by the Lithuanian Scientific Publications List of the
Departamentos science and higher Education and 4 conference proceedings.
Volume of teh work. The doctor dissertation is written in Lithuanian
language. It consists of 94 page, 24 tables and 20 figures. The dissertation is
constituted of introduction, literature review, materials and methods, results,
discussion, conclusion, cited literature (212 literature sources) and publication
4 RESEARCH MATERIALS AND METHODS
Research object, site and experimental scheme. Fruits, seeds, oil and oil
cake of oil pumpkin Cucurbita pepo L. var. styriaca cultivars 'Danaja',
'Golosemiannaja', 'Herakles', 'Miranda' and 'Olga' were investigated.
The experiment was conducted in the period of 2007-2010 in training
vegetable garden of Horticulture department, Lithuanian University of Agriculture
(LUA). Sprouts of oil pumpkins were planted in a belt at 1 m distance in the third
decade of May, in repetition of four. The crop was harvested in the third decade of
September. Total plot area – 2×4 m., width of protective belt – 2 m., registration
2plot area - 16 m .
Meteorological conditions. Air temperature, precipitations and sunshine
data in the period of 2007-2010 is present according to the registration at
Kaunas Meteorological station in Noreikiškes.
Methods of chemical analyses. Chemical analyses were conducted at
laboratories of Food raw materials, agronomical and zootechnical
investigations, LUA; laboratory of food technologies, department of
Horticulture LUA; chemistry laboratory, Lithuanian Research Centre of
Agriculture and Forestry (LAMMC). Compositions of fatty acids were
established at Chemistry laboratory of Lithuanian University of Health
Sciences; composition of carotenoids, colour of seeds, oil and oil cake, the
descriptive sense analysis of seeds and oxidative stability of oil were established
at Fat and Oil laboratory and Food Concentrates Technology laboratory of Food
Science department, Warsaw University of Life Science (SGGW).
In the course of the experiment 3 fruits were taken from each repetition
and one total sample was made of them for the analysis of chemical composition
of oil pumpkin pulp. From this sample five fruits were selected for the analyses,
a pulp sample of at least 1 kg was taken from these fruits (LST ISO 2859-
10:2007). Of all seeds of the total sample, the amount of 100 g was taken for
chemical analyses. The remaining seeds were used for oil pressing. Chemical
analyses of pumpkin fruits, seeds, oil cake and oil were done in two repetitions.
Methods of chemical analyses. Oil pumpkin pulp, seeds and oil cake
were analyzed in dry matter for:
odry matter content - by draying samples at temperature of 105 C to the
constant weight (LST ISO 751:2000);
amount of crude protein – by the Kjeldahl method (LST 1523:1998);
amount of crude fats – by Soxhlet method (Methodenbuch – VDLUFA,
5 amount of crude fiber – by the method of Heneberg – Shtoman.
(Methodenbuch – VDLUFA, 1983-1999);
amount of MADF fiber – gravimetrically by washing with modified
solution (sulfuric acid and cetyltrimethylammonium bromide (CTAB) solution)
(Methodenbuch – VDLUFA, 1983-1999).;
amount of NDF fiber – using neutral washing solution (detergent)
(Methodenbuch – VDLUFA, 1983-1999);
amino acids were separated by ion exchange chromatography and were
determined photometrically by ninhydrin reaction at a wavelenght of 570 nm
with automatic analyzer of amino acids Mikrotechna AAA 339 according to the
normative act compendium;
fatty acids – analyzed by using gas chromatography GC-2010
SHIMADZU with hydrogen flame detector (Folch, 1975; Christopherson &
amount of carotenoids (β-carotene ir luteine) – were determined by high-
performance liquid chromatography (HPLC) with UV-Vis detector (Konings et al,
1997; Helsper et al, 2003; Collera-Zúñiga et al, 2005).
Pumpkin seeds oil were analyzed for:
amount of free fatty acids – acidity,% by oleic acid (ISO 660);
peroxide value - iodometric (visual) endpoint determination (LST EN
oxidative stability of oil – accelerated oxidation test, when increased the
heat to 120 °C degrees and the flow rate of air flow 20l/h (ISO/FDIS
RESULTS AND DISCUSSION
Pulp of oil pumpkin fruits. Dry matter content in plants determines
their yield quality. This content depends on the cultivar characteristics and
meteorological conditions (Tarek et al., 2001, Danilčenko et al., 2001, 2004;
Nawirska et al., 2008). According to the data obtained in this work, the dry
matter content accumulated in pulp of oil pumpkins varied from 5,12 to 7,02 %
(Fig.1). The significant lowest dry matter content was accumulated by 'Olga'
cultivar pumpkins - 5,12 %. Dry matter contents in fruits of other cultivar did
not differ significantly.
A medium strong correlation was established between the dry matter content and
hours of sunshine (r =0,670, p<0,01). Determination coefficient showed that hour
of sunshine even by 45 % influenced accumulation of these materials in pulp of oil
pumpkin. The higherer amount of light is absorbed by the plant as well as the more
ira aM nd
intensive photosynthesis. In the course of photosynthesis the synthesis of organic
materials – proteins, carbohydrates and fats, which influence the dry matter
content, takes place (Jensen & Knutsen, 1993). Positive medium strong correlation
between dry matter and crude proteins was established (r=0,656, p<0,01).
Pulp Seeds Oil cake
% 0 10 20 30 40 50 60 70 80 90 100
Fig. 1 Amount of dry matter in oil pumpkins pulp, seeds and cake, %
Value and properties of dietary fiber depends on the relative proportion of
its various fractions. An important interaction is the one between different
components of fiber and other materials - proteins, oligosaccharides, lipides,
mineral materials (Nawirska et al., 2008; Nawirska & Uklańska, 2008). Types,
amount and composition of crude fiber depend on the type, cultivar and
physiological maturity of pumpkin fruit. The amount of crude fiber depends on
genetical characteristics of the cultivar (Scholfield et al.,1990). Analysis of the
experimental results established no essential difference of crude fiber content in
different pumpkin cultivar, the average content was 10,34 %.
* - means located on the same line (from right to left) and marked with different letters
reliably, when p<0,05.
Fig. 2 Amount of crude fiber in oil pumpkins pulp, seeds and cake, % d.m,
7 Slightly lower amount of crude fiber was accumulated in pulp of 'Danaja'
pumpkin cultivar – 9,36 % (Fig. 2). Evaluation of nutritious value of the
products, particularly fodder, establishes not only total amount of crude fiber
tissue, containing lignin and cellulose, but also its fractions. In the pumpkin
pulp, investigated in this experiment, amounts of MADF and NDF fiber
fluctuated respectively within 13,04 - 22,74 and 18,63 – 26,26 % of dry matter
(Fig. 3). The essentially highest amount of fiber of both kinds was established in
pulp of ′Herakles′ pumpkins, the lowest one - in 'Miranda' pumpkins.
NDF fiber MADF fiber
0 5 10 15 20 25 30
Fig. 3 Amounts of NDF and MADF fiber in oil pumpkins pulp % d. m.,
Reliable correlation was established between the amounts of NDF and
MADF fiber in pumpkin pulp and precipitation during the vegetation period
(respectively r=0,821 and 0,645, p<0,01). The calculated determination
coefficient showed that precipitation content influenced accumulation of NDF
fiber fraction by 67 %, of MADF fiber fraction - by 42 %, as sufficient moisture
content created favourable conditions for normal synthesis of structural
carbohydrates (Herrera et al., 2000). Strong positive correlation (r=0,885) was
established between NDF and MADF fiber fractions, which indicated
interdependence between the increase of both fiber fractions.
The investigation also established amounts of soluble dry matter, crude
proteins, amino acids, ascorbic acid, carotenoids and water soluble carbohydrates
in pulp of oil pumpkins. Analysis of the experimental results established that pulp
of all investigated pumpkin cultivars tended to accumulate similar amounts of
these materials. Pumpkin cultivar 'Olga' accumulated the lowest amounts of the
mentioned materials. Pulp of 'Golosemianaja' pumpkin cultivar fruits was rich in
such amino acids as alanine, glutamine, isoleucine, leucine and phenylalanine.
Seeds of oil pumpkins. Accumulation of dry matter and other chemical
components in seeds is influenced by the same factors as that in pulp. The obtained
experimental data indicates that in oil pumpkin seeds dry matter content makes
94,24 % on average. The essentially lowest dry matter content was accumulated in
%seeds of 'Golosemiannaja' pumpkin cultivar - 90,88 %, while other investigated
cultivar accumulated similar amounts of dry matter and no important differences
were established (Fig. 1).
This experiment indentified that 'Olga' pumpkin cultivar seeds had the
reliably lowest amount of crude fiber - 4,16 % (Fig. 2). Seeds of other pumpkin
cultivars contained similar amounts of this fiber. The investigated pumpkin
seeds accumulated on average 5,59 % MADF and 13,54 % NDF fiber (Fig. 4).
The reliably lowest amounts of these fiber were identified in seeds of 'Olga'
cultivar, respectively 9,95 and 4,21 % d.m. Seeds of other investigated pumpkin
cultivar contained similar amounts of these fiber.
Analysis of the obtained experimental results showed dependence of
fractional contents of pumpkin seeds fiber on meteorological conditions. A
reliable strong correlation (p<0,01) was established between sunshine hours
during vegetation period and all fractions of fiber – crude (r =0,690), NDF (r
=0,793) and MADF (r =0,643). According to the analysis of precipitation during
phases of vegetation period, all years of the investigation were favourable for
accumulation of structural oligosaccharides. Determination coefficient showed
that moisture content influenced accumulation of these materials by 31 %.
Draught or inssuficient moisture content reduces synthesis of organic materials,
including carbohydrates (Herrera et al., 2000).
NDF fiber MADF fiber
% 0 2 4 6 8 10 12 14 16 18
Fig. 4. Amounts of NDF and MADF fiber in oil pumpkins seeds, % d. m.,
Literature sources indicate that in seeds ratio of components can highly
fluctuate depending on different growing conditions, although specific
characteristics of the crop remain. Amount of crude fats in seeds depended on the
cultivar of pumpkins, their growing environment, climate and ripeness (Murkovic et
al., 2004; Abdel-Rahman, 2006). In the investigated pumpkin cultivar the amount of
crude fats fluctuated from 44,4 to 50,39 % (Table 1). The reliably highest amount
(p<0,05) was established in seeds of 'Olga' cultivar, the lowest one – in 'Miranda'
cultivar seeds. Reliable strong correlation was established between crude fats and
9 hour of sunshine (p<0,01) (r = -0,742); medium strong inverse correlation was
established between crude fats and the sum of active temperatures of month (r = -
0,654). The completed scientific investigations show that higher amounts of fats are
accumulated in seeds of the oil-bearing plants that grow in north and east zones, and
significantly lower ones - in west and south zones. The amount of fats in seeds of the
pumpkins growing in south regions is by 16 % lower than that of the pumpkins
growing in north regions. During the period of oily seeds ripening the synthesis of
fats usually requires more water in comparison with proteins, therefore, lack of
moisture weakens the synthesis of fats, which causes increase of protein content.
Decreased amount of light energy slows the process of photosynthesis, which is the
reason of slowing down synthesis of proteins and increase that of fats (Mailer &
Cornish, 1987). Data of this experiment and the calculated determination coefficient
corroborate 55 % influence of the number of sunshine hours on decreased amount of
fats. Thus, closely interrelated and competing processes – synthesis of fats from
glycerin and fatty acids and synthesis of proteins from amino acids, take place in the
time of seed ripening. Results of this experiment established strong negative
correlation between crude fats and crude proteins (r = -0,997, p<0,01), which
confirm the latter statement.
Fatty acids make approximately 29,8 % of pumpkin seed dry matter.
Linoleic polyunsaturated fatty acid was established to dominate in seeds of the
investigated oil pumpkins. The amount of this acid fluctuated within 65,08 – 68,23
% of the total amount of fatty acids (Table 1). The significantly highest amount of
this acid was accumulated in seeds of ′Danaja′ and ′Olga′ pumpkin cultivar.
Linoleic acid made almost two thirds of the total amount of acids. Meanwhile,
according to literature sources, this acid makes only up to one third of the total
amount of acids in seeds of oil pumpkins. Amount of oleic fatty acid in seeds
fluctuated from 13,59 to 18,03 %. The highest content of this acid was identified
in seeds of 'Golosemiannaja' cultivar, the lowest one – in seeds of ′Danaja′ and
′Olga′ (Table 1). The highest amount of palmitic acid was established in ′Danaja′
and ′Olga′ cultivar (respectively 12,49 and 12,91 %). Seeds of other investigated
cultivar contained similar amounts of this acid. Amounts of stearic fatty acid
differed significantly: the highest content was established in seeds of ′Olga′
cultivar – 4,16, the lowest one was in 'Miranda' – 3,18 %.
Composition of carotenoids in oils differ significantly. Lutein dominated in
seeds of the oil pumpkins investigated in this work and its amount fluctuated from
-1 20,25 to 187,29 μg g (Fig. 5). Reliable differences of the amount were
established among seeds of all pumpkin cultivars. The highest content of lutein
was established in 'Golosemiannaja' (p<0,05), the lowest one - in 'Miranda'. In the
investigated seeds the amounts of β-carotene were three times lower than those of
-1lutein – from 2,78 to 5,97 μg g . The reliably highest amount (p<0,05) was
established in seeds of 'Golosemiannaja'.
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