Application of heat before or during extraction results in the rupturing of cell
emulsion and decreases oil viscosity, which facilitates oil fluidity, movement, and
lowers oil surface tension. At the same time, it can have a negative effect on
chemical composition and susceptibility to oxidation (Rodríguez-Miranda et al.
2013). A special type of pumpkin (Cucurbita pepo var.) seed oil is manufactured
in southeastern Austria and adjacent regions using press method after roasting the
hulled seeds having an oil concentration of around 38%. The characteristic nutty and
roasted aroma results from heat application before pressing where the temperature
goes as high as 130
C. In general, roasting of seed meal at the temperature of 110
C
for 50–60 min imparts dark green color to the oil (Teppner 2004).
The naked seed oil has dark color with green to red tinge due to the presence of
protochlorophyll which is present in the innermost layer of seed-chlorenchyma.
Clear or straw color oil is extracted from pumpkin seeds having seed coat (Lelley
et al. 2009). Protochlorophyll is light sensitive and initiates lipid oxidation; hence
this oil should be stored in dark. Dark green color and the foam formation in the oil
limit its use in cooking (Murkovic 2009).
19.3.3 Seed Meal
A valuable byproduct of pumpkin seed oil production is seed meal (Makni et al.
2011), also referred to as defatted pumpkin flour (Lazos 1992). Due to its high
protein content, it can be used for substituting breadcrumbs or flour in the bakery
industry. In Central Europe, it is mainly used as a high protein stock feed (Baxter
et al. 2012).
19.4 Chemical Composition
Proximate composition of seeds varies with characteristics of seeds, genus, species,
conditions of harvest, fruit maturity level, and cultivation zone (Rodríguez-Miranda
et al. 2013).
19.4.1 Carbohydrates
Pumpkin seeds contain approximately 25.19–28.03% carbohydrates (Elinge et al.
2012; Gohari Ardabili et al. 2011). However, Kim et al. (2012) observed
12.22 Æ 7.47 g/100 g carbohydrates (on dry weight basis) in pumpkin seeds. Total
carbohydrates in defatted pumpkin seed meal extracted with hexane were found to
be 9.13 g/100 g, and the amount of sucrose, raffinose, and stachyose was 1.79 g/
100 g, 0.41 g/100 g, and 0.81 g/100 g, respectively (Mansour et al. 1993). The crude
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S. Adsul and V. Madkaikar
emulsion and decreases oil viscosity, which facilitates oil fluidity, movement, and
lowers oil surface tension. At the same time, it can have a negative effect on
chemical composition and susceptibility to oxidation (Rodríguez-Miranda et al.
2013). A special type of pumpkin (Cucurbita pepo var.) seed oil is manufactured
in southeastern Austria and adjacent regions using press method after roasting the
hulled seeds having an oil concentration of around 38%. The characteristic nutty and
roasted aroma results from heat application before pressing where the temperature
goes as high as 130
C. In general, roasting of seed meal at the temperature of 110
C
for 50–60 min imparts dark green color to the oil (Teppner 2004).
The naked seed oil has dark color with green to red tinge due to the presence of
protochlorophyll which is present in the innermost layer of seed-chlorenchyma.
Clear or straw color oil is extracted from pumpkin seeds having seed coat (Lelley
et al. 2009). Protochlorophyll is light sensitive and initiates lipid oxidation; hence
this oil should be stored in dark. Dark green color and the foam formation in the oil
limit its use in cooking (Murkovic 2009).
19.3.3 Seed Meal
A valuable byproduct of pumpkin seed oil production is seed meal (Makni et al.
2011), also referred to as defatted pumpkin flour (Lazos 1992). Due to its high
protein content, it can be used for substituting breadcrumbs or flour in the bakery
industry. In Central Europe, it is mainly used as a high protein stock feed (Baxter
et al. 2012).
19.4 Chemical Composition
Proximate composition of seeds varies with characteristics of seeds, genus, species,
conditions of harvest, fruit maturity level, and cultivation zone (Rodríguez-Miranda
et al. 2013).
19.4.1 Carbohydrates
Pumpkin seeds contain approximately 25.19–28.03% carbohydrates (Elinge et al.
2012; Gohari Ardabili et al. 2011). However, Kim et al. (2012) observed
12.22 Æ 7.47 g/100 g carbohydrates (on dry weight basis) in pumpkin seeds. Total
carbohydrates in defatted pumpkin seed meal extracted with hexane were found to
be 9.13 g/100 g, and the amount of sucrose, raffinose, and stachyose was 1.79 g/
100 g, 0.41 g/100 g, and 0.81 g/100 g, respectively (Mansour et al. 1993). The crude
476
S. Adsul and V. Madkaikar