fiber content of the seeds varies greatly and has been reported to be 3.80% (Sharma
and Lakhawat 2017), 1.0% (Elinge et al. 2012), 5.34% (Gohari Ardabili et al. 2011),
and 14.82 Æ 0.55 g/100 g (Kim et al. 2012)
19.4.2 Proteins
Protein content in pumpkin seeds ranged from 24.50 to 32.00 g/100 g (Kim et al.
2012; Elinge et al. 2012; Aliu et al. 2016; Nyam et al. 2009) and approximately
55.40 g/100 g in defatted seed flour (Lazos 1986). Sharma and Lakhawat (2017)
have reported 29.65% protein content in roasted pumpkin seed flour. Pumpkin
seed’s protein contains all 9 essential amino acids (Table 19.1) (El-Adawy and
Taha 2001; Patel 2013). Cucurbita pepo seeds have the highest content of arginine
(63.99 Æ 0.88 mg/kg) as compared to other species such as Cucurbita maxima and
Cucurbita moschata (Kim et al. 2012).
Higher concentrations of essential amino acids were reported in protein isolates
(40.92–42.59 g per 16 g N) than concentrate (36.13 g per 16 g N) and meal (35.03 g
per 16 g N). During isolate preparation, a few protein fractions are lost which may
result in loss of non-essential amino acids and increase levels of essential amino
acids (Mansour et al. 1993). Table 19.2 provides a summary of the estimated
biological quality of pumpkin (Cucurbita pepo) seed flours/protein by different
researchers.
After oil extraction, the protein content of oil cake can increase up to 65%.
Various fractions of this protein are cucurbitin and albumin. The major fraction is
represented by cucurbitins, 12S globulins composed of six similar subunits
(hexamer) with molecular weights of 54 kDa each and are the major storage proteins
in pumpkin seeds (Bučko et al. 2016). Zdunczyk et al. (1999) conducted a comparative study on the chemical composition as well as the nutritive value of pumpkin
seed cake (PSC), soybean meal, and casein. The authors reported higher content of
protein (59.8 g/100 g) in PSC. The amino acid profile of PSC showed substantial
amounts of tryptophan (1.54 g/16 g N) and low levels of lysine (3.21) and isoleucine
(3.83 g/16 g N). True digestibility coefficient (TD) of PSC protein was found to be
83.1% which was not significantly different than soybean meal. Though protein
efficiency ratio (PER) of pumpkin seed was lower (1.01) than soybean meal, it can
be at par after supplementing with lysine. PER of the diet containing PSC and
soybean meal in equal proportion of protein demonstrated the higher value of PER
(1.98) in comparison with only soybean meal (PER 1.50).
19.4.3 Lipids
Stevenson et al. (2007) studied the oil content of 12 different cultivars of pumpkin
seeds, which was found to be ranging from 22 to 50% depending on variety and
19 Pumpkin (Cucurbita pepo) Seed
477
and Lakhawat 2017), 1.0% (Elinge et al. 2012), 5.34% (Gohari Ardabili et al. 2011),
and 14.82 Æ 0.55 g/100 g (Kim et al. 2012)
19.4.2 Proteins
Protein content in pumpkin seeds ranged from 24.50 to 32.00 g/100 g (Kim et al.
2012; Elinge et al. 2012; Aliu et al. 2016; Nyam et al. 2009) and approximately
55.40 g/100 g in defatted seed flour (Lazos 1986). Sharma and Lakhawat (2017)
have reported 29.65% protein content in roasted pumpkin seed flour. Pumpkin
seed’s protein contains all 9 essential amino acids (Table 19.1) (El-Adawy and
Taha 2001; Patel 2013). Cucurbita pepo seeds have the highest content of arginine
(63.99 Æ 0.88 mg/kg) as compared to other species such as Cucurbita maxima and
Cucurbita moschata (Kim et al. 2012).
Higher concentrations of essential amino acids were reported in protein isolates
(40.92–42.59 g per 16 g N) than concentrate (36.13 g per 16 g N) and meal (35.03 g
per 16 g N). During isolate preparation, a few protein fractions are lost which may
result in loss of non-essential amino acids and increase levels of essential amino
acids (Mansour et al. 1993). Table 19.2 provides a summary of the estimated
biological quality of pumpkin (Cucurbita pepo) seed flours/protein by different
researchers.
After oil extraction, the protein content of oil cake can increase up to 65%.
Various fractions of this protein are cucurbitin and albumin. The major fraction is
represented by cucurbitins, 12S globulins composed of six similar subunits
(hexamer) with molecular weights of 54 kDa each and are the major storage proteins
in pumpkin seeds (Bučko et al. 2016). Zdunczyk et al. (1999) conducted a comparative study on the chemical composition as well as the nutritive value of pumpkin
seed cake (PSC), soybean meal, and casein. The authors reported higher content of
protein (59.8 g/100 g) in PSC. The amino acid profile of PSC showed substantial
amounts of tryptophan (1.54 g/16 g N) and low levels of lysine (3.21) and isoleucine
(3.83 g/16 g N). True digestibility coefficient (TD) of PSC protein was found to be
83.1% which was not significantly different than soybean meal. Though protein
efficiency ratio (PER) of pumpkin seed was lower (1.01) than soybean meal, it can
be at par after supplementing with lysine. PER of the diet containing PSC and
soybean meal in equal proportion of protein demonstrated the higher value of PER
(1.98) in comparison with only soybean meal (PER 1.50).
19.4.3 Lipids
Stevenson et al. (2007) studied the oil content of 12 different cultivars of pumpkin
seeds, which was found to be ranging from 22 to 50% depending on variety and
19 Pumpkin (Cucurbita pepo) Seed
477