113
selenium, chromium (Adedayo et al. 2011). Some yeast species, e.g. Saccharomyces
cerevisiae, have a probiotic effect only in the human body (Muszyńska et al. 2013).
Nucleic acid component (2–18% of dry substance) is also a component of biomass,
which is a potential danger for the human body, as it may lead to the accumulation
of uric acid crystals in the kidneys or joints, leading to gout. Their content is highest
in bacterial cells and the lowest in algae cells (Nasseri et al. 2011). Nucleic acids are
also present in conventional foods and constitute a permanent component of the
diet, both meat and vegetarian (Głazowska et al. 2016). The content of nucleic acids
in the diet should not exceed 2 g per day, so the consumption of SCP cannot exceed
30 g per day (Piasecka-Kwiatkowska and Stasińska 2016). Yadav et al. (2017)
proved that the use of a combination of two chemical substances: N-Lauroiol sarcosine and NH 4 OH allows to reduce the content of nucleic acids in biomass to the
desired level (<2%). The proteins of unicellular organisms may also adversely affect
the human immune system, causing allergies (Nasseri et al. 2011). An obstacle in
the use of microbial protein in human nutrition is the presence of anti-nutritive substances, such as nucleic acids, as well as residues of atypical biomass components
and the possibility of microbial contamination difficult to eliminate during the production process (Nasseri et al. 2011; Bueschke et al. 2017). SPC on an industrial
scale is mainly produced as an additive to animal feed, because the cost as production costs of microbiological proteins that could be a component of human food are
too high (Nasseri et al. 2011, 2016).
Table 7.1 Amino acid profile of proteins derived from alternative sources (g/100 g)
Amino acids
Sources of protein
Algae Bacteria Yeast Mushrooms Krill
Insects FAO pattern
Isoleucine
4.7
3.3
2.5
1.8
2.5
3.8
2.8
Leucine
8.6
5.4
3.6
2.9
4.0
6.5
6.6
Valine
6.2
4.2
2.7
2.2
2.6
5.2
3.5
Lysine
6.3
4.3
3.5
3.0
4.4
5.1
5.8
Phenylalanine
9.0
5.8
4.1
3.1
5
9.7
6.3
Metionine
3.1
2.2
1.5
1.0
2.4
3.5
2.5
Tryptophan
0.9
0.8
0.6
0.3
0.7
1.2
1.1
Threonine
5.4
3.3
2.5
2
2.2
3.7
3.4
Arginine
6.9
3.7
2.3
2.7
3.8
4.5
nd
Histidine
2.1
1.5
1.2
1.0
1.1
2.2
nd
Aspartic acid
9.7
nd
nd
nd
5.3
nd
nd
Glutamine
10.9
nd
nd
nd
6.7
9.7
nd
Glycine
6.2
nd
nd
nd
3.4
5.1
nd
Proline
4.3
nd
nd
nd
2.3
4.6
nd
Serine
4.3
nd
nd
nd
1.9
4
nd
Alanine
nd
nd
nd
nd
2.9
5.9
nd
Total protein (% DM) 40–60 50–65
44–55 30–45
60–65 5–77
nd
Source: Becker (2007), Nalage et al. (2016), Nasseri et al. (2011), Piasecka-Kwiatkowska and
Stasińska (2016), Rumpold and Schlüter (2013), Tou et al. (2007), and Zielińska et al. (2017)
DM dry mass, nd no data
7 Alternative and New Protein Sources
selenium, chromium (Adedayo et al. 2011). Some yeast species, e.g. Saccharomyces
cerevisiae, have a probiotic effect only in the human body (Muszyńska et al. 2013).
Nucleic acid component (2–18% of dry substance) is also a component of biomass,
which is a potential danger for the human body, as it may lead to the accumulation
of uric acid crystals in the kidneys or joints, leading to gout. Their content is highest
in bacterial cells and the lowest in algae cells (Nasseri et al. 2011). Nucleic acids are
also present in conventional foods and constitute a permanent component of the
diet, both meat and vegetarian (Głazowska et al. 2016). The content of nucleic acids
in the diet should not exceed 2 g per day, so the consumption of SCP cannot exceed
30 g per day (Piasecka-Kwiatkowska and Stasińska 2016). Yadav et al. (2017)
proved that the use of a combination of two chemical substances: N-Lauroiol sarcosine and NH 4 OH allows to reduce the content of nucleic acids in biomass to the
desired level (<2%). The proteins of unicellular organisms may also adversely affect
the human immune system, causing allergies (Nasseri et al. 2011). An obstacle in
the use of microbial protein in human nutrition is the presence of anti-nutritive substances, such as nucleic acids, as well as residues of atypical biomass components
and the possibility of microbial contamination difficult to eliminate during the production process (Nasseri et al. 2011; Bueschke et al. 2017). SPC on an industrial
scale is mainly produced as an additive to animal feed, because the cost as production costs of microbiological proteins that could be a component of human food are
too high (Nasseri et al. 2011, 2016).
Table 7.1 Amino acid profile of proteins derived from alternative sources (g/100 g)
Amino acids
Sources of protein
Algae Bacteria Yeast Mushrooms Krill
Insects FAO pattern
Isoleucine
4.7
3.3
2.5
1.8
2.5
3.8
2.8
Leucine
8.6
5.4
3.6
2.9
4.0
6.5
6.6
Valine
6.2
4.2
2.7
2.2
2.6
5.2
3.5
Lysine
6.3
4.3
3.5
3.0
4.4
5.1
5.8
Phenylalanine
9.0
5.8
4.1
3.1
5
9.7
6.3
Metionine
3.1
2.2
1.5
1.0
2.4
3.5
2.5
Tryptophan
0.9
0.8
0.6
0.3
0.7
1.2
1.1
Threonine
5.4
3.3
2.5
2
2.2
3.7
3.4
Arginine
6.9
3.7
2.3
2.7
3.8
4.5
nd
Histidine
2.1
1.5
1.2
1.0
1.1
2.2
nd
Aspartic acid
9.7
nd
nd
nd
5.3
nd
nd
Glutamine
10.9
nd
nd
nd
6.7
9.7
nd
Glycine
6.2
nd
nd
nd
3.4
5.1
nd
Proline
4.3
nd
nd
nd
2.3
4.6
nd
Serine
4.3
nd
nd
nd
1.9
4
nd
Alanine
nd
nd
nd
nd
2.9
5.9
nd
Total protein (% DM) 40–60 50–65
44–55 30–45
60–65 5–77
nd
Source: Becker (2007), Nalage et al. (2016), Nasseri et al. (2011), Piasecka-Kwiatkowska and
Stasińska (2016), Rumpold and Schlüter (2013), Tou et al. (2007), and Zielińska et al. (2017)
DM dry mass, nd no data
7 Alternative and New Protein Sources