Agriculture Reference
In-Depth Information
broth of green seaweed was superior to those levels in red and brown seaweeds. Particularly,
the levels of lysine, methionine, tyrosine and phenylalanine constituted a substantial amount
of the total amino acids of green seaweed compared with those levels in both red and brown
seaweeds. The sulfur-containing amino acid, methionine, was known to be a nutritionally
important essential amino acid and to be the precursor of several metabolites that regulate
plant growth (Amir et al., 2002). Relatively high levels of methionine that were in the culture
broths of green and red seaweeds could increase their fertilizing value.
As shown in Table 2, there were some pronounced differences among the amino acid
compositions of green, red and brown seaweeds. These differences were most likely due to
the seaweed species that were used and to the degree of microbial degradation. These levels
of total amino acids that were in the culture broth of seaweeds were less than half of that in
fermented fish wastes (Kim et al., 2010).
The reported amino acid compositions of different seaweed extracts are presented in
Table 3. The levels of each essential amino acid that were in seaweed extracts were almost
higher than that of biodegraded culture broths of seaweeds that were used in this study, which
resulted in much higher levels of total amino acids. This finding indicates that some amino
acids were consumed by microorganisms during the culturing of the seaweeds. It was
reported that high levels of aspartic acid and glutamic acid contribute to the special flavor and
taste of the seaweeds (Mabeau et al., 1992).
Table 3. The reported amino acid composition of seaweeds (unit: g 100 g protein
-1
)
U. lactuca
a
(Green)
P. tenra
b
(Red)
L.digitata
c
(Brown)
FAO/WHO
requirement
d
Amino acid
Lysine
6.5
4.5
4.8
1.6
Histidine
1.4
1.4
2.4
1.6
Arginine
6.2
16.4
3.0
Aspartic acid
12.9
7.0
4.7
Threonine
6.3
4.0
3.4
0.9
Serine
6.9
2.9
2.5
Glutamic acid
12.9
7.2
3.9
Proline
4.1
6.4
1.9
Glycine
6.7
7.2
3.3
Alanine
9.2
7.4
4.5
Valine
9.2
6.4
6.0
1.3
1.7
e
Cysteine
1.9
-
2.0
Tryptophan
-
1.3
0.2
0.5
Methionine
2.4
1.1
1.5
Leucine
8.3
8.7
4.5
1.9
Tyrosine
6.0
2.4
1.7
1.9
f
Isoleucine
4.8
4.0
2.6
1.3
Phenylalanine
2.7
3.9
2.8
a
Data that were obtained from Yaich et al. (2011).
b
Data that were obtained from Fleurence (1999).
c
Data that were obtained from Kolb et al. (2004).
d
Requirement pattern for adults.
e
Cysteine + Methionine.
f
Tyrosine + Phenylalanine.
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