Chemistry Reference
In-Depth Information
Table 10.4
Active peptides from fish protein hydrolyzates.
Active
peptides
Raw
materials
Active
peptides
Enzyme
IC50
References
Antioxidative
Tuna
backbone
protein
Pepsin
Val-Lys-Ala-Gly-Phe-
Ala-Trp-Thr-Ala-Asn-
Gln-Gln-Leu-Ser
NR
64
Peptides
Hoki frame
protein
Pepsin
Glu-Ser-Thr-Val-Pro-
Glu-Arg-Thr-His-Pro-
Asp-Phe-Asn
41.37
µ
M for
DPPH radical
46
ACE
inhibitory
peptides
Alaska pollack
frame protein
Mackerel
intestine crude
enzyme (MICE)
Leu-Pro-His-Ser-Gly-
Tyr
17.77
µ
M for
hydroxyl
radical
Yellowfin sole
frame protein
MICE-pepsin
Arg-Pro-Asp-Phe-Asp-
Leu-Glu-Pro-Pro-Tyr
18.99
µ
M for
peroxyl
radical
68
Shark meat
Cys-Phe
172.10
µ
M
for superoxide
radicals
Yellowfin sole
frame protein
Protease
SM98011 from
Bacillus sp.
Glu-Tyr
NR
52
Alaska pollack
frame protein
α
-Chymotrypsin
Phe-Glu
NR
66
Alaska pollack
skin gelatin
Pepsin
Met-Ile-Phe-Pro-Gly-
Ala-Gly-Gly-Pro-Glu-
Leu
1.96
µ
M
65
Alcalase-Pronase
E-collagenase
Phe-Gly-Ala-Ser-Thr-
Arg-Gly-Ala
2.68
µ
M
Gly-Pro-Leu
1.45
µ
M
45
28.7
µ
gmL
−1
Gly-Pro-Met
44
14.7
µ
M
2.6
µ
M
17.13
µ
M
NR: not reported.
- glutamyl) lysine linkages.
79
via formation of iso-peptide,
ε
-(
γ
This occurs through the
exchange of the
-amino group of the lysine residue for the ammonia at the carboxyamine
group of a glutamine residue in protein molecules (see Fig. 10.6). Formation of covalent
cross-links between proteins is the basis of the ability of TGase to modify the physical
properties of protein foods.
80
The cross-linking capability is influenced by the amino acid
sequence and the charge of amino acids surrounding the susceptible glutamine residue and
local secondary structures.
81
ε
Proteolysis of non-reactive protein can convert it to a TGase
substrate.
82
Endogenous TGase in fish muscle varies with species and is most likely associated with the
setting phenomenon. Setting or suwari involves network formation of fish proteins, mainly
myosin, due to the cross-linking by endogenous TGase in the temperature range of 5-40
◦
C.
Fish muscle contains TGase ranging from 0.10-2.41 U g
−
1
.
83
This enzyme induces the
cross-linking of muscle proteins and affects the textural properties of fish protein gels.
84-87
Benjakul
et al
.
88
confirmed the role of TGase in setting of the surimi from tropical fish
