354
glauca ) skin gelatin was recently investigated to modify properties such as the water
vapour barrier and fl exibility due to their hydrophobicity and plasticizing effect,
respectively (Limpisophon et al. 2010 ). Addition of stearic acid from 0 to 100 % of
protein concentration in the fi lm-forming solution considerably decreased water
vapour permeability of gelatin– fatty acid emulsion fi lms, compared to addition of
oleic acid at the same fatty acid concentration. Increasing concentrations of both
fatty acids decreased tensile strength, but increased elongation at break due to their
plasticizing effect. At the same concentration, oleic acid gave a greater plasticizing
effect than did stearic acid. On the other hand, transparency of the gelatin–stearic
acid emulsion fi lm was lower than that of the gelatin–oleic acid emulsion fi lm.
Faster stirring speed during homogenization improved properties of only the gelatin–stearic acid emulsion fi lm.
Intriguingly, gelatin derived from shark skin was recently hydrolysed to obtain
antifreeze peptides (Wang et al. 2012 ). Antifreeze proteins can inhibiting the growth
of crystals, decreasing the injury of cells, and can retain the structure, texture and
quality of productions. The purpose of the study reported was to obtain natural antifreeze peptides, and to investigate the hypothermia protection activity on bacteria.
The most appropriate protease and hydrolysis time was selected with the index of
the hypothermia protection activity on bacteria. The hydrolysate was subsequently
added on to Sephadex G-50 gel fi ltration column and SP-Sephadex C-25 column to
acquire high activity fractions. The fraction of cationic peptides termed P2 showed
higher antifreeze activity. The hypothermia protection assay showed that the survival rate of E. coli was 80.8 % when the concentration of peptides complexes was
at 500 μg/mL (Wang et al. 2012 ).
9.3 Conclusion
Gelatin is a multifunctional ingredient used in foods, pharmaceuticals, cosmetics,
and photographic fi lms as a gelling agent, stabilizer, thickener, emulsifi er, and fi lm
former. As a thermoreversible hydrocolloid with a narrower gap between its melting
and gelling temperatures, both of which are below human body temperature, gelatin
provides unique advantages over carbohydrate-based gelling agents (Boran and
Regenstein 2010 ). Gelatin is widely used as a medical biomaterial because it is
readily available, cheap, biodegradable and demonstrates favorable biocompatibility
(Elvin et al. 2010 ). In spite of the very intriguing title of the patent by Andre et al
( 2000 ) “ Use of collagen of aquatic origin for the production of supports for tissue
engineering, and supports and biomaterials obtained ”, there are unfortunately only
few reports on biomedical application of fi sh gelatins. However, some of these
biopolymers possess interesting properties. For example, Nagai et al ( 2008 ) investigated blood compatibility evaluation of elastic gelatin gel from salmon collagen.
It was shown that the platelet adhesion rate was markedly lower on the elastic fi sh
gelatin -gel compared to collagen-coated and fi brinogen-coated surfaces. Moreover
this gel demonstrated good blood compatibility.
9 Marine Gelatins
glauca ) skin gelatin was recently investigated to modify properties such as the water
vapour barrier and fl exibility due to their hydrophobicity and plasticizing effect,
respectively (Limpisophon et al. 2010 ). Addition of stearic acid from 0 to 100 % of
protein concentration in the fi lm-forming solution considerably decreased water
vapour permeability of gelatin– fatty acid emulsion fi lms, compared to addition of
oleic acid at the same fatty acid concentration. Increasing concentrations of both
fatty acids decreased tensile strength, but increased elongation at break due to their
plasticizing effect. At the same concentration, oleic acid gave a greater plasticizing
effect than did stearic acid. On the other hand, transparency of the gelatin–stearic
acid emulsion fi lm was lower than that of the gelatin–oleic acid emulsion fi lm.
Faster stirring speed during homogenization improved properties of only the gelatin–stearic acid emulsion fi lm.
Intriguingly, gelatin derived from shark skin was recently hydrolysed to obtain
antifreeze peptides (Wang et al. 2012 ). Antifreeze proteins can inhibiting the growth
of crystals, decreasing the injury of cells, and can retain the structure, texture and
quality of productions. The purpose of the study reported was to obtain natural antifreeze peptides, and to investigate the hypothermia protection activity on bacteria.
The most appropriate protease and hydrolysis time was selected with the index of
the hypothermia protection activity on bacteria. The hydrolysate was subsequently
added on to Sephadex G-50 gel fi ltration column and SP-Sephadex C-25 column to
acquire high activity fractions. The fraction of cationic peptides termed P2 showed
higher antifreeze activity. The hypothermia protection assay showed that the survival rate of E. coli was 80.8 % when the concentration of peptides complexes was
at 500 μg/mL (Wang et al. 2012 ).
9.3 Conclusion
Gelatin is a multifunctional ingredient used in foods, pharmaceuticals, cosmetics,
and photographic fi lms as a gelling agent, stabilizer, thickener, emulsifi er, and fi lm
former. As a thermoreversible hydrocolloid with a narrower gap between its melting
and gelling temperatures, both of which are below human body temperature, gelatin
provides unique advantages over carbohydrate-based gelling agents (Boran and
Regenstein 2010 ). Gelatin is widely used as a medical biomaterial because it is
readily available, cheap, biodegradable and demonstrates favorable biocompatibility
(Elvin et al. 2010 ). In spite of the very intriguing title of the patent by Andre et al
( 2000 ) “ Use of collagen of aquatic origin for the production of supports for tissue
engineering, and supports and biomaterials obtained ”, there are unfortunately only
few reports on biomedical application of fi sh gelatins. However, some of these
biopolymers possess interesting properties. For example, Nagai et al ( 2008 ) investigated blood compatibility evaluation of elastic gelatin gel from salmon collagen.
It was shown that the platelet adhesion rate was markedly lower on the elastic fi sh
gelatin -gel compared to collagen-coated and fi brinogen-coated surfaces. Moreover
this gel demonstrated good blood compatibility.
9 Marine Gelatins