348
2005 ) and organic substances, guided the progress in developing of fi sh gelatinbased composites (Shakila et al. 2012 ). Here, are some examples.
Nanoclay composite fi lm was produced using warm water fi sh gelatin as a base
material and its physical, mechanical, and molecular weight change properties were
observed after treatment with microbial transglutaminase (MTGase) (Bae et al.
2009 ). The viscosity of the MTGase-treated gelatin solution (2 % w/w) increased
from 86.25 ± 1.77 (0 min) to 243 ± 12.37 cp (80 min). SDS–PAGE results indicated
that the molecular weight of fi sh gelatin solutions increased after treatment with
microbial transglutaminase. Tensile strength decreased from 61.60 ± 1.77 (0 min) to
56.42 ± 2.40 MPa (30 min), while E% increased from 13.94 ± 5.09 (0 min) to
15.78 ± 5.97 % (30 min) at 2 % (w/w) MTGase concentration. The oxygen permeability and water vapour permeability did not change as a function of treatment time
at 2 % (w/w) MTGase concentration. The incorporation of nanoclay inhibited the
increase of oxygen permeability. Film colour values (L, a, and b) did not change,
but haze values increased from 5.24 ± 0.40 (0 min) to 6.44 ± 0.94 (50 min). XRD
and TEM results suggested that the nanoclay was exfoliated in fi sh gelatin fi lm
(Bae et al. 2009 ).
Composite fi lms were prepared from pectin and fi sh skin gelatin, as reported by
Liu et al. ( 2007 ). The inclusion of protein promoted molecular interactions. This
resulted in a well-organized homogeneous structure, as revealed by scanning electron microscopy and fracture-acoustic emission analysis. The resultant composite
fi lms showed an increase in stiffness and strength and a decrease in water solubility
and water vapor transmission rate, in comparison with fi lms cast from pectin alone.
The composite fi lms inherited the elastic nature of proteins, and were thus more
fl exible than the pure pectin fi lms. Treating the composite fi lms with glutaraldehyde/methanol induced chemical cross-linking with the proteins and reduced the
interstitial spaces among the macromolecules and, consequently, improved their
mechanical properties and water resistance. Treating the protein-free pectin fi lms
with glutaraldehyde/methanol also improved the Young’s modulus and tensile
strength, but showed little effect on the water resistance, as the treatment caused
only dehydration of the pectin fi lms and the dehydration is reversible. The composite fi lms were biodegradable and possessed moderate mechanical properties and a
low water vapor transmission rate (Liu et al. 2007 ).
The effectiveness of using hydroxylpropylmethylcellulose (HPMC) to enhance
mechanical strength and thermal stability in fi sh skin gelatin was studied by Chen
et al. ( 2009 ). The signifi cant increase in absorbance observed after HPMC had been
added to fi sh gelatin and then matured indicated successful formation of a composite gel. Increased gel strength and storage modulus (G′) indicated the enhanced
gelation ability of the matured composite gel, while increased melting temperature
(T m ) and enthalpy (ΔH) indicated its improved thermal stability. Maturation-related
rheological property improvements were more noticeable at 4 °C than 10 °C, but no
apparent differences in Tm improvement were observed between 4 and 10 °C
maturation. Nevertheless, the composite gel exhibited reversible cold and thermal
gelation properties (Chen et al. 2009 ).
Due to the poor mechanical properties of the fi sh gelatin membranes, composite
nanofi bers made of fi sh gelatin and poly(L-lactide) (PLLA) were recently produced
9 Marine Gelatins
2005 ) and organic substances, guided the progress in developing of fi sh gelatinbased composites (Shakila et al. 2012 ). Here, are some examples.
Nanoclay composite fi lm was produced using warm water fi sh gelatin as a base
material and its physical, mechanical, and molecular weight change properties were
observed after treatment with microbial transglutaminase (MTGase) (Bae et al.
2009 ). The viscosity of the MTGase-treated gelatin solution (2 % w/w) increased
from 86.25 ± 1.77 (0 min) to 243 ± 12.37 cp (80 min). SDS–PAGE results indicated
that the molecular weight of fi sh gelatin solutions increased after treatment with
microbial transglutaminase. Tensile strength decreased from 61.60 ± 1.77 (0 min) to
56.42 ± 2.40 MPa (30 min), while E% increased from 13.94 ± 5.09 (0 min) to
15.78 ± 5.97 % (30 min) at 2 % (w/w) MTGase concentration. The oxygen permeability and water vapour permeability did not change as a function of treatment time
at 2 % (w/w) MTGase concentration. The incorporation of nanoclay inhibited the
increase of oxygen permeability. Film colour values (L, a, and b) did not change,
but haze values increased from 5.24 ± 0.40 (0 min) to 6.44 ± 0.94 (50 min). XRD
and TEM results suggested that the nanoclay was exfoliated in fi sh gelatin fi lm
(Bae et al. 2009 ).
Composite fi lms were prepared from pectin and fi sh skin gelatin, as reported by
Liu et al. ( 2007 ). The inclusion of protein promoted molecular interactions. This
resulted in a well-organized homogeneous structure, as revealed by scanning electron microscopy and fracture-acoustic emission analysis. The resultant composite
fi lms showed an increase in stiffness and strength and a decrease in water solubility
and water vapor transmission rate, in comparison with fi lms cast from pectin alone.
The composite fi lms inherited the elastic nature of proteins, and were thus more
fl exible than the pure pectin fi lms. Treating the composite fi lms with glutaraldehyde/methanol induced chemical cross-linking with the proteins and reduced the
interstitial spaces among the macromolecules and, consequently, improved their
mechanical properties and water resistance. Treating the protein-free pectin fi lms
with glutaraldehyde/methanol also improved the Young’s modulus and tensile
strength, but showed little effect on the water resistance, as the treatment caused
only dehydration of the pectin fi lms and the dehydration is reversible. The composite fi lms were biodegradable and possessed moderate mechanical properties and a
low water vapor transmission rate (Liu et al. 2007 ).
The effectiveness of using hydroxylpropylmethylcellulose (HPMC) to enhance
mechanical strength and thermal stability in fi sh skin gelatin was studied by Chen
et al. ( 2009 ). The signifi cant increase in absorbance observed after HPMC had been
added to fi sh gelatin and then matured indicated successful formation of a composite gel. Increased gel strength and storage modulus (G′) indicated the enhanced
gelation ability of the matured composite gel, while increased melting temperature
(T m ) and enthalpy (ΔH) indicated its improved thermal stability. Maturation-related
rheological property improvements were more noticeable at 4 °C than 10 °C, but no
apparent differences in Tm improvement were observed between 4 and 10 °C
maturation. Nevertheless, the composite gel exhibited reversible cold and thermal
gelation properties (Chen et al. 2009 ).
Due to the poor mechanical properties of the fi sh gelatin membranes, composite
nanofi bers made of fi sh gelatin and poly(L-lactide) (PLLA) were recently produced
9 Marine Gelatins