Structural, Thermal and Film forming properties of Gelatin from Pink Perch Surimi Refiner Discharge

Abstract

The objective of the present study was to characterize
the gelatin obtained from pink perch (Nemipterus
japonicus) surimi refiner discharge [referred as
refiner discharge gelatin (RDG)] with reference to
its structural, thermal and film forming ability.
Fourier transform infrared (FTIR) and Differential
Scanning Calorimetry (DSC) techniques were used
to characterize the gelatin. An edible film was
developed with different concentrations of RDG
(2-6%) by casting method. FTIR analysis showed
that the gelatin from refiner discharge has similar
spectra with porcine gelatin (PG). The amide I and
amide II bands of RDG occurred at around 1654 and
1578 cm-1 respectively. RDG has a broad endothermic
peak at 85.64oC with transition enthalpy (ΔH)
of 208.02 J g-1 as revealed by thermal analysis
indicating the thermal transition temperature and
the energy required for the transition respectively.
RDG showed good film forming property. The
gelatin concentration had strong significant (p<0.05)
effect on the viscosity of film forming solution.
Films were more opaque at higher concentration of
gelatin compared to the films prepared at lower
concentration. Higher L* values were observed for
all the films prepared and there were no significant
differences among the gelatin concentrations. Tensile
strength of the film increased with increasing
gelatin concentration whereas the film swelling was
found to be decreased. The study clearly demonstrated
that the waste from the surimi processing
industries like refiner discharge can be an alternative
raw material for gelatin production and can be
used for edible packaging films development.