Development And Characterization Of Edible Films From Sago Starch/Surimi By-Products Fish Gelatin Blends
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Date
2011-07
Authors
Al-Hassan, Ahmed Ali S.
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
Physicochemical and thermal properties of extracted fish gelatin (EFG) obtained from surimi wastes were investigated and compared with those of fish gelatin (CFG) and halal bovine gelatin (HBG) from commercial preparations. Extracted fish gelatin was characterized for its physicochemical properties such as colour, amino acid composition, elemental content, structural analysis by FTIR and for its thermal properties. From differential scanning calorimetry (DSC) experiments, melting and gelling temperatures of EFG obtained were 16.2 ± 0.2 °C and 5.27 ± 0.4 °C, respectively and from rheological measurements, they were 16.7 ± 0.1 °C and 5.1 ± 0.1 °C, respectively. Both results obtained for EFG were much lower than that of CFG and HBG. Significantly lower viscosity of EFG was observed compared to other gelatins. To enhance the physical and thermal properties of EFG, transglutaminase (TGs) was added in different amounts (0.5, 1.0, 3.0 and 5.0 mg/g gelatin) to the EFG samples. Treated gelatin samples showed reduction in the amino acid groups from degree of crosslinking test and polymerization bands were observed in SDS-PAGE analysis in all treated samples. Likewise, FTIR scans showed a decrease in the intensity of the peaks involving the έ-amine of lysine. TGs increased the melting temperature of treated EFG up to 19 ± 0.7 °C from DSC scans. From rheological measurements, melting temperature increased to 17.5 ± 0.5 °C whilst the gelling temperatures increased up to 5.7 ± 0.1 °C compared to untreated samples (5.1 ± 0.1 °C). Gel strengths increased to 101.1 g and 90.56 g with TGs of 1.0 and 3.0 mg/g, respectively. However, with addition of 5.0 mg/g enzyme the gel strength decreased (75.06 g) but was still higher than untreated samples. In the preparation of edible films from sago starch/extracted fish gelatin blends, film forming solutions (FFS) of different ratios of sago starch to fish gelatin (1:0, 2:1, 3:1, 4:1 and 5:1) plasticized with 25, 30 and 35% (w/w) glycerol or sorbitol were used. The rheology of FFS and morphology, physicochemical, thermal and mechanical properties of the developed films were investigated.
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Keywords
Development and characterization of , edible films from sago starch