Properties Of Edible Films Prepared From Fish Skin Gelatin Added With Different Fatty Acids And Their Sucrose Esters

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dc.contributor.authorAhmad, Nor Amalini
dc.date.accessioned2016-09-23T08:21:19Z
dc.date.available2016-09-23T08:21:19Z
dc.date.issued2015-12
dc.description.abstractAmong biopolymers used to prepare edible films, gelatin has received much attention for its good film forming ability. However, gelatin films are very hydrophilic thus modification is needed to reduce this drawback. In this study, the fish gelatin was extracted from Tilapia fish skins and its physico-chemical properties determined. The yield of extracted fish gelatin (EFG) was 20.2 % with 91.5 % protein, 7.0 % moisture, and 1.3 % ash contents. The bloom strength of EFG was 241.1 g, considered relatively high and also showed the presence of high molecular weight proteins such as α and β chains in the electrophoresis protein pattern. FTIR spectra of EFG showed amide groups (A, B, I, II and III) in regions of wavenumbers similar to those of commercial gelatins from bovine sources. Extracted fish gelatin (EFG) was then further utilized to produce glycerol plasticized protein based edible films. Glycerol was added at concentrations, 5, 10 and 15 % based on weight of gelatin. The use of EFG as biopolymer matrix successfully formed free-stand and stable gelatin films. Addition of glycerol as plasticizer reduced tensile strength (TS) and Young’s modulus (E) but increased elongation at break (EAB) of gelatin films compared to unplasticized gelatin film. However, with increasing amount of glycerol from 5 to 15 %, the plasticized films also exhibited increasing water vapour permeability (WVP) and opacity but decreasing solubility. Thus to improve the film properties especially the water barrier properties, modification on the plasticized gelatin films was carried out by addition of palmitic acid (PA) or stearic acid (SA), or their sucrose esters; palmitic acid sucrose ester (PASE) or stearic acid sucrose ester (SASE) as substitutes for glycerol at various ratios. The effects of adding these fatty acids (FAs) or fatty acid sucrose esters (FASEs) on the physical, mechanical and morphological properties of gelatin based films were investigated. Addition of all these FAs or FASEs successfully improved water and light barrier properties of gelatin films by increasing opacity while decreasing WVP. Greatest WVP reduction was observed at 15 % plasticizer level, with percentage reduction of 62.5, 60.1, 62.6 and 68.7 % for PA, SA, PASE and SASE added films, respectively. In general, highest TS values were observed in films: PA (62.3 MPa), SA (74.8 MPa), PASE (72.6 MPa) and SASE (68.7 MPa). The E values of all FAs and FASEs added films were higher than those of films plasticized with glycerol only (at all glycerol concentrations). These results indicated stronger/stiffer films were formed with addition of the FAs or FASEs. The EAB decreased with increasing amounts of these hydrophobic materials in gelatin films, except for PA added film at 15 % plasticizer concentration, in which 15P-PA75 film showed significantly highest EAB. Sorption isotherm studies showed that gelatin films exhibited J-shape curves with increasing moisture uptake in the order of SA < PA < SASE < PASE added films. Overall, films added with the FAs or FASEs showed improved water and light barrier properties as well as high film strength. In addition, FASE added films exhibited lower WVP but less flexible than FA added films. In conclusion, these films can be used as secondary packagings to complement the use of synthetic packagings, with potential applications as water and light barrier packaging materials for low moisture foods such as nuts, cereals and spices.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/2604
dc.language.isoenen_US
dc.publisherUniversiti Sains Malaysiaen_US
dc.subjectFish skin gelatinen_US
dc.titleProperties Of Edible Films Prepared From Fish Skin Gelatin Added With Different Fatty Acids And Their Sucrose Estersen_US
dc.typeThesisen_US
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