CHARACTERISTICS OF GELATIN FROM SWIM BLADDER OF YELLOWFIN TUNA (THUNNUS ALBACORES) AS INFLUENCED BY EXTRACTING TEMPERATURES

Gelatin was extracted from the swim bladder of yellowfin tuna (Thunnus albacores) at different temperatures (60, 70 and 80°C) with the extraction yields of 35.6%, 41.1% and 47.3% (dryweight basis), respectively. The α-chains of gelatin decreased with increasing extraction temperatures.Similar amino acid compositions were noticeable among all gelatins, in which glycine constituted the major amino acid. Imino acids ranged from 169 to 172 residues/1,000 residues. Thegel strength of gelatin extracted at lower temperature was higher than that of gelatins extracted at higher temperatures. Gelling and melting temperatures for swim bladder gelatin were 11.07-15.24 and 20.36-22.33°C, respectively. Higher gelling and melting points were observed for gelatin extracted at lower temperatures. Microstructure of gel of gelatin extracted at 60°C was finerwith smaller voids, compared with others. FTIR spectra of obtained gelatins revealed the significant loss of molecular order of the triple-helix. Thus, extraction temperatures showed the directimpact on characteristics of gelatin from swim bladder

Properties and characteristics of salmon frame protein isolate films influenced by glycerol and squalene

Characteristics of edible/biodegradable film based on salmon frame protein isolate (SFPI), a processing by-product, containing glycerol at two different concentrations (50 and 65% by weight of protein) with and without 30% squalene (by weight of protein) were investigated. Without squalene, the SFPI film generally had higher hydrophilicity when higher concentration of glycerol was used as indicated by higher (p < 0.05) water-vapour permeability (WVP). The addition of squalene augmented yellowness and hydrophobicity of SFPI film as indicated by higher b* colour coordinate and lower WVP (p < 0.05), respectively, in comparison to those without squalene. The squalene also promoted the interactions in SFPI film matrix as revealed by Fourier-transform infrared spectra. These interactions were related to a superior mechanical properties, high barrier properties, and increased thermal resistance of the resulting SFPI film. Therefore, the addition of 30 squalene along with 50% glycerol as plasticiser improved physicochemical, mechanical, barrier, and thermal properties of SFPI film, which could be used as an alternative film for edible/biodegradable food packaging