|
Channel Catfish fish skin as raw materials, process conditions and the nature of the fish skin gelatin skin gelatin extracted and fish skin gelatin modified konjac glucomannan composite film preparation and properties of study. The results are as follows: four factors quadratic regression general rotation design test, the concentration of hydrochloric acid, liquid ratio, extraction temperature and extraction time on the yield of fish skin gelatin, each factor with fish skin gelatin yield mathematical regression model. Determine the optimum extraction conditions: hydrochloric acid concentration of 3.20%, the solid-liquid ratio of 2.915, extraction temperature of 64.5 ° C, the extraction time for-3.95h conditions, the skin gelatin yield up to 11.55%. Measured under optimum extraction conditions skin gelatin composition: 88.53% protein, 0.62% fat, moisture 10.04% and 0.17% ash. Fish skin gelatin composition, structure and properties. Amino acid composition analysis showed that the amino acid composition of the fish skin gelatin rich in glycine, proline, alanine, lack of tryptophan and cysteine. Skin gelatin SDS-PAGE showed skin glue contains three bands, respectively, for the β chain, α1 chains and the α2 chain, corresponding to a molecular weight of approximately 200 kDa, 120kDa, 105kDa. Determination of the gel strength, gelation temperature and the melting temperature of the skin adhesive, 223g, 15.7 ℃ and 24.4 ° C, respectively. Using fluorescence detection agent ANS Determination of the hydrophobicity of the surface of the fish skin gelatin, and the results showed that the surface of the fish skin gelatin less hydrophobic. Skin gelatin in Cd content of 0.04 mg / kg, Pb, As, Cr was not detected, the sample almost free of heavy metals. The the konjac glucomannan oxidation modified conditions, and skin gelatin modified konjac glucomannan composite polymer material nature study. Through single factor and orthogonal experiments, its modified reaction conditions to optimize the viscosity (η) and the product of the degree of substitution (DS) Evaluation integrated both oxidation of the best conditions as follows: reaction temperature of 55 ° C, pH11 reaction time 3h, get η 10.13Pa · s, the product DS reached 0.4926. Transparent analysis showed that the 8:2 ratio of modified konjac glucomannan - fish skin gelatin made of the transparency of the film. With increasing the content of fish skin gelatin in the composite film, the film tensile strength, elongation at break decreases. Water vapor permeability ratio 8:2 modified konjac glucomannan - fish skin gelatin composite film moisture barrier properties. When the increase in the proportion of fish skin gelatin, water vapor permeability coefficient declined and enhanced moisture barrier.
|