The effect of processing conditions on the properties of gelatin from skate (Raja Kenojei) skins
ABSTRACT Effects of several conditions (liming concentrations, extraction solution pH, extraction temperature and extraction time) to extract gelatin from skate skin on the yield and quality properties were investigated. The optimum conditions for gelatin extraction are as follows; place skin in a lime solution of 1.5% (w/v) calcium hydroxide, extract with three volumes of water (pH 6.0) for 4 h at 50%, filter gelatin through activated carbon (250–350 mesh, 3%) and freeze-dry the colloidal suspension. The functional properties of skate skin gelatin produced by optimum extraction conditions were: gelling point 16.12 °C; melting point 19.30 °C; isoelectric point 6.45; and turbidity 6.98.
- SourceAvailable from: Trakul Prommajak[Show abstract] [Hide abstract]
ABSTRACT: An investigation on optimal conditions for gelatin extraction from the Thai fish panga (Pangasius bocourti Sauvage) skin was performed by response surface methodology. A Box-Behnken design was applied to examine the effects of extraction temperature (40-70°C), pH (3.7-7.4) and extraction time (1-5 h) on gelatin yield, gel strength and gel colour. All regression models were significant (P≤0.01) and lack-of-fit of the models was insignificant, except for that of the gel strength. The Anderson-Darling normality test of the standardized residuals showed adequacy of all models. The optimal conditions for gelatin extraction were at 55°C, pH 4.55 for 1 h. The predicted responses were 20.22% gelatin yield, 506.55 g gel strength, 42.22 lightness (L*), 3.56 chroma (C*) and 43.35° hue angle (h°). The experimental responses of gelatin extracted at the optimal conditions were not significantly different (P>0.5) from the predicted value.01/2010;
- [Show abstract] [Hide abstract]
ABSTRACT: Gelatin was extracted from alkali-pretreated skin of zebra blenny (Salaria basilisca) using commercial pepsin with a yield of 18 g/100 g of skin sample. The polypeptides pattern, gel strength, viscosity, textural parameters and functional properties of the zebra blenny skin gelatin (ZBSG) were investigated. Amino acid analysis revealed that ZBSG contained almost all essential amino acids, with glycine being the most predominant one. ZBSG was identified as a type I gelatin, containing α1 and α2-chains as the major constituents. Its gel strength and viscosity were 170.2 g and 5.95 cP, respectively. Fourier transformed infrared spectroscopy (FT-IR) spectra showed helical arrangements in its structure. Its solubility and functional properties were concentration-dependent. While foam expansion (FE) and foam stability (FS) increased with the increase of concentration, emulsifying activity index (EAI) and emulsion stability index (ESI) were noted to decrease. ZBSG also showed strong clarification ability particularly for apple juice, without affecting nutritional value.Lebensmittel-Wissenschaft und-Technologie 10/2014; 58(2):602–608. · 2.55 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: We attempted to isolate a collagenase-1 inhibitory peptide from skate Dipturus chilensis skin protein. The protein from skate skin was digested by various enzymes (alcalase, -chymotrypsin, neutrase, papain, pepsin, and trypsin) to produce a collagenase-1 inhibitory peptide. The collagenase-1 inhibitory activity of the peptides obtained was measured by gelatin digestion assay. Among the six hydrolysates, pepsin hydrolysate exhibited the highest collagenase-1 inhibitory activity. The peptide showing strong collagenase-1 inhibitory activity was purified by Sephadex G-25 gel chromatography and HPLC using an octadecylsilyls (ODS) column. The amino acid sequence of purified collagenase-1 inhibitory peptide was identified to be Asn-Leu-Asp-Val -Leu-Glu-Val-Phe (961 Da) by quadrupole time of flight (Q-TOF) and electrospray ionization mass spectrometry (ESI-MS) mass spectroscopy. The value of purified peptide was 87.0 . Moreover, the peptide did not exhibit cytotoxic effects on human dermal fibroblast cell lines.Korean Journal of Fisheries and Aquatic Sciences. 10/2011; 44(5).