Effects of different types and concentration of salts on the rheological and thermal properties of sin croaker and shortfin scad skin gelatin (original) (raw)
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Thermal characteristics of gelatin extracted from shaari fish skin
Journal of Thermal Analysis and Calorimetry, 2011
Gelatin extraction yield increased with the increase of acetic acid concentration and temperature. Gelatin extracted from shaari skin using 0.1 N acid solutions and temperatures of 323 and 353 K gave highest protein content comparable to that of commercial bovine and porcine gelatins. In general, gelatin extracted from shaari gelatin showed lower onset of glass transition temperature than mammalian gelatins. For shaari skin gelatin, the onset of glass transition temperature decreased with the increase of extraction temperature up to 323 K and then remained nearly constant. The decrease in glass transition was more pronounced for gelatin extracted at 0.01 N compared to the 0.1 and 1.0 N samples. Unfolding temperature decreased exponentially with the increase of extraction temperature. The unfolding temperature shifted to lower temperature, and the decrease was more pronounced in the case of higher (1.0 N) concentrated samples. The extraction concentration and temperature did not show significant effect on the onset solids-melting temperature.
Gelatins were prepared from the skins of the tropical fish, sin croaker (Johnius dussumeiri) and shortfin scad (Decapterus macrosoma). Visual appearance, colour, pH, bloom strength, viscoelasticity, melting point and amino acid profiles of the fish gelatins were evaluated. Shortfin scad gelatin had higher melting and gelling temperatures than those of sin croaker gelatin. The bloom strengths of gelatins from sin croaker and from shortfin scad were 125 and 177 g, respectively, compared to 240 g for commercial bovine gelatin. The pH values were significantly different between the solutions of the two fish gelatins. The elastic modulus (G 0 ) of the fish gelatin gels increased by more than 10-fold and the viscous modulus (G 00 ) of fish gelatin solution increased sixfold after holding at 5°C for 2 h. These viscoelastic properties of bovine gelatin only increased by less than twice.
Food Hydrocolloids, 2009
The rheological and functional properties of gelatin from the skin of bigeye snapper (Priacanthus hamrur) fish were assessed. The protein content of dried gelatin was 94.6% and moisture content was 4.2 %. The amino acid profile of gelatin revealed high proportion of glycine and imino acids. The bloom strength of solidified gelatin was 108 g. The average molecular weight of fish skin gelatin was 282 kDa as determined by gel filtration technique. The emulsion capacity (EC) of gelatin at a concentration of 0.05% (w/v) was 1.91ml oil /mg protein and with increase in concentration, the EC values decreased. The gelling and melting temperatures of gelatin were 10 o and 16.8 o C respectively as obtained by small deformation measurements. The flow behavior of gelatin solution as a function of concentration and temperature revealed non-Newtonian behavior with pseudoplastic phenomenon. The Casson and Herschel-Bulkley models were suitable to study the flow behavior. The yield stress was maximum at 10 o C with the concentration of 30 mg / ml. Thermal gelation behavior of threadfin bream (Nemipterus japonicus) mince in presence of different concentration of gelatin was assessed. Gelatin at a concentration of 0.5% yielded higher storage modulus (G') value than control. Frequency sweep of heat set gel with gelatin revealed strong network formation.
Physical properties of gelatin extracted from skin of Thai panga fish (Pangasius bocourti Sauvage)
2013
Gelatin from the skin of Thai panga fish (Pangasius bocourti Sauvage) was pretreated with a solution of 0.8 M sodium chloride and 0.1 M sodium hydroxide and extracted by acetic acid solution pH 4.55 at 55°C for 1 h. Physical properties of the obtained fish gelatin and the commercial bovine bone gelatin were compared. The gel strength (513.75 g), viscosity (3.88 cP), turbidity (73.21%), foaming properties (foam formation ability 1.13 and foam stability 0.71), emulsion stability (34.2 to 44.6%) and adhesiveness (-369.1 g.sec) of the fish skin gelatin were higher, but color (L* 43.62, C* 3.66 and h° 45.28), cohesiveness (0.838) and gel elasticity were lower than those of the bovine bone gelatin. Gelling and melting points of the fish skin gelatin (16.40°C and 26.87°C, respectively) were lower than those of the bovine bone gelatin (18.45°C and 29.90°C, respectively). Results obtained suggest that the gelatin extracted from the skin of Thai panga fish was a potential raw material for producing a gelatin film or use as foaming agent, emulsifying agent or thickener, but not suitable for use as gelling agent.
Physical properties of gelatin extracted from skin of Thai panga fish
Gelatin from the skin of Thai panga fish (Pangasius bocourti Sauvage) was pretreated with a solution of 0.8 M sodium chloride and 0.1 M sodium hydroxide and extracted by acetic acid solution pH 4.55 at 55°C for 1 h. Physical properties of the obtained fish gelatin and the commercial bovine bone gelatin were compared. The gel strength (513.75 g), viscosity (3.88 cP), turbidity (73.21%), foaming properties (foam formation ability 1.13 and foam stability 0.71), emulsion stability (34.2 to 44.6%) and adhesiveness (-369.1 g.sec) of the fish skin gelatin were higher, but color (L* 43.62, C* 3.66 and h° 45.28), cohesiveness (0.838) and gel elasticity were lower than those of the bovine bone gelatin. Gelling and melting points of the fish skin gelatin (16.40°C and 26.87°C, respectively) were lower than those of the bovine bone gelatin (18.45°C and 29.90°C, respectively). Results obtained suggest that the gelatin extracted from the skin of Thai panga fish was a potential raw material for producing a gelatin film or use as foaming agent, emulsifying agent or thickener, but not suitable for use as gelling agent.
Food Chemistry, 2007
Gelatins were prepared from the skins of the tropical fish, sin croaker (Johnius dussumeiri) and shortfin scad (Decapterus macrosoma). Visual appearance, colour, pH, bloom strength, viscoelasticity, melting point and amino acid profiles of the fish gelatins were evaluated. Shortfin scad gelatin had higher melting and gelling temperatures than those of sin croaker gelatin. The bloom strengths of gelatins from sin croaker and from shortfin scad were 125 and 177 g, respectively, compared to 240 g for commercial bovine gelatin. The pH values were significantly different between the solutions of the two fish gelatins. The elastic modulus (G 0 ) of the fish gelatin gels increased by more than 10-fold and the viscous modulus (G 00 ) of fish gelatin solution increased sixfold after holding at 5°C for 2 h. These viscoelastic properties of bovine gelatin only increased by less than twice.
Characteristics and functional properties of gelatin from seabass skin as influenced by defatting
Gelatins from nondefatted and defatted seabass skins were characterised and evaluated for their functional properties in comparison with commercial fish skin gelatin. All gelatins contained a 1-and a 2-chains as the predominant components and showed a high imino acid content (199–201 residues/1000 residues). All gelatins had a relative solubility greater than 90% in the wide pH ranges (1–10). Foaming properties of all gelatins increased with increasing concentrations (1–3%, w/v). Gelatin from defatted skin had higher foam expansion and stability than that extracted from nondefatted skin. Emulsion containing gela-tin from defatted skin had smaller oil droplet size (d 32 , d 43), compared with that having gelatin from non-defatted skin (P < 0.05). After 10 days of storage at room temperature (28–30 °C), emulsion stabilised by gelatin from defatted skin showed the higher stability as indicated by the lower increases in d 32 and d 43 , and lower flocculation factor and coalescence index. Coincidentally, emulsion stabilised by gelatin from defatted skin had higher zeta potential than that containing gelatin from nondefatted skin. Thus, defatting of seabass skin directly affected characteristics and functional properties of resulting gelatin.
The effect of drying temperature on the properties of gelatin from carps (Cyprinus carpio) skin
Czech Journal of Food Sciences
The influence of drying temperature on the characteristics and gel properties of gelatine from Cyprinus carpio L. skin was studied. Gelatine was extracted from the carp skin using NaOH and ethanol pre-treatment method, extracted in water in 45°C and then dried in 4 different temperatures: 50, 70, 80°C and freeze-dried. The electrophoresis and functional properties of gelatines were investigated. Freeze drying allowed to obtain a high gelling force, and all other methods did not give satisfactory results. The proteins in gelatines dried at higher temperatures separated by electrophoresis gave severely blurred bands. It may be explained by thermal hydrolysis of collagen fibrils. Freeze drying is the only effective method for drying this product, which can be used in industry.
Rheological properties of skin gelatin of Beluga Sturgeon (Huso Huso) from The Caspian Sea
The effect of Pre-treatment condition has been studied for extracting gelatin from Beluga Sturgeon fish skin with acetic Acid (0.2 N and 2.0 N) and NaOH (0.2 N and 2.0 N) on gelatin extraction yield, melting point, viscosity and SDS-PAGE electrophoresis pattern of the solution. The results showed that extraction yield increased by increasing acid concentration or decreasing NaOH concentration (p<0.05). The samples treated with 2.0 N acid-2.0 N NaOH solutions and 0.2 N Acid – 2.0 N NaOH solutions had the lowest and the highest melting point respectively. The values were respectively 17°C and 23°C. The results showed a significant correlation between the type of gelatin and its functionality.
Gelatin extraction yield increased with the increase of acetic acid concentration and temperature. Gelatin extracted from shaari skin using 0.1 N acid solutions and temperatures of 323 and 353 K gave highest protein content comparable to that of commercial bovine and porcine gelatins. In general, gelatin extracted from shaari gelatin showed lower onset of glass transition temperature than mammalian gelatins. For shaari skin gelatin, the onset of glass transition temperature decreased with the increase of extraction temperature up to 323 K and then remained nearly constant. The decrease in glass transition was more pronounced for gelatin extracted at 0.01 N compared to the 0.1 and 1.0 N samples. Unfolding temperature decreased exponentially with the increase of extraction temperature. The unfolding temperature shifted to lower temperature, and the decrease was more pronounced in the case of higher (1.0 N) concentrated samples. The extraction concentration and temperature did not show significant effect on the onset solids-melting temperature. Keywords Fish skin gelatin Á Glass transition Á Solidsmelting Á Shaari Á Amino acid List of symbols T gi Onset temperature of glass transition (K) T gp Peak temperature of glass transition (K) T ge End temperature of glass transition (K) T mi Onset temperature of solids-melting (K) T mm Maximum slope temperature of solids-melting (K) T mp Peak temperature of solids-melting (K) T me End temperature of solids-melting (K) T ui Onset unfolding temperature (K) T um Maximum slope of unfolding temperature (K) T up Peak of unfolding temperature (K) X w Moisture content (g/100 g sample) DC p Change of specific heat (J/kg K) DH u Enthalpy change for unfolding (kJ/kg) DH m Enthalpy change for solids-melting (kJ/kg)