Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin (original) (raw)
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Ciência Rural
ABSTRACT: The effect of pretreated method to remove the non-collagenous protein by using alkaline and enzyme Alcalase, as well as the temperature and time for extracting on the properties of gelatin from tra catfish skin were investigated. Yields of gelatin extracted at 70 °C for 1h from pretreated skin by enzyme method (16.2%) was significantly higher than that of the sample by alkaline method (12.14%). However, the gel strength of gelatin from skin treated via enzyme Alcalase was lower than gelatin sample pretreated by alkaline while the turbidity values was higher than gelatin from skin pretreated via alkaline. From SDS-PAGE profile, gelatin from skin pretreated by alkaline consisted of two different α- chains in protein pattern while enzymatic gelatin had low molecular weight peptides. The FT-IR spectra showed the lower wavenumber in amide I and III of enzymatic gelatin in compare to alkaline gelatin by the loss of triple helical structure during enzyme treatment. From the resul...
Journal of Food Science, 2007
ABSTRACT: To optimize the extraction of gelatin from channel catfish (Ictalurus punctatus) skin, a 2-step response surface methodology involving a central composite design was adopted for the extraction process. After screening experiments, concentration of NaOH, alkaline pretreatment time, concentration of acetic acid, and extraction temperature were selected as the independent variables. In the 1st step of the optimization the dependent variables were protein yield (YP), gel strength (GS), and viscosity (V). Seven sets of optimized conditions were selected from the 1st step for the 2nd-step screen. Texture profile analysis and the 3 dependent variables from the 1st step were used as responses in the 2nd-step optimization. After the 2nd-step optimization, the most suitable conditions were 0.20 M NaOH pretreatment for 84 min, followed by a 0.115 M acetic acid extraction at 55 °C. The optimal values obtained from these conditions were YP = 19.2%, GS = 252 g, and V = 3.23 cP. The gelatin obtained also showed relatively good hardness, cohesiveness, springiness, and chewiness. The yield of protein and viscosity can be predicted by a quadratic and a linear model, respectively.
Re-extraction, Recovery, and Characteristics of Skin Gelatin from Farmed Giant Catfish
Food and Bioprocess …, 2010
This study was aimed to investigate the reextraction process for gelatin recovery from the skin of farmed giant catfish. The first extraction was done by incubating the acid-treated fish skin at 45°C for 12 h. The remnant was re-extracted at temperatures of 60-90°C for 1-12 h. The gelatin yield of the first extraction was 10.14%, while the re-extraction at high temperature provided higher recovery (19.5%). Low band intensity of α 1 and α 2 chains of gelatin was observed when it was reextracted at high temperature for a longer time. The absorption bands of amide I and II from both extracted gelatins were similar. Low-transition temperature with high transition enthalpy of gelatin extracted at 90°C was observed. The obtained results suggested that the reextraction process could be applied as a supplemental step for other sources to obtain high recovery with the desired properties.
2014
In order to optimize the extraction of gelatin from pangasius catfish skin, a response surface method (RSM) involving a Central Composite Design (CCD) was applied. Four variables, namely NaOH concentration (0-0.3 N), acetic acid concentration (0.025-0.125 N), extraction time (2-4 h) and extraction temperature (40-80°C) were selected as independent variables for the optimization using RSM. The dependent variable was calculated by hydroxyproline recovery. The optimum conditions for extraction were produced by a pre-treatment of 0.2 N NaOH and 0.1 N acetic acid along with hot water extraction at 63.7°C for 2.41 h. The results showed that the predicted response by RSM (68.53%) closely matched the experimental response of 68.16%. The results indicated that the extracted gelatin possessed high gel strength (438 g) and high content of imino acid (proline and hydroxyproline) (18.01%) with a viscosity of 4.67 mPa s. The results showed that RSM was a great optimizing tool for extraction of gelatin from pangasius catfish skin. The gelatin was also proven to have significantly (p<0.05) higher quality of physicochemical properties than those from bovine skin gelatin.
International Food Research Journal
The extraction of catfish (Clarias gariepinus) bone gelatin was optimized by using Response Surface Methodology (RSM) involving 4-factors, 5-levels Central Composite Design (CCD). The optimum conditions for extraction were produced by a pre-treatment of 3.35% HCl for 14.5 h along with hot water extraction at 67.23°C for 5.2 h. Results showed that the predicted yield by RSM (61.81%) was closely matched the experimental yield of 60.54%. The results also indicated that the extracted bone gelatin possessed high protein content (81.75%) and imino acid (proline and hydroxyproline) (144 residues per 1000 residues), with gel strength (230.25 g), viscosity (4.64 mPa.s) and isoionic point (5.35) comparable to that of bovine gelatin. The results suggested that RSM is a great optimizing tool for extraction of gelatin from clarias catfish bone and values of the physicochemical properties of gelatin are higher or comparable than those from other fish species and bovine gelatin.
2021
Production of gelatin from the aquatic source is gradually replacing the mammalian sources because of some socio-cultural and religious issues. The Pangasius pangasius catfish is a native species and very popular in Bangladesh due to their availability and cheap price. The perspective of this study was to extract the gelatin from the skin and bones of this catfish and compare them with commercial gelatin. Gelatin was extracted by applying the acid-base extraction process and the resultant gelatins were evaluated based on some physical properties. The gelatin yield was found significantly higher from the skin sample (10.85±0.93%) than the bone (5.23±0.39%) of Pangasius. The extracted skin gelatin had higher moisture and fat content than the bone and Commercial gelatin, while the ash content was significantly higher in bone gelatin. Protein content was noted in skin gelatin (81.34±3.45%), bone gelatin (73.44±2.58%), Where commercial gelatin (92.38±3.89%). Skin gelatin exerted significantly higher (p<0.05) viscosity (4.62±0.3 mPa.s) than the extracted bone gelatin (3.11±.24 mPa.s) and lower than the commercial gelatin (5.76±0.34 mPa.s). The melting and setting temperature of this catfish skin and bone gelatin were very near to each other and significantly lower than the commercial gelatin. Skin gelatin had exerted higher water holding capacity (2.36±0.11 ml/g), fat binding capacity (3.23±0.05 ml/g), foaming capacity ratio (1.88±0.07), and foam stability (1.51±0.04). Both the skin and bone gelatins were acidic. In this comparative study, it was noticed that the skin gelatin had better physical properties than the bone gelatin of native Pangasius catfish. Pangasius skin may be recognized as a potential aquatic source of edible gelatin with good yield and desirable physical properties comparing with commercial gelatin.
Food Hydrocolloids, 2008
The objective of this study was to illustrate the correlation between the physical properties and nanostructure of gelatins made of channel catfish (Ictalurus punctatus) skins. The gelatin samples were first pretreated with sodium hydroxide, acetic acid, or water, and then extracted with hot water before the measurement. Physical properties including the yield of protein, viscosity and textural properties were determined on gelatins obtained with different pretreatment conditions. The acid pretreatment group showed the highest gel strength and protein yield, and a reasonable viscosity. The water pretreatment group showed the lowest values for all of the physical properties. Four samples including water, 0.1 M acid and 0.25 and 1.0 M alkaline-pretreated groups’ nanostructures were then studied using atomic force microscopy (AFM). The AFM images showed that the acid-pretreated gelatin was composed of sponge-like aggregates, while the others showed separated individual aggregates. Annular pores were only found in the alkaline pretreatment group. There was no significant correlation between the diameters of the spherical aggregates and the physical properties; however, the different AFM patterns may relate to the gelatin's physical properties.
African Journal of Biotechnology
Functional properties of gelatin from skin of striped catfish with and without bleaching for 48 h by 5% H 2 O 2 (w/v)) were studied. Gelatin from skin bleached with 5% H 2 O 2 for 48 h showed the highest yield (16.18 g). Bleaching not only improved the colour of gelatin gel by increasing the L* (lightness)-value and decreasing a*(redness/greenness)-value, but also enhanced the bloom strength and the emulsifying and foaming properties of the resulting gelatin. Fourier transform infrared spectroscopic study showed higher intermolecular interactions and denaturation of gelatin from bleached skin than that of the control. These results indicated that hydrogen peroxide most likely induced the oxidation of gelatin, resulting in the formation of gelatin cross-links, hence improved functional properties.
IOSR Journals , 2019
Gelatin is a hydrocolloid product obtained by hydrolyzing the protein collagen found in the skin, bones and connective tissue. Gelatin is obtained by heat denaturation from collagen. Gelatin has been applied in food as a gelling agent, thickener, emulsifier, pharmaceutical, health, cosmetics and photography industry. gelatin sourced from fish is still small. The purpose of this study was to determine the characteristics of milkfish skin gelatin with acetic acid 4%, 6% and 8%. The results showed that gelatin with the highest percentage of glycine. the best research results at a concentration of 8%, namely gel strength 98.07 g / bloom, Viscosity 6 cP, yield 19.4%. Use of high concentrations of acetic acid can decide which amino acids have been formed so that the amino acid chain of the damaged gelatin causes the gel strength to decrease. While the use of acid solutions with low concentrations can produce small gel strength because collagen is converted into less gelatin.It is also stated that amino acids in the skin of fish contain amino acids, such as Alanine, Arginine, Aspartate Acid, Cysteine, Glutamine, Glysin, Histidine Hydroxyprolin, Isoleucine and explained that the highest amino acid is Glycine. The quality of gelatin is influenced by the stages of the gelatin making process, namely swelling (extraction), extraction, and drying.
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.