Thermal characteristics of gelatin extracted from emperor (shaari) skin: effects of acid concentration and temperature of extraction (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.
International Food Research Journal
The aims of this study were to examine the effect of salts (CaCl2, CaSO4 and MgSO4) on the rheological and thermal properties of gelatin extracted from the skins of tropical fishes, sin croaker (Johnius dussumeiri) and shortfin scad (Decapterus macrosoma). It was found that the melting temperatures of fish skin gelatins were increased by 1.5 times as compared to bovine gelatin which was only increased by 0.5 times after holding for 2 h at 5°C. The storage (G’) and loss (G”) modulus of fish skin gelatins were improved with the addition of calcium sulphate (CaSO4) and magnesium sulphate (MgSO4), respectively. However, the storage (G’) and loss (G”) modulus of gelatin solutions were decreased with the addition of calcium chloride (CaCl2). Magnesium sulphate (MgSO4) was found to be an effective salt to improve the bloom value, elastic and viscous moduli of the fish skin gelatin. This study showed that shortfin scad skin gelatin with salt addition possessed better thermal and rheological...
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.
International Journal of Food Properties
Physicochemical properties of gelatin extracted from chicken head at 60, 75, and 90 °C for 3 and 6 h, respectively were determined. Increased in extraction temperature (ETE) from 60 to 75 °C and extraction time (ETI) contributed to higher yield and bloom. ETE was highly correlated with yield (r = 0.954). Despite a higher yield, the gelatin bloom and viscoelastic properties began to drop at 90 °C. Gelatin extracted at 75 °C exhibited superior properties with high bloom strength of > 309 g, high in G', G", gelling (27-28 °C), and melting temperatures (33-34 °C) with great viscoelastic properties. All gelatins were of type A with α-chains as major protein. FTIR amide bands indicated different degrees of structural changed. Glycine was the main amino acid in G75/6 (20.69%) with total imino acid of 23.19%. Regression models were significant (p < .05), and highly fitted for yield and a* (R 2 > 0.9090%). Present findings suggest the feasibility to extract high quality gelatin from chicken head by manipulating ETE and ETI.
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.
Review of Fish Gelatin Extraction, Properties and Packaging Applications
Based on physico-functional properties, gelatin is a biopolymer of great interest in food industry. Especially, its rheological and thermal properties diversify its applications. Mammalian gelatin is the main contributor to total gelatin production, but fish gelatin is also a potential alternative. The extraction method, fish type and intensity of the treatment determines the fate of produced gelatin. However, fish gelatin presents some less desirable properties due to the lesser amount of proline and hydroxyproline residues compared to the mammalian gelatins. Nonetheless, it has a good film forming ability and has been suggested as an alternative to the petroleum-based polymers. This review focusses on extraction, physicochemical properties and film forming ability of fish gelatin. Additionally, studies related to possible improvement in film barrier and mechanical properties are also enlisted. Furthermore, a minor description of legislation regarding toxicity issues of the frequently used active additives (plant extract and nanoparticles) in gelatin films is also presented. Fish gelatin applications should be expanded with the growing technological advances in industrial processes. 1. Introduction: As the global demand for gelatin is continuously on the rise, many potential sources are being sought for combating this growing need. In 2009, the global production of gelatin reached 326 thousand tons; majorly derived from pig skin, bovine hides, bones and others sources contributing 46%, 29.4%, 23.1% and 1.5%, respectively. Due to the fact that half of the production is harvested from porcine source, concerns about Halal or Kosher market strongly dominate. Moreover, in the case of bovine gelatin, the prevalence of spongiform encephalopathy necessitates a look up for possible alternatives (Karim and Bhat, 2009). Thus, fish (skin and bone) and other marine sources, along with insects (melon and sorghum bugs) are being exploited simultaneously. Nevertheless, fish, being in bulk and abundant, accounts more significantly than the insects. A number of studies have addressed the properties of fish skin gelatins, indicating that their properties differ from those of mammalian gelatins and vary among fish species. Technically, the term gelatin, applies for a series of proteins obtained from collagen after partial hydrolysis, obtained from bones, skin, hides, ligaments and cartilages, etc. (Gómez-Guillén and Montero, 2001). In the conversion process of collagen to gelatin, acid or alkali pretreatment hydrolyze the cross-linking bonds between polypeptides and irreversibly results in gelatin (Yang et al., 2008). The gelatin is water soluble and forms thermo-reversible gels with the melting temperature near to the body temperature (Norziah et al., 2009). The quality of resultant gelatin is determined by its physicochemical behavior that is further based on the species as well as the process of manufacture. Moreover, the specific amino acids and their respective amounts determine physical and functional behavior of gelatin. The higher the level of proline and hydroxyproline, the higher will be the melting point and gel strength (Karim and Bhat, 2009). According to one report (Farris et al., 2009) fish gelatin holds around 20% of proline and hydroxyproline than the bovine or porcine gelatins, which lower the gelling and melting by 5-10°C. Generally, compared to mammalian gelatin, fish gelatins hold lower gelling and melting temperatures, and lower gel strength as well (Norland, 1990). Gelatin is one of the most commonly used food additive and is an ingredient of many recipes. The proteinaceous nature of gelatin makes it an ideal food ingredient with high digestibility in certain types of diets (Johnston-Banks, 1990). As an additive, it improves water holding capacity, texture, elasticity, consistency and stability of foods (Zhou and Regenstein, 2005). Additionally, it has been used as a stabilizer, emulsifier, clarifying agent and as a protective coating material. Desserts, ice cream, jelled meat, confectionary, dairy and bakery foods are few of the main consumption areas for gelatin. Moreover, in pharmaceutics, it is used in manufacturing of capsules, tablet coatings, emulsions, ointments and skincare products. Despite the vast applicability of gelatin, theories about structure-function relationship are still under discussion. A 3D model is widely presented using fringed micelle model where microcrystallites are interconnected to amorphous segments of randomly-coiled regions. Some others suggest the presence of quaternary structures that are self-limiting in size, making triple helix or partial triple helix or turn and sheet motifs (Pena et al., 2010).
Fourier Transform Infrared (FTIR) Analysis was used to characterize secondary structure of gelatins extracted from shaari skin and compared with bovine and porcine gelatin obtained from commercial source. The concentration and temperature of extracted solutions were varied from 0.01 to 1.0 N and 4 to 80 o C, respectively. The intensity ratio of amide III and I as a measure of denaturation process showed that all samples had almost the same protein structure at 0.1 and 1.0 N concentration for all extraction temperatures. At low acid concentration (0.01 N) and low temperature (4 o C) significant amount of triple helix remained intact (i.e. less denaturation).
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.
Foods
Optimum conditions for high-quality gelatin recovery from camel skin and its molecular, structural, and rheological characterization were carried out in this study. Increased yield and gel strength were recorded, with an increase in camel skin pretreatment times of 6 to 42 h and 0.50 and 0.75 M-NaOH. Gelatin from skin pretreated with 0.75 and 0.5 M-NaOH for 42 h showed the highest yield (22.60%) and gel strength (365.5 g), respectively. Structural characterization by Fourier transformation infrared spectra, X-ray diffraction, and nuclear magnetic resonance indicated that all gelatins possessed major peaks in the amide region, and diffraction peaks around 22° were basically amorphous. The temperatures for gelling and melting ranged from 20.9 °C to 25.8 °C and 27.34 °C to 30.49 °C. Microstructure revealed loose network with more voids in gelatin from skin pretreated with 0.5 and 0.75 M-NaOH for 6 h, while a highly cross-linked network and less voids were observed in those pretreated w...
Frontiers in Nutrition
The poultry processing industrial wastes are rich sources of gelatin protein, which can be utilized for various industrial sectors. The present investigation was conducted to evaluate the effect of freeze-drying (FD) and hot air drying (HAD) on the physicochemical, structural, thermal, and functional characteristics of chicken feet gelatin. The yield (%) of extracted FD and HAD gelatin was 14.7 and 14.5%, respectively. The gelatin samples showed lower percent transmittance in the UV region. The FTIR bands were at 3,410–3,448 cm−1, 1,635 cm−1, 1,527–334 cm−1, and 1,242–871 cm−1 representing amide-A, amide-I, amide-II, and amide-III bands, respectively. The water activity of HAD was higher (0.43) than in FD (0.21) samples and pH were 5.23 and 5.14 for HAD and FD samples, respectively. The flow index (n) of 6.67% gelatin solutions was 0.104 and 0.418 with consistency coefficient (k) of 37.94 and 31.68 for HAD and FD samples, respectively. The HAD sample shows higher gel strength (276 g...