Gelatin Extraction Research Articles

Element distribution and morphology of spotted golden goatfish fish scales as affected by demineralisation

Scales of spotted golden goatfish were subjected to non-collagenous protein removal followed by demineralisation with hydrochloric acid at different concentrations (0.25, 0.5, 0.75 and 1M) for various times (30, 60 and 90min). The morphology and element composition/distribution of scales from spotted golden goatfish as influenced by demineralisation conditions were determined. The appropriate demineralisation was pertained using 0.75M hydrochloric acid for 30min, in which the ash content was 0.62% (dry weight basis). The scales having non-collagenous protein removal with, and without, subsequent demineralisation were analysed for element content using X-ray fluorescence spectrometer. Images of different scales were determined using scanning electron microscopy (SEM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX). Based on the images, an external layer rich in inorganic elements was removed. Most of Ca and P were eliminated with the coincidental increases in organic substances (C, N and O) after demineralisation. Demineralisation therefore mainly removed the external layer of scales, which facilitated the further extraction of collagen or gelatin.

Effects of Pre-Treatment Conditions on Black Tilapia Fish Scales for Gelatin Extraction

Black tilapia (Oreochromis mossambicus) fish scales are good sources of gelatin. Fish scales needs to undergo adequate demineralization (pre-treatment) process in order to be a suitable medium for gelatin extraction. The effect of hydrochloric acid (HCl) concentrations (1-5 %) and pre-treatment time (4-20 h) on the raw tilapia scales have been determined. Scanning Electron Microscopy (SEM) analysis was done on the raw scales before and after pre-treatment process. SEM images reveal the pattern of ridges on the scales that fades away at different treatment conditions. Energy Dispersive X-ray Spectroscopy (EDX) results indicate that 3% of HCl with 12 h of treatment time is adequate for demineralization of the fish scales. These were further proved by Fourier Transform Infrared Spectroscopy (FTIR) analysis, where no any inorganic components been detected in the pre-treated scales in comparison to raw scales.

Characteristics and functional properties of gelatin extracted from squid (Loligo vulgaris) skin

The characteristics and functional properties of gelatin extracted from squid skin (Loligo vulgaris), using commercial pepsin at a level of 15 Units/g skin, were investigated. The gelatin extraction yield was 6.82 g/100 g wet basis, showing high protein content and low fat and ash contents. SDS-PAGE of squid skin gelatin showed high band intensity for the major protein components, especially, α- and β-components. The amino acid profile of squid skin gelatin showed a high percentage of imino acids, essential amino acids and hydrophobic amino acids. Fourier transformed infrared spectroscopy (FT-IR) spectra showed helical structure. Squid skin gelatin was able to form a completely thermo-reversible gel. Gelatin possessed interesting functional properties, which were governed by gelatin concentration.

Effects of defatting and tannic acid incorporation during extraction on properties and fishy odour of gelatin from seabass skin

Gelatins from seabass skin without and with defatting, extracted in the absence and presence of tannic acid at various concentrations (0–0.4 g/kg), were characterised. Gelatins from skin without defatting had higher gel strength (p < 0.05) with coincidentally higher band intensity of α- and β-chains, compared with those extracted from defatted skin. Gelatins from defatted skin had lower fishy odour with concomitantly lower thiobarbituric acid reactive substances and peroxide value. Lower abundance of volatile compounds, including aldehydes, ketones and alcohols was found in gelatin extracted from defatted skin. The addition of tannic acid during gelatin extraction could lower lipid oxidation, fishy odour as well as the formation of volatile compounds, especially hexanal and heptanal, in the resulting gelatins, regardless of defatting. Therefore, gelatin with reduced fishy odour could be prepared from seabass skin, in which 0.2 g/kg tannic acid was incorporated during extraction.

Antioxidant activities and selected characteristics of gelatin hydrolysates from seabass (Lates calcarifer) skin as affected by production processes.

Antioxidant activities and selected characteristics of gelatin hydrolysates from seabass skin as affected by production processes were investigated. Hydrolysates were prepared using different processes, including hydrolysis during and after gelatin extraction. Samples hydrolysed during gelatin extraction showed a higher degree of hydrolysis (DH) and yield compared with those hydrolysed after gelatin extraction (p < 0.05). All hydrolysates had a creamy yellowish colour. A lower abundance of volatile compounds was found in the hydrolysates produced during gelatin extraction, in comparison with those obtained after gelatin extraction. Hydrolysates prepared during gelatin extraction had higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidative power (FRAP) and ferrous ion chelating activity (p < 0.05). Following a simulated in vitro gastrointestinal digestion, the DPPH radical scavenging activity and FRAP of the hydrolysates was retained, whilst ferrous ion chelating activity increased. The most appropriate conditions for the generation of antioxidant hydrolysates from seabass skin were identified.

Characteristics and gel properties of gelatin from goat skin as affected by pretreatments using sodium sulfate and hydrogen peroxide.

Goat skin can be used as an alternative raw material for gelatin production, in which pretreatment conditions can determine the characteristics or properties of the resulting gelatin. The present study aimed to investigate the effect of pretreatment using sodium sulfate (Na2SO4) and hydrogen peroxide (H2O2) on properties of goat skin gelatin. Pretreatment of skin using Na2SO4 (0-1 mol L(-1)) increased the yield of gelatin in a concentration-dependent manner. When skins with prior Na2SO4 treatment were bleached using H2O2 (0-2 mol L(-1)), the resulting gelatin showed higher yield and gel strength than those without prior Na2SO4 treatment. All gelatins had α-chain as a major component, followed by β-chain. The degradation induced by H2O2 was lower in gelatin with prior Na2SO4 treatment. L* values increased with increasing H2O2 concentrations (P < 0.05) due to the bleaching effect of H2O2. With Na2SO4 and H2O2 pretreatments, gelatin gel had a finer and more ordered microstructure. Gelatin had an imino acid content of 217 residues/1000 residues with gelling and melting temperature of 22.49 and 32.28 °C, respectively. The optimal pretreatment conditions for gelatin extraction from goat skin included soaking the skin in 0.75 mol L(-1) NaOH, followed by treatment using 0.75 mol L(-1) Na2SO4 and subsequent bleaching with 2 mol L(-1) H2O2. This resulted in gelatin with superior quality to the untreated counterpart.

POTENSI EDIBLE FILM ANTIMIKROBA SEBAGAI PENGAWET DAGING

&lt;p&gt;Fresh meat are highly perishable due to their enriched nutrient composition which is easily contaminated by almost any microorganisms. The application of antimicrobial edible films is one of the effective method to extend the shelf life of fresh meat. This study aimed to get antimicrobial edible films formula that have the potential to preserve fresh meat. The study consisted of several steps: 1) research for making a fresh garlic extract, 2) extraction of gelatin from chicken feet, 3) formulation and manufacturing of antimicrobial edible films and 4) the application of edible films on fresh meat. Gelatin-based antimicrobial edible films was the best one that can be applied on fresh meat. Characteristics of the antimirobial edible film: color L 97.28; elongation: 20 mm; tensile strength &amp;lt;0.1 kgf; thickness 0.06 mm; WVTR 15.49 g/(mm.jam); Aw 0.526; moisture content: 22.73%, and has antimicrobial characteristic because of it’s inhibition ability to the growth of S. aureus and E. coli.&lt;/p&gt;&lt;p&gt;(Key words: Antimicrobial, Edible film, Meat)&lt;/p&gt;

Development and Evaluation of a Smart Packaging for the Monitoring of Ricotta Cheese Spoilage

Colorimetric Smart packaging pH indicator offers a potential use that could allow consumer evaluation of the food quality. In this study, it was developed a film based on chitosan, gelatin, PVA and red cabbage extract for food quality monitoring. Films were characterized by Thickness and swelling index. Proofof-Concept application tests were conducted with Ricotta cheese for evaluated the potential use in the food spoilage. The results show that indicator film has high hydration capacity and during application in cheese, the film did not visually indicated color change after 7 days refrigeration storage.

Polymer-immobilized ready-to-use recombinant yeast assays for the detection of endocrine disruptive compounds

Recombinant yeast assays (RYAs) constitute a suitable tool for the environmental monitoring of compounds with endocrine disrupting activities, notably estrogenicity and androgenicity. Conventional procedures require yeast reconstitution from frozen stock, which usually takes several days and demands additional equipment. With the aim of applying such assays to field studies and making them more accessible to less well-equipped laboratories, we have optimized RYA by the immobilization of Saccharomyces cerevisiae cells in three different polymer matrices – gelatin, Bacto agar, and Yeast Extract Peptone Dextrose agar – to obtain a ready-to-use version for the fast assessment of estrogenic and androgenic potencies of compounds and environmental samples. Among the three matrices, gelatin showed the best results for both testosterone (androgen receptor yeast strain; AR-RYA) and 17β-estradiol (estrogen receptor yeast strain; ER-RYA). AR-RYA was characterized by a lowest observed effect concentration (LOEC), EC50 and induction factor (IF) of 1nM, 2.2nM and 51, respectively. The values characterizing ER-RYA were 0.4nM, 1.8nM, and 63, respectively. Gelatin immobilization retained yeast viability and sensitivity for more than 90d of storage at 4°C. The use of the immobilized yeast reduced the assay duration to only 3h without necessity of sterile conditions. Because immobilized RYA can be performed either in multiwell microplates or glass tubes, it allows multiple samples to be tested at once, and easy adaptation to existing portable devices for direct in-field applications.

Characteristics of Gelatin from Giant Grouper (Epinephelus Lanceolatus) Skin

Gelatin extraction from the skin of giant grouper (Epinephelus lanceolatus) was conducted by acid process with a yield of 20.27 g/100 g wet skin sample. The characteristics of extracted gelatin from giant grouper was investigated in this study, and further compared to that from commercial tilapia. Results showed that when compared to commercial tilapia, giant grouper had lower levels of bloom strength and foam formation ability, but greater values of viscosity, foam stability, and lightness (L*) on gelatin skin. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis revealed three high-bands intensities of major protein components of giant grouper skin gelatin, representing α1-chain, α2-chain, and β-components, and was similar to that of standard calf skin collagen type I. Compared to giant grouper, commercial tilapia contained extra proteins with molecular weight less than 70 kDa on the sodium dodecyl sulphate-polyacrylamide gel electrophoresis of both skin gelatins.

Modified Gelatin Films from Croaker Skins: Effects of pH, and Addition of Glycerol and Chitosan

AbstractThis work evaluated the effects of pH (3, 4 and 5) and addition of glycerol (10, 20 and 30%, w/w) in films of gelatin extracted from croaker skins, and afterward modified by chitosan. The gelatin films were produced by casting technique. The chitosan additions (10, 20 and 30% w/w) in relation to the gelatin films were analyzed. Films were characterized as tensile strength (TS), elongation, water vapor permeability (WVP) and optical properties (color, color variation and opacity). Gelatins were characterized for gel strength (221 g) and viscosity (3.7 cP), and chitosan was obtained from shells of shrimp and characterized (150 kDa and deacetylation degree of 85%). The gelatin film with 10% (w/w) glycerol and pH 4 showed the best TS value and suitable WVP value. The amount of chitosan of 10% (w/w) added to the gelatin film on the best conditions produced the modified films with the best properties of TS and WVP.Practical ApplicationsSeveral types of biopolymeric films have been developed, combining proteins and polysaccharides, and among these, gelatin and chitosan take on homogeneous form because of miscibility between the two biopolymers. Improvements in the connection crossed in gelatin mixture with chitosan are attributed to the formation of polielectrolic compounds, among the groups of amino of the chitosan and of the groups of lateral chains charged negatively of the gelatin through electrostatic interaction. The study of the mechanical properties of the biodegradable films is a subject of great importance, because of its influence on the acting of the product and the consumer's acceptance. In this context, the intensification need is observed in the studies about the gelatin extraction starting from fish skins and its application in the production of pure and modified films with chitosan and plasticizer.

Molecular characteristics and properties of gelatin from skin of seabass with different sizes

Gelatin was extracted from the skin of seabass (Lates calcarifer) with different average sizes (2, 4 and 6kg/fish), termed G2, G4 and G6, respectively and their characteristics and functional properties were determined. Yields of G2, G4 and G6 were 38.22, 40.50 and 43.48% (based on dry weight), respectively. G2 contained α-chains as dominant component, whilst G4 and G6 comprised α-, β- and γ-chains with a larger content of high MW cross-links. All gelatins had the similar imino acid (hydroxyproline and proline) content. Net charge of G2, G4 and G6 became zero at pH of 6.73, 6.41 and 7.12, respectively. Amongst all gelatin samples, G6 exhibited the highest gel strength (321.5g) (p<0.05), but had the lowest turbidity (p<0.05). Gels of G6 sample had the lower L*-value but higher a*-, b*- and ΔE*-value, compared with others. Gelling and melting temperatures of all gelatins were 17.09–19.01 and 26.92–28.85°C, respectively. Furthermore, all gelatins were able to set at room temperature, regardless of size of seabass used. G6 had the shorter setting time at room temperature than others. Therefore, size of seabass, in which skin was used for gelatin extraction, had the impact on yield, composition and properties of resulting gelatin.

Chemical and biophysical properties of gelatins extracted from the skin of octopus (Octopus vulgaris)

Gelatins from alkali-pre-treated skin of Octopus (Octopus vulgaris) were extracted with different concentrations of pepsin at pH 2.0. The resulting octopus skin gelatins OSG0, OSG5, OSG10 and OSG15, extracted, respectively, without enzyme treatment or with 5, 10 and 15 U of pepsin/g alkaline treated skin were evaluated for gel strength, textural parameters, thermal and gelling properties. The yield of gelatin extracted without enzymatic pretreatment was only 3.21% and the addition of pepsin (15 U/g) increased the yield of gelatin extraction to 7.78%. Molecular weight distribution of gelatins indicates that OSG10 and OSG15 contain peptides with molecular weights less than 10 kDa (>40%). In addition, Fourier transform infrared (FTIR) spectra of extracted gelatins were slightly different, indicating that the triple helical structure of gelatins was affected by pepsin treatment. Compared to OSG0, pepsin gelatins exhibited lower gel strength, hardness, adhesiveness, transition, gelling and melting temperatures and all of the values decreased with increasing enzyme concentration. In addition foam expansion (FE) was affected by enzyme treatment, and the values decreased as pepsin increased. However, the emulsifying activity index (EAI) values of all gelatins were the same. Further, FE and EAI increased with increasing concentrations (1–3%, w/v). The results showed that octopus skin can be a good source for gelatin.

Study of the Optimization of the Ultrasonic Extraction Technology of Gelatin from the Scales of Aristichthys Nobilis by Means of Quadratic Regression Orthogonal Optimization

In order to reasonably use of the aristichthys nobilis scale resources, gelatin was extracted from the scales of aristichthys nobilis with the aid of ultrasonic method. The ultrasonic power, time, temperature and the ratio of material to solvent on extraction of gelatin from aristichthys nobilis scales were studied. The ultrasonic extraction conditions of gelatin from aristichthys nobilis scales were optimized by quadratic regression orthogonal test based on single factor experiments. The results showed that the optimum conditions were ultrasonic temperature of 72 °C, ultrasonic time of 121 min, ultrasonic power of 300 W, the ratio of solid of solvent 1:11 (g/mL), and the extraction rate of gelatin from aristichthys nobilis scale was 48.58% under optimal extraction conditions.

Optimization of fibrinolytic protease production from Bacillus subtilis I-2 using agro-residues

The aim of this work was to study the production of fibrinolytic protease by Bacillus subtilis I-2 on agricultural residues. Molasses substantially enhanced (63%) protease production (652.32 U/mL) than control (398.64 U/mL). Soybean meal supported maximum protease production (797.28 U/mL), followed by malt extract (770.1 U/mL), cotton cake (761.04 U/mL), gelatin (742.92 U/mL) and beef extract (724.8 U/mL). Based on the Plackett-Burman designed experiments, incubation time, soybean meal, mustard cake and molasses were identified as the significant fermentation parameters. Ammonium sulfate precipitation and DEAE sephadex chromatography resulted 4.8-fold purification of protease. Zymography showed the presence of three iso-forms in the partially purified protease preparation, which was confirmed by the SDS-PAGE analysis (42, 48, 60 kDa). Protease exhibited maximum activity at 50oC and at pH 8.0. Significant stability was observed at 30-50oC and at pH 7.0-10.0. Mg2+, Zn2+, Co2+, Ca2+, Mn2+ and Cu2+,EGTA, EDTA and aprotinin severely decreased the enzyme activity.

Screening of factors influencing the extraction of gelatin from the skin of cuttlefish using supersaturated design

Supersaturated design (SSD) was used for screening the key parameters influencing gelatin extraction yield from cuttlefish (Sepia officinalis) skin. Results indicated that among a list of 17 factors only five parameters, namely, alkali (NaOH) concentration, acid reagent (acetic acid), enzyme, thermal treatment temperature and centrifugation time, were factors influencing gelatin yield. The optimal conditions for gelatin extraction were found to be: pretreatment with NaOH 0.03M for 1h; treatment with pepsin for 24h at 4°C in acetic acid 100mM; extraction for 14h at 40°C. The yield of gelatin extraction was 54.6%. Cuttlefish skin gelatin (CSG) contained protein as the major compound (90.95%) and low fat (0.3%) and ash (0.05%) contents. The physico-chemical properties of the CSG were characterized and compared with those of bovine gelatin (BG). The result of textural properties showed that hardness, elasticity and cohesiveness of CSG were lower than those of BG. Further, the gel strength of CSG (192.01g) was lower than that of BG (259.65g), possibly due to lower imino-acid content. The functional properties, including emulsion activity index and foam stability were similar to those of BG. The CSG showed stronger ability of apple juice clarification, than BG without affecting its nutritional values.

Recovery, viscoelastic and functional properties of Barbel skin gelatine: Investigation of anti-DPP-IV and anti-prolyl endopeptidase activities of generated gelatine polypeptides

The characteristics and functional properties of gelatine from freshwater fish skin (Barbus callensis) were investigated. The gelatine extraction efficiency was improved by an acid-swelling process in the presence of barbel crude acid protease extract. Barbel skin gelatine (BSG) contained 92.15% protein, 0.31% lipid and 0.72% ash. The amino acid profile of BSG showed a high percentage of imino acids. The electrophoretic profile showed that BSG is mainly composed of α- and β-components. BSG showed an excellent solubility and possessed interfacial properties, which were governed by the protein concentration. Biological activities of the hydrolysates obtained after digestion of BSG with several commercial proteases were evaluated. The results suggested that these hydrolysates are a good source of natural inhibitors of dipeptidyl peptidase-IV and prolyl endopeptidase and could potentially be used as dietary ingredients in the management of type 2-diabetes and/or neuropathological disorders.

Extraction and characterization of gelatin from two edible Sudanese insects and its applications in ice cream making.

Three methods were used for extraction of gelatin from two insects, melon bug (Coridius viduatus) and sorghum bug (Agonoscelis versicoloratus versicoloratus). Extraction of insect gelatin using hot water gave higher yield reached up to 3.0%, followed by mild acid extraction which gave 1.5% and distilled water extraction which gave only 1.0%, respectively. The obtained gelatins were characterized by FTIR and the spectra of insect's gelatin seem to be similar when compared with commercial gelatin. Amide II bands of gelatins from melon and sorghum bug appeared around at 1542-1537 cm(-1). Slight differences in the amino acid composition of gelatin extracted from the two insects were observed. Ice cream was made by using 0.5% insect's gelatin and compared with that made using 0.5% commercial gelatin as stabilizing agent. The properties of the obtained ice cream produced using insects gelatin were significantly different when compared with that made using commercial gelatin.

Functional Properties of Gelatin Hydrolysate from Salmon Skin (Salmo salar)

Gelatin hydrolysate is derived from a hydrolysis of gelatin (denatured collagen) to expose the functional properties of the hydrolysate obtained. This study was carried out to determine functional properties of gelatin hydrolysate from salmon skin as influenced by the degree of enzymatic hydrolysis. Aqueous extraction of gelatin from salmon skin was done at 45oC for 60 minutes. The extracted gelatin was then hydrolysed using 1% alcalase at 54.5oC and pH 8. The functional properties determined were molecular weight, solubility, foaming capacity and stability, emulsifying activity and stability index were analysed. It was found that different time of hydrolysis (5, 15, 45 and 180 minutes) resulted in different degree of hydrolysis (DH) (10, 20, 30 and 40%, respectively). The gelatin hydrolysate at 40% DH showed the highest solubility (p&lt;0.05). However, the foaming and emulsifying properties were the highest at 10% degree of hydrolysis (p&lt;0.05).

Characterization of edible films based on tilapia (Tilapia zillii) scale gelatin with different extraction pH

Gelatin was extracted from tilapia scales at pH ranges from 3 to 9, and the properties of resulting gelatin films were investigated. The ash and calcium contents in gelatin extracted at pH 3 was the highest compared to gelatin extracted at pH 5, 7 and 9. Amino acid composition of gelatin extracted at pH 3 was similar to that from pH 9, but was obviously different compared to that from pH 5 or pH 7. The films with higher tensile strength (TS) were prepared from scale gelatin extracted at pH 5, and the film strength became lower with increasing or decreasing extraction pH. On the other hand, the effect of gelatin extraction pH was not significant on WVP, color and transparency properties of films. When films were prepared with gelatin extracted at pH 3, although high molecular weight polymer and high glass transition temperature (Tg) were observed, the obtained films were not strong. Nevertheless, it is interesting to note a high correlation between TS of films and A1658/A1642 ratio derived from FTIR peak deconvolution. It is concluded that α-helix structures rather than molecular weight distribution and Tg were involved in the formation of gelatin films.