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The antimicrobial and physico-mechanical properties of fish gelatin-alginate film incorporated with oregano (Origanum vulgare L.) essential oil (OEO) were assessed. The blended films were prepared with 75% fish gelatin and 25% sodium alginate and OEO (0, 0.5, 1.0, 1.5%) was added to the film solutions. Results showed that adding 0.5% OEO into films improved tensile strength about 2.54 MPa compared to the control films. The incorporation of 1.5% essential oil decreased tensile strength and the elongation percentage by 3.16 MPa and 15.59%, respectively; water vapor permeability, viscosity and opacity also significantly declined (P < 0.05). Scanning electron microscopy (SEM) of the surface of the film confirmed these results. Although 1.5% OEO-films showed higher antimicrobial activity, fish gelatin-alginate films incorporated with lower level of OEO can be can be more appropriate for food preservationl.

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Aims: In this study, gelatin was extracted from Siberian sturgeon waste and used in film making.
Materials and Methods: Gelatin was extracted using NaOH and HCl. After evaluating the extracted gelatin properties (bloom grade, pH, zeta test, melting and setting temperature and time), the edible film was prepared by using glycerol.
Findings: The results showed that the extraction efficiency of the gelatin was %20.06. The protein content, pH, degree of gel hardness, setting and melting temperature and time were 79.2 ± 0.6%, 4, 160.2 ± 0.4 g, 13.1 ± 0.2 ° C in 180.3 ± 0.5 seconds and 19.33 ± 0.5 ° C in 140.66 ± 0.5 seconds, respectively. Zeta potential indicated a positive surface charge in gelatin. The thickness, moisture, solubility, tensile strength, tensile strength and permeability tensile strengths properties of gelatin film reported 0.05 mm, %10.2 ± 1.5, %79 ± 3.7, 30.01 ± 0.7 MPa, %77.5 ± 3.6 and 3.5 ± 0 g mm/h mm²kpa×10^-6­, respectively. SEM images of the film showed smooth structure without cracking. Moreover, the FTIR result showed the formation of amide bands in the region of 3277.62, 1633.92, 1530.11 and 1236.49 cm^-1.
Conclusion: Due to the efficiency and properties of gelatin, and the mechanical and physical properties of the edible film, it can be used as a good candidate for the production of biodegradable films in food storage.

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This study was designed and conducted to investigate the mechanical and physical properties of fish gelatin films and the effect of Glutaraldehyde crosslinking on antimicrobial control of poly-l-lysine. In this study, the film was prepared by casting method and then 0.05% Glutaraldehyde and 0.05% poly-l-lysine added to fish gelatin film. After that, physical and mechanical properties, antimicrobial activity and release of poly-l-lysine from the film were observed. The results showed that the addition of glutaraldehyde to the fish gelatin film increased tensile pressure (6.80 MPa) and reduced solubility (38.51%), moisture (8.05%), and water vapor permeability (2.03 mm/h mm²kpa×10^-6­). The fish gelatin film with glutaraldehyde as a crosslinking agent was showed a smooth surface without porosity according to the SEM results. Moreover, the release of poly-l-lysine from the biopolymer containing the Glutaraldehyde was slower and more continuous due to crosslinking. Considering the mechanical and physical properties of the films and release control of the antimicrobial compound, it seems that films containing crosslinking agents can be used in food storage.

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Manufacturing of low-fat spread products due to the prevalence of obesity and cardiovascular disease in the world is expanding. Utilization of silver carp (Hypophthalmichthys molitrix) waste as a cultured species with high abundance and relatively low price, gelatin was prepared from the waste.The aim of this study was to in vitro production of the fat spread samples containing the three formula 1-3%with different cultured silver carp gelatin to pectin ratio (1:1 and 1:2) and evaluating the color and texture characteristics of the fat spread samples prepared by different fish gelatin to pectin ratio using colorimeter and texture analyzer.Firmness (69.75±1.767 g), compressibility (767.26±28.41 g.s) and adhesiveness (262.03±13.852 g.s) attributes were found at the highest level in the treatment contains fish gelatin to pectin ratio of 1:2 withformula 3% (p≤0.05). The highest yellowness index (39.70±0.027%) and the lowest whiteness index (71.54±0.014%) were measured in the treatment contains 1:1 (fish gelatin to pectin) with formula 1% (p≤0.05). Significant positive correlation between the shear test (kg) and firmness results of the samples was observed (r²=0.973). It was found that decreasing with higher substitution of fish gelatin with pectin leads to increase firmness, compressibility, adhesiveness and elasticity properties of fat spread samples significantly. With respect to low-fat productions due to their importance in society health and the results of this investigation, applying a formula with fish gelatin to pectin ratio of 1:1 (3%) at a larger scale is recommended.  

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Gelatin is mainly produced by collagen denaturation. Gelatin obtained from cold-water fish has low sol-gel transition temperatures. Chemical and physical treatments can be used to modify the gelatin network by establishing cross-links between the gelatin chains to improve the properties of the gel. In this study, cross-linking in cold-water fish gelatin-based hydrogels was established by tannic acid (TA) and caffeic acid (CA), each at concentrations of 1, 3 and 5%. The effect of CA and TA concentrations on the physicochemical properties of gelatin hydrogels was investigated. The strength of the gel and the degree of crosslinking increased with increasing the concentration of tannic acid from 1 to 3%, which increased the strength of the gel from 325.00 to 343.62 N/mm² and the degree of crosslinking from 82.01 to 84.99%. At higher levels of tannic acid, a decrease in gel strength and degree of crosslinking was observed 301.90 N/mm² and 75.48%, respectively. However, these properties of hydrogels increased steadily with increasing levels of caffeic acid (p <0.05). The swelling rate also decreased due to the combination of different levels of tannic acid and caffeic acid. The maximum swelling rate for the control was 1732.30% and the minimum swelling rate for 3% tannic acid was 594.79%. The crosslinked gelatins by tannic acid significantly improved the denaturation temperature and their thermal stability was higher than that of caffeic acid. This temperature was 89° C in untreated hydrogels and increased to 94 °C and 98 °C in caffeic acid and tannic acid treated hydrogels, respectively. Scanning electron microscopy images of the hydrogel samples showed that the structure of the hydrogels based on cold-water fish gelatin was spongy. The addition of crosslinking agents only slightly reduced the pore size of the gelatin and had no significant effect.