Evaluation of Plasticizing and Antioxidant Properties of Silver Carp Protein Hydrolysates in Fish Gelatin Film

UV Radiation and Protein Hydrolysates in Bio-Based Films: Impacts on Properties and Italian Salami Preservation

UV radiation was combined with the incorporation of fish protein hydrolysates to improve the performance of active bio-based films for food packaging. UV radiation was not used previously to enhance the packaging performance of blend films of starch/protein, and fish protein hydrolysates were not incorporated in bio-based polymer surfaces previously. Rice starch and fish proteins (from Whitemouth croaker muscle) were utilized to prepare films by the casting technique, which were UV-radiated under different exposure times (1, 5, and 10 min). The packaging performance of the films was determined according to the mechanical and barrier performance, solubility, and color. Fish protein hydrolysates (from Argentine croaker muscle) were then incorporated into the films (bulk structure or surface). The results showed that UV radiation for 1 min increased the tensile strength and modified the optical properties of films. It also altered the structure of the polymeric matrix, as demonstrated by the microstructure and thermal analysis, in agreement with the data obtained in packaging properties. The evaluation of antioxidant capacity through 2,2-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and reducing power indicated that incorporating fish protein hydrolysates either in the films' bulk structure or film surface promoted antioxidant properties; control films (produced with rice starch/fish proteins without hydrolysates) also presented antioxidant potential. According to the peroxide value and thiobarbituric acid reactive substance (TBARS) assays, control films and the films containing hydrolysates in their bulk structure or on the surface could prevent the lipid oxidation of Italian salami. Thus, combining UV radiation to shape the characteristics of bio-based materials with fish protein hydrolysates to reduce lipid oxidation contributes to the performance of active bio-based films for food packaging.

Factors affecting sericin hydrolysis and application of sericin hydrolysate in sericin films

Sericin is a natural protein and a by-product obtained from silk processing. To enhance the antioxidant properties of sericin, sericin hydrolysis was studied. The solvent effects (distilled water, citric acid and hydrochloric acid) and hydrolysis methods (heat treatment (water bath) and mild ultrasonic treatment at 20%, 40% or 60% amplitude) were investigated on the properties of sericin hydrolysate (SH). Furthermore, solvent effects (distilled water and 15% ethanol) were examined for the properties of the sericin films incorporated with selected SH. The SH samples from acid hydrolysis and the ultrasonic method had a darkened visual appearance. However, the degree of hydrolysis and antioxidant activity of SH increased with ultrasonic-assisted acid hydrolysis. The molecular weight (MW) of sericin was notably reduced. As expected, hydrochloric acid hydrolysis resulted in a lower MW for the SH than from citric acid. Thus, SH from hydrochloric acid and 20% amplitude in the ultrasonic method were selected to produce a sericin film. As revealed, using distilled water as a general solvent provided films with lower solubility and water vapor permeability but higher tensile strength. Furthermore, the addition of SH enhanced the antioxidant properties of its hydrolysate as a novel protein packaging film material for various applications.

Recent Developments in Smart Food Packaging Focused on Biobased and Biodegradable Polymers

Food packaging has a crucial function in the modern food industry. New food packaging technologies seek to meet consumers and industrial's demands. Changes related to food production, sale practices and consumers' lifestyles, along with environmental awareness and the advance in new areas of knowledge (such as nanotechnology or biotechnology), act as driving forces to develop smart packages that can extend food shelf-life, keeping and supervising their innocuousness and quality and also taking care of the environment. This review describes the main concepts and types of active and intelligent food packaging, focusing on recent progress and new trends using biodegradable and biobased polymers. Numerous studies show the great possibilities of these materials. Future research needs to focus on some important aspects such as possibilities to scale-up, costs, regulatory aspects, and consumers' acceptance, to make these systems commercially viable.

Synergistic Effect of Halloysite Nanotubes and Glycerol on the Physical Properties of Fish Gelatin Films

Fish gelatin (FG)/glycerol (GE)/halloysite (HT) composite films were prepared by casting method. The morphology of the composite films was observed by scanning electron microscopy (SEM). The effects of HT and GE addition on the mechanical properties, water resistance and optical properties of the composites were investigated. Results showed that with increasing GE content, the elongation at composite breaks increased significantly, but their tensile strength (TS) and water resistance decreased. SEM results showed that GE can partly promote HT dispersion in composites. TS and water resistance also increased with the addition of HTs. Well-dispersed HTs in the FG matrix decreased the moisture uptake and water solubility of the composites. All films showed a transparency higher than 80% across the visible light region (400⁻800 nm), thereby indicating that light transmittance of the resulting nanocomposites was slightly affected by GE and HTs.