Preparation, properties and antioxidant activity of an active film from silver carp (Hypophthalmichthys molitrix) skin gelatin incorporated with green tea extract

Application of Protein-Based Films and Coatings for Food Packaging: A Review

As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.

Effects of environmental stresses on physiochemical stability of β-carotene in zein-carboxymethyl chitosan-tea polyphenols ternary delivery system

β-Carotene is a natural nutrient that serves as a natural food colorant. However, the weak physical stability restricts its development in food industrial production. Here, the influences of a variety of external environmental conditions on the stability of β-carotene enriched zein-carboxymethyl chitosan (CMCS)-tea polyphenols (TP) ternary composite nanoparticles were investigated. Compared with zein unitary and zein-CMCS binary complexes, it was interesting to note that ternary complexes had the best stability against color fading and there was little impact on its nanoparticle size during storage with change in temperature. Besides excellent antioxidant properties, ternary complexes were extremely effective in inhibiting β-carotene color degradation when exposed to ultraviolet light. Based on our results, the novel zein-CMCS-TP nanoparticles are expected to be an effective delivery system to encapsulate hydrophobic bioactive compounds, which is a promising approach to improve their storage stability against external environmental stresses.

Effectiveness of combined acetic acid and ascorbic acid spray on fresh silver carp (Hypophthalmichthys molitrix) fish to increase shelf-life at refrigerated temperature

This experiment was conducted to evaluate the efficacy of application of acetic acid and ascorbic acid spray on the surface decontamination and shelf-life of silver carp fish at refrigerated temperature (40C) during 9 days of storage period. Silver carp is one of the most abundant freshwater fish speciesin the world. However, the rapid quality degradation soon after post-mortem makes them highly putrefactive while reducing the nutritional attributes. In this regard, our study aimed at applying organic acids to extend shelf-life of silver carp fish while investigating the quality attributes such as sensory, peroxide values, pH and microbial loads of the fish fillets during 9 days of refrigerated temperature storage (40C). Acetic acid and ascorbic acid are found to have strong antibacterial activities against different microorganisms. Fish fillets samples were treated with alone or in combination with acetic acid and ascorbic acid spray while keeping one group of fish fillets untreated. Total Viable Count (TVC) was found greater in the samples kept untreated and treated alone with acetic acid and ascorbic acid. However, fish fillets treated with acetic acid and ascorbic acid in combination were reported with lesser number of microbial counts. Moreover, Peroxide Value (PV) and pH were significantly lower in the sample treated with in combination of acetic acid and ascorbic acid. Sensory analysis revealed that fish fillets treated with combined treatment had better quality retention at the end of 9 days storage period. The findings suggest that the application of acetic acid and ascorbic acid alone or in different combination have the potential to decrease microbial loads while facilitating the shelf-life of fish fillets during 9 days of refrigerated temperature (40C) storage period.

Evaluation of antimicrobial and antioxidant activities for cellulose acetate films incorporated with Rosemary and Aloe Vera essential oils

Enhancement of natural based polymeric membranes for active packaging takes the attention of scientists. Their biological activities can be obtained by adding essential oils, which are natural extracts with antimicrobial and antioxidant properties. The target of current work aimed to produce bio-active membranes from cellulose acetate incorporated with Rosemary and Aloe Vera oil. The developed film's chemical structures and morphologies were investigated using FT-IR and SEM characterization tools. The impact of essential oils incorporation on water uptake, wettability behavior, and mechanical properties were explored. The results displayed that antimicrobial activity against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) increased as Rosemary and Aloe Vera oil percentage increases in cellulose acetate membranes. In addition, higher activity against B. subtilis compared to E. coli was also observed. Moreover, free radical scavenger activity (ABTS and DPPH) of cellulose acetate membranes, improved by increasing the essential oil content in the feed mixture. The obtained results provide a high potential for production of an efficient food packaging membrane from cellulose acetate containing Rosemary and Aloe Vera oil.

Bioactive Multilayer Polylactide Films with Controlled Release Capacity of Gallic Acid Accomplished by Incorporating Electrospun Nanostructured Coatings and Interlayers

The present research reports on the development of bi- and multilayer polylactide (PLA) films by the incorporation of electrospun nanostructured PLA coatings and interlayers containing the antioxidant gallic acid (GA) at 40 wt% onto cast-extruded PLA films. To achieve the bilayer structures, submicron GA-loaded PLA fibers were applied on 200-µm cast PLA films in the form of coatings by electrospinning for 1, 2, and 3 h. For the multilayers, the cast PLA films were first coated on one side by electrospinning, then sandwiched with 10-µm PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 °C without pressure. Whereas the bilayer PLA films easily delaminated and lacked transparency, the multilayers showed sufficient adhesion between layers and high transparency for deposition times during electrospinning of up to 2 h. The incorporation of GA positively contributed to delaying the thermal degradation of PLA for approximately 10 °C, as all films were thermally stable up to 345 °C. The in vitro release studies performed in saline medium indicated that the GA released from the bilayer PLA films rapidly increased during the first 5 h of immersion while it stabilized after 45–250 h. Interestingly, the PLA multilayers offered a high sustained release of GA, having the capacity to deliver the bioactive for over 1000 h. In addition, in the whole tested period, the GA released from the PLA films retained most of its antioxidant functionality. Thus, during the first days, the bilayer PLA films can perform as potent vehicles to deliver GA while the multilayer PLA films are able to show a sustained release of the natural antioxidant for extended periods.

Characterization of antioxidant and antibacterial gelatin films incorporated with Ginkgo biloba extract

Ginkgo biloba extract (GBE) contains Ginkgo biloba flavonoids, which are phenolic compounds. These compounds can be introduced into films for their functional properties (such as their antioxidant and antibacterial property), allowing this film to be used as food packaging. Thus, the aim of this study was to introduce the GBE into a gelatin solution to prepare gelatin films and evaluate the influence of the natural extract addition on the physicochemical and antimicrobial properties. The gelatin films were successfully prepared by casting technique, and GBE was incorporated at concentrations of 0, 0.5, 1.5, 2.5, 3, 4, and 5 g/100 g of gelatin. The mechanical properties, film solubility, moisture content, water vapor permeability, infrared spectroscopic characteristics, film microstructure, light barrier property, antioxidant property and antibacterial property of the films were investigated. The incorporation of gelatin films with GBE increased the UV-visible shielding performance of films. The antioxidant ability of the film was improved, which was supposed to be related to the active substances of the GBE. The GBE also exhibited potential antimicrobial activity against tested microorganisms. With the increase in the GBE concentration incorporated into the films, the antimicrobial activity of the gelatin film with GBE was also enhanced.

The incorporation of gelatin films with GBE increased the UV-visible shielding performance of films.

Application of Adzuki Bean Starch in Antioxidant Films Containing Cocoa Nibs Extract

In this study, starch extracted from adzuki bean (ABS) was used as a biodegradable film source. In addition, to develop a new antioxidant film, various amounts of cocoa nibs extract (CNE, 0.3%, 0.7%, and 1%) were incorporated. With the addition of CNE, the elongation at break of the ABS films increased and the tensile strength decreased. The ABS films with CNE showed increased 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities with increasing amounts of CNE. In particular, the ABTS and DPPH radical scavenging activities of the ABS films containing 1% CNE were 100% and 94.9%, respectively. Furthermore, decomposition of the films was observed after 28 days of biodegradation. Thus, ABS films containing CNE can be applied as a new active packaging material.

Development, characterization and application of hydroxypropylmethylcellulose films enriched with cypress seed extract

The phenolic profile of cypress seed extract (CSE) was investigated by means of liquid chromatography with photodiode array and electrospray ionisation mass spectrometric detection (LC/PDA/ESI-MS). The total phenolic (TP) and flavonoid (TF) contents as well as the antioxidant capacity of CSE were determined. The effects of CSE concentration (0.1, 0.3, 0.5, 1, and 2% (w/v)) on the functional properties of hydroxypropylmethylcellulose (HPMC) films were studied. Results showed that CSE presents a good antioxidant capacity due to its high phenolic/flavonoid contents and particularly the presence of bi-flavonoid compounds including cupressuflavone and amentoflavone derivatives. The incorporation of CSE in HPMC films led to a significant decrease in their water vapor permeability (WVP) and enhanced their mechanical strength. The lowest WVP value, the greatest opacity and the highest antioxidant capacity were obtained with the highest CSE concentration. HPMC films with and without CSE were applied on virgin olive oil to study their effect on the oxidative stability of olive oil during accelerated storage by periodically analyzing changes in FTIR spectra and peroxide values. HPMC-2% CSE films were the most effective in lowering light transmission, and consequently decreasing peroxide formation and delaying oxidation of olive oil.

Physical properties and antioxidant activity of gelatin-sodium alginate edible films with tea polyphenols

Active edible films were prepared by incorporating tea polyphenols (TP) into gelatin and sodium alginate. The effects of 0.4%-2.0% TP (w/w, TP/gelatin) on physical, antioxidant, and morphological properties of gelatin-sodium alginate films were evaluated. Tensile strength (Ts), contact angle (CA), and cross-linking degree showed an enhanced trend as TP concentration in the film increased, whereas elongation at break (EAB) and water vapor permeability (WVP) possessed a decline trend. The light transmittance of the film was decreased by the incorporation of TP. Antioxidant capacity was improved by increasing TP content in the films. For DPPH and ABTS radical, the films with 2.0% TP possessed the highest values of 90.62 ± 2.48% and 53.36 ± 1.06 Trolox (mg Trolox equivalent/g film), respectively. Fourier transform infrared spectroscopy analyses (FTIR) indicated the interactions existed between gelatin‑sodium alginate and TP. Smooth and continuous surface and dense internal structure of the films with TP were observed by scanning electron microscopy (SEM). Thus, incorporating TP into gelatin and sodium alginate film solution was an effective method in order to improve physical properties and antioxidant activity of the films. Gelatin-sodium alginate films with TP could be used as an edible film for food packaging applications.

Influence of Various Phenolic Compounds on Properties of Gelatin Film Prepared from Horse Mackerel Trachurus japonicus Scales

Influence of various phenolic compounds on physical properties and antioxidant activity of gelatin film from horse mackerel Trachurus japonicus scales was investigated. Tensile strength (TS) of the film was enhanced whereas elongation at break was declined by adding 1% to 5% phenolic compounds. Rutin was the most effective to improve the TS compared to the other tested phenolic compounds including ferulic acid, caffeic acid, gallic acid, and catechin. Gelatin films with the phenolic compounds showed the excellent UV barrier properties. FTIR spectra exhibited that wavenumber of amide-A band of films decreased with formation of hydrogen bonding between amino groups of gelatin and hydroxyl groups of the phenolic compounds. Gelatin film incorporated with rutin which has the largest number of hydroxyl groups among the tested compounds demonstrated the lowest wavenumber for the amide-A peak. It is indicated that hydroxyl groups contained in the phenolic compounds contribute to formation of hydrogen bonds involved in improvement of the mechanical properties of the films. The incorporation of the phenolic compounds with gelatin films also led to the increasing of total phenolic contents and DPPH radical scavenging activities. Thus, it is concluded that phenolic compounds can promote the quality of gelatin film.

PRACTICAL APPLICATION

Properties of gelatin film derived from horse mackerel scales can be improved by adding of phenolic compounds. Phenolic compounds containing a large number of hydroxyl groups should be selected to enhance physical properties of the gelatin film. A biodegradable film prepared from horse mackerel gelatin incorporated with phenolic compounds, which has good physical properties and antioxidant properties, can solve environmental problems caused by synthetic plastic materials.

Changes in the amino acid profiles and free radical scavenging activities of Tenebrio molitor larvae following enzymatic hydrolysis

Tenebrio molitor (T. molitor) larvae provide food at low environmental cost and contribute positively to livelihoods. In this research, we compared the amino acids compositions and antioxidant activities of various extracts of T. molitor to enhance their quality as food. For the comparison, distilled water extracts, enzymatic hydrolysates, and condensed enzymatic hydrolysates of T. molitor larvae were prepared. Their amino acids (AAs) profiles and antioxidant activities, including ferric-reducing antioxidant power, oxygen radical absorption capacity, and DPPH, hydroxyl radical, and hydrogen peroxide radical scavenging properties assay were analyzed. DW extracts had the lowest AAs contents and antioxidant activity compared with enzymatic extracts. Condensed hydrolysates with a combination of alcalase and flavourzyme (C-A+F) exhibited the highest levels of total free AAs (11.1759 g/100 g). C-A+F produced higher total hydrolyzed AAs (32.5292 g/100 g) compared with the other groups. The C-A+F possessed the strongest antioxidant activity. Notably, the antioxidant activities of the hydrolysates and the total hydrolyzed AAs amount were correlated. Taken together, our findings showed that C-A+F was a promising technique for obtaining extracts of T. molitor larvae with antioxidant activity as potential nutritious functional food.