Recent progress on Pickering emulsion stabilized essential oil added biopolymer-based film for food packaging applications: A review.

Nowadays food safety and protection are a growing concern for food producers and food industry. The stability of food-grade materials is key in food processing and shelf life. Pickering emulsions (PEs) have gained significant attention in food regimes owing to their stability enhancement of food specimens. PE can be developed by high and low-energy methods. The use of PE in the food sector is completely safe as it uses solid biodegradable particles to stabilize the oil in water and it also acts as an excellent carrier of essential oils (EOs). EOs are useful functional ingredients, the inclusion of EOs in the packaging film or coating formulation significantly helps in the improvement of the shelf life of the packed food item. The highly volatile nature, limited solubility and ease of oxidation in light of EOs restricts their direct use in packaging. In this context, the use of PEs of EOs is suitable to overcome most of the challenges, Therefore, recently there have been many papers published on PEs of EOs including active packaging film and coatings and the obtained results are promising. The current review amalgamates these studies to inform about the chemistry of PEs followed by types of stabilizers, factors affecting the stability and different high and low-energy manufacturing methods. Finally, the review summarizes the recent advancement in PEs-added packaging film and their application in the enhancement of shelf life of food.

Biological potential of polysaccharides extracted from Nostoc colonies for film production - Physical and biological properties.

Cyanobacteria of the Nostoc genus secrete a number of biologically active compounds, including polysaccharides, which may exhibit antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. The aim of the study was to investigate the biological properties of Nostoc polysaccharides (NPs) (antioxidative and antimicrobial) and the possibility of using NPs addition in the production of biofoils. Our results allow to indicate that NPs were compatible with the used biopolymer matrix (furcellaran and chitosan) and showed antioxidant properties. The tested polysaccharide extracts (0.14%) exhibited the ability to neutralize free radicals - 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) at a level of 4.46% and 10.14%, respectively. NP extracts demonstrated reducing properties of 15.35 and 30.07 mg Trolox equivalents (FRAP and CUPRAC methods, respectively) and 2.64 mg chlorogenic acid equivalents (tested with Folin's reagent). NP extracts showed: a growth-stimulating effect (Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae), no effect (Penicillum sp.), or a slight inhibitory effect (Streptomyces sp.) on the tested microorganisms. The enrichment of the film with NPs influenced the physic-chemical properties of the obtained biofoils. The addition of polysaccharides to furcellaran and chitosan films decreased their water solubility (by approximately 40% and 9%, respectively, compared to the control) and, at the same time increased, their water absorption.

Double-Layered Films Based on Furcellaran, Chitosan, and Gelatin Hydrolysates Enriched with AgNPs in Yerba Mate Extract, Montmorillonite, and Curcumin with Rosemary Essential Oil.

Double-layered active films based on furcellaran (1st layer-FUR), chitosan, and gelatin hydrolysates (2nd layer-CHIT+HGEL) were successfully prepared. Bioactive ingredients were added to the 1st film layer: AgNPs, which were synthesized in situ with yerba mate extract; montmorillonite clay (MMT); and different loads of ethanolic curcumin (CUR) extract enriched with rosemary essential oil (REO). SEM images confirmed the presence of AgNPs with a size distribution of 94.96 ± 3.33 nm throughout the films, and AFM and SEM photos indicated that the higher substance concentrations had rougher and more porous film microstructures. However, the water vapor transmission rate was reduced only at the lowest load of this ingredient. Despite the tensile strength of the films having decreased, the incorporation of the compounds showed a tendency towards reducing the modulus of elasticity, resulting in a lower stiffness of the composites. The addition of CUR and AgNPs improved the UV light barrier properties of the materials. The presented films showed quick reactions to changes in the pH value (from orange to red along with an increase in pH from 2 to 10), which indicates their potential use as indicators for monitoring the freshness of food products. Composite No. 2 showed the highest antimicrobial potential, while none of the presented films showed an antifungal effect. Finally, the antioxidant activities of the films increased dramatically at higher AgNP and CUR loads, suggesting an outstanding potential for active food packaging applications.