Characterization of Tri-Phasic Edible Films from Chitosan, Guar Gum, and Whey Protein Isolate Loaded with Plant-Based Antimicrobial Compounds

Nanocrystalline cellulose as a reinforcing agent for poly (vinyl alcohol)/ gellan-gum-based composite film for moxifloxacin ocular delivery

Nanocrystalline cellulose (NCC) is a star material in drug delivery applications due to its good biocompatibility, large specific surface area, high tensile strength (TS), and high hydrophilicity. Poly(Vinyl Alcohol)/Gellan-gum-based innovative composite film has been prepared using nanocrystalline cellulose (PVA/GG/NCC) as a strengthening agent for ocular delivery of moxifloxacin (MOX) via solvent casting method. Impedance analysis was studied using the capacitive sensing technique for examining new capacitance nature of the nanocomposite MOX film. Antimicrobial properties of films were evaluated using Pseudomonas aeruginosa and Staphylococcus aureus as gram-negative and gram-positive bacteria respectively by disc diffusion technique. XRD revealed the characteristic peak of NCC and the amorphous form of the drug. Sustained in vitro release and enhanced corneal permeation of drug were noticed in the presence of NCC. Polymer matrix enhanced the mechanical properties (tensile strength 22.05 to 28.41 MPa) and impedance behavior (resistance 59.23 to 213.23 Ω) in the film due to the presence of NCC rather than its absence (16.78 MPa and 39.03 Ω respectively). Occurrence of NCC brought about good antimicrobial behavior (both gram-positive and gram-negative) of the film. NCC incorporated poly(vinyl alcohol)/gellan-gum-based composite film exhibited increased mechanical properties and impedance behavior for improved ocular delivery of moxifloxacin.

Physical properties of zein-alginate-glycerol edible films and their application in the preservation of chili peppers (Capsicum annuum L.)

Edible films elaborated from macromolecules, like carbohydrates, proteins, and lipids, must protect and maintain the integrity of foods during their handling, storage, and transportation. In this work, the effect of the concentration of zein (1-2% w/v), sodium alginate (1.5-2% w/v), and glycerol (2-4% w/v) on edible films physicochemical properties was evaluated. The Zein-Alginate-Glycerol interaction was evidenced by the FTIR analysis, the high permeability to water vapor and contact angles less than 90° of the polymer matrices formed. The film made with 2% zein, 1.5% sodium alginate and 4% glycerol preserved the quality of the chili pepper during 15 days of storage at 20 °C, the edible films allowed 3 more days of shelf life for weight loss and 10 more days for firmness. Edible films could be used in chili peppers that are destined for industrial processing, and before use, remove the film with a simple wash.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01393-z.

Macro and nano level intervention of reinforcing agents for production of novel edible whey composite films and their applications in food systems: A review

Whey protein-based biocomposite films (WBF) are gaining significant importance as edible packaging materials due to their eco-friendly, biodegradable and barrier properties. The review aims to explore the impact of different reinforcing agents on the techno-functional properties of WBF. The incorporation of reinforcing agents, such as polysaccharides, lipids, starch, chitosan, cellulose, essential oils, and hydrocolloid gums, plays a crucial role in shaping the techno-functional properties of WBF. The review article suggests that whey biocomposite films, when strengthened with various additives, have the potential to be used as edible food packaging materials with desirable attributes. However, despite extensive studies, the utilization of WBF in model food systems remains limited, highlighting a significant gap for further exploration. Further research in this domain could potentially unlock new opportunities for utilizing WBF in various model food systems.

Influence of guar gum and chitosan enriched with lemon peel essential oil coatings on the quality of pears

Pear is a typically climacteric fruit and highly perishable with a low shelf life owing to extreme metabolic activity after harvesting. The present study aimed to reduce weight loss and improve the firmness of pear during storage. The lemon peel essential oil (LPEO) has gained considerable attention due to being the richest source of bioactive compounds that behaved as a natural antioxidant agent, being cost-effective, and being generally recognized as safe. Edible coatings equipped with a natural antioxidant agent and renewable biopolymers have gained more research fame owing to their involvement in the direction of biodegradability and food safety. In this work, edible skin coating materials (ESCMs) embedded by chitosan (1%) and guar gum (2%) were fabricated, and afterward, five concentrations of LPEO (1, 1.5, 2, 2.5, and 3.0%) were incorporated individually into the ESCMs. Findings revealed that LPEO-ESCMs significantly reduced the weight loss and improved the firmness of pear up to 45 days of storage at 4 ± 2°C. Furthermore, the LPEO-ESCMs have enhanced the antioxidant capacity, antibacterial efficiency, and malondialdehyde level of pear during storage time. It was concluded that 3% of LPEO-ESCMs improved the overall acceptability of pear fruits. Taken together, the novel insights of guar gum and chitosan-based ESCMs entrapped with LPEO will remain a subject of research interest for researchers in the future.

Impact of Various Essential Oils and Plant Extracts on the Characterization of the Composite Seaweed Hydrocolloid and Gac Pulp (Momordica cochinchinensis) Edible Film

Edible films and coatings have currently received increasing interest because of their potential in food applications. This study examined the effect of incorporated essential oils and natural plant extracts on the characteristics of the composite seaweed hydrocolloid and gac pulp films. Films were prepared by a casting technique, followed by measurement of physical, optical, barrier, mechanical, and structural properties. The results showed that adding plant oils and extracts significantly affected the physical, optical, mechanical, and structural properties of the composite films. Incorporation of the essential oils resulted in a reduction in moisture content and opacity while increasing values for Hue angle and elongation at break of the composite films. Besides, incorporation of the plant extracts showed increases in thickness, opacity, ΔE, Chroma, and elongation at the break, while there is a decrease in the Hue angle values of the composite films. In conclusion, incorporating plant essential oils and extracts into composite seaweed hydrocolloid and gac pulp films can enhance film properties, which can potentially be applied in food products.

Essential Oil-Containing Polysaccharide-Based Edible Films and Coatings for Food Security Applications

The wastage of food products is a major challenge for the food industry. In this regard, the use of edible films and coatings have gained much attention due to their ability to prevent the spoilage of the food products during handling, transport, and storage. This has effectively helped in extending the shelf-life of the food products. Among the various polymers, polysaccharides have been explored to develop edible films and coatings in the last decade. Such polymeric systems have shown great promise in microbial food safety applications. The inclusion of essential oils (EOs) within the polysaccharide matrices has further improved the functional properties of the edible films and coatings. The current review will discuss the different types of polysaccharides, EOs, methods of preparing edible films and coatings, and the characterization methods for the EO-loaded polysaccharide films. The mechanism of the antimicrobial activity of the EOs has also been discussed in brief.

Extension of postharvest shelf life of strawberries (Fragaria ananassa) using a coating of chitosan-whey protein isolate conjugate

Chitosan and whey protein isolate (WPI) conjugate films were prepared as a novel matrix for encapsulating and extending the postharvest shelf life of strawberries. Film forming solutions of chitosan, WPI, and chitosan-WPI conjugate were mixed with glycerol, casted for films at 60 ± 2 °C and assessed for their colour, water vapour and oxygen transfer rate, textural, functional groups and secondary structure, thermal, crystallinity, and antioxidant properties. Chitosan-WPI conjugate films were applied as an edible coating on strawberries, and studied for storage stability at 5 °C and 20 °C by assessing physical and biochemical parameters. A considerable reduction in colour indices, weight loss, pH and titratable acidity, reducing sugars, ascorbic acid, total phenolics, DPPH and ABTS assay was noted in the coated strawberries over the control at both the studied temperatures. The control strawberries had a shelf life of 5 and 3 days, whereas coating enhanced the shelf life of strawberries to 8 and 5 days when stored at 5 °C and 20 °C, respectively.

Physicochemical Properties and Bioactivity of a New Guar Gum-Based Film Incorporated with Citral to Brown Planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae)

The brown planthopper (BPH), Nilaparvata lugens (Stål), is the most notorious rice insect pest. In order to repel BPH effectively while being environmentally friendly, a new film based on guar gum incorporated with citral (GC film) was formulated. A toxicity bioassay of citral and guar gum at different proportions (ratios of 3:1, 2:1, 1:1, 1:2, and 1:3 in w/w) of GC film-forming emulsion to BPH was performed with the rice stem dipping method. Results showed that the most effective ratio of citral to guar gum was 1:1 with the median lethal concentration (LC₅₀) of 4.30 mg/mL, far below the LC₅₀ of guar gum (GG)/citral individual (141.51 and 44.38 mg/mL, respectively). The mortality of BPH adults and nymphs in the third instar treated with different dilution multiples of GC film-forming emulsion ranged from 46.67% to 82.22% and from 37.78% to 71.11%, respectively. These indicated that GC film-forming emulsion had a direct toxicity on BPH, and the mixture of citral and GG had synergistic interactions. Subsequently, Fourier-transform infrared spectroscopy showed that the incorporation of guar gum with citral was successful and did not result in the formation of new chemical bonds. The GC film exhibited a darker color and rougher surface topography with larger apertures and deeper gullies (Ra = 1.42 nm, Rq = 2.05 nm, and Rmax = 25.40 nm) compared to the guar gum film (GG film) (Ra = 1.00 nm, Rq = 1.33 nm, and Rmax = 16.40 nm), as determined by transmission electron microscopy and atomic force microscopy. The GC film exhibited a 50.4% lower solubility in water (30.30% vs. 15.00%) and 71.3% oxygen permeability (8.26 × 10⁻⁹ vs. 2.37 × 10⁻⁹ cm³/m²·d·Pa) (p < 0.05) but did not demonstrate any significant difference in mechanical properties, such as thickness (39.10 vs. 41.70 mm), tensile strength (41.89 vs. 38.30 N/mm²), and elongation at break (1.82% vs. 2.03%) (p < 0.05) compared to the GG film. Our findings established a link between physicochemical properties and bioactivity, which can provide useful information on developing and improving GC films and may offer an alternative approach for the control of BPH in the near future.

Synthesis, characterization, and antimicrobial efficacy of composite films from guar gum/sago starch/whey protein isolate loaded with carvacrol, citral and carvacrol-citral mixture

The aim of this research was to formulate antimicrobial, composite films of guar gum, sago starch, and whey protein isolate for the prophylaxis of the bacterial gastroenteritis. The model antibacterial agents incorporated were essential oils, namely, carvacrol, citral and their combination. The films became darker and brownish in color due to the entrapment of the oils. The surface of the oil-entrapped films was more rough and coarse compared to the control film. Confocal micrographs affirmed the uniform distribution of the oil droplets within the biopolymeric network. The highest crystallite size and lowest lattice strain were estimated in the citral-containing film. FTIR analysis demonstrated that the incorporation of citral increased the proportion of the β-sheet structures of the whey protein isolate within the film matrix. However, the film formulation containing combination of carvacrol and citral demonstrated the lowest water vapor transmission rate (WVTR), highest tensile strength, Young's modulus and work to failure. All the oil-containing films demonstrated good antibacterial potency against the model bacterial gastroenteritis causing bacteria, namely, Bacillus cereus and Escherichia coli. In gist, it can be concluded that the prepared antimicrobial films could be used for the prophylaxis of the bacterial gastroenteritis.