Combined effects of lemon essential oil and surfactants on physical and structural properties of chitosan films

Stability and biological activity enhancement of fucoxanthin through encapsulation in alginate/chitosan nanoparticles

A response surface methodology based on the Box-Behnken design was employed to develop fucoxanthin (FX) delivery nanocarrier from alginate (ALG) and chitosan (CS). The FX-loaded ALG/CS nanoparticles (FX-ALG/CS-NPs) were fabricated using oil-in-water emulsification and ionic gelation. The optimal formulation consisted of an ALG:CS mass ratio of 0.015:1, 0.71 % w/v Tween™ 80, and 5 mg/mL FX concentrations. The resulting FX-ALG/CS-NPs had a size of 227 ± 23 nm, a zeta potential of 35.3 ± 1.7 mV, and an encapsulation efficiency of 81.2 ± 2.8 %. These nanoparticles exhibited enhanced stability under simulated environmental conditions and controlled FX release in simulated gastrointestinal fluids. Furthermore, FX-ALG/CS-NPs showed increased in vitro oral bioaccessibility, gastrointestinal stability, antioxidant activity, anti-inflammatory effect, and cytotoxicity against various cancer cells. The findings suggest that ALG/CS-NPs are effective nanocarriers for the delivery of FX in nutraceuticals, functional foods, and pharmaceuticals.

Effect of Nano-Silica and Sorbitol on the Properties of Chitosan-Based Composite Films

Chitosan and its derivatives are widely used in food packaging, pharmaceutical, biotechnology, medical, textile, paper, agriculture, and environmental industries. However, the flexibility of chitosan films is extremely poor, which limits its relevant applications to a large extent. In this paper, chitosan/sorbitol/nano-silica (CS/sorbitol/SiO2) composite films were prepared by the casting film method using chitosan, sorbitol, Tween-80 and nano-SiO2 as raw materials. The structure of the films was characterized by infrared spectroscopy, electron scanning microscopy, and X-ray diffraction analysis. The effects of sorbitol and nano-silica dosage on the mechanical properties, thermal properties and water vapor barrier properties of the composite film were investigated. The results show that with the gradual increase in sorbitol (≤75 wt %), the elongation at the break of chitosan/sorbitol films significantly increased. When the addition of sorbitol was 75 wt %, the elongation at break of the chitosan/sorbitol composite film was 13 times higher than that of the chitosan film. Moreover, nano-SiO2 can further improve the mechanical properties and thermal stability of the chitosan/sorbitol composite films. When the amount of nano-silica was 4.5 wt %, the composite film became more flexible, with a maximum elongation of 90.8% (which is 14 times that of chitosan film), and its toughness increased to 10.52 MJm-3 (which is 6 times that of chitosan film). This study balances the tensile strength and elongation at break of the composite films by adding a plasticizer and nano-filler, providing a reference for the preparation of chitosan composites or their blending with other polymers, and has practical guiding significance for the industrial production of biomass plastics.

Insight on Incorporation of Essential Oils as Antimicrobial Substances in Biopolymer-Based Active Packaging

The increasing interest in microbiological food safety requires the development of sensitive and reliable analyses and technologies for preserving food products' freshness and quality. Different types of packaging systems are one of the solutions for controlling microbiological activity in foods. During the last decades, the development of biopolymer-based active packaging with essential oil incorporation systems has resulted in technologies with exceptional application potential, primarily in the food industry. There is no doubt that this principle can facilitate food status monitoring, reduce food waste, extend the shelf life, improve the overall quality of food, or indicate a larger problem during the storage, production, and distribution of foodstuffs. On the other hand, most antimicrobial packaging systems are in the development phase, while the sensitivity, selectivity, complexity, and, above all, safety of these materials are just some of the essential questions that need to be answered before they can be widely used. The incorporation of essential oils as antimicrobial substances in biopolymer-based active packaging holds significant promise for enhancing food safety, extending shelf life, and offering more sustainable packaging solutions. While challenges exist, ongoing research and innovation in this field are likely to lead to the development of effective and environmentally friendly packaging systems with enhanced antimicrobial properties.

Effect of Surfactant Formula on the Film Forming Capacity, Wettability, and Preservation Properties of Electrically Sprayed Sodium Alginate Coats

Surfactants are always added to coating formulations to ensure good adhesion of edible coatings to a product's surface and to maintain freshness. In this study, the effects of the mix surfactants Tween 20 and Span 80 with different hydrophile-lipophile balance (HLB) values on the film-forming ability, wettability, and preservation capacity of blueberry sodium alginate coating were investigated. The results indicated that Tween 20 obviously ensured favorable wettability and improved the uniformity and mechanical properties of the resulting film. While the addition of Span 80 reduced the mean particle size of the coating, enhanced the water resistance of the film, and helped to reduce blueberry weight loss. A sodium alginate coating with low viscosity and medium HLB could better inhibit the galactose, sucrose, and linoleic acid metabolism of blueberries, reduce the consumption of phenols, promote the accumulation of flavonoids, and thus display superior coating performance. In summary, sodium alginate coating with medium HLB had comprehensive advantages in film-forming ability and wettability and was conducive to the fresh-keeping role.

Preparation and Characterization of Bioactive Chitosan Film Loaded with Cashew (Anacardium occidentale) Leaf Extract

Chitosan is a biopolymer known for its rapid biodegradability and film-forming properties. This research aimed to synthesize and characterize chitosan films loaded with cashew leaf extract (CLE) obtained from immature and mature cashew leaves via aqueous and 70% ethanolic extraction methods. Freeze-dried CLE samples were dissolved in 50% dimethyl sulfoxide for in vitro analysis and chitosan film preparation. The total phenolic content of mature cashew leaves extracted in ethanol (MECLE) showed higher free radicle scavenging activity by a 2,2-diphenyl-1-picrylhydrazyl assay than the other extracts (p < 0.05). MECLE displayed a lower minimal inhibitory concentration, minimum fungal concentration, and higher zone of inhibition against Aspergillus niger compared to the other treatments (p < 0.05). Film-forming solutions were prepared using 2% chitosan, 2% chitosan with 5% mature cashew leaves extracted in deionized water (MACLE) (w/v), and 2% chitosan with 5% MECLE (w/v), respectively, to cast films. Of these, 2% chitosan (CH) with 5% MECLE (CH-MECLE-5) displayed the highest thickness and water vapor transmission rate, water vapor permeability, and oxygen transmission rate when compared to other film samples (p < 0.05). The CH-MECLE-5 film showed the highest inhibition zone of A. niger compared to the control and treated films (p < 0.05). The lightness (L*) of the CH-MECLE-5 film decreased with increment in b* values, which represented the yellow color of the film. In addition, two-photon microscopy revealed a uniform distribution via the auto-fluorescent 3D structure of MECLE in the CH-MECLE-5 film. Therefore, chitosan combined with 5% MECLE may be a potential bioactive and eco-friendly packaging film.

Polysaccharide-Based Active Coatings Incorporated with Bioactive Compounds for Reducing Postharvest Losses of Fresh Fruits

This review reports recently published research related to the application of polysaccharide-based biodegradable and edible coatings (BECs) fortified with bioactive compounds obtained from plant essential oils (EOs) and phenolic compounds of plant extracts. Combinations of polysaccharides such as starches, pectin, alginate, cellulose derivatives, and chitosan with active compounds obtained from clove, lemon, cinnamon, lavender, oregano, and peppermint have been documented as potential candidates for biologically active coating materials for retardation of quality changes in fresh fruits. Additionally, polysaccharide-based active coatings supplemented with plant extracts such as cashew leaves, pomegranate peel, red roselle, apple fiber, and green tea extracts rich in phenolic compounds and their derivatives have been reported to be excellent substituents to replace chemically formulated wax coatings. Moreover, EOs and plant polyphenolics including alcohols, aldehydes, ketones phenols, organic acids, terpenes, and esters contain hydroxyl functional groups that contribute bioactivity to BECs against oxidation and reduction of microbial load in fresh fruits. Therefore, BECs enriched with active compounds from EOs and plant extracts minimize physiological and microbial deterioration by reducing moisture loss, softening of flesh, ripening, and decay caused by pathogenic bacterial strains, mold, or yeast rots, respectively. As a result, shelf life of fresh fruits can be extended by employing active polysaccharide coatings supplemented with EOs and plant extracts prior to postharvest storage.

Chitosan nanoemulsion: Gleam into the futuristic approach for preserving the quality of muscle foods

Trend for consumption of healthy meat without synthetic additives is blooming globally and has attracted the interest of consumers and research sphere to look for enhancement of quality and safety of food. Chitosan is multi-functional marine biopolymer with several befitting properties such as non-toxicity, ease of modification, antimicrobial activity, biodegradability and bio-compatibility, making it suitable for use in meat based food systems, which are highly prone to putrescence due to availability of high level protein, micronutrients and moisture. Bioactive components from plant extracts on account of their natural lineage are exquisite determinants for meat preservation in association with chitosan to replace synthetic molecules, which are considered to evince toxicological effects. Nanoemulsions are viable systems for integrating a myriad of active constituents framed by microfluidization, high-pressure homogenization, ultra-sonication, phase inversion (PIC and PIT) and spontaneous-emulsification with benefits of droplet size reduction, improved solubility, stability and their biological activity. This article summarizes the most important information on formulation, fabrication and advancements in chitosan-based nanoemulsions highlighting their potential benefit for applications in the muscle food system. Supervising the all-around executions of chitosan nanoemulsions for various food systems, the current review has been framed to lay down understandings regarding improvements made in the production and functionality of chitosan nanoemulsions for quality retention of meat products. Furthermore, it highlights the novel trends in chitosan-nanoemulsions application in meat based food systems from a preservation and shelf-life prolongation perspective.

Emerging chitosan-essential oil films and coatings for food preservation - A review of advances and applications

With the rising demand for fresh and ready-to-eat foods, antimicrobial packaging has been developed to control or prevent microbial growth as well as maintain food quality and safety. Chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus, chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. This review summarized the effect of essential oils on modifying the physicochemical characteristics of chitosan-based films. Notably, the antimicrobial efficacy of the developed composite films or coatings was highlighted. The advances in the preparation methods and application of chitosan films were also discussed. Broadly, this review will promote the potential applications of chitosan-essential oils composite films or coatings in antimicrobial packaging for food preservation.

Functional Properties of Biopolymer-Based Films Modified with Surfactants: A Brief Review

An increase of environmental awareness recently has increased the interest of researchers in using of biopolymer-based films. The films have been prepared extensively by utilizing starch, carboxymethyl cellulose, chitosan, protein, gelatin, carrageenan, alginate, pectin, guar gum and pullulan. They are typically modified with surface-active agents (surfactants) such as glycerol monostearate, sucrose ester, sodium stearoyl lactate, sodium dodecyl sulfate, ethyl lauroyl arginate HCl, Span 20 to 80, Tween-20 to 80 and soy lecithin for improving the functional properties of the films. In this brief review, two types of biopolymer-based films that prepared through casting method were categorized, specifically solution- and emulsion-based films. The four types of surfactants, namely non-ionic, anionic, cationic and amphoteric surfactants that are regularly used to modify biopolymer-based films are also described. The functional properties of the films modified with different types of surfactants are briefly reviewed. This study enhances the attraction of researchers in biopolymer-based films and the improvement of new concepts in this niche area.

Flavor, antimicrobial activity, and physical properties of composite film prepared with different surfactants

Different surfactants (lecithin, Tween-20, and Tween-80) were added in composite film during the preparation. Flavor, antimicrobial activity, and physical properties of ginger essential oil -gelatin film were investigated, in order to study the effect of surfactants on the properties of film. The flavor of GEO was not detected in the film prepared with Tween-20 and film prepared with Tween-80, and these two films exhibited stronger antimicrobial activity; film prepared with lecithin possessed higher value in thickness, elongation at break, water solubility, ΔE and opacity, lower value in water vapor property, and tensile strength; attenuated total reflectance-Fourier transform infrared spectrum results suggested, Tween-20 and Tween-80 enhanced the strength of covalent bond, and lecithin weakened the strength of hydrogen bond; and the result of scanning electron microscope showed that Tween-20 and Tween-80 improved the dispersion of oil droplets in film. Therefore, this study suggested that surfactants had an influence on the physical properties and molecular structure of a resulting film; in addition, Tween-20 and Tween-80 could reduce the flavor of GEO in film, improving the antimicrobial activity of film.

Chitosan/Thyme Oil Systems as Affected by Stabilizing Agent: Physical and Antimicrobial Properties

Antimicrobial biopolymer films and coatings are of great interest for many applications. Different chitosan systems were prepared and characterized to evaluate the effect of their composition on the physical and antimicrobial properties. Three types of emulsifiers (Tween 20, 80, and 85) were used as stabilizing agents, combined with thyme essential oil (from two producers) applied as an active substance. A predominant role of the applied stabilizer and its hydrophilic–lipophilic balance value was proven. The incorporation of thyme essential oil and surfactant into the chitosan matrix led to a significant decrease of particle size in film-forming solutions, as well as a thickness increase and the enhancement of the barrier properties in chitosan films. Antimicrobial effects were provided even at the lowest tested concentration of thyme essential oil. Hence, the prepared chitosan films represent promising candidates in antimicrobial packaging applications.

Chitosan films incorporated with Thymus capitatus essential oil: mechanical properties and antimicrobial activity against degradative bacterial species isolated from tuna (Thunnus sp.) and swordfish (Xiphias gladius)

Chitosan-based coatings and films have been widely studied, demonstrating to be an efficient and eco-friendly approach to extend the shelf life of food products. The effect of incorporating Thymus capitatus essential oil (TCEO) at different concentrations (0.5, 1.0, and 1.5% w/w) on physical, mechanical and antimicrobial properties of chitosan films was studied. The antimicrobial activity of the films was evaluated by agar diffusion method, against 23 spoiling microorganisms isolated from tuna and swordfish (ten Shewanella baltica, one S. morhuae, one S. putrefaciens, two Pseudomonas fluorescens, two P. fragi, five Serratia spp., one Aeromonas molluscorum, and one Acinetobacter radioresistens) and Shewanella putrefaciens ATCC 49138. The films exerted antimicrobial activity against all the tested strain, although not proportional to increasing TCEO concentration. In particular, S. baltica was the most sensitive species and the inhibition was stable after 72 h. In general, TCEO incorporation in chitosan films, significantly (p < 0.05) decreased the water permeability (from 0.577 ± 0.060 gmm/kPahm² at 61% R.U. for chitosan to 0.487 ± 0.037 gmm/kPahm² for the film with 1.5% TCEO), the elongation at brake (from 27.322 ± 2.35% for chitosan to 14.695 ± 3.99% for the film with 1.5% TCEO) and increased the tensile strength (from 1.697 ± 0.16% for chitosan to 19.480 ± 2.86% for the film with 1.5% TCEO). Moisture content and water contact angle of the films also showed a similar trend with TCEO introduction, because of crosslinking reaction among the polymer chains and TCEO components. Scanning electron microscopy confirmed structure-properties relationships. These results suggest chitosan films incorporated with TCEO as an alternative treatment to inhibit the growth of degradative bacteria with potential application in the fish industry. The importance of testing more than one strain of the same bacteria species to evaluate the effectiveness of chitosan-essential oils coatings was also demonstrated.

Effect of Oregano and Marjoram Essential Oils on the Physical and Antimicrobial Properties of Chitosan Based Systems

The effect of two essential oils (EOs), from Origanum vulgare and Origanum majorana, their structural properties, and concentration on physical and antimicrobial characteristics of chitosan based solutions as well as films was investigated. Results showed that significantly different behaviour was induced by variation in the compositions of given essential oils. Film-forming solutions (FFS) containing oregano oil comprised considerably greater particles in comparison with the marjoram samples. Similarly, structural changes were confirmed by SEM analysis of chitosan films modified with the EOs; the smaller particles of the marjoram oil demonstrated better compatibility with chitosan matrix. However, chitosan films enriched with the oregano oil showed significantly superior antimicrobial activity compared to the marjoram. The dissimilar effects of the two EOs were also observed by water vapour pressure (WVP) measurement; increasing the amount of oregano oil triggered a drop in the WVP of the prepared films, whereas the marjoram oil had a negligible impact in this respect. These results suggest that the structural features of active substances in the EOs play a crucial role in determining the final properties of FFS and biofilm systems.

Physicochemical and Antioxidant Properties of Chitosan Films Incorporated with Cinnamon Oil

Chitosan films (CF) with cinnamon bark oil (CO) incorporated at 0% (control), 0.25%, 0.5%, and 1.0% v/v were prepared by an emulsion method. The films were characterized based on their physical properties (solubility, water vapor permeability, optical property, and microstructure) and antioxidant properties (DPPH, ABTS, and its protective effects on human erythrocytes). The results showed that the incorporation of 0.5 and 1.0% of CO into the CF significantly decreased its solubility to 22% of the control (p<0.05). The water vapor permeability of the CF-CO was significantly reduced to 40% with low concentrations of CO (0.25%) incorporated into the CF. In general, the films presented a yellow coloration and an increase in transparency with the incorporation of CO into the CF. It was also observed that the incorporation of CO increased the antioxidant activity between 6.0-fold and 14.5-fold compared to the control, and the protective capacity against erythrocyte hemolysis increased by as much as 80%.