Active Edible Coatings Research Articles

Investigating the Synergistic Effects of Carvacrol and Citral-Edible Polysaccharide-Based Nanoemulgels on Shelf Life Extension of Chalkidiki Green Table Olives

Modern bioeconomy and sustainability demands lead food technology in the development of novel biobased edible food preservatives. Herein, the development and characterization of novel polysaccharide (xanthan gum and kappa-carrageenan)-based nanoemulgels (NGs) enhanced with essential oil derivatives; pure citral (CT); pure carvacrol (CV); and various CT:CV ratios (25:75, 50:50, and 75:25) are presented. The obtained NGs are applied as active edible coatings for extending the shelf life of Protected Designation of Origin (PDO) green table olives of Chalkidiki. The zeta potential demonstrated the high stability of the treatments, while light scattering measurement and scanning electron microscopy images confirmed the <100 nm droplet size. EC50 indicated high antioxidant activity for all the tested samples. The fractional inhibitory concentration (FIC) confirmed the synergistic effect of NG with a CT:CV ratio at 50:50 against Staphylococcus aureus and at CT:CV ratios 25:75 and 75:25 against E. coli O157:H7. NG coatings with CT:CV ratios at 50:50 and at 25:75 effectively controlled the weight loss at 0.5%, maintained stable pH levels, and preserved the visual quality of green olives on day 21. The synergistic effect between CT and CV was confirmed as they reduced the spoilage microorganisms of yeasts and molds by 2-log [CFU/g] compared to the control and almost 1 log [CFU/g] difference from pure CT and CV-based NGs without affecting the growth of beneficial lactic acid bacteria crucial for fermentation. NGs with CT:CV ratios at 50:50 and at 25:75 demonstrated superior effectiveness in preventing discoloration and maintaining the main sensory attributes. Overall, shelf life extension was achieved in 21 compared to only 7 of the uncoated ones. Finally, this study demonstrates the potential of polysaccharide-based NGs in mixtures of CT and CV for the shelf life extension of fermented food products.

Edible coating functionalized with ornamental plant extracts affect the postharvest quality of guava (Psidium guajava) during storage

Present study was carried out during 2021–23 at ICAR-Indian Agricultural Research Institute, New Delhi to investigate the efficacy of active edible coatings, incorporated with extracts from rose leaves and marigold petals in preserving the quality of mature green guava (Psidium guajava L.) cv. Allahabad Safeda during storage at both ambient (25±2°C) and cold (10±1°C) conditions. The coatings, particularly carboxy methyl cellulose combined with rose leaf extract (CMC+RL) demonstrated the highest effectiveness in minimizing per cent firmness reduction (PFR; 77.02% and 84.71%) compared to the control (89.95% and 89.73%) after 4 and 18 days of ambient and cold storage, respectively. Additionally, the coatings significantly influenced total soluble solids (TSS), total sugar content (TSC) and yellowness index (YI) showing potential in slowing down the fruit ripening. Moreover, the coatings demonstrated notable antioxidant activity with CMC+RL coating exhibited the highest activity. Furthermore, the coatings exhibited a substantial inhibitory effect on polygalactouronase (PG) activity, indicating a potential to mitigate cell wall degradation. Overall, the results highlight the promise of these biodegradable coatings as an alternative to synthetic preservatives in preserving postharvest quality and enhancing the shelf-life of guava fruits.

Application and evaluation of plant-based edible active coatings to enhance the shelf-life and quality attributes of Jara lebu (Citrus medica)

Edible coatings for fruits and vegetables are the subject of intensive agro-based research. These coatings provide value to the product due to their multifunctionality and sustainability. The current study focuses on the development and evaluation of plant-based edible active coatings for Jara lebu (Citrus medica), with the aim of determining the effectiveness of these coatings in extending the shelf-life and preserving the quality attributes. Different blends of corn starch and various plant extracts were formulated and all formulations were applied by immersion onto the fruit surface. The study had five treatment groups: T0, T1, T2, T3, and T4. T0 served as the control group, while T1 consisted of a mixture of 2% corn starch and 0.5% glycerol. T2 included a combination of 2% corn starch, 0.5% glycerol, and 1.5% holy basil. T3 comprises 2% corn starch, 0.5% glycerol, and 1.5% wild turmeric. Lastly, T4 consisted of 2% corn starch, 0.5% glycerol, and 1.5% Indian pennywort. Control and coated samples were kept under the same conditions for 35 days before being evaluated for changes in their physiological, physicochemical, and sensory qualities. Coated sample T2 significantly prolonged the shelf-life of Jara lebu samples, having the least weight reduction (26.25%) and retaining most of the essential nutrients (TSS = 7.09%, pH = 3.0, vitamin C = 22.03 mg/100 g, TPC = 44.57 mg GAE/g DW, TFC = 45.24 mg QE/g DW, antioxidant = 86.09%). This sample received the highest overall acceptability score, a maximum of 8.24. Sensory evaluations revealed no adverse effects on taste, aroma or appearance, suggesting these coatings can be an eco-friendly and efficient method for preserving the freshness and quality of Jara lebu and potentially other citrus fruits.

Agricultural waste as a sustainable source for nanoparticle synthesis and their antimicrobial properties for food preservation

Traditional agriculture from cropping to harvesting is contributing to climate change by increasing global greenhouse emissions. Circular economy approaches and biorefinery technologies based on the reuse, recycling, and remanufacturing might result in the valorization of wastes that consequently would avoid environmental pollution. Nanoparticles synthesis using bio-waste such as stems, leaves, seeds, pulp, stubble, and bagasse is considered a green approach with low energy consumption, and low-cost production. Characteristics of raw materials influence the final application of nanoparticles in edible coatings, and films. Therefore, the preparation of nanoparticles based on cellulose, pectin, metal (titanium oxide, silver, zinc oxide), or silica are considered organic, inorganic, or hybrid nanocomposites, are resulted in several benefits including shelf-life extension and broad-spectrum antimicrobial properties by its capacity to encapsulate active compounds that greatly improve food preservation. For considering agro-waste-based nanoparticles in food, challenges in homogenization and synthesis, yield, and toxicity are mainly described. Therefore, this review examines the employment of agro-industrial waste for the development of sustainable nanoparticles and their synthesis methods (top-down and bottom-up). Moreover, it discusses their incorporation and role in active edible coatings and films by highlighting their bioactive properties, mechanisms of action, and applications in food group preservation.

Comparison of the Properties of Pullulan-Based Active Edible Coatings Implemented for Improving Sliced Cheese Shelf Life.

The development of active edible coatings with improved mechanical and barrier properties is a huge challenge. In this study, active edible coatings for sliced cheese have been developed using pullulan (Pull) in combination with two different biopolymers, chitosan (CS) and gelatine (Gel), and a combination of hydrolats as a source of active compounds with antimicrobial effects. In comparison to the monolayer coating, the bilayer coating system demonstrates improved barrier and mechanical properties. A preliminary assessment of the antimicrobial effect of lemongrass and curry plant hydrolats has revealed that both hydrolats exhibited antimicrobial activity against the targeted bacterium Staphylococcus aureus, albeit at different levels. The obtained results suggest that a mixture of 1.56% lemongrass and 12.5% curry plant hydrolats yielded a lower fractional inhibitory concentration (FIC) value. Bilayer coating systems (Pull/CS and Pull/Gel) with an incorporated mixture of hydrolats have demonstrated effectiveness in both cases: artificial contamination before application of the coating system and after application of the coating system. In both contamination scenarios, the coating systems consistently effectively limited bacterial proliferation, indicating the antimicrobial effect of the hydrolat mixture in the coating layers. In the case of artificial contamination before applying the coating system, both coatings demonstrated antimicrobial effectiveness, but the formulation with chitosan had a biocide effect, while the other, with gelatine, had only a bacteriostatic effect in a long-term setting. In the second case, both Pull/CS and Pull/Gel coatings demonstrated effectiveness in inhibiting bacterial growth regardless of the moment of contamination of the sample; the Pull/CS coating showed slightly better antimicrobial activity, achieving complete elimination of bacteria earlier compared with the Pull/Gel coating system.

The Development of a Novel Sodium Alginate-Based Edible Active Hydrogel Coating and Its Application on Traditional Greek Spreadable Cheese.

The necessity of reducing the greenhouse effect by decreasing the carbon dioxide fingerprint directed the food packaging technology to use biobased raw materials. Alginates, which are derived from brown algae species, are one of the most promising biobased biopolymers for the development of edible active coatings capable of protecting food from oxidation/bacterial spoilage. In this study, sodium alginate, which was plasticized with glycerol and mixed with a biobased thymol/natural halloysite nanohybrid, was used to develop novel edible active coatings. Nanocomposite coatings were also developed in this project by mixing pure halloysite with sodium alginate/glycerol matrix and were used as reference material for comparison reasons. Instrumental analysis indicated a higher compatibility of a thymol/halloysite nanohybrid with a sodium alginate/glycerol matrix compared to pure halloysite with a sodium alginate/glycerol matrix. Increased compatibility resulted in improved tensile properties, water/oxygen barrier properties, and total antioxidant activity. These edible active coatings were applied to traditional Greek spread cheese and showed a reduction in the mesophilic microbial population over one log10 unit (cfu/g) compared to uncoated cheese. Moreover, the reduction in the mesophilic microbial population increased with the increase in halloysite and thymol content, indicating such sodium alginate/glycerol/thymol/halloysite hydrogels as promising edible active coatings for dairy products.

Enhancing plantain epicarp active edible coating performance through investigation of optimal spray coating conditions

The current research presents a comprehensive investigation aimed at predicting and optimizing the adhesion characteristics of Nanoemulsion coatings sprayed onto plantains epicarps. To achieve this, a full factorial experimental design and an artificial neural network model were deployed. The process parameters, consisting of the height of the nozzle, pressure, and time, served as inputs for the artificial neural network model, while the coating amount and thickness were measured and treated as targets for both models. Through meticulous training, the artificial neural network model demonstrated remarkable efficiency and reliability, evident in the high degree of coherence between predicted and experimental results (R² = 0.99 and MSE = 1.98 %). The study identified a critical sequence of variables (height/pressure/time: 0.15 m / 0.6 MPa / 5 s) that yielded optimal coating characteristics, including a thickness of 38.5 µm, permeance of 1.388 × 10–05 kg s−1 m−1 Pa−1, and water vapor permeability of 2.7 × 10–09 kg s−1 m−1 Pa−1, along with a contact angle of 11.3° indicative of enhanced wettability. Significantly, the coated epicarps exhibited lower water vapor permeability, implying an extended shelf life. This promising technology of edible coatings not only contributes to preserving fruit quality and prolonging shelf life for plantainss but also holds potential for application in other food products and fortifying food packaging practices. The current findings shed light on the valuable role of active edible coatings in advancing food preservation methods and sustainability within the food industry.

Impact of edible coatings reinforced with mesoporous silica nanoparticles added with cinnamon and lemongrass essential oils applied on sourdough bread

Active edible coatings may be used to increase the shelf life of food products, free of chemical additives. An edible coating comprising chitosan (CH) and quinoa protein (QP), incorporated with lemongrass and cinnamon essential oils (LEO and CEO, respectively) encapsulated in mesoporous silica nanoparticles (MSN) (6% w/v) was developed, and further applied on sourdough bread to evaluate its shelf life. Films were prepared at two QP:CH ratios, 4:1 and 9:1 (w/w), containing the essential oils (EO) encapsulated in MSN (individually or in 1:1 or 2:1 LEO:CEO ratios, v/v mixture). EO were extracted by steam distillation, and the antifungal effect of both oils alone and in mixture was preserved after encapsulation in MSN. The films were tested for mechanical, antifungal, and barrier properties. Films at 4:1 QP:CH ratio (w/w), added with EO (2:1 LEO:CEO ratio) encapsulated in MSN showed the best mechanical (tensile strength of 28 MPa) and barrier [5.11 × 10−5±6.4 × 10−7 g/(day*m*Pa)] properties, an antifungal index of 95%. The film-forming solution was used to coat sourdough bread, to evaluate its impact on shelf life and sensory properties. The coated bread showed low hardness (49 N) up to 10.5 d of accelerated storage conditions, indicating delayed bread staling, while at the same time preventing color loss and microbial spoilage. Coated breads were found sensory acceptable by 60 untrained panelists.

Antimicrobial and Antioxidant Edible Films and Coatings in the Shelf-Life Improvement of Chicken Meat.

Meat deterioration during processing, distribution, and display can compromise the quality and safety of products, causing several undesirable changes and decreasing products' shelf-life, which has a negative impact on the industry and consumers. In recent years, studies have been carried out using decontamination techniques and new packaging methodologies to overcome deterioration problems, increase sustainability, and reduce waste. Edible films and coatings obtained from biopolymers such as polysaccharides, proteins, and lipids, combined with active compounds, can be an alternative approach. This article focused on recent studies that used alternative biodegradable polymeric matrices in conjunction with natural compounds with antioxidant/antimicrobial activity on chicken meat. Its impact on physicochemical, microbiological, and sensory characteristics was evident, as well as the effect on its shelf-life. In general, different combinations of active edible films or coatings had a positive effect on the chicken meat. Different studies reported that the main results were a decrease in microbial growth and pathogen survival, a slowdown in lipid oxidation evolution, and an improvement in sensory quality and shelf-life (an increase from 4 to 12 days).

An overview on smart and active edible coatings: safety and regulations

An overview on smart and active edible coatings: safety and regulations

Influence of a Transparent and Edible Coating of Encapsulated Cannabidiol Nanoparticles on the Quality and Shelf Life of Strawberries.

Cannabidiol (CBD) has been shown to have antioxidant and antibacterial effects. The investigation into CBD's potential as an antioxidant and antibacterial agent, meanwhile, is still in its initial stages. The study goals were to prepare encapsulated cannabidiol isolate (eCBDi), evaluate the effect of eCBDi edible active coatings on the physicochemical properties of strawberries, and determine whether CBD and sodium alginate coatings could be used as a postharvest treatment to promote antioxidation and antimicrobial activity and prolong the strawberry shelf life. A well-designed edible coating on the strawberry surface was achieved using eCBDi nanoparticles in combination with a sodium alginate polysaccharide-based solution. Strawberries were examined for their visual appearance and quality parameters. In the results, a significantly delayed deterioration was observed in terms of weight loss, total acidity, pH, microbial activity, and antioxidant activity for coated strawberries compared to the control. This study demonstrates the capability of eCBDi nanoparticles as an efficient active food coating agent.

Essential Oils and Bacteriocin-Based Active Edible Coating: An Innovative, Natural and Sustainable Approach for the Control of Listeria monocytogenes in Seafoods

The anti-Listeria monocytogenes activity of four essential oils (EOs) (Salvia officinalis, Citrus limon, Mentha piperita and Thymus vulgaris) and bacteriocin bacLP17, added alone or in mixture in active edible coatings, was determined in artificially contaminated shrimps. The minimal inhibitory concentration (MIC) values of the EOs were determined against the NCTC 10888 strain of L. monocytogenes by using the broth microdilution method. The checkerboard method was carried out in tryptic soy broth (TSB), using microdilution to obtain the Fractional Inhibitory Concentration Index (FIC-Index) for six associations of EOs, chosen based on the best MIC results. All the EOs confirmed their anti-Listeria activity, both “in vitro” and inside the coatings. The coating matrix was suitable for use in the food field, allowing a gradual release of the EOs in packaged food. When the EOs were used in association (EO/EO) they were demonstrated to act synergistically, leading to a significant reduction in the amount (10–20 times) of EOs needing to be used, and consequently a decrease in the strong smell on the food. This effect was also confirmed when the compounds were incorporated into the coatings. The inclusion of the EOs within the coating not only ensured the anti-Listeria activity by increasing the shelf-life of food products, but also further mitigated the strong smell of the EOs, improving the organoleptic impact on the food and its sensory properties.

Kiwi Fruits Preservation Using Novel Edible Active Coatings Based on Rich Thymol Halloysite Nanostructures and Chitosan/Polyvinyl Alcohol Gels.

The concept of this study is the replacement of previous fossil-based techniques for food packaging and food shelf-life extension, with novel more green processes and materials following the spirit of circular economy and the global trend for environmentally positive fingerprints. A novel adsorption process to produce thymol-halloysite nanohybrids is presented in this work. The high dispersion of this thymol-halloysite nanostructure in chitosan biopolymer is one of the goals of this study. The incorporation of this biodegradable matrix with poly-vinyl-alcohol produced a very promising food-packaging film. Mechanical, water-oxygen barrier, antimicrobial, and antioxidant properties were measured. Transparency levels were also tested using a UV-vis instrument. Moreover, the developed films were tested in-vivo for the preservation and the extension of the shelf-life of kiwi fruits. In all cases, results indicated that the increased fraction of thymol from thyme oil significantly enhances the antimicrobial and antioxidant activity of the prepared chitosan-poly-vinyl- alcohol gel. The use of the halloysite increases the mechanical and water-oxygen barrier properties and leads to a control release process of thymol which extends the preservation and the shelf-life of kiwi fruits. Finally, the results indicated that the halloysite improves the properties of the chitosan/poly-vinyl-alcohol films, and the thymol makes them further advantageous.

Physicochemical, Morphological, and Functional Characterization of Edible Anthocyanin-Enriched Aloevera Coatings on Fresh Figs (Ficus carica L.).

In the present investigation, Aloe vera gel (AVG)-based edible coatings enriched with anthocyanin were prepared. We investigated the effect of different formulations of aloe-vera-based edible coatings, such as neat AVG (T1), AVG with glycerol (T2), Aloe vera with 0.2% anthocyanin + glycerol (T3), and AVG with 0.5% anthocyanin + glycerol (T4), on the postharvest quality of fig (Ficus carica L.) fruits under refrigerated conditions (4 °C) for up to 12 days of storage with 2-day examination intervals. The results of the present study revealed that the T4 treatment was the most effective for reducing the weight loss in fig fruits throughout the storage period (~4%), followed by T3, T2, and T1. The minimum weight loss after 12 days of storage (3.76%) was recorded for the T4 treatment, followed by T3 (4.34%), which was significantly higher than that of uncoated fruit (~11%). The best quality attributes, such as the total soluble solids (TSS), titratable acidity (TA), and pH, were also demonstrated by the T3 and T4 treatments. The T4 coating caused a marginal change of 0.16 in the fruit titratable acidity, compared to the change of 0.33 in the untreated fruit control after 12 days of storage at 4 °C. Similarly, the total soluble solids in the T4-coated fruits increased marginally (0.43 °Brix) compared to the uncoated control fruits (>2 °Brix) after 12 days of storage at 4 °C. The results revealed that the incorporation of anthocyanin content into AVG is a promising technology for the development of active edible coatings to extend the shelf life of fig fruits.

Development of active edible coatings based on fish gelatin enriched with Moringa oleifera extract: Application in fish (Mustelus mustelus) fillet preservation.

An edible coating was developed using gelatin extracted from the skin of gray triggerfish (Balistes capriscus) and applied to the fillet of the smooth-hound shark (Mustelus mustelus). Moringa oleifera leaf extract was added to gelatin coating solution to improve its preservative properties. The phenolic profiles and antioxidant and antibacterial activities of M. oleifera extracts were determined. Phenolic acids constituted the largest group representing more than 77% of the total compounds identified in the ethanol/water (MOE/W) extract, among which the quinic acid was found to be the major one (31.48 mg/g extract). The MOE/W extract presented the highest DPPH• scavenging activity (IC50=0.53 ± 0.02 mg/ml) and reducing (Fe3+) power (EC0.5=0.57 ± 0.02 mg/ml), as well as interesting inhibition zones (20-35 mm) for the most tested strains. Coating by 3% of gelatin solution significantly reduced most deterioration indices during chilled storage, such as malondialdehyde (MDA), total volatile basic nitrogen (TVB-N), weight loss, pH, and mesophilic, psychrophilic, lactic, and H2S-producing bacterial counts. Interestingly, coating with gelatin solution containing MOE/W extract at 20 μg/ml was more effective than gelatin applied alone. Compared with the uncoated sample, gelatin-MOE/W coating reduced the weight loss and MDA content by 26% and 70% after 6 days of storage, respectively. Texture analysis showed that the strength of uncoated fillet increased by 46%, while the strength of fillet coated with gelatin-MOE/W only increased by 12% after 6 days of storage. Fish fillet coated with gelatin-MOE/W had the highest sensory scores in terms of odor, color, and overall acceptability throughout the study period.

Edible Coatings to Enhance Shelf Life of Fruits and Vegetables: A Mini-Review

Abstract: Recently, edible coatings or films have gained significant importance in fruit and vegetable preservation. This review summarises edible coatings, the classification of coating materials, formulation procedures, and the benefits of active edible coating. Studies reported that edible coating or films from natural resources benefit the consumer as well as the environment. In general, edible coatings or films are a combination of polysaccharides, proteins, lipids, and plasticizers, used to enhance the functional properties and the general quality parameters of fruits and vegetables, such as texture, colour, acidity, total soluble solids, thus preventing their browning and oxidation. Casting (wet process) and extrusion (dry process) are two prominent methods used to fabricate edible thin films. General techniques for applying edible coatings are dipping, spraying, coating, panning, using a fluidized bed, and film wrapping. Active edible coatings or films are developed with herbal extracts to improve the functional properties, i.e., antioxidant and antimicrobial. Therefore, based on the literature review, future research exploration will focus on underutilized edible natural resources, along with some natural edible plasticizers used to improve the postharvest quality of fruits and vegetables without affecting their nutritional, organoleptic, and sensory attributes. The primary objective of the present review was to summarize the different types of edible coatings with an infusion of herbal extracts and their application on fruits and vegetables.

Lemongrass essential oil and aloe vera gel based antimicrobial coatings for date fruits

• Bioactive edible coatings were developed for shelf life extension of date fruit. • Aloe vera gel and lemongrass essential oil were used as natural antimicrobials. • Emulsion-based coatings of 3% essential oil in 25% gel provided optimum results. In fruit processing industry, edible coatings/films are usually applied on various fruits to provide protection against microorganisms and to regulate various biological functions of the fruit. The current research in this domain is more focused on exploring naturally occurring bioactive materials to develop active edible coatings that can offer an extended functionality than just providing barrier properties. Therefore, here we report the application of aloe vera gel-based edible coatings, either as standalone or in combination with lemongrass essential oil to enhance the shelf life of the soft date fruit variety (as soft dates are usually more prone to spoilage). The pure aloe vera gel coatings were aqueous mixtures of 25% aloe vera gel; whereas, nanoemulsion-based coatings of lemongrass essential oil (1-5%) and aloe vera gel (25% aqueous mixture) were prepared through a high-pressure homogenizer. After preliminary physicochemical characterization of the prepared coating mixtures, the date fruit samples were dipped in coating mixtures, dried, and then stored at room temperature for 4 weeks. The analyses of date fruits during the storage revealed that the applied coatings did help in retention of physicochemical attributes (e.g., moisture, texture, and pH) and also significantly prevented microbial growth. More specifically, the nanoemulsions based coatings of lemongrass essential oil (up to 3%) and aloe vera gel exhibited excellent antifungal properties, which is quite remarkable as the date fruits are usually more susceptible to fungal growth than the bacterial growth. Based on these findings, the date fruit processing industry can utilize these natural antimicrobial coatings for the shelf life extension of date fruits.

Optimization of Cassava Starch, Glycerol, and Lactic Acid Concentrations as Active Edible Coating for Pork Meat

Optimization of active edible coating formulations for pork meat application was conducted using response surface methodology. Effects of active edible coating formulations (i.e. cassava starch, glycerol, and lactic acid) on the color change, pH, % drip loss, coating interaction (thickness), and sensory acceptability (general acceptability, color, odor, and texture) of the coated pork meat samples stored at ambient temperature were investigated using a three- block rotatable central composite design. Mathematical models were generated that predicted the effects of individual and combined influences of coating formulations on the response variables. Statistical tests for reliability and adequacy were done to evaluate the goodness of fit of the generated models. Optimization of the coating formulation revealed that the optimum formulation for active edible coating applied in pork meat was 1.81–1.88% cassava starch, 1.90–3.55% glycerol, and 0.51–0.57% lactic acid. A verification test was performed and showed that actual values were within the confidence and/or prediction intervals. Overall, the results of this study revealed that the developed active edible coating can be used for pork meat stored at ambient temperature.

Effect of gelatin-based active coatings formulated with rosemary extract on quality of cold stored meatballs

Meatballs were coated by gelatin-based mixes incorporated with potassium sorbate and rosemary extract. Coated samples were evaluated by free fatty acids (FFAs), thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVB-N) content. In addition, texture profile analysis (TPA) was performed to evaluate the textural features of meatballs. Uncoated sample as control along with 3 other samples coated by different formulations were stored in zipped plastic bags at +4 °C for 10 days. No significant difference was observed between samples regarding FFA and TBARS although coating with potassium sorbate showed suppressive effect on TVB-N initially. The starting pH of meatball was 6.22 and the coatings generally limited the change in pH compared to the control. Although significant differences in color were observed due to the color of coating itself, the coatings limited the variations in color to some extent. Other quality parameters were not improved much with the studied formulations. It is concluded that active edible coatings might be utilized in muscle foods for preservation and shelf-life extension if appropriately formulated and applied. Comprehensive studies are needed to determine the performance of carrier polymers in release of active ingredients and suitable formulations for every single group of food.

Design of an Active Edible Coating Based on Sodium Caseinate, Chitosan and Oregano Essential Oil Reinforced with Silica Particles and Its Application on Panela Cheese

Active edible films and coatings incorporating antimicrobial agents such as essential oils are studied to improve the shelf-life of fresh foods. The aim of this work was to study a mixture of sodium caseinate-chitosan (SC:CH), added with mesoporous silica nanoparticles filled with oregano essential oil (MSN-OEO), to produce an active edible coating for Panela cheese and to evaluate its properties during refrigerated storage for 15 days. The OEO was extracted by hydrodistillation and was incorporated into the MSN. Films based on SC:CH of 4:1 and 8:1 ratios with and without MSN-OEO were produced and the mechanical, barrier, physicochemical and microbiological properties of the films were evaluated. The SC:CH 8:1 ratio (w/w) with MSN-OEO showed reduced mean particle size (764.8 ± 23.3 nm), and a stable solution (zeta potential = 29.9 ± 1.1 mV). The thickness and solubility were influenced by the incorporation of MSN-OEO making it thinner and less soluble. Panela cheese samples were coated by the spray method using the SC:CH 8:1 containing MSN-OEO film forming solution. The final pH of the control cheese was 0.5 units lower than that of the coated cheese, whereas final moisture loss of the control cheese was 4.2 times that of the coated cheese. The mesophilic aerobic bacteria and of molds and yeasts populations achieved a reduction of about 2 Log10 UFC/g after 15 days of storage. Due to microbial growth delay, and little moisture loss, this active coating may improve the quality and safety of Panela cheese.