Edible antimicrobial films based on microencapsulated lemongrass oil

Insights into chemistry, extraction and industrial application of lemon grass essential oil -A review of recent advances

Lemongrass essential oil (LEO), extracted from high-oil lemongrass, gains prominence as a versatile natural product due to growing demand for safe health solutions. LEO comprises beneficial compounds like citral, isoneral, geraniol, and citronellal, offering diverse pharmacological benefits such as antioxidant, antifungal, antibacterial, antiviral, and anticancer effects. LEO finds applications in food preservation, cosmetics, and pharmaceuticals, enhancing profitability across these sectors. The review focuses on the extraction of LEO, emphasizing the need for cost-effective methods. Ultrasound and supercritical fluid extraction are effective in reducing extraction time, increasing yields, and enhancing oil quality. LEO shows promise as a valuable natural resource across industries, with applications in packaging, coating, and film development. LEO's ability to extend the shelf life of food items and impart natural flavors positions it as a valuable asset. Overall, the review emphasizes LEO's therapeutic, antimicrobial, and antioxidant properties, strengthening its potential in the food, pharmaceutical, and cosmetic sectors.

Lemongrass essential oil micro- and nanoencapsulation for industrial application: Production techniques and potential applications

Due to its characteristic aroma and diverse therapeutic properties, lemongrass essential oil (LEO) has garnered increased attention in the pharmaceutical, food, and cosmetic industries. However, LEO's volatile nature, low chemical stability, and limited solubility in water limits its applications in the industry. Micro- and nanoencapsulation technologies emerge as a promising solution to overcome these challenges. A systematic methodology involving keyword searches in databases was employed to gather relevant literature on LEO micro- and nanoencapsulation, providing an extensive overview of techniques, processes, encapsulating materials, and possible applications. Beyond established methods, emerging techniques were explored. This review highlights the critical role of encapsulation in enhancing the thermal and chemical stability, applicability, bioavailability, and controlled release of LEO.

Advances in Designing Essential Oil Nanoformulations: An Integrative Approach to Mathematical Modeling with Potential Application in Food Preservation

Preservation of foods, along with health and safety issues, is a growing concern in the current generation. Essential oils have emerged as a natural means for the long-term protection of foods along with the maintenance of their qualities. Direct applications of essential oils have posed various constraints to the food system and also have limitations in application; hence, encapsulation of essential oils into biopolymers has been recognized as a cutting-edge technology to overcome these challenges. This article presents and evaluates the strategies for the development of encapsulated essential oils on the basis of fascination with the modeling and shuffling of various biopolymers, surfactants, and co-surfactants, along with the utilization of different fabrication processes. Artificial intelligence and machine learning have enabled the preparation of different nanoemulsion formulations, synthesis strategies, stability, and release kinetics of essential oils or their bioactive components from nanoemulsions with improved efficacy in food systems. Different mathematical models for the stability and delivery kinetics of essential oils in food systems have also been discussed. The article also explains the advanced application of modeling-based encapsulation strategies on the preservation of a variety of food commodities with their intended implication in food and agricultural industries.

Enhanced antimicrobial and antioxidant properties of Nano chitosan and pectin based biodegradable active packaging films incorporated with fennel (Foeniculum vulgare) essential oil and potato (Solanum tuberosum) peel extracts

Active packaging materials are generally prepared by incorporating antimicrobial agents. The main objective of the present research is the development and characterization of active packaging with Nano chitosan and pectin. Active packaging film was prepared by incorporating essential oil of Fennel (EOF) along with potato peel extract (PPE) to improve the antioxidant and antimicrobial property of the film. Incorporation of EOF into Nano chitosan and pectin-based films increased antimicrobial activity, whereas; PPE increased the antioxidant property of the films. In the present study, thickness, optical property, mechanical property, antioxidant and antimicrobial property, total soluble matter, morphological study, FTIR analysis, and microbial degradation study of the prepared active packaging material was done. The addition of the PPE and EOF together improved the surface, optical, mechanical, antimicrobial and antioxidant properties of the packaging film. Enhanced antimicrobial and antioxidant property of the Nano chitosan-PPE-PVA-EOF and pectin-PPE-PVA-EOF-based packaging films can extend the shelf life of the packed food; hence it is suggested for the active packaging for perishable food commodity. In short, the prepared active packaging film with biodegradable property is suggested as an effective packaging material to replace synthetic plastic packages for food and hence reduce plastic pollution.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05333-9.

Antimicrobial Compounds in Food Packaging

This review presents current knowledge on antimicrobial agents that are already used in the food packaging industry. At the beginning, innovative ways of food packaging were discussed, including how smart packaging differs from active packaging, and what functions they perform. Next, the focus was on one of the groups of bioactive components that are used in these packaging, namely antimicrobial agents. Among the antimicrobial agents, we selected those that have already been used in packaging and that promise to be used elsewhere, e.g., in the production of antimicrobial biomaterials. Main groups of antimicrobial agents (i.e., metals and metal oxides, organic acids, antimicrobial peptides and bacteriocins, antimicrobial agents of plant origin, enzymes, lactoferrin, chitosan, allyl isothiocyanate, the reuterin system and bacteriophages) that are incorporated or combined with various types of packaging materials to extend the shelf life of food are described. The further development of perspectives and setting of new research directions were also presented.

Source of Nanocellulose and Its Application in Nanocomposite Packaging Material: A Review

Food packaging nowadays is not only essential to preserve food from being contaminated and damaged, but also to comply with science develop and technology advances. New functional packaging materials with degradable features will become a hot spot in the future. By far, plastic is the most common packaging material, but plastic waste has caused immeasurable damage to the environment. Cellulose known as a kind of material with large output, wide range sources, and biodegradable features has gotten more and more attention. Cellulose-based materials possess better degradability compared with traditional packaging materials. With such advantages above, cellulose was gradually introduced into packaging field. It is vital to make packaging materials achieve protection, storage, transportation, market, and other functions in the circulation process. In addition, it satisfied the practical value such as convenient sale and environmental protection, reduced cost and maximized sales profit. This review introduces the cellulose resource and its application in composite packaging materials, antibacterial active packaging materials, and intelligent packaging materials. Subsequently, sustainable packaging and its improvement for packaging applications were introduced. Finally, the future challenges and possible solution were provided for future development of cellulose-based composite packaging materials.

Valorisation of lemongrass essential oils onto chitosan-starch film for sustainable active packaging: Greatly enhanced antibacterial and antioxidant activity

To meet the global demand for sustainability aspects, the past few decades have witnessed magnificent evidence in the pursuit of sustainable active food packaging. As part of our contribution, herein, we explored the utilization of chitosan (Ch) modified with Dioscorea hispida (Dh) starch and incorporated with lemongrass essential oil (LO) as an attempt to obtain a novel active packaging formulation of Ch/Dh/LO in food. To obtain the optimum formulation of Ch/Dh/LO, 15 experiments were designed using the Box-Behnken design (BBD) with Ch (1-2% w/v), Dh starch (0.5-1.5% w/v) and LO (0.25-0.75% v/v) against E. coli, S. typhi, S. aureus and S. epidermidis bacteria. The presence of LO caused enhancements in physical, mechanical, and thermal stability, along with the antimicrobial, and antioxidant activity. Additionally, molecular docking and molecular dynamic (MD) simulations of the active compounds in LO against the active site of the FtsA enzyme were provided to unveil the mechanism of antibacterial action. Ultimately, this result suggests hydrogen bonds and hydrophobic interactions are involved between the active compounds in LO and FtsA enzymes. In general, this research provides valuable information that sheds light on the pivotal role of LO in enhancing the mechanical, thermal, and biological properties of sustainable active food packaging-based Ch film.

Uncovering the Industrial Potentials of Lemongrass Essential Oil as a Food Preservative: A Review

The food industry is growing vastly, with an increasing number of food products and the demand of consumers to have safe and pathogen-free food with an extended shelf life for consumption. It is critical to have food safe from pathogenic bacteria, fungi, and unpleasant odors or tastes so that the food may not cause any health risks to consumers. Currently, the direction of food industry has been shifting from synthetically produced preservatives to natural preservatives to lower the unnecessary chemical burden on health. Many new technologies are working on natural prevention tools against food degradation. Lemongrass is one such natural preservative that possesses significant antimicrobial and antioxidant activity. The essential oil of lemongrass contains a series of terpenes that are responsible for these activities. These properties make lemongrass acceptable in the food industry and may fulfill consumer demands. This article provides detailed information about the role of lemongrass and its essential oil in food preservation. The outcomes of the research on lemongrass offer room for its new technological applications in food preservation.

Effects of UV-C and Edible Nano-Coating as a Combined Strategy to Preserve Fresh-Cut Cucumber

The objective of this study was to evaluate the effectiveness of a combination of UV-C disinfection treatment and a nano-coating lemon essential oil nanocapsules. The nanocapsules were prepared by ionic gelation with an alginate-pectin wall and the lemon essential oil had a particle size of 219 ± 22 nm and a zeta potential of -7.91 ± 0.18 mV. The lemon essential oil had an encapsulation efficiency of 68.19 ± 1.18%. The fresh-cut cucumber was stored for 15 days at 4 °C. Six formulations of nanocapsules were evaluated, and hydroxypropyl methylcellulose was used as matrix polysaccharide in four coatings. Three formulations were treated with UV-C at 4.5 kJ/m². The results showed that the combination of UV-C and nano-coatings (lemon essential oil = 200 mg/L) increased the shelf life by up to 15 days. Using UV-C and nano-coatings, the ∆E value was 7.12 at the end of the storage period, while the Control samples had an ∆E of 28.1. With nano-coating treatment, the amount of polyphenols decreased by 23% within 9 days. In contrast, with combined UV-C and nano-coating treatment, the amount of polyphenols was reduced by 38.84% within 15 days. The antioxidant capacity remained stable at 459 μmol TE/100 g for the fresh product when the combined treatment was used. A good correlation was also observed between the increasing of the fruit's shelf life and decreasing of its enzymatic activity. The inclusion of UV-C treatment contributed to the reduction in the initial total bacteria at 3.30 log CFU/g and its combination with nano-coatings helped in the control of microbial growth during storage.

Seaweed Polysaccharide in Food Contact Materials (Active Packaging, Intelligent Packaging, Edible Films, and Coatings)

Food contact materials (FCMs) are materials that come in contact with food products such as food packaging which play a significant role in the food quality and safety. Plastic, which is a major food packaging material, harms the eco-system, wildlife, and the environment. As a result, numerous researches have been in progress on alternative polymers, which has similar properties as plastic but is also environmentally friendly (biodegradable). In recent years, the utilization of seaweed polysaccharides has piqued interest due to its biodegradability, non-toxicity, antioxidant capabilities, and excellent film formation ability. However, it has a number of drawbacks such as low tensile strength, water solubility, and moderate antibacterial characteristics, among others. The addition of other biopolymers, nanoparticles, or natural active agents improves these features. In this review article, we have summarized the current state of seaweed polysaccharide research in active packaging, intelligent packaging, edible films, and coatings. It also highlights the physical, thermal, antioxidant, and other properties of these materials. Finally, the article discusses the relevant legislation as well as the field’s future prospects. Research shows that seaweeds polysaccharide looks promising as a sustainable food contact material, but there is always a potential for development to make it market feasible.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

Encapsulation of Grapefruit Essential Oil in Emulsion-Based Edible Film Prepared by Plum (Pruni Domesticae Semen) Seed Protein Isolate and Gum Acacia Conjugates

A dry-heated Maillard reaction was used to prepare plum seed protein isolate and gum acacia conjugates. Emulsion-based edible films (EBEF) were prepared by the encapsulation of grapefruit essential oil using conjugates solution as the continuous phase. The conjugates formed from 3 days of dry heating showed a significant improvement in emulsifying properties due to the unfolding of protein, as confirmed by structure analysis. The droplet size, electrical charge, and viscosity of emulsions increased with the increasing essential oil concentration, and all emulsions exhibited ‘gel’-like behavior. The water vapor barrier property, surface hydrophobicity, mechanical properties, and thermal stability of the films were improved as the essential oil content increased in the range of 1–4% due to enhancement in intermolecular interaction and compatibility, as well as a denser microstructure. Furthermore, all films exhibited an inhibitory effect against E. coli, while their radical scavenging activity depended on the release rate from films. The results obtained in this work confirmed that EBEF could be used as a novel food active packaging in the near future.

New Edible Packaging Material with Function in Shelf Life Extension: Applications for the Meat and Cheese Industries

Nowadays, biopolymer films have gained notoriety among the packaging materials. Some studies clearly test their effectiveness for certain periods of time, with applicability in the food industry. This research has been carried out in two directions. Firstly, the development and testing of the new edible material: general appearance, thickness, retraction ratio, color, transmittance, microstructure, roughness, and porosity, as well as mechanical and solubility tests. Secondly, testing of the packaged products-slices of cheese and prosciutto-in the new material and their maintenance at refrigeration conditions for 5 months; thus, the peroxide index, color, and water activity index were evaluated for the packaged products. The results emphasize that the packaging is a lipophilic one and does not allow wetting or any changes in the food moisture. The results indicate the stability of the parameters within three months and present the changes occurring within the fourth and fifth months. Microbiological tests indicated an initial microbial growth, both for cheese slices and ham slices. Time testing indicated a small increase in the total count number over the 5-month period: 23 cfu/g were found of fresh slices of prosciutto and 27 cfu/g in the case of the packaged ones; for slices of cheese, the total count of microorganisms indicated 7 cfu/g in the initial stage and 11 cfu/g after 5 months. The results indicate that the film did not facilitate the growth of the existing microorganisms, and highlight the need to purchase food from safe places, especially in the case of raw-dried products that have not undergone heat treatment, which may endanger the health of the consumer. The new material tested represents a promising substitute for commercial and unsustainable plastic packaging.

From waste/residual marine biomass to active biopolymer-based packaging film materials for food industry applications – a review

Waste/residual marine biomass represents a vast and potentially underexplored source of biopolymers chitin/chitosan and alginate. Their isolation and potential application in the development and production of bio-based food packaging are gaining in attractiveness due to a recent increment in plastic pollution awareness. Accordingly, a review of the latest research work was given to cover the pathway from biomass sources to biopolymers isolation and application in the development of active (antimicrobial/antioxidant) film materials intended for food packaging. Screening of the novel eco-friendly isolation processes was followed by an extensive overview of the most recent publications covering the chitosan- and alginate-based films with incorporated active agents.

Antimicrobial Paper Coatings Containing Microencapsulated Cymbopogon citratus Oil

Essential oils are environmentally friendly candidates for antimicrobial smart packaging systems. Encapsulation is needed to reduce their volatility and achieve controlled release. Within this study, the essential oil of Cymbopogon citratus (citronella oil) was microencapsulated and applied in pressure-sensitive antimicrobial functional coatings on papers for secondary packaging. Two microencapsulation methods were used: complex coacervation of gelatine with carboxymethylcellulose or with gum arabic, and in situ polymerization of melamine-formaldehyde prepolymers with a polyacrylic acid modifier. Minimum inhibitory concentrations of citronella oil microcapsules were determined for Bacillus subtilis (B. subtilis), Escherichia coli (B. subtilis), Pseudomonas aeruginosa (P. aeruginosa) and Saccharomyces cerevisiae (S. cerevisiae). Microcapsule suspensions were coated on papers for flexible packaging, 2 and 30 g/m2, and mechanically activated in the weight pulling test. A novel method on agar plates in sealed Petri dishes was developed to evaluate the antimicrobial activity of released citronella vapours on E. coli and S. cerevisiae. The results showed that both microencapsulation methods were successful and resulted in a container type single-core microcapsules. In situ microcapsule suspensions had better paper coating properties and were selected for industrial settings. The antimicrobial activity of 2 g/m2 coatings was not detected; however, the antimicrobial activity of 30 g/m2 partially activated coated papers was confirmed. The product enabled a prolonged use with the gradual release of citronella oil at multiple exposures of functional papers to pressure, e.g., by a human hand during product handling.

Alginate-Based Edible Films and Coatings for Food Packaging Applications

Alginate is a naturally occurring polysaccharide used in the bio industry. It is mainly derived from brown algae species. Alginate-based edible coatings and films attract interest for improving/maintaining quality and extending the shelf-life of fruit, vegetable, meat, poultry, seafood, and cheese by reducing dehydration (as sacrificial moisture agent), controlling respiration, enhancing product appearance, improving mechanical properties, etc. This paper reviews the most recent essential information about alginate-based edible coatings. The categorization of alginate-based coatings/film in food packaging concept is formed gradually with the explanation of the most important titles. Emphasis will be placed on active ingredients incorporated into alginate-based formulations, edible coating/film application methods, research and development studies of coated food products and mass transfer and barrier characteristics of the alginate-based coatings/films. Future trends are also reviewed to identify research gaps and recommend new research areas. The summarized information presented in this article will enable researchers to thoroughly understand the fundamentals of the coating process and to develop alginate-based edible films and coatings more readily.

Incorporating Phage Therapy into WPI Dip Coatings for Applications on Fresh Whole and Cut Fruit and Vegetable Surfaces

There is a significant unmet need to develop antimicrobial solutions to reduce the risk of contamination in fresh produce. Bacteriophages have been proposed as a potential approach for controlling foodborne pathogens. This study evaluated the combination of edible dip coatings with T7 bacteriophages on whole and cut produce. The evaluation includes an assessment of phage loading, phage storage stability, antimicrobial activity, and phage stability during simulated gastric digestion on sliced cucumbers, sliced apples, and whole cherry tomatoes. In this evaluation, phages coated on fresh produce using edible whey protein isolate (WPI) were compared with phages coated from an aqueous suspension (control coating). The results demonstrated that WPI coatings load more phages than the control and enhanced phage stability during cold storage (4 °C) for cut apples and whole cherry tomatoes. Phage stability decreased by 1 to 3 log(PFU) in a simulated gastric environment. Phage antimicrobial activity against Escherichia coli BL21 decreased 2 to 4 log(CFU) of bacteria on cut apples and whole cherry tomatoes, while no significant bacterial reduction was observed for sliced cucumbers. Overall, the results show that WPI dip coating provides phage loading, stability, and antimicrobial activity to produce surfaces compared to the control coating, and thus may be considered an effective approach for extending phage therapy on fresh produce.

PRACTICAL APPLICATION

The practical application is to prevent bacterial cross contamination of fresh produce by using a combination of edible coating with bacteriophages. The results demonstrate enhanced loading and stability of phages on fresh produce when used in combination with an edible coating.

The Functionalization of Nanostructures and Their Potential Applications in Edible Coatings

Nowadays, edible coatings incorporated with nanostructures as systems of controlled release of flavors, colorants and/or antioxidants and antimicrobial substances, also used for thermal and environmental protection of active compounds, represent a gap of opportunity to increase the shelf life of food highly perishable, as well as for the development of new products. These functionalized nanostructures have the benefit of incorporating natural substances obtained from the food industry that are rich in polyphenols, dietary fibers, and antimicrobial substances. In addition, the polymers employed on its preparation, such as polysaccharides, solid lipids and proteins that are low cost and developed through sustainable processes, are friendly to the environment. The objective of this review is to present the materials commonly used in the preparation of nanostructures, the main ingredients with which they can be functionalized and used in the preparation of edible coatings, as well as the advances that these structures have represented when used as controlled release systems, increasing the shelf life and promoting the development of new products that meet the characteristics of functionality for fresh foods ready to eat.

Alginate edible films containing microencapsulated lemongrass oil or citral: effect of encapsulating agent and storage time on physical and antimicrobial properties

Active edible films have been proposed as an alternative to extend shelf life of fresh foods. Most essential oils have antimicrobial properties; however, storage conditions could reduce their activity. To avoid this effect the essential oil (EO) can be microencapsulated prior to film casting. The aim of this study was to determine the effects of the type of encapsulating agent (EA), type of EO and storage time on physical properties and antimicrobial activity of alginate-based films against Escherichia coli ATCC 25922. Trehalose (TH), Capsul^® (CAP) and Tween 20 (Tw20) were used as EA. Lemongrass essential oil (LMO) and citral were used as active agents. The results showed that the type of EA affected the stability of the film forming-emulsions as well as the changes in opacity and colour of the films during storage but not the antimicrobial activity of them. Both microencapsulated EOs showed a prolonged release from the alginate films during the 28 days of storage. Trehalose was selected to encapsulate both active compounds because the films made with this microencapsulated EA showed the greatest physical stability and the lowest color variation among all the films studied.