Bioactive edible films for food applications: mechanisms of antimicrobial and antioxidant activity

Methods of Incorporating Plant-Derived Bioactive Compounds into Films Made with Agro-Based Polymers for Application as Food Packaging: A Brief Review

Plastic, usually derived from non-renewable sources, is among the most used materials in food packaging. Despite its barrier properties, plastic packaging has a recycling rate below the ideal and its accumulation in the environment leads to environmental issues. One of the solutions approached to minimize this impact is the development of food packaging materials made from polymers from renewable sources that, in addition to being biodegradable, can also be edible. Different biopolymers from agricultural renewable sources such as gelatin, whey protein, starch, chitosan, alginate and pectin, among other, have been analyzed for the development of biodegradable films. Moreover, these films can serve as vehicles for transporting bioactive compounds, extending their applicability as bioactive, edible, compostable and biodegradable films. Biopolymer films incorporated with plant-derived bioactive compounds have become an interesting area of research. The interaction between environment-friendly biopolymers and bioactive compounds improves functionality. In addition to interfering with thermal, mechanical and barrier properties of films, depending on the properties of the bioactive compounds, new characteristics are attributed to films, such as antimicrobial and antioxidant properties, color and innovative flavors. This review compiles information on agro-based biopolymers and plant-derived bioactive compounds used in the production of bioactive films. Particular emphasis has been given to the methods used for incorporating bioactive compounds from plant-derived into films and their influence on the functional properties of biopolymer films. Some limitations to be overcome for future advances are also briefly summarized. This review will benefit future prospects for exploring innovative methods of incorporating plant-derived bioactive compounds into films made from agricultural polymers.

Film formation and deposition methods of edible coating on food products: A review

The greatest challenge encountered by the food manufacturer is the loss of quality of food products during storage, which eventually adds to the waste. Edible packaging is known as a potential alternative to protecting food quality and improving shelf life by delaying microbial spoilage and providing moisture and gas barrier properties. Developments in edible packaging and technology have shown promising results in enhancing the shelf life of food products. In 2016, the edible packaging market was valued at $697 million and by 2023 is expected to hit $1097 million growing at a compound annual growth rate (CGAR) of 6.81% from 2017 to 2023 at global level. In global edible packaging markets specific industries including MonoSol LLC, Tate & Lyle Plc, WikiCell Designs Inc., JRF Technology LLC, Safetraces, Inc., BluWrap, Skipping Rocks Lab, Tipa Corp., Watson Inc., and Devro plc have played a key role. Edible packaging can be applied in two forms: (i) edible coating applied directly on the food product or (ii) preformed film wrapped around the food product. The aim of this study is to review different methods of film formation and edible coating depositions. Edible films can be produced using two methods, wet (casting) and dry (extrusion) processes; and methods such as dipping, spraying, fluidized-bed, and panning are used for deposition of edible coatings on the surface of food product. Casting and dipping methods for film formation and coating deposition, respectively, are easy to use and are preferred methods on a lab scale; whereas extrusion and spraying are preferred methods for film formation and coating deposition, respectively, on a commercial scale. This work can help researchers and industries to select an efficient and cost-effective method for the development of edible film/coating for specific application. Further study and evaluation of practical applications of methods of edible packaging should be carried out within the main purpose of keeping food safe with acceptable quality for extended period of time.

Polysaccharide and Protein Films with Antimicrobial/Antioxidant Activity in the Food Industry: A Review

From an economic point of view, the spoilage of food products during processing and distribution has a negative impact on the food industry. Lipid oxidation and deterioration caused by the growth of microorganisms are the main problems during storage of food products. In order to reduce losses and extend the shelf-life of food products, the food industry has designed active packaging as an alternative to the traditional type. In the review, the benefits of active packaging materials containing biopolymers (polysaccharides and/or proteins) and active compounds (plant extracts, essential oils, nanofillers, etc.) are highlighted. The antioxidant and antimicrobial activity of this type of film has also been highlighted. In addition, the impact of active packaging on the quality and durability of food products during storage has been described.

Chemical and Physical Characteristics of Edible Films, Based on κ- and ι-Carrageenans with the Addition of Lapacho Tea Extract

The aim of the study was to characterize antioxidant and textural property differences of edible films prepared with the addition of lapacho extract (LE). The experimentally produced edible films also contained different carrageenans (ι- and κ-carrageenan). The κ- and ι-carrageenan, glycerol and the different addition of LE (5%, 10%, 20%) were used as ingredients for forming films. The pH and viscosity were measured for film forming solutions (before drying). The following analyses were performed on films: the total polyphenol content (TPC), Ferric Reducing Antioxidant Power (FRAP) and 2-Diphenyl–1-Picrylhydrazyl (DPPH). Optical parameters were analyzed by the determination of UV-Vis spectra. The structure of films was characterized by scanning electron microscopy. The gained results indicated that the use of different gelling agents (ι- and κ-carrageenan) resulted in statistically significant (p < 0.05) differences in textural properties (strength and breaking strain) of produced edible films. The highest antioxidant properties and TPC had a κ film with 20% LE (DPPH: 87.63 ± 0.03%; TPC: 233.75 ± 0.104 mg gallic acid/g). According to these results, it can be concluded that edible films with the highest concentrations of added lapacho extract can serve as a good source of antioxidant compounds. Certainly, these properties can be usefully incorporated into the wrapped food commodity.

Preparation of Coated Corrugated Box for Controlled-Release of Chlorine Dioxide and Its Application in Strawberry Preservation

Chlorine dioxide (ClO2) has received great attention as a nontoxic and efficient antimicrobial agent for the preservation of fresh fruits and vegetables. A novel two-layer coated corrugated box was developed to release gaseous ClO2 under the trigger of moisture in this study. The inner surface of the box was firstly coated with a mixture of polyvinyl alcohol-NaClO2-diatomite and then with chitosan acetic acid solution. Results showed that ClO2 was successfully released under high humidity due to the reaction of NaClO2, water vapor and acid. The concentration of released ClO2 increased with the increasing NaClO2 content in the coating, while the addition of diatomite stabilized and extended the release. To evaluate the preservation effect, strawberries were packed in the coated box and stored at room temperature. Compared with the control, the decay rate and weight loss of the strawberries packed in the coated box (9 g/L NaClO2) were reduced up to 21.88% and 6.84%, respectively. The surface color, firmness and nutrients content were also better maintained. Therefore, this coated corrugated box with the capability to release ClO2 under the trigger of moisture has great potential to be applied as an antimicrobial packaging for fresh fruits and vegetables.

Vegetable Additives in Food Packaging Polymeric Materials

Plants are the most abundant bioresources, providing valuable materials that can be used as additives in polymeric materials, such as lignocellulosic fibers, nano-cellulose, or lignin, as well as plant extracts containing bioactive phenolic and flavonoid compounds used in the healthcare, pharmaceutical, cosmetic, and nutraceutical industries. The incorporation of additives into polymeric materials improves their properties to make them suitable for multiple applications. Efforts are made to incorporate into the raw polymers various natural biobased and biodegradable additives with a low environmental fingerprint, such as by-products, biomass, plant extracts, etc. In this review we will illustrate in the first part recent examples of lignocellulosic materials, lignin, and nano-cellulose as reinforcements or fillers in various polymer matrices and in the second part various applications of plant extracts as active ingredients in food packaging materials based on polysaccharide matrices (chitosan/starch/alginate).

Edible Films and Coatings Functionalization by Probiotic Incorporation: A Review

Edible coatings and films represent an alternative packaging system characterized by being more environment- and customer-friendly than conventional systems of food protection. Research on edible coatings requires multidisciplinary efforts by food engineers, biopolymer specialists and biotechnologists. Entrapment of probiotic cells in edible films or coatings is a favorable approach that may overcome the limitations linked with the use of bioactive compounds in or on food products. The recognition of several health advantages associated with probiotics ingestion is worldwide accepted and well documented. Nevertheless, due to the low stability of probiotics in the food processing steps, in the food matrices and in the gastrointestinal tract, this kind of encapsulation is of high relevance. The development of new and functional edible packaging may lead to new functional foods. This review will focus on edible coatings and films containing probiotic cells (obtaining techniques, materials, characteristics, and applications) and the innovative entrapment techniques use to obtained such packaging.

Application of Edible and Biodegradable Starch-Based Films in Food Packaging: A Systematic Review and Meta-Analysis

In recent years, natural polymers such as starch have been widely considered as alternatives to plastics derived from petroleum derivatives in the production of packaging films. Currently, modified starches with new functional features are available that can be used in the production of the above mentioned films. The aim at this study is a systematic review and meta-analysis of application of edible and biodegradable starch-based films in food packaging. At first all of the studies related to our title by using some keywords (edible and biodegradable starch-based films and food packaging) searched for English databases; Google, Google scholar, PubMed, Embase, CINAHL, PsycInfo, SCOPUS and ISI web of Science during the 2010 to 2018 was run consisting a predefined inclusion and exclusion factors. Inclusion and exclusion criteria were: papers related to edible and biodegradable starch-based films and food packaging, papers were English, types of papers were original and all the papers were free full text. As a result, related to inclusion and exclusion criteria papers were found and analyses. Data were collected based on study characteristics, edible and biodegradable starch-based films, food packaging. In the initial search, 589 articles were found that after reviewing the titles and abstract articles and removing repetitive and non-related, 33 possible related articles were examined. Of these, 24 articles were omitted from the abstract because of lack of access to the original article and lack of sufficient information. Finally, 13 papers were included in the study. Due to novel research on the application of bio-degradable biofilms in the packaging industry of food, starch is one of the most promising and promising sources. Different needs in the food packaging industry for bio-films have led to the diverse sources of starch being studied, because each source has its own specific characteristics. The properties of films obtained from starch indicated the rigidity and reduced flexibility of the films. To prevent this and the corresponding effects on the film, other polymers can be used as additive compounds. Extending the use of starch structure techniques and the use of this material in combination with other materials to reduce the inherent weaknesses of this natural polymer has led to its further development in various industries, especially packaged industries. Starch is a proper substitute for polymers extracted from oil derivatives. In order to improve the characteristics of the produced films, a high number of compounds can be added to the matrix, and various variations can be applied during the processing. Optimizing conditions will produce transparent, non-odorous, non-flavored, and color-free films with improved mechanical, optical and deterrent features.