Antimicrobial activity, mechanical and thermal properties of cassava starch films incorporated with beeswax and propolis.

Edible films can be formed from different polymeric compounds. The use of starch has gained extra value; because it can be used in combination with plasticizers and lipids, helping to improve mechanical properties. Besides, with the addition of an antimicrobial, the function of these films can be extended. The objective of this research was to evaluate the effect of native cassava starch, beeswax and ethanolic propolis extract (EPE) on the mechanical, thermal and inhibitory properties against the Aspergillus niger fungus. An experimental Box-Behnken design with three factors: cassava starch concentration (2-4%w/v), beeswax (0.5-0.9%w/w) and EPE (1-4%v/w) was used. The films obtained were opaque and with low mechanical properties. EPE concentration affected tensile strength, elongation at break (EB) and Young's modulus (YM), and cassava starch content only affected EB and YM. In thermal properties, the weight loss was affected by the cassava starch-beeswax interaction, where the most loss occurred at high levels of these factors in the temperature range of 200-360 °C. The films reduced the growth of the Aspergillus niger by 51%, where the beeswax-EPE interaction had a significant positive effect. The characteristics of the developed films suggest that they would be more acceptable as fruit and vegetable coatings.

Active edible films with plant extracts: a updated review of their types, preparations, reinforcing properties, and applications in muscle foods packaging and preservation.

Currently, edible films have been increasingly explored to solve muscle food spoilage during storage, especially through the incorporation of plant extracts to develop edible packaging materials. Natural polymers matrices with plant extracts are befitting for fabricating edible films by casting methods. In the films system, the structure and physicochemical properties were strengthened via chemical interactions between active molecules in plant extracts and the reactive groups in the polymer chain. The antibacterial and antioxidant properties were dramatically reinforced through both physical and chemical actions of the plant extracts. Additionally, edible films imbedded with color-rich plant extracts could be considered as potential sensitive indicators to monitor the spoilage degree of muscle foods in response to change in gas or temperature. Furthermore, these films could increase sensory acceptability, improve quality and prolong the shelf life of muscle foods. In this article, the types, preparation methods and reinforcing properties of the edible films with plant extracts were discussed. Also, the applications of these films were summarized on quality maintenance and shelf-life extension and intelligent monitoring in muscle foods. Finally, a novel technology for film preparation achieving high-stability and sustained release of active compounds will become an underlying trend for application in muscle food packaging.

Films of biopolymers, pectin and gellan, enriched with natamycin and clove essential oils for the packaging of Corn tortilla: Protection against Staphylococcus aureus and Candida parapsilosis.

It was investigated the microbial protection of corn tortilla, traditional Mexican food with high acceptance, for food safety. We elaborated a functional film (FF) prepared with 0.4% (w/v) gellan gum, 2% (w/v) citrus pectin, 0.5% (w/v) glycerol, 0.0003% (w/v) natamycin, 0.03% (v/v) essential clove oils, and 0.1% (v/v) tween 80. The FF impeded the growth of indicator microorganisms in corn tortilla medium: Staphylococcus aureus (i.e., 35 °C, 50% RH, 7 days) and Candida parapsilosis (i.e., 27 °C, 42% RH, 7 days; and 9 °C, 95% RH, 30 days). In packaged artisanal corn tortilla storage at 22 °C and 50% RH for 30 days, the FF-treatments showed 5.5 log CFU/g total aerobes and 4.8 log CFU/g yeasts and moulds, being two and three logs lower than the concentrations recorded in the controls with no film, respectively. Some physical-mechanical properties of FF were Young's modulus, 500 MPa; elongation at break, 10%; stress at break, 18.5 MPa; oxygen permeability, 4 × 10-13 g m Pa-1 s-1 m-2; and water vapour permeability, 4.8 × 10-11 g m Pa-1 s-1 m-2. Also, the sensory evaluation of wrapped tortilla suggested no negative effects. The obtained results envisage potential food-packaging applications with the elaborated films.

Identification of lactic acid bacteria with anti-listeria activity. Characterization and application of a bacteriocinogenic strain in the control of Listeria monocytogenes in cheese.

The purpose of the research paper was firstly to identify bacteriocin-producing lactic acid bacteria characterizing strains with anti-listeria activity and, secondly, to characterize bacteriocin evaluating its in vitro efficiency as a natural preservative and, thirdly, to evaluate the anti-listeria effect of the bacteriocinogenic strain of Lactiplantibacillus plantarum in cheeses and produce an edible film with anti-listerial effect. Of 355 lactic acid bacteria strains tested, two were able to produce bacteriocin against Listeria monocytogenes and were identified as Lactiplantibacillus plantarum and Lactiplantibacillus pentosus. A bactericidal effect of strain QS494 (Lactiplantibacillus plantarum) was observed in the first 8 h, with a reduction of 1.7 log, using cell-free supernatant with Listeria monocytogenes, where viable cells were counted on listeria selective agar. Both strains showed good technological characteristics and were without production of virulence factors. Changes in the pH of the cell-free supernatant obtained from Lactiplantibacillus plantarum did not affect its antimicrobial activity, which remained stable after heat treatments for up to 15 min at 121°C. Inhibitory activity was also observed after 12 weeks of storage at -20°C. In the evaluation of the anti-listeria effect in cheeses, a 3 log reduction in the Listeria monocytogenes count was observed in 120 h in cheeses produced with bacteriocinogenic lactic acid bacteria, while in cheeses produced with non-bacteriocinogenic culture, we observed a 2 log increase in the count. Edible films produced with the addition of precipitate from the cell free supernatant showed an antimicrobial effect against Listeria monocytogenes. Thus, the two strains studied have technological and biosafety potential.

Physical and Chemical Properties of Vegetable Films Based on Pumpkin Purée and Biopolymers of Plant and Animal Origin.

Highly methylated apple pectin (HMAP) and pork gelatin (PGEL) have been proposed as gelling agents for pumpkin purée-based films. Therefore, this research aimed to develop and evaluate the physiochemical properties of composite vegetable films. Granulometric analysis of film-forming solutions showed a bimodal particle size distribution, with two peaks near 25 µm and close to 100 µm in the volume distribution. The diameter D4.3, which is very sensitive to the presence of large particles, was only about 80 µm. Taking into account the possibility of creating a polymer matrix from pumpkin purée, its chemical characteristic was determined. The content of water-soluble pectin was about 0.2 g/100 g fresh mass, starch at the level of 5.5 g/100 g fresh mass, and protein at the level of about 1.4 g/100 g fresh mass. Glucose, fructose, and sucrose, the content of which ranged from about 1 to 1.4 g/100 g fresh mass, were responsible for the plasticizing effect of the purée. All of the tested composite films, based on selected hydrocolloids with the addition of pumpkin purée, were characterized by good mechanical strength, and the obtained parameters ranged from about 7 to over 10 MPa. Differential scanning calorimetry (DSC) analysis determined that the gelatin melting point ranged from over 57 to about 67 °C, depending on the hydrocolloid concentration. The modulated differential scanning calorimetry (MDSC) analysis results exhibited remarkably low glass transition temperature (Tg) values, ranging from -34.6 to -46.5 °C. These materials are not in a glassy state at room temperature (~25 °C). It was shown that the character of the pure components affected the phenomenon of water diffusion in the tested films, depending on the humidity of the surrounding environment. Gelatin-based films were more sensitive to water vapor than pectin ones, resulting in higher water uptake over time. The nature of the changes in water content as a function of its activity indicates that composite gelatin films, with the addition of pumpkin purée, are characterized by a greater ability to adsorb moisture from the surrounding environment compared to pectin films. In addition, it was observed that the nature of the changes in water vapor adsorption in the case of protein films is different in the first hours of adsorption than in the case of pectin films, and changes significantly after 10 h of the film staying in an environment with relative humidity RH = 75.3%. The obtained results showed that pumpkin purée is a valuable plant material, which can form continuous films with the addition of gelling agents; however, practical application as edible sheets or wraps for food products needs to be preceded with additional research on its stability and interactions between films and food ingredients.

Development and application of fruit and vegetable based green films with natural bio-actives in meat and dairy products: a review.

In recent years, foodborne outbreaks and food plastic waste accumulation in the environment have impelled a hunt for new, sustainable, novel and innovatory food packaging interventions to face microbial contamination, food quality and safety. Pollution caused from wastes generated by agricultural activities is one of chief rising concerns of the environmentalists across the globe. A solution to this problem is effective and economic valorization of residues from agriculture sector. It would ensure that the by-products/residues from one activity act as ingredients/raw materials for another industry. An example is fruit and vegetable waste based green films for food packaging. Edible packaging is a well-researched area of science where numerous biomaterials have been already explored. Along with dynamic barrier properties, these biofilms often exhibit antioxidant and antimicrobial properties as function of the bioactive additives (e.g. essential oils) often incorporated in them. Additionally, these films are made competent by use of recent technologies (e.g. encapsulation, nano-emulsions, radio-sensors) to ensure high end performance and meet the principles of sustainability. Livestock products such as meat, poultry and dairy products are highly perishable and depend largely upon the mercy of packaging materials to enhance their shelf life. In this review, all the above-mentioned aspects are thoroughly covered with a view to project fruit and vegetable based green films (FVBGFs) as a potential and viable packaging material for livestock products, along with a discussion on role of bio-additives, technological interventions, properties and potential applications of FVBGFs in livestock products. © 2023 Society of Chemical Industry.

Formulation and characterization of starch-based novel biodegradable edible films for food packaging.

Petroleum-based plastics were widely used as packaging materials. However, plastic materials were not reusable and biodegradable, causing a severe negative impact on the environment. Edible films can be a suitable alternative to plastic films, particularly in food packaging. This research work prepared edible films containing blends of cornstarch, arrowroot powder, refined wheat flour, vinegar, and glycerol. Arrowroot powder added strength and nutritional value to the films. Glycerol, as a plasticiser, improved the flexibility of films. The combination of vinegar and glycerol increased the film's strength. The characteristic properties of prepared films, like thickness, bursting strength, moisture content, transparency, water-solubility, water vapour permeability, tensile strength, elongation, and Young's modulus, were analysed. The thermal stability of the films was evaluated by thermogravimetric analysis. The films were characterised by FTIR spectroscopy, and their surface morphology was analysed by scanning electron microscopy. The prepared films exhibited excellent properties suitable for food packaging. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05803-2.

Plasticizing effect of Apis mellifera honey on whey protein isolate films.

The aims of this study were to analyze the plasticizing effect of Apis mellifera honey on the mechanical, physicochemical and optical properties of whey protein isolate (WPI) films and to compare the results collected with the plasticizing effect of glycerol on WPI-films. Response surface was applied to optimize the amounts of WPI and glycerol in order to obtain films with higher tensile strength (TS), moderate elongation, and lower water vapor permeability so that they could be used as reference films. Honey was added at different concentrations (60%, 80%, and 100%) of g honey/100 g WPI, as a plasticizer to the WPI-films. In comparison to glycerol-plasticized films, an increase in the percentage of honey produced a reduction of 20 ± 10 to 48 ± 0.5% of TS, a 66 ± 0.5% lower in Young's modulus (WPI-films with 100% honey), and an increase of 186 ± 11% in elongation at break in the WPI-films with 100% honey. Honey-plasticized WPI-films were from 29 ± 11 to 43 ± 3% less permeable to water vapor than glycerol-plasticized WPI films. The mechanical characteristics of the 80% honey formulation did not differ significantly from those of the reference film (p > 0.05). Findings from this study indicate that honey has great potential as a plasticizer in WPI-films.

Edible films and coatings: properties for the selection of the components, evolution through composites and nanomaterials, and safety issues.

Edible films and coatings, despite their practical applications, have only entered the food industry in the last decade. Their main functions are to protect the food products from mechanical damage and from physical, chemical and microbiological deteriorative changes. The ingredients used for their formation are polysaccharides, proteins and lipids, in individual or combined formulations. The edible films and coatings have already been applied on various food products, such as fruits, vegetables, meat products, seafood products, cheese, baked products and deep fat fried products. The techniques for their application on foods are of particular interest. Nowadays, composite edible films and coatings are also being studied, based on combinations of the properties of individual components. In addition to conventional materials, new ones, such as nanomaterials, are being investigated, aiming to enhance the resulting properties. However, before the incorporation of new materials to films and coatings, they must be thoroughly checked according to the legislation, to assure their lawful use. This review covers the recent developments on the edible films and coatings area in terms of the contribution of novel constituting materials to the improvement of their properties.

Preservation of aquatic food using edible films and coatings containing essential oils: a review.

Edible films and coatings have recently received growing attention in the food packaging sector due to their protective ability from the external environment and biodegradability characteristic. Generally, any layer of biomaterial incorporated into food to prolong its shelf-life and that can be consumed along with the food with or without further peeling is defined as an edible film or coating. These biodegradable films improve mechanical properties, moisture and gas barriers, microbial protection, sensory perception, and the shelf-life of food products. In particular, films obtained from polysaccharides are characterized by better gas barrier properties, whereas proteins are known for their excellent mechanical properties. However, both polysaccharides and proteins show poor water barrier properties in films which can be improved by incorporating lipids as well as combining one or more hydrocolloids (proteins and polysaccharides). Moreover, essential oils (EOs) consist mainly of volatile components obtained from plants, which can be added to the film to improve antimicrobial and antioxidant properties. On the other hand, fishery products are highly perishable due to the combined action of chemical reaction, lipid oxidation, endogenous enzymes, and microbial growth. Cold storage and freezing with or without vacuum packaging are often used to preserve fishery products, but they do not always completely preserve quality. Therefore, this review aims to summarize the components and chemistry of edible films and coatings, and their application to aquatic food for quality preservation. Moreover, deterioration of aquatic food and how these films and coatings can improve antimicrobial, antioxidant, physical, and sensory properties are also discussed.

Edible films/coatings containing bioactive ingredients with micro/nano encapsulation: A comprehensive review of their fabrications, formulas, multifunctionality and applications in food packaging.

Due to the consumer's pursuit of safe, nontoxic and nutritious foods, edible and/or biodegradable materials have stood out in food packaging and preservation. In this context, the preparation and application of micro/nano encapsulated active ingredients (M/N-E-BAIs) represent a step toward reinforcing the properties of sustainable and controllable food packaging, particularly for the successful incorporation of new substances and functionalities into traditional edible films/coatings. This review, from the preparation of M/N-E-BAIs, the fabrication of edible film/coating containing M/N-E-BAIs to their characterization of multifunction and the application in food, makes a systematic summary and in-depth discussion. Food-grade polymers can encapsulate bioactive ingredients (BAIs) by chemical, physicochemical and mechanical methods, thereby forming M/N-E-BAIs with suitable sustained-release and unique biological activities. Furthermore, M/N-E-BAIs is incorporated into biopolymer substrates by solvent casting, 3D printing or electrostatic spinning to obtain novel edible films/coatings. This advanced packaging material exhibits superior physicochemical and functional properties over traditional food films/coatings. Besides, their applications in foods as active and intelligent packaging can improve food quality, prolong shelf life and monitor food corruption. Even so, there are still many challenges and limitations in formulation, preparation and application of this new packaging technology that need to be addressed in the future.

Properties and Biodegradability of Films Based on Cellulose and Cellulose Nanocrystals from Corn Cob in Mixture with Chitosan.

The increase in consumer demand for more sustainable packaging materials represents an opportunity for biopolymers utilization as an alternative to reduce the environmental impact of plastics. Cellulose (C) and chitosan (CH) are attractive biopolymers for film production due to their high abundance, biodegradability and low toxicity. The objective of this work was to incorporate cellulose nanocrystals (NC) and C extracted from corn cobs in films added with chitosan and to evaluate their properties and biodegradability. The physicochemical (water vapor barrier, moisture content, water solubility and color) and mechanical properties of the films were evaluated. Component interactions using Fourier-transform infrared (FTIR) spectroscopy, surface topography by means of atomic force microscopy (AFM), biodegradability utilizing a fungal mixture and compostability by burying film discs in compost were also determined. The C-NC-CH compared to C-CH films presented a lower moisture content (17.19 ± 1.11% and 20.07 ± 1.01%; w/w, respectively) and water vapor permeability (g m−1 s−1 Pa−1 × 10−12: 1.05 ± 0.15 and 1.57 ± 0.10; w/w, respectively) associated with the NC addition. Significantly high roughness (Rq = 4.90 ± 0.98 nm) was observed in films added to NC, suggesting a decreased homogeneity. The biodegradability test showed larger fungal growth on C-CH films than on CH films (>60% and <10%, respectively) due to the antifungal properties of CH. C extracted from corn cobs resulted in a good option as an alternative packaging material, while the use of NC improved the luminosity and water barrier properties of C-CH films, promoting strong interactions due to hydrogen bonds.

Edible Bioactive Film with Curcumin: A Potential "Functional" Packaging?

Edible packaging has been developed as a biodegradable and non-toxic alternative to traditional petroleum-based food packaging. Biopolymeric edible films, in addition to their passive protective function, may also play a bioactive role as vehicles for bioactive compounds of importance to human health. In recent years, a new generation of edible food packaging has been developed to incorporate ingredients with functional potential that have beneficial effects on consumer health. Curcumin, a bioactive compound widely used as a natural dye obtained from turmeric rhizomes (Curcuma longa L.), has a broad spectrum of beneficial properties for human health, such as anti-inflammatory, anti-hypertensive, antioxidant, anti-cancer, and other activities. To demonstrate these properties, curcumin has been explored as a bioactive agent for the development of bioactive packaging, which can be referred to as functional packaging and used in food. The aim of this review was to describe the current and potential research on the development of functional-edible-films incorporating curcumin for applications such as food packaging.

Long-Term Refrigerated Storage of Beef Using an Active Edible Film Reinforced with Mesoporous Silica Nanoparticles Containing Oregano Essential Oil (Lippia graveolens Kunth).

Beef is a fundamental part of the human diet, but it is highly susceptible to microbiological and physicochemical deterioration which decrease its shelf life. This work aimed to formulate an active edible film (AEF) incorporated with amino-functionalized mesoporous silica nanoparticles (A-MSN) loaded with Mexican oregano (Lippia graveolens Kunth) essential oil (OEO) and to evaluate its effect as a coating on fresh beef quality during refrigerated storage. The AEF was based on amaranth protein isolate (API) and chitosan (CH) (4:1, w/w), to which OEO emulsified or encapsulated in A-MSN was added. The tensile strength (36.91 ± 1.37 MPa), Young's modulus (1354.80 ± 64.6 MPa), and elongation (4.71%) parameters of AEF made it comparable with synthetic films. The antimicrobial activity of AEF against E. coli O157:H7 was improved by adding 9% (w/w) encapsulated OEO, and interactions of glycerol and A-MSN with the polymeric matrix were observed by FT-IR spectroscopy. In fresh beef, after 42 days, AEF reduced the population growth (Log CFU/cm2, relative to uncoated fresh beef) of Brochothrix thermosphacta (5.5), Escherichia coli (3.5), Pseudomonas spp. (2.8), and aerobic mesophilic bacteria (6.8). After 21 days, odor acceptability of coated fresh beef was improved, thus, enlarging the shelf life of the beef and demonstrating the preservation capacity of this film.

Lipid oxidation and antioxidant delivery systems in muscle food.

Lipid oxidation accelerates quality deterioration in muscle-based foods (fish, red meat, and poultry), resulting in off-odors/flavors, color problems, texture defects, and safety concerns. Adding antioxidants is one approach to control lipid oxidation, and several delivery strategies have been applied, such as supplementing antioxidants to the feed, direct mixing into minces, or, for whole muscle pieces; spraying, glazing, and injection. However, some issues linked to these technologies hinder their wide utilization, such as low effectiveness, noncompatibility with clean label, and off-flavor. These shortcomings have promoted the development of new antioxidant delivery technologies. In this review, the main focus is on the principles, characteristics, and implementation of five novel antioxidant delivery methods in different types of muscle food products. Their advantages and drawbacks are also summarized, plus comments about future trends in this area. Among novel routes to deliver antioxidants to muscle foods are, for whole tissues, recyclable dipping solutions; for minces, encapsulation; and, for both minces and whole tissues, cross-processing with nonmuscle antioxidant-containing raw materials as well as applications of edible films/coatings and active packaging. Advantages of these technologies comprise, for example, low price, the possibility to control the antioxidant release rate, overcoming strong aromas from natural antioxidants, and allowing antioxidant-containing raw materials from the food industry to be valorized, providing an opportunity for more circular food production.

Valorization and Application of Fruit and Vegetable Wastes and By-Products for Food Packaging Materials.

The important roles of food packaging are food protection and preservation during processing, transportation, and storage. Food can be altered biologically, chemically, and physically if the packaging is unsuitable or mechanically damaged. Furthermore, packaging is an important marketing and communication tool to consumers. Due to the worldwide problem of environmental pollution by microplastics and the large amounts of unused food wastes and by-products from the food industry, it is important to find more environmentally friendly alternatives. Edible and functional food packaging may be a suitable alternative to reduce food waste and avoid the use of non-degradable plastics. In the present review, the production and assessment of edible food packaging from food waste as well as fruit and vegetable by-products and their applications are demonstrated. Innovative food packaging made of biopolymers and biocomposites, as well as active packaging, intelligent packaging, edible films, and coatings are covered.

Development and Characterization of Novel Composite Films Based on Soy Protein Isolate and Oilseed Flours.

The possibility of using oilseed flours as a waste source for film-forming materials with a combination of soy protein isolate in preparation of edible films was evaluated. Physical, mechanical and barrier properties were determined as a function of the oilseed type: hemp, evening primrose, flax, pumpkin, sesame and sunflower. It was observed that the addition of oilseed flours increased the refraction and thus the opacity of the obtained films from 1.27 to 9.57 A mm-1. Depending on the type of flours used, the edible films took on various colors. Lightness (L*) was lowest for the evening primrose film (L* = 34.91) and highest for the soy protein film (L* = 91.84). Parameter a* was lowest for the sunflower film (a* = -5.13) and highest for the flax film (a* = 13.62). Edible films made of pumpkin seed flour had the highest value of the b* color parameter (b* = 34.40), while films made of evening primrose flour had the lowest value (b* = 1.35). All analyzed films had relatively low mechanical resistance, with tensile strength from 0.60 to 3.09 MPa. Films made of flour containing the highest amount of protein, pumpkin and sesame, had the highest water vapor permeability, 2.41 and 2.70 × 10-9 g·m-1 s-1 Pa-1, respectively. All the edible films obtained had high water swelling values from 131.10 to 362.16%, and the microstructure of the films changed after adding the flour, from homogeneous and smooth to rough. All blended soy protein isolate-oilseed flour films showed lower thermal stability which was better observed at the first and second stages of thermogravimetric analysis when degradation occurred at lower temperatures. The oilseed flours blended with soy protein isolate show the possibility of using them in the development of biodegradable films which can find practical application in the food industry.

Films from cashew byproducts: cashew gum and bacterial cellulose from cashew apple juice.

ABSTRACT: Cashew is a major crop in several tropical countries. Its cultivation is mostly aimed to the production of cashew nuts, whereas its byproducts (including cashew tree gum and cashew apples) are underutilized. In this study, cashew tree gum (CG) has been combined to nanofibrillated bacterial cellulose (NFBC) produced from cashew apple juice, at different ratios (from CG-only to NFBC-only), to produce edible films. While the CG-only dispersion (at 1 wt%) behaved as a quasi-Newtonian fluid, the addition of NFBC provided a shear-thinning behavior, making the dispersions easier to process, especially to cast. Moreover, the films containing increasing NFBC contents exhibited better physico-mechanical performance. When compared to the CG-only film, the films containing at least 25% NFBC presented remarkably higher strength and modulus (even similar to some conventional petroleum-derived polymers), lower water vapor permeability (WVP), and lower water solubility, although at the expense of lower elongation and higher opacity values. The combined use of both polysaccharides was demonstrated to be useful to overcome the limitations of both CG-only films (very low viscosity, poor tensile properties and very high WVP) and NFBC-only films (very high viscosity, making the dispersions difficult to mix and spread). Moreover, the use of different NFBC/CG ratios allow properties to be tuned to meet specific demands for different food packaging or coating purposes.

Effects of Candelilla and Carnauba Wax Incorporation on the Functional Properties of Edible Sodium Caseinate Films.

The aim of this study was to evaluate the effects of candelilla (CAN) or carnauba wax (CAR) incorporation on functional properties of edible sodium caseinate (CAS) films. Glycerol and Tween-80 were used as the plasticizer and the emulsifier, respectively. The results showed that the incorporation of waxes increased film opacity, total color differences (∆E), and mechanical resistance and reduced film lightness, water vapor permeability (WVP), and elongation at break. Scanning electron microscopy showed heterogeneous structure of emulsion films with regular distribution of lipid particles. A different internal arrangement was observed as a function of the film composition with both layered and incorporated film structure. Films containing candelilla wax exhibited more regular lipid reorganization, which resulted in better water vapor barrier efficacy and mechanical resistance in comparison to control films. The presence of Tween-80 resulted in better dispersion of lipid particles in film-forming solutions and lower water solubility, lightness, film opacity, and water vapor permeability, whereas the total color differences (∆E) were significantly larger and the improvement in mechanical properties was also achieved.

Microbial Transglutaminase as a Tool to Improve the Features of Hydrocolloid-Based Bioplastics.

Several proteins from animal and plant origin act as microbial transglutaminase substrate, a crosslinking enzyme capable of introducing isopeptide bonds into proteins between the aminoacids glutamines and lysines. This feature has been widely exploited to modify the biological properties of many proteins, such as emulsifying, gelling, viscosity, and foaming. Besides, microbial transglutaminase has been used to prepare bioplastics that, because made of renewable molecules, are able to replace the high polluting plastics of petrochemical origin. In fact, most of the time, it has been shown that the microbial enzyme strengthens the matrix of protein-based bioplastics, thus, influencing the technological characteristics of the derived materials. In this review, an overview of the ability of many proteins to behave as good substrates of the enzyme and their ability to give rise to bioplastics with improved properties is presented. Different applications of this enzyme confirm its important role as an additive to recover high value-added protein containing by-products with a double aim (i) to produce environmentally friendly materials and (ii) to find alternative uses of wastes as renewable, cheap, and non-polluting sources. Both principles are in line with the bio-economy paradigm.