Active Biodegradable Films Research Articles

Development of PLA-PBSA based biodegradable active film and its application to salmon slices

Abstract Due to negative impacts of non-biodegradable plastic films to the environment, biodegradable packaging materials have become a research hotspot. Novel biodegradable active films based on polylactic acid (PLA) blended with poly (butylene succinate adipate) (PBSA), carvacrol, and thymol were developed. Mechanical properties of films including tensile strength (TS), elongation at break (EAB), optical properties including transmittance (T) and haze (H), barrier properties including water vapor permeability (WVP), oxygen transmission rate (OTR), and releasing rates of active compound from films and antioxidant efficiency of films were investigated to evaluate the films. A shelf life test of salmon slices packed with PLA-PBSA bags (with and without active compound) were carried out. The results showed that PLA-PBSA based films had better mechanical properties than those of similar biodegradable films such as PLA-PHB, and even better than EVOH in terms of two major mechanical properties, TS and EAB. As to active properties, the results also showed a high release of active compound and high antioxidant efficiency of PLA-PBSA films with either carvacrol or thymol. The shelf life test of salmon slices showed the antibacterial and antioxidant properties of the PLA–PBSA films were enhanced when the active compound were released into salmon slices at equilibrium. As a result, spoilage and deterioration of the salmon slices were reduced, which extended the shelf life of salmon slices by 3–4 days during cold storage. Thus, the biodegradable PLA–PBSA films with active compound could prolong shelf life of fisheries products in particular, and food in general.

Comparative evaluation of edible films impregnated with sage essential oil or lactoperoxidase system: Impact on chemical and sensory quality of carp burgers

The aim of this study was to examine alginate (AL), chitosan (CH), and gelatin (ZH) films incorporated with Salvia officinalis essential oil (SOE) or lactoperoxidase system (LPS) for their antioxidant characteristics, and their effects on main chemical spoilage parameters (Total volatile basic nitrogen [TVB-N], thiobarbituric acid reactive substances [TBARs], peroxide value [PV], and free fatty acids [FFA]), and sensorial characteristics of refrigerated carp burgers. A good correlation was observed between total phenolic content and DPPH radical scavenging activity of the developed films. Among the active composites, the minimum TVB-N (10.61 mg/100 g), TBARs (3.11 mg of malonaldehyde/kg), and FFA (5.34% of oleic acid) values were recorded for the samples treated with CH/LPS, on the final day of storage, while gelatin films were least effective. Sensory evaluation revealed that the burgers treated with active CH and AL films received better scores, especially for odor and overall acceptability attributes, compared to untreated control sample. Practical applications This manuscript addresses an important area in active food packaging by developing and comparing bioactive edible films based on natural ingredients. Biodegradable active films were developed based on alginate, chitosan, and gelatin with sage essential oil and lactoperoxidase system. Considering all the health concerns related to synthetic chemical preservatives, the potential relevance of using these newly packaging films in foods products was emphasized. This manuscript will be of interest to food science researchers from the perspective of presenting natural-based packaging films for extending foods shelf life.

Valorization of Olive Industry Waste Products for Development of New Eco-sustainable, Multilayer Antioxidant Packaging for Food Preservation.

This work deals with the design, production and evaluation of the effectiveness of novel multilayer active films, based on biopolymers and natural antioxidants, suitable for food packaging applications.Three phenolic olive extracts (named OEs), deriving from olives milling wastewaters, were analyzed in order to assess their suitability to develop antioxidant polymeric systems. The most performing extract was then selected to produce the active biodegradable films, spreading a polylactic acid (PLA) coating layer, at different percentages of OE (0-3% w/w), on a biodegradable substrate. The produced multilayer structures were then characterized by several techniques, in order to evaluate the interaction of the antioxidant phase with the polymer matrix, and its effect on the physical and functional performance of the active systems. Finally, the antioxidant capacity by ,2-diphenyl-1-picrylhydrazyl (DPPH) spectroscopic method was carried out, suggesting that the formulated active bio-films could be considered an innovative and promising solution for antioxidant packaging of sensitive food products.

Yerba mate extract in active starch films: Mechanical and antioxidant properties

The growing concern on environment preservation and the impact of the packaging from the non-renewable materials improve the interest at biodegradable and active packages development for food applications. The aim was to develop starch films with yerba mate extract (YME) made with water: ethanol (50:50% vol/vol) at 50°C followed by characterization. The YME was applied to the cassava starch films (control, 5, 10, 15, and 20%). The thickness, water vapor permeability (WVP), tensile strength, elongation as well as the Young’s Modulus, water solubility, phenolic compounds, antioxidant activity (DPPH•), color and opacity and sorption isotherms of the films were characterized. The starch films decrease tensile strength, Young’s module and elongation increased as the YME concentration increased. In addition, the sorption isotherms were adjusted to the GAB model (R2 > 0.96). The moisture absorption by the samples of starch films with 5, 10, and 15%, had similar moisture absorption, higher than the control samples. Practical applications In this research, we developed a biodegradable active film with Yerba mate extract (YME), which is in good agreement with the growing concern in the preservation of the environment through minimization of the environmental impact of packaging from the non-renewable raw material. YME increased the phenolic compounds and antioxidant activity of the starch films. This behavior is good for fatty food applications, since fat acids may undergo oxidative processes and change sensorial and nutritional characteristics; and antioxidants will slow down these reactions. The YME also promoted a plasticizing effect in the cassava starch films, decreasing tensile strength and increasing the elongation. This behavior allows the application of systems that do not need high mechanical efforts.

Corn starch and gelatin-based films added with guabiroba pulp for application in food packaging

Abstract The guabiroba pulp (GP) has natural antioxidant compounds, such as phenolic compounds and ascorbic acid. The aim of this work was to produce an active biodegradable film based on blends of gelatin (GEL) and corn starch (NCS) and activated with GP, for application as package for extra-virgin olive oil, as a sachet. For that, the effect of blends composition was first evaluated in passive films, and then, a formulation was chosen to produce the active film with guabiroba pulp. The effect of the incorporation of GP on the barrier, mechanical and optical properties of these films was studied, and the antioxidant effect on the storage of extra virgin olive oil was verified in a specific test. Blends with GEL (5 and 10%) and NCS (2 and 4%) were prepared, in the different ratios. The film with 5% GEL and 2% NCS in the 1:1 ratio, was selected for the addition of GP (10 and 20%). The addition of GP caused a reduction in tensile strength and increased elongation values. The film with 10% GP was selected for the preparation of the sachet, due to its lower value of water vapor permeability. At the end of the storage period (15 days), the values of acidity index and peroxide index of the extra-virgin olive oil did not reach the maximum limit allowed by the current legislation. It can be concluded that the results obtained may be useful for future studies and applications using active and biodegradable packaging.

Development and characterization of semi-refined carrageenan (SRC) films from Eucheuma cottonii incorporated with glycerol and α-tocopherol for active food packaging application

This works focuses on the development of biodegradable active films packaging using all natural compounds with the aim of contributing sustainable film not only by reducing the plastic waste to environment but also as a potential substitute of synthetic preservative in food. Active film packaging was formulated using semi-refined carrageenan (SRC) biopolymer extracted from Eucheuma cottonii plasticized with glycerol (G) and incorporated with different concentrations of α-tocopherol (Tp) at 0.1, 0.2, 0.3 and 0.4% v/v as natural antioxidants. Opacity, water solubility and mechanical properties of the resultant film were analysed whereas the migration behaviour of antioxidant films into food simulant during 30 days storages were determined using total phenolic content and DPPH assay. The addition of Tp in SRC + G film decreased the tensile strength but increased the value of elongation at break significantly (p<0.05). Opacity and water solubility were improved with increasing concentration of Tp (p<0.05). The highest and prolonged release of antioxidant to food simulant was determined by SRC+G+Tp0.4% through 30 day storage with total phenolic content value of 2 mg GAE/L sample and 88.59% inhibition for DPPH assay. Hence, the new formulation of SRC+G with tocopherol could be an alternative degradable active packaging that might reduce the need of adding antioxidants directly into food products and also prolong the food shelf life.

Characterization of Active Biodegradable Films Based on Proso Millet Starch and Curcumin

Starch extracted from proso millet (PMS) is used as a base material for preparing biodegradable films and curcumin is added to endow antioxidant properties to the films. The effect of various concentrations (0%, 0.5%, 1%, 2%, and 3%) of curcumin on the properties of the PMS films is reported. As the concentration of curcumin increases, tensile strength decreases and elongation at break increases. Although thermal stability of the PMS film is not improved by the addition of curcumin, water and UV–visible light barrier properties are enhanced. Moreover, the antioxidant properties of the PMS films with curcumin are enhanced with increasing curcumin content. In particular, the scavenging activities of the 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) and 2,2‐diphenyl‐1‐picrylhydrazyl radicals in the PMS film containing 3% curcumin are 100% and 42.96%, respectively. A migration test is carried out on the films for 7 days; phenolic compounds migrate faster in water than in 95% ethanol medium. These results imply that the PMS films containing curcumin can be used as new active packaging materials.

Characterization of active chitosan films as a vehicle of potassium sorbate or nisin antimicrobial agents

Antimicrobial and biodegradable active films were obtained by incorporating potassium sorbate (PS) and nisin (NIS) into chitosan matrix films. The diffusion mechanism of antimicrobial compounds through chitosan matrix was studied, applying Fick's Second Law and the Power Law. Films were produced by casting and the antimicrobial agents were added at different concentrations. They were also characterized by moisture content, water solubility, mechanical properties, contact angle, and microstructure. It was observed that the tensile strength decreased by 49.7% for PS films, and elongation increased by 206% for NIS films, when comparing 10.0 with 2.5 mg/g films. The presence of antimicrobial agents provided a significant increase in contact angle. The modeling fitted to the PS-chitosan films and the diffusivity coefficients did not show significant differences for different compound concentrations. The diffusion coefficients of PS (1.909–2.292×10−13 m2/s) were approximately two times higher than the diffusion coefficient of NIS active films.

Effect of microalgae addition on active biodegradable starch film

Despite its great importance, the traditional packaging is produced from non-renewable and non-biodegradable sources, causing several environmental problems. Therefore, biodegradable packaging has been attracting attention and interest from researchers and industries worldwide. This work developed biodegradable films with antioxidant properties, using cassava starch combined with biomass or biomass extract of microalgae Heterochlorella luteoviridis and Dunaliella tertiolecta. The films were characterized by their physicochemical, mechanical, barrier, optical and antioxidant properties. The film with the best characteristics was used as salmon packaging aiming protection against lipid oxidation. In general, the addition of biomass increased films' solubility, biodegradability and opacity, while the films with the addition of biomass extract showed the lowest values of these parameters. The addition of biomass increased films' elongation, rupture, and reduced the tensile strength and Young's modulus. Conversely, the addition of microalgae extract caused the inverse effect on these properties. All films with microalgae showed higher antioxidant activity, evaluated by peroxide index, compared to the control ones. The film containing 2.0% of H. luteoviridis extract presented the lowest water vapor permeability and good mechanical characteristics, and was applied in salmon packaging. The selected packaging decreased fish moisture and delayed lipid oxidation evaluated by TBARS index. The results showed incorporation of microalgae biomass resulted in biodegradable and highly soluble films, making it difficult to apply in moist foods. The films containing microalgae extracts were suitable to be used in foods with high water content.

Characterization of active biodegradable films based on cassava starch and natural compounds

Abstract Biodegradable films with antimicrobial and antioxidant properties were developed from cassava starch with the addition of minimally processed pumpkin residue extract (PRE) (0 to 6%) and oregano essential oil (OEO) (0 to 2%). The films were characterized regarding their physicochemical, mechanical, barrier, and antioxidant (DPPH and TBARS) properties. The films that had the best barrier, mechanical and antioxidant properties were selected and further characterized by their optical, thermal, and antimicrobial properties. Oregano essential oil and glycerol contributed to increasing the elongation and reducing the tensile strength of the films. The films showed satisfactory antioxidant and antimicrobial activity when tested in vitro. From these results, two formulations were selected to test the protection against oxidation in ground beef (F8, with 4.8% PRE and 1.6% OEO and F12 with 3% PRE and 2% OEO). It was observed that adding pumpkin residue extract was important to provide opacity to the films, but it was not effective in improving the antioxidant or antimicrobial activity when compared to adding essential oregano oil. When applied to ground beef, the films protected the meat against lipid oxidation until the third day of storage.

Effect of oxidized phenolic compounds on cross-linking and properties of biodegradable active packaging film composed of turmeric and gelatin

Cross-linking effects of different phenolic substances (tannic acid, caffeic acid, and green tea extract) on mechanical and barrier properties of biodegradable films consisting of turmeric (Curcuma longa) and gelatin were investigated. The results showed that degree of protein cross-linking increased with concentration of oxidized phenolic compounds, resulting in denser and stiffer film structures. Cross-link formation led to higher tensile strength and lower elongation-at-break (%), water vapor permeability, and water solubility of films with formation of aggregations. However, at high concentrations of phenolic compounds, molecular mobility increased due to grafting/branching reactions resulting in plasticizing effect. The developed films were applied as active packaging materials to fresh ground pork to extend shelf life, demonstrating good antioxidant activity and preventing lipid oxidation of fresh pork. No significant difference (p> 0.05) was noted in the overall acceptability of all samples by sensory analysis.

Development of guar gum based active packaging films using grape pomace.

The objective of this study was to develop biodegradable active film to improve the shelf-life of minimally processed fresh-produce. Guar gum (GG) based films with improved properties were fabricated by employing tween-80 (0.88%) as emulsifier, nanoclay (13.9%) as reinforcement, beeswax (1.21%) for hydrophobicity, glycerol (3.07%) as plasticizer, and grape pomace extract (5%) as active ingredient (%w/w of GG). Active films had a tensile strength of 122MPa and water vapor transmission rate of 69 gm-2d-1. Films demonstrated significant antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Salmonella Typhimurium. The 2kGy irradiated minimally processed pomegranate arils packed in film demonstrated a shelf-life of 12days as compared to 4days for unirradiated samples. The observed improvement in shelf-life was due to a radiation-induced release of antimicrobial volatiles from active films as confirmed by headspace analysis using GC-MS. Suitability of active films for food irradiation applications is thus demonstrated.

Sweet Potato Starch‐Based Nanocomposites: Development, Characterization, and Biodegradability

The primary objective of this study is to develop and characterize a novel active biodegradable nanocomposite film using sweet potato starch (SPS) for food packaging. Montmorillonite (MMT) nanoclay at a constant weight of 3% and thyme essential oil (TEO) at three levels (2%, 4%, and 6% v/v) are incorporated into SPS film. The results show that incorporating MMT and TEO into SPS film greatly enhanced (P &lt; 0.05) water resistance by 50%. MMT incorporation also hinders the degradation rate of the film. Furthermore, the combined effect of MMT and TEO (up to 4%) improve tensile strength, elongation, and tristimulus color values (P &lt; 0.05). Fourier transform infrared (FT‐IR) spectroscopy and X‐ray diffraction (XRD) results confirm that the noted improvements are related to MMT exfoliation and good interaction between SPS and MMT in the presence of TEO. These results suggest that SPS may provide a viable solution to the waste disposal of plastic packaging materials used for food products.

Physico-functional and Anti-oxidative Properties of Carp Swim Bladder Gelatin and Brown Seaweed Fucoidan Based Edible Films

Films were prepared with fish gelatin extracted from swim bladder of rohu (Labeo rohita) and fucoidan extracted from brown seaweed (Padina tetrastromatica) using 3% gelatin and sorbitol (30% of protein) as plasticizer. Fucoidan was incorporated at concentrations of 5, 10, 15 and 20% of protein concentration to form GF-5, GF-10, GF-15 and GF-20 films, respectively. Results indicated that the average thickness of films ranged from 61.60 to 66.25 μm. Tensile strength (TS) increased from 55.37 to 63.37 MPa and elastic modulus (EM) from 1278.40 to 1482.20 MPa with the increase in fucoidan. WVTR and water solubility of films decreased from 917.44 to 634 g/m2/day and 91–82%, respectively with the addition of fucoidan. GF-50 films possessed lesser whiteness (39.59) compared to control films (55.79). FTIR spectra and SEM analysis clearly depicted the interaction of fucoidan with gelatin. GF-20 films exhibited high DPPH radical scavenging activity (46.26%), ABTS radical scavenging activity (49.95%) and Ferric reducing power (0.12 absorbance units) than other films. Thus, incorporation of fucoidan in fish gelatin films enhanced anti-oxidative properties besides improving mechanical and barrier properties, to serve as an active biodegradable edible film.

Effect of Organic Acids on Physical-Mechanical and Antifungicidal Properties of Anchovy Protein Films

ABSTRACTThe use of active biodegradable films from renewable sources like anchovy, with the incorporation of organic acids, such as sorbic acid (SA) and benzoic acid (BA), is an alternative to decrease environmental pollution and minimize the development of fungi in foods. This study investigated the respective influences of SA and BA at 0, 0.50, 0.75, and 1.50% on the growth of Aspergillus flavus and Rhizopus oryzae and on Argentine anchovy protein film properties (L*, a*, b*, tensile strength, elongation at break, solubility in water, water vapor permeability, and Fourier transform infrared spectroscopy (FTIR)). Results showed that the incorporation of SA or BA at different levels significantly increased the water vapor permeability, water solubility, and elongation at break of the films, but decreased the tensile strength and L* parameter (p < 0.05). FTIR evidenced an interaction between the BA and Argentine protein isolate. Also, the influences of the SA or BA concentration on antifungal activity was observed. The greatest effectiveness was obtained for films containing SA against R. oryzae compared to BA film treatments. In conclusion, the Argentine anchovy protein films could retain their antifungal property by incorporation of these organic acids.

Synthesis of biodegradable films based on cassava starch containing free and nanoencapsulated β‐carotene

β‐Carotene may represent an excellent natural antioxidant, and nanoscale encapsulation may contribute to development of a new technique for addition of antioxidants in active packaging. The objective of this work was to develop active biodegradable films with addition of free β‐carotene or β‐carotene–loaded lipid‐core nanocapsules and to evaluate the interaction with the polymeric matrix. The addition of free β‐carotene led to a decrease in the mechanical properties of films, result of their hydrophobic character and less interaction with the matrix. β‐Carotene nanocapsules caused the increase of colour intensity of films, elongation at rupture, and less light transmission, with the gradual increase according to increase in concentration. Films with β‐carotene nanocapsules presented greater protection of sunflower oil, with lower formation of oxidation products. The lower stability of free antioxidant led to behavior similar to control film, with less oxidation protection. The addition of nanocapsules can provide better interaction with the structure, since the encapsulated carotenoid exhibits solubility in aqueous medium and present better distribution, without altering the rapid biodegradability and thermal stability of films. The results show that encapsulated bioactive compounds can be used as hydrophobic natural antioxidants and added in active biodegradable packages for maintaining food safety and extending the shelf life.

Influence of starch oxidation on the functionality of starch-gelatin based active films

Biodegradable active films were prepared by casting, using corn starch, with differing oxidation degree, bovine gelatin, glycerol, as a plasticizer, and ethyl lauroyl arginate (LAE) as antimicrobial compound. The films were characterized as to their microstructure, physical properties and water affinity. Starch oxidation with sodium periodate (SP) greatly improved polymer compatibility and crosslinking, especially at 1:1 glucose:SP molar ratio, which promoted the films’ strength (40–92%) and barrier capacity (33 and 40% reduction in water vapour and oxygen permeability, respectively in LAE-free films), while Maillard reactions promoted the film browning. LAE, with amino and carbonyl groups, participated in the condensation reactions, interfering in the network crosslinking. All films with LAE showed bactericidal effect against Listeria innocua and Escherichia coli and LAE free films with oxidized starch inhibited the growth of both bacteria by 1–2 log CFU, due to the antimicrobial properties of Maillard compounds. Blend films with the most oxidized starch and gelatin containing LAE are promising materials for food packaging applications.

Effect of cellulose and lignocellulose nanofibers on the properties of Origanum vulgare ssp. gracile essential oil-loaded chitosan films

In this study, active biodegradable films from chitosan (CS) containing 5% w/w Origanum vulgare ssp. gracile essential oil (EO) and 4% w/w cellulose nanofibers (CNF) or lignocellulose nanofibers (LCNF) as nanoreinforcement were developed. GC–MS analysis showed that the most components of EO were carvacrol (49.43%) and then γ-terpinene (17.71%). The CS-EO film had high antioxidant activity and was more effective against E. coli and B. cereus bacteria than bionanocomposite films, which shows the release controlling effect of CNF and LCNF on the bioactive compounds from CS films. EO had not significant effect on the mechanical properties of the films (p>0.05), while nanofibers had significant effects (p<0.05) on strain to break (STB) and ultimate tensile strength (UTS). Incorporation of EO and CNF/LCNF in the CS-film also considerably improved solubility and water vapor barrier properties of the films. Color properties were significantly affected by adding of EO and CNF/LCNF. Formation of new hydrogen bonds between the chitosan chains, the EO and nanofibers were confirmed using FT-IR spectroscopy. Morphology of films was viewed using AFM and SEM, suggesting good dispersion of the CNF/LCNF. In general, the properly dispersion state and improving effect of LCNF on properties of CH-EO films was more than CNF.

Active starch-gelatin films for shelf-life extension of marinated salmon

Biodegradable active films were obtained by casting, using glycerol plasticized oxidized corn starch (OS) and bovine gelatine (BG) blends (1:1 mass ratio), with and without ethyl lauroyl arginate (LAE) as antimicrobial agent (1.3 g LAE/100 g polymer). Water vapour barrier capacity and colour of the films conditioned at 53 or 88% relative humidity were determined. Both LAE incorporation and high RH promoted film browning, coherently with the progression of Maillard reactions between amino groups of gelatine or LAE and carbonyl groups of oxidized starch. These compounds imparted antimicrobial properties to the films with and without LAE, both exhibiting antilisterial activity in in vitro tests. Packaging of marinated salmon samples in these films greatly reduced the total viable counts, which remained below the legal limit after 45 storage days at 5 °C. Nevertheless, films were not effective at controlling weight loss of salmon samples during the cold storage.

Improving the physical and protective functions of semolina films by embedding a blend nanofillers (ZnO-nr and nano-kaolin)

Abstract Regarding the reduction of synthetic food packaging materials’ pollution, the purpose of the present study is to examine a new biopolymer-based film to be employed in food packaging. Diverse ratios (1:4, 2:3, 3:2, and 4:1 w/w) of ZnO nanorod (ZnO-nr) and nano-kaolin combinations were incorporated into semolina film matrices, and nanocomposite films were formed using the solvent casting method. We examined the resultant films in terms of their barrier, optical, heat sealability, and structural attributes. Whilst increasing the level of ZnO-nr resulted in the decline of the oxygen permeability (OP) of the films, the increase in the percentage of nano-kaolin led to the improvement in the heat sealability of such films. Moreover, the intensification of the nanoparticle loading triggered a decline in the moisture content and water solubility of the nanocomposite films at all different nanofiller ratios. The increase of the ZnO-nr content also significantly affected the light absorbance level of the semolina films. Remarkable differences in the surface morphology were observed between the control and bio-nanocomposite films as revealed by the FESEM images. The semolina-based bioactive films exhibited distinctive antimicrobial activity against gram-negative food pathogens, namely Escherichia coli. Succinctly, regarding food packaging purposes, the findings of this study advocate the direct incorporation of ZnO-nr and nano-kaolin into semolina matrices to produce active biodegradable films.