Active Biodegradable Films Research Articles

Novel carboxymethyl cellulose-polyvinyl alcohol blend films stabilized by Pickering emulsion incorporation method

The aim of this study was to investigate the possibility of increasing the antimicrobial and antioxidant properties of biodegradable active films stabilized via Pickering emulsions. The blend films were prepared from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), emulsified with oleic acid (OL) and incorporated with rosemary essential oil (REO). Formation of Pickering emulsion was confirmed by scanning electron microscopy (SEM), optical microscopy, mean droplet size and emulsion stability. Morphological, optical, physical, mechanical, thermal, antifungal and antioxidant properties of the films incorporated with different concentrations of REO (0.5, 1.5 and 3%) were determined. The results showed an increase in UV absorbance and elongation at break but, a decrease in tensile strength and thermal stability of the films. Interestingly, films containing REO exhibited considerable antioxidant and antimicrobial properties. In vitro microbial tests exhibited 100% fungal inhibition against Penicillium digitatum in the films containing 3% REO. In addition, no fungal growth were observed after 60days of storage at 25°C in bread slices were stored with active films incorporated with 3% REO, could attributed to the slow and regular release of REO caused by Pickering emulsions. The results of this study suggest that Pickering emulsion is a very promising method, which significantly affects antioxidant and antimicrobial activities of the films.

Active biodegradable film with encapsulated anthocyanins: Effect on the quality attributes of extra-virgin olive oil during storage

The aim of this study was to verify the effectiveness of an active biodegradable film on the maintenance of extra-virgin olive oil (EVOO) quality attributes. Level of peroxides, acidity, K232, color, chlorophylls, and carotenoids were determined as parameters to verify the oil quality over storage period. Maltodextrin was used to encapsulate anthocyanins and was the major component in the films, which were used as pouches to pack the oil. The samples were stored at 40°C, exposed to fluorescent light, and monitored during 12 days. The film successfully maintained the quality of EVOO under the limits established by Codex Alimentarius for over 8 days (13.6 meq O2/kg of peroxides at the 8th day), while the oil packed in polypropylene pouches was degraded before the 4th day of storage (326.5 meq O2/kg). Therefore, the results demonstrated the effectiveness of the film on maintaining the quality of EVOO and its promising application as active packaging. Practical application Extra-virgin olive oil (EVOO) is an oxidation-sensitive product and has been shown to quickly deteriorate when stored under less than ideal conditions. The study brings a new packaging possibility to the commercialization of EVOO with longer shelf-life. The storage of extra-virgin olive oil in biodegradable pouches produced with anthocyanins could preserve EVOO from oxidation and consequently extent its shelf-life. The study proves the efficacy of an active biodegradable packaging on maintaining quality attributes of EVOO. The commercialization of EVOO in active biodegradable pouches could be an eco-friendly and sustainable way to bring health and practicality to consumers.

Functional Properties of Plasticized Bio-Based Poly(Lactic Acid)_Poly(Hydroxybutyrate) (PLA_PHB) Films for Active Food Packaging

Fully bio-based and biodegradable active films based on poly(lactic acid) (PLA) blended with poly(3-hydroxybutyrate) (PHB) and incorporating lactic acid oligomers (OLA) as plasticizers and carvacrol as active agent were extruded and fully characterized in their functional properties for antimicrobial active packaging. PLA_PHB films showed good barrier to water vapor, while the resistance to oxygen diffusion decreased with the addition of OLA and carvacrol. Their overall migration in aqueous food simulant was determined and no significant changes were observed by the addition of carvacrol and OLA to the PLA_PHB formulations. However, the effect of both additives in fatty food simulant can be considered a positive feature for the potential protection of foodstuff with high fat content. Moreover, the antioxidant and antimicrobial activities of the proposed formulations increased by the presence of carvacrol, with enhanced activity against Staphylococcus aureus if compared to Escherichia coli at short and long incubation times. These results underlined the specific antimicrobial properties of these bio-films suggesting their applicability in active food packaging.

Valorization of food-grade industrial waste in the obtaining active biodegradable films for packaging

The use of industrial waste as a material for the development of biodegradable and active packaging is economical and environmentally appealing. The aim of this study was to develop and characterize biodegradable and antioxidant packaging using wastes from the production of gelatin capsules and ingredients obtained from waste of juice blueberry processing. Fiber and ethanolic extract, obtained from the blueberry waste, were used at different weights in film formulation based on gelatin capsules waste: FF series with fiber concentration of 0.05, 0.10 and 0.15g/mL; FE series with 30, 40 and 50mL extract; and a control formulation. The morphological, mechanical, barrier, optical, thermal and antioxidant (AA) properties of the films were analyzed. The results suggest that the addition of fiber promoted a decrease in tensile strength from 2.51 (control formulation) to 1.51MPa (0.15g fiber/mL) and an increase in water vapor permeability from 59 (control formulation) to 99 (0.15g fiber/mL) h gmm/m2kPa. However, the addition of fiber also provided a significant increase in the UV light barrier at 500nm (+0.16%) in AA films (+67.36%) and was effective in reducing lipid oxidation of sunflower oil. Films with added extract did not exhibit altered mechanical or barrier properties compared with the control formulation and were effective as a barrier to UV light. Furthermore, these films exhibited very stable antioxidant capacity for 28 days. The use of gelatin capsules and blueberry juice processing waste are promising for the development of environmental friendly packaging to be used in food preservation.

Microencapsulation of Anthocyanins with Different Wall Materials and Its Application in Active Biodegradable Films

Wine grape pomace, a by-product known for its high polyphenolic content, was used as a source of anthocyanins in the acquisition of active biodegradable films, which were produced with anthocyanins encapsulated with different wall materials endowed with film-forming properties. Gum arabic and maltodextrin were used in different proportions during the encapsulation process, and the anthocyanin contents of the powders obtained were quantified by high-efficiency liquid chromatography (HPLC), resulting in up to 91.5 % retention. The antioxidant properties, solubility, and color stability of powders were analyzed. Because the microcapsules were added in the highest proportion, it was considered the major component in the formation of films. Microcapsules produced with gum arabic showed higher antioxidant activity as compared to microcapsules produced with maltodextrin. Nevertheless, based on a comparison of the films obtained in this study, the films made with anthocyanins encapsulated with maltodextrin showed better mechanical properties and higher protective effect on oil oxidation, which makes maltodextrin a promising material enabling the formation of films with satisfactory mechanical properties endowed with anthocyanins.

Antimicrobial films based on cellulose-derived hydrocolloids. A synergetic effect of host–guest interactions on quality and functionality

A series of active films based on biodegradable cellulose-derived hydrocolloids capable of controlled release of antimicrobial propionic acid (PA) was prepared.β-Cyclodextrin (β-CD), usually used for encapsulation of lipophilic compounds, was utilized in this research to host the hydrophilic PA. It was found that addition of β-CD to the film forming solutions notably enhanced the hydrocolloid matrix capacity and resulted in up to a ten-fold increase in the amount of uploaded PA. In addition, β-CD resulted in a two-fold prolongation of the effective PA release duration. β-CD alone caused undesired effects on the physical, mechanical and morphological properties of the hydrocolloid films. Interestingly, when β-CD was combined with PA in the film formulation, its undesired effects were significantly subdued. The antifungal activity of the films was demonstrated on fresh harvested wheat grains. Films containing β-CD and PA were found to be effective in preventing fungal growth on wheat grains. Thus, incorporation of β-CD and PA in hydrocolloids matrices demonstrated a synergetic effect and resulted in the formation of biodegradable active films that benefit good physical and mechanical properties, high active agent content, prolonged release ability and effective antimicrobial properties.

Acetate cellulose film with bacteriophages for potential antimicrobial use in food packaging

The search for new technologies that guarantee the safety and quality of food has intensified, as has concern for consumer health, leading to the adoption of measures to reduce food-related risks. The purpose of the study was to evaluate the efficiency of active biodegradable films incorporated with bacteriophage for future application in packaging materials. Cellulose acetate films incorporated with solution of bacteriophages showed antimicrobial activity against Salmonella Typhimurium ATCC 14028 displayed the formation of inhibition zones in Muller-Hinton agar, and a growth curve, using the diffusion method in liquid medium. There was an increase in the lag phase and slower growth of microorganisms in the environment containing bacteriophages with the films, compared to control. The mechanical and physical properties of films, such as thickness, elongation and puncture resistance showed no significant effects. However, tensile resistance was different between control and treatments. The addition of bacteriophage altered the film surface, as observed by atomic force microscopy. There was a higher porosity of the films containing the bacteriophage solution compared to control. The acetate films may be incorporated with bacteriophages, since the physical and mechanical properties of the films were not changed drastically and there was an effect of the antimicrobial film.

Development and characterization of biodegradable chitosan films containing two essential oils

Active biodegradable films from chitosan containing 10% to 30% w/w of citronella essential oil (CEO) and cedarwood oil (CWO) were developed by casting and solvent-evaporation method, and their physical, mechanical and thermal properties were investigated. Possible interactions between the chitosan chains and the essential oils were confirmed using Fourier-transform infrared spectroscopy (FTIR). Various amounts of CEO or CWO had significant effects on the films’ mechanical properties, with the exception of 10% of CEO, which did not significantly affect the tensile strength of the films. The incorporation of the two tested oils provoked a remarkable reduction in the water-vapor permeability properties, with a decrease of about 63% when 30% CEO was added in chitosan films. Thermogravimetric analysis showed that degradation temperatures of the films containing CEO and CWO improved only slightly in comparison to control films without essential oils. FTIR spectra analysis provided some insights on the possible interactions between chitosan and the two essential oils used. This study suggests that active films can be developed by including CEO and CWO in a chitosan matrix. Such films can provide new formulation options for packaging industries in developing active packaging with potential food-technology applications.

Ferulic acid-coupled chitosan: Thermal stability and utilization as an antioxidant for biodegradable active packaging film

The aim of the present research was to study the thermal stability of ferulic acid after coupling onto chitosan, and the possibility of using ferulic acid-coupled chitosan (FA-CTS) as an antioxidant for biodegradable active packaging film. FA-CTS was incorporated into biodegradable film via a two-step process, i.e. compounding extrusion at temperatures up to 150°C followed by blown film extrusion at temperatures up to 175°C. Although incorporation of FA-CTS with a content of 0.02–0.16% (w/w) caused decreased water vapor barrier property and reduced extensibility, the biodegradable films possessed improved oxygen barrier property and antioxidant activity. Radical scavenging activity and reducing power of film containing FA-CTS were higher than those of film containing naked ferulic acid, by about 254% and 94%, respectively. Tensile strength and rigidity of the films were not significantly affected by the addition of FA-CTS with a content of 0.02–0.08% (w/w). The above results suggested that FA-CTS could potentially be used as an antioxidant for active packaging film.

Release of cinnamon essential oil from polysaccharide bilayer films and its use for microbial growth inhibition in chilled shrimps

Active biodegradable bilayer films based on agar and sodium alginate were developed by the incorporation of cinnamon essential oil in the upper layer. The release of both cinnamaldehyde and eugenol from the agar and alginate bilayer films into water at 4 °C and 20 °C did not increase significantly from 9 h onwards, and consequently increasing values of antioxidant activity measured by ferric reducing ability and radical scavenging capacity were observed until 9 h in both cases. Agar bilayer films showed an antimicrobial activity approximately 1.4-fold higher than the alginate bilayer films, although both of them were effective against all the microorganisms tested in this study, especially against Photobacterium phosphoreum. Both agar and alginate bilayer films allowed to reduce significantly the microbial growth, including the pathogenic bacteria Listeria monocytogenes, in peeled shrimps during the chilled storage without a negative impact on the organoleptic properties.

Release of volatile compounds and biodegradability of active soy protein lignin blend films with added citronella essential oil

Active biodegradable bilayer films based on soy protein isolate, lignin and formaldehyde were developed. These films showed high water resistance and malleability, making them suitable for use in extreme environmental conditions. The presence of lignin in the formulation provided greater protection against light, especially UV. With the addition of 3% w/w citronella essential oil, the films showed good antifungal activity against Fusarium oxysporum pathogen microorganism in bananas. When the bananas were covered by the films during storage, there was a noticeable reduction in total aerobic mesophiles and moulds and yeasts. As the films aged (1, 3, 6 months), in both controlled and environmental conditions, the main active compounds in the citronella essential oil, citronellal and geraniol, were progressively released from the film matrix, citronellal more than geraniol. Over 30 days of soil degradation, the films lost around 30% of weight irrespective of the conditioning time.

Characterization of soluble soybean polysaccharide film incorporated essential oil intended for food packaging

This study examines the development of new bio-active polysaccharide-based bioplastics through casting and solvent-evaporation. Soluble soybean polysaccharide (SSPS) films incorporated with Zataria multiflora Boiss (ZEO) or Mentha pulegium (MEO) at various concentrations were prepared and characterized. The presence of ZEO and MEO improved polysaccharide interactions, reducing the films’ water solubility and water vapor barrier properties, but did not markedly modify their moisture content or thickness. Differing amounts of ZEO or MEO had no significant effect on mechanical behavior, with the exception of 3% oil concentration, which decreased tensile strength and significantly increased elongation at break. DMTA curves revealed a single Tg, which may indicate the compatibility of essential oil and SSPS. The electron scanning micrograph for the composite film was homogeneous, without signs of phase separation between the components. These results suggest that ZEO and MEO can potentially be directly incorporated into SSPS to prepare active biodegradable films for food-packaging applications.

Encapsulation and controlled release of antifungal propionic acid utilizing biodegradable active films based on natural polymers

Propionic acid represents a powerful and volatile antifungal agent widely used for protection of dry agricultural products such as grain and cereals. To improve its effectiveness and safety, we incorporated propionic acid into an active film matrix. A series of biodegradable antifungal films loaded with propionic acid and based on natural polymers chitosan and gelatin were prepared. The structural and functional properties of the prepared active films were studied utilizing various spectroscopic, microscopic and analytical techniques. The release of propionic acid from the active films was examined at varying temperatures and humidity conditions. An edible oligosaccharide, β-cyclodextrin, was added during film preparation to form hydrogen bond interactions with propionic acid. It was found that β-cyclodextrin significantly increases loading capacity of the film matrix resulting in high amounts of encapsulated propionic acid. It was found that encapsulation into active film matrix allows for the control and therefore for the inhibition of the propionic acid release rate, thus enabling the maintenance of an effective concentration of the antimicrobial agent for prolonged periods.

Active biodegradable films produced with blends of rice flour and poly(butylene adipate co-terephthalate): Effect of potassium sorbate on film characteristics

The objective of work was to produce and characterize biodegradable films from rice flour, poly(butylene adipate co-terephthalate) (PBAT), glycerol and potassium sorbate, for application as active packaging for fresh lasagna pasta. The films were evaluated with respect to their optical, water vapor barrier, mechanical and microstructural properties. The mechanical properties and microstructure were evaluated after use as packaging material for fresh pasta for 45days at 7°C. The blends of rice flour, PBAT, glycerol and potassium sorbate showed good processability and allowed for the pilot scale production of films by blow extrusion process. The addition of 1 to 5% potassium sorbate as plasticizer agent of films in place of glycerol did not alter the film mechanical properties and a sorbate concentration greater or equal than 3% reduced the opacity, although increasing the water vapor permeability. The films could be used as active packaging for fresh food pasta, since they remained integral and easy to handle after application. The rice flour was shown to be an excellent material for the formulation of biodegradable films, since it is a low-cost raw material from a renewable source. The addition of potassium sorbate did not affect the extrusion process, and could be used in the production of packaging for use with foods.

Release of active compounds from agar and agar–gelatin films with green tea extract

Active biodegradable films based on agar and agar–fish gelatin were developed by the incorporation of green tea aqueous extract to the film forming solution. The effect of the partial replacement of agar by fish skin gelatin as well as the addition of the green tea extract on the physical properties of the resultant films was evaluated. Special attention was given to the release of antioxidant and antimicrobial compounds from the agar film matrices with and without gelatin. Agar–gelatin films were less resistant and more deformable than agar films. The inclusion of green tea extract decreased tensile strength and elongation at break in both agar and agar–gelatin films. Water vapour permeability and water resistance was not affected either by the replacement of agar by gelatin or the addition of green tea extract, but the water solubility noticeably increased in the films containing green tea extract. The presence of gelatin in the agar–green tea matrix film hindered the release of total phenolic compounds, catechins and flavonols in water. As a consequence, the antioxidant power released by the films was lower in the case of films containing gelatin. However, the antimicrobial activity of the films was not affected by the presence of gelatin.

Antimicrobial Activity of Chitosan Films Enriched with Essential Oils

ABSTRACT: Antimicrobial and physicochemical properties of chitosan films and chitosan films enriched with essential oils (EO) were determined in vitro and on processed meat. Antimicrobial effects of pure EO of anise, basil, coriander, and oregano, and of chitosan-essential oil films against Listeria monocytogenes and Escheri-chia coli O157:H7 were determined by an agar diffusion test. The antibacterial effects of the EO were similar when applied alone or incorporated in the films. The intensity of antimicrobial efficacy was in the following order: oregano > > coriander > basil > anise. The chitosan films and chitosan-oregano EO films were applied on inoculated bologna samples and stored 5 d at 10 °C. Pure chitosan films reduced L. monocytogenes by 2 logs, whereas the films with 1% and 2% oregano EO decreased the numbers of L. monocytogenes by 3.6 to 4 logs and E. coli by 3 logs. Pure chitosan films were 89 μm thick, whereas addition of 1% and 2% oregano EO increased thickness to 220 and 318 μm, respectively. During application on bologna discs, the films absorbed moisture, resulting in the final thickness of 143, 242, and 333 μm, respectively. Addition of oregano essential oil into the chitosan films decreased water vapor permeability, puncture and tensile strength, but increased elasticity of the films. The films have the potential to be used as active biodegradable films with strong antimicrobial effects.