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  The use of edible films to release antimicrobial constituents in food packaging is a form of active packaging. There are many studies about antimicrobial properties of spice extracts; however their application to edible films is limited. In this study chitosan-based edible films containing thyme and clove essential oils were prepared at 0.5, 1 and 1.5 percent v/v. Antibacterial properties of edible films were tested against five strains of Gram-positive and Gram-negative bacteria. Physical and mechanical properties of films including humidity content, water vapor permeability, tensile strength and elongation at break were measured. Films containing thyme essential oil showed larger inhibitory zones (p<0.05) compared to those of containing clove essential oil. Films were more effective against Gram-positive bacteria than Gram-negative ones. Incorporation of essential oils increased water vapor permeability of chitosan-based films. Incorporation of essential oils decreased tensile strength of films. Films containing thyme essential oil showed larger reduction in tensile strength property compared to those of containing clove essential oil.

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  Due to the environmental hazards of using plastic films, studies on the development of plant based films such as soy protein films, are receiving more attention.  In this research, edible films were prepared from soy protein isolate and the effect of glycerol as a plasticizer at three concentration levels of 0.4, 0.6 and 0.8 g/g of soy protein isolate on the properties of these films was investigated. Some Mechanical properties, i.e. tensile strength and extension, and physical properties, i.e. water vapor transmission rate, opacity, water adsorption and solubility were examined. Films prepared without glycerol were very brittle and could not be examined. Results showed that increasing the concentration of glycerol led to a significant (p<0.05) increase in extension rate and decrease in tensile strength of soy protein isolate films. Solubility percentage, water adsorption and water vapor transmission rate of the films were found to increase when the glycerol level increased.  Although glycerol addition reduced the opacity of the films, its concentration did not have a significant correlation with this parameter (p<0.05).

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The objectives of this study were to investigate the potential of faba bean protein isolate (FPI) in preparation of an edible film and to determine the effects of film forming solution pH and plasticizer concentration on film properties. So film samples were prepared in three different pH levels (7, 9 and 12) and plasticizer concentrations (40, 50 & 60% w/w protein isolate). Results showed that increasing of pH improved mechanical properties (tensile strength and elongation) and solubility of films but caused water vapor permeability (WVP) and lightness of films to decrease. Plasticizer concentration did not affect WVP over the studied range. Elongation and solubility of films increased and tensile strength decreased by increasing of plasticizer content of film forming solutions. The lowest WVP and the highest tensile strength was observed at pH 12 and 40% (w/w of FPI ) glycerol concentration.

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  Nowadays, edible films are commonly and increasingly used for covering food products, as a replacement for synthetic films. Their advantages are being edible, safe and functionally effective. Many researches have been being done in this regard. This article reviews fundamental and applied aspects of edible films in food industry including definitions, classifications, applications and common types of used materials.

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In this study two film-forming formulations were prepared. First one was prepared by slowly adding 5gr of sodium alginate & 45gr of dextrose monohydrate in 270ml of distilled water which constantly stirred. Second formulation was as the firs one, but we substituted dextrose monohydrate by maltodextrine and added 20gr glycerol in 210ml distilled water. 50cc film solutions were extended on the 30*40cm polexy glass plates which covered by polyethylene selofan. Films dried after 45h in 23±2˚c & RH50±5%. The dried film layers were immersed for 30" in second solution that was prepared by slowly adding 2.74gr of calcium choloride & 0.9gr of carboxy methylcellulose in 49ml of distilled water which constantly stirred. Film thickness was measured using a digital micrometer at a 0.001mm accuracy. Mechanical properties including tensile strength (TS) and elongation at break (E) were evaluated by a Instron Machin (Zwick, ModelZ 2.5). Results had no statistical significant differences between 2 film formulations. Physical properties including WVP (Water Vapor Permeability) & OTR (Oxygen Transformation Rate) were measured. WVP results had no statistical significant differences between 2 film formulations but OTR in second formulation had a significant decrease. Finally, by all aspects like decrease moisture loss, lipid & myoglobin oxidation, volatile compounds loss and volatile compounds absorb during storage, we recognize second film formulation as a suitable one.

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Being biodegradable, edible and efficient have caused edible films to be widely investigated and used as a good replacement for synthetic materials in packaging of food products. Coating confectionaries, fresh fruits and vegetables, some meat products, some dairy products, chocolate, snacks, breakfast cereals, fish and poultries, frozen products, dried and freeze dried products are from those food materials that are regularly coated by edible films. The efficiency of edible films depends on their quality parameters, the latter are principally affected by the type of film-producing materials as well as its method of preparation. This article reviews quality parameters of edible films, their test methods and principal production techniques.

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  In the recent years, interest in the use of biodegradable biopolymers for packaging applications has raised. One of the potential uses of these biopolymers is for production of active packaging containing antimicrobials. In this review manuscript, has presented some examples for applications of these packaging materials for different foods and then has mentioned the different kinds of antimicrobial agents that may be incorporated in their formulations. Many factors are involved in designing the antimicrobial packaging system. Most factors are closely related to the chemical characteristics of antimicrobial agents, the nature of the food and target microorganisms that all will be discussed in this paper.  

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  In this study, antimicrobial effects of the carboxymethyl celloluse (CMC) based-edible films containing 1-4% potassium sorbate (as a antimicrobial agent), were tested against Aspergillus flavus (PTCC 5004), Aspergillus parasiticus (PTCC 5286) and Aspergillus parasiticus (PTCC 5018) by using agar diffusion assay. The films containing 1 and 2 % potassium sorbate showed the inhibitory zone against first and second molds however, they were not effective against Aspergillus parasiticus (PTCC 5018) at these levels of antimicrobial compound. Maximum inhibition zone was observed in 3 and 4% potassium sorbate for all molds. Fresh pistachios were purchased from local market and immersed in aqueous filmogenic solutions of CMC with different concentrations of sorbate (0.25, 0.5 and 1%). In uncoated pistachios, molds counting, showed 2.02×10⁶ CFUg^-1 while in the coated samples there was no growth of any molds.

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Due to disadvantages of synthetic packaging materials such as migration into food, polluting of environment, difficulty of recovery, high costs of raw materials and production, also modifying properties of starch based edible film, in this study different kinds of edible films from starch and tragacanth (Iranian gum) will be formulated and their properties investigated.  In this regard, edible films formulated by mixing potato starch, tragacanth (1-5%), Glycerol plasticizer (10-40%) and sunflower oil (0-20%), then the film mechanical (tensile strength and elongation), optical, solubility and water vapor permeability (WVP) properties measured. The results showed that physical and mechanical properties of potato starch-based edible films were affected by the content of tragacanth, glycerol and sunflower oil. The tragacanth gum increased tensile strength and reduced chroma, while glycerol reduced tensile strength and increased elongation at break. Also, the sunflower oil decreased solubility and water vapor permeability and increased elongation. Finally, amounts of 2% tragacanth, 30% glycerol and 17% sunflower oil were determined as optimum points for production of starch based edible films with optimum properties.  

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Pistachio kernel Akbari variety cultivated at damghan coated by whey protein based edible film incorporated with zataria multiflura essential oil. Minimum inhibition concentration and minimum lethal concentration of zataria multiflora essential oil against Aspergilus flavus were determined by inspection of mould growth inhibition on culture surface by direct method. Different concentrations 100,500,1000,1500,2000,2500,3000,3500,4000,5000 and 5500 ppm of  zataria multiflura essential oil were used in edible coating composition of pistachio kernel for measuring extension inhibition of  inoculated disk growth including nine days mould culture in coated pistachio. Results shown that  in essential oil concentrations lower than 4000 ppm, A.flavus grown in samples. With increasing essential oil concentration, inoculated mould growth reduced significantly . Afterward inhibition of above mentioned concentrations of zataria multiflura essential oil in  pistachio kernel coated by  whey protein based edible film incorporated with different concentrations on production aflatoxins B1,B2,G1 and G2 were analysed  by high performance liquid chromatography (HPLC) ,results shown that concentrations higher than 4000ppm could inhibited aflatoxin production in pistachio kernel.  

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Protein rich legumes are suitable for the production of edible films and coatings. In this research,  pea protein isolate was obtained from defatted pea flour by alkaline extraction and acid precipitation. Then edible films were prepared from pea protein isolate. The effects of protein and glycerol concentrations on water vapor transmission rate (WVTR), mechanical properties, thickness, opacity and total color difference (ΔE) of the films were evaluated, using response surface methodology (RSM).  The results showed that WVTR, elongation, ΔE, thickness and opacity were increased, while tensile strength decreased by glycerol concentration. Increasing the concentration of protein increased tensile strength, opacity and ΔE, while decreased WVTR and elongation of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R² >0.87) and significant F values.

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Edible films and coatings are developed to improve quality and to extend shelf-life of food products. In this study, soy protein isolate was obtained from defatted soy flour by alkaline extraction and acid precipitation. Then edible films were prepared from soy protein isolate. The effects of protein concentrations and two plasticizers of glycerol and sorbitol on some physical and mechanical properties of the films were evaluated, using response surface methodology (RSM). The results showed that  tensile strength, opacity, thickness and water vapor transmission rate (WVTR) were increased, while elongation of the films decreased by protein concentration. Increasing the concentration of glycerol and sorbitol increased WVTR, elongation, total color difference (ΔE), thickness and opacity, while declined tensile strength of the films. The model developed by RSM for the physical and mechanical properties of the films had high coefficient of multiple determination (R² >0.87) and significant F values. The models suggested that the concentration of soy protein and the type and concentrations of the plasticizers are the most influential factors with significant effects on the properties of soy protein isolate films.

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In present study, the chemical (ash, protein, fat, minerals, and pH) and functional (ability in stabilizing emulsions and producing edible films) properties of the soluble and insoluble fractions of Persian gum were evaluated. The O/W emulsions were prepared using the soluble fraction at various concentrations vs. oil content.  In order to prepare edible films, the soluble and insoluble fractions as well as whole gum were used at constant concentration (3 w/v%) in the presence of glycerol ( up to 8 wt % based on the gum weight) at pH 8. According to the findings, the Persian gum was consisted of 70 and 30 wt% of insoluble and soluble fractions respectively; where their protein content was negligible (0.062 and 0.146 wt%). The emulsion E4 containing 2 w/v% of soluble fraction and 1 w/v% of oil had the maximum (~99% at room temperature) emulsifying stability index (ESI) up to 5 weeks which was even higher than gum Arabic as control. Moreover, these findings were proven by the optical density and particle size distribution data. In terms of filmability, our findings showed that the edible film containing 3 w/v% of soluble fraction and 4 w/w% of glycerol at pH 8 had the most acceptable characteristics regarding appearance and mechanical properties.

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The objective of this study was to investigate the effect of different glycerol concentrations (15, 30, 45, 60 & 75% w/w of methylcellulose) and film thickness (15, 30 & 60µm) on methylcellulose (MC) films water vapor permeability and mechanical properties. Finally, 15µm films containing 45% glycerol (the best conditions) were selected. Results showed the significant effect of glycerol concentration on films water vapor barrier and mechanical properties. Film thickness affected WVP and tensile strength but not elongation at break.  

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Edible films as natural, environmentally- friendly and renewable products, can be an appropriate alternative for petroleum-based packaging materials that are common today.  In this study, the effects of Sodium Caseinate (SC) edible coating on quality of rainbow trout (Oncorhynchus mykiss) during refrigerated storage (4±1˚^C) were investigated. Fish samples were treated with 8% Sodium Caseinate solution and stored in refrigerator for 20 days after drying the coating solution. The control and the coated fish samples were analyzed periodically each 4 days of storage time (0, 4, 8, 12, 16, 20 days) for chemical (PV, TBA, FFA, pH, TVB-N) and microbiological (total viable count and scycrophilic count) characteristics. The sodium caseinate coating reduced peroxide values (16.1±0.1 and 7.1±0.01 in control and SC, respectively) and during last days of storage, reduced bacterial count significantly (9.1±1 and 7.7±0.07 in control and SC, respectively) (P<0.05) in rainbow trout samples during the refrigerated storage.  

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The aim of this study was production of chitosan from chitin of local shrimp shell and comparison its qualitative properties with commercial chitosan which has been produced by crab shell. In the first step, the shells of Persian Gulf   shrimps were prepared and chitin was produced from them by demineralization, deproteinization and discoloration treatments. Then, chitosan was obtained by deacetylation of the chitin. Film samples were prepared by the chitosan and their thickness and water vapor permeability (WVP) were determined and compared with the commercial chitosan. Also, chemical composition (moisture, ash and protein), degree of deacetylation, water binding capacity, fat binding capacity and color of  the produced chitosan samples were determined and compared with the commercial chitosan. The results showed that the chitosan production yield was acceptable (%19.43). In view of the chemical properties, the produced chitosan had lower protein and ash impurites, lower degree of deacetylation, higher water binding capacity and higher fat binding capacity than the commercial chitosan. The prepared film samples of the produced chitosan showed lower water vapor permeability (WVP) than the commercial ones. Also, the produced chitosan had more color lightness than the commercial chitosan. Overall, it can be concluded that it is possible to produce suitable quality chitosan by shells and waste of local shrimp, therefore, the shrimp production and shrimp packaging factories of Iran can be proposed to produce chitosan.  

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This study investigates the effect of olive oil on the caseinate‐based films. Edible films based on caseinate (5% (w/v)) and glycerol (30% (w/w)) by varying olive oil concentrations (0, 10, 20 and 30% (w/w), were prepared by casting method films. The impact of the incorporation of olive oil into the film matrix was studied by investigating the physical and mechanical properties of films. Scanning electron microscopy (SEM) was also used in order to analyse films microstructure. Increasing the olive oil concentrationup to30%(w/w) decreased values for thickness and solubility from 0.050mm and 92.18% to 0.042mm and 61.84% respectively and caused the films to become opaque. Also addition of olive oil to caseinate emulsion significantly improved the WVP (upto9×10^-10g/s.m.pa)of prepared films, but lowered the mechanical properties. The results indicate that the structure and properties of caseinate edible films were modified and improved by the olive oil.

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There has been a renewed interest in edible films made of renewable and natural polymers such as protein, polysaccharide and lipids. Natural polymers derived from natural sources like food protein, offer the greatest opportunities because of their biodegradability and their ability to supplement nutritional value of foods. Faba bean is a valuable source of protein and is cultivated in large quantities in Iran. Therefore, in this study, we investigated the potential of faba bean protein isolate (FPI) as a new protein source for preparation of an edible film and determined the effects of film forming solution pH and plasticizer concentration on the film properties. Results showed that increasing the pH improved mechanical properties (tensile strength and elongation) and solubility of the films, but, caused the water vapor permeability (WVP) and lightness of the films to decrease. Plasticizer concentration did not affect WVP over the studied range. Elongation and solubility of the films increased and the tensile strength decreased by increasing plasticizer content of the film forming solutions. The lowest WVP and the highest tensile strength were observed at pH 12 and 40% (w/w of FPI) glycerol concentration.

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Salep composite films containing 0±30% (w/w)  oleic acid or stearic acid – were prepared through emulsification and their physical, mechanical, and barrier properties were evaluated and compared. Emulsified films were softer than pure films. Addition of the fatty acids to salep films significantly improved the WVP (P<0.05), but lowered the tensile strength. Stearic acid was more effective than oleic acid in reducing the WVP, but films with oleic acid showed better mechanical properties overall than those with stearic acid . Also the presence of fatty acids decreased solubility in water and caused the films to become opaque. On the other, fatty acids showed different effects on the elongation at break. This work showed that when taking all the studied variables into account, films formulated with oleic acid were found most suitable for various food applications.