Solubility and mechanical properties of heat-cured whey protein-based edible films compared with that of collagen and natural casings

Water solubility, tensile strength (TS), wet strength (WS) and elongation at break (%E) of whey protein isolate (WPI) films were compared to that of collagen films and natural casings. Increase in heat-curing temperature and time caused decreased ( P <  0.001) water solubility and increased TS and WS of the films. Heat-cured WPI films with similar properties (solubility, TS, WS and %E) to collagen films were obtained by optimizing heat-curing conditions. Overall, natural casings had lower solubility, TS and %E but higher WS than collagen and heat-cured WPI films. Heat-cured WPI films have the potential as an alternative to collagen films and casings.     

Antimicrobial Effects of Lactoferrin, Lysozyme, and the Lactoperoxidase System and Edible Whey Protein Films Incorporating the Lactoperoxidase System Against Salmonella enterica and Escherichia coli O157:H7

Lactoferrin (LF), lysozyme (LZ), the lactoperoxidase system (LPOS), and edible whey protein isolate (WPI) films incorporating LPOS were studied for inhibition of Salmonella enterica and Escherichia coli O157:H7. Antimicrobial effects of LF (5 to 40 mg/mL), LZ (1 to 20 mg/mL), and LPOS (0.5% to 5.0% [w/v] [0.03–.25 g/g, dry basis]) were examined by measuring turbidity of antimicrobial‐containing media after inoculation and by examining cell inhibition by WPI films incorporating LPOS (LPOS‐WPI films) on an agar recovery medium. Elastic modulus (EM), tensile strength (TS), percent elongation (%E), oxygen permeability (OP), and Hunter L, a and b of WPI films incorporating 0.03 to 0.25 g/g of LPOS were compared with those of plain WPI films without LPOS. The growth of S. enterica and E. coli O157:H7 (4 log colony‐forming units [CFU]/mL) in tryptic soy broth (TSB) was not prevented by LF at ≥20 and ≥40 mg/mL, respectively. S. enterica and E. coli O157:H7 in TSB were not inhibited by LZ at ≥ 6 and ≥ 20 mg/mL, respectively. LPOS at concentrations of 2.75% (w/v) and 1.0% (w/v) reduced S. enterica and E. coli O157:H7 to below the limit of detection (1 CFU/mL) in TSB, respectively. LPOS‐WPI films (0.15 g/g) completely inhibited S. enterica and E. coli O157:H7 (4 log CFU/cm²), inoculated either onto agar before placing the film disc or onto top of the film disc. Incorporation of 0.25 g/g of LPOS decreased EM, TS, and %E. The oxygen barrier property of WPI films was improved with the incorporation of LPOS at 0.15 to 0.25 g/g.     

Thermal Properties, Heat Sealability and Seal Attributes of Whey Protein Isolate/ Lipid Emulsion Edible Films

ABSTRACT: From 5% w/v whey protein isolate (WPI), whey protein/lipid emulsion edible films were produced that were sorbitol- or glycerol-plasticized, containing butterfat (0.2% w/v) or candelilla wax (0.8% w/v). Thermal properties of the films determined by Differential Scanning Calorimetry (DSC) showed onset temperatures (To) of 126 to 127 °C for sorbitol- and 108 to 122 °C for glycerol-plasticized films. To values were used as the basis for heat sealing temperatures. Temperature (110, 120, 130 °C), pressure (296,445 kPa), and dwell time (1,3 s) affected seal strength. Optimum heat sealing temperature was 130 °C for sorbitol- and 110 °C for glycerol-plasticized films. All films were heat sealable with an impulse heat-sealer. Electron Spectroscopy for Chemical Analysis (ESCA) of the surfaces of both sealed and unsealed films showed increase in hydrogen and covalent bonds involving C-O-H and N-C, which may be the main forces responsible for the sealed joint formation of the films.     

Whey protein isolate-based edible films as affected by protein concentration,glycerol ratio and pullulan addition in film formation

Edible films were prepared from whey protein isolate (WPI), and characterized in order to select a best combination of protein concentration and glycerol (Gly) ratio. 5%, 7% and 9% (w/v) WPI were used at three WPI:Gly ratios (3.6:1; 3:1; and 2:1). 5% WPI with a 3.6:1 WPI:Gly ratio showed the best combination with factors considered being thickness and water vapor permeability (WVP), while the 9% WPI with 3.6:1 WPI:Gly showed the best result as seen from the oxygen permeability (OP). Further studies were conducted by adding pullulan (PUL) at different WPI:PUL ratios (1:0; 1:1; 2:1; 3:1; 4:1; 5:1; 6:1; 8:1; 10:1) to a selected film in order to investigate the effect of pullulan on thickness, OP, WVP, moisture content (MC), film solubility (FS) and morphology using scanning electron microscopy (SEM). WPI–PUL film had a good appearance and 1:1 WPI:PUL resulted in films with greatest values of OP, WVP, MC, FS, and transmittance. The SEM micrographs showed many pinholes and a favorable structure for the low barrier ability. However, addition of PUL at low concentration was good enough to significantly modify these properties, hence improving the potential characteristics of WPI-based films for food applications.     

Formation Conditions, Water-vapor Permeability, and Solubility of Compression-molded Whey Protein Films

ABSTRACT: Films based on whey protein isolate (WPI) were formed using compression molding. Compression molded films could be formed using 30% to 50% moisture content or glycerol content WPI at 104 °C to 160 °C for 2 min. Films made from water-WPI mixtures were brittle and insoluble and had water-vapor permeability values independent of starting water-WPI mixture moisture content, molding temperature, or molding pressure. Gly-WPI films produced at 104 °C were flexible and partially soluble. Gly-WPI films produced at 140 °C were also flexible but nearly insoluble. Glycerol content and molding temperature and pressure had little effect on water-vapor permeability values of Gly-WPI films over the range of conditions studied.     

Rheology and Oxidative Stability of Whey Protein Isolate-Stabilized Menhaden Oil-in-Water Emulsions as a Function of Heat Treatment

ABSTRACT:  Menhaden oil-in-water emulsions (20%, v/v) were stabilized by 2 wt% whey protein isolate (WPI) with 0.2 wt% xanthan gum (XG) in the presence of 10 mM CaCl₂ and 200 μM EDTA at pH 7. Droplet size, lipid oxidation, and rheological properties of the emulsions were investigated as a function of heating temperature and time. During heating, droplet size reached a maximum at 70 °C and then decreased at 90 °C, which can be attributed to both heating effect on increased hydrophobic attractions and the influence of CaCl₂ on decreased electrostatic repulsions. Combination of effects of EDTA and heat treatment contributed to oxidative stability of the heated emulsions. The rheological data indicate that the WPI/XG-stabilized emulsions undergo a state transition from being viscous like to an elastic like upon substantial thermal treatment. Heating below 70 °C or for less than 10 min at 70 °C favors droplet aggregation while heating at 90 °C or for 15 min or longer at 70 °C facilitates WPI adsorption and rearrangement. WPI adsorption leads to the formation of protein network around the droplet surface, which promotes oxidative stability of menhaden oil. Heating also aggravates thermodynamic incompatibility between XG and WPI, which contributes to droplet aggregation and the accumulation of more WPI around the droplet surfaces as well.     

Comparative effect of thermal treatment on the physicochemical properties of whey and egg white protein foams

The optimization of the functionalities of commercial protein ingredients still constitutes a key objective of the food industry. Our aim was therefore to compare the effect of thermal treatments applied in typical industrial conditions on the foaming properties of whey protein isolate (WPI) and egg white proteins (EWP): EWP was pasteurized in dry state from 1 to 5 days and from 60 °C to 80 °C, while WPI was heat-treated between 80 °C and 100 °C under dynamic conditions using a tubular heat exchanger. Typical protein concentrations of the food industry were also used, 2% (w/v) WPI and 10% (w/v) EWP at pH 7, which provided solutions of similar viscosity. Consequently, WPI exhibited a higher foamability than EWP. For WPI, heat treatment induced a slight decrease of overrun when temperature was above 90 °C, i.e. when aggregation reduced too considerably the amount of monomers that played the key role on foam formation; conversely, it increased foamability for EWP due to the lower aggregation degree resulting from dry heating compared to heat-treated WPI solutions. As expected, thermal treatments improved significantly the stability of WPI and EWP foams, but stability always passed through a maximum as a function of the intensity of heat treatment. In both cases, optimum conditions for foam stability that did not impair foamability corresponded to about 20% soluble protein aggregates. A key discrepancy was finally that the dry heat treatment of EWP provided softer foams, despite more rigid than the WPI-based foams, whereas dynamically heat-treated WPI gave firmer foams than native proteins.     

Foams Prepared from Whey Protein Isolate and Egg White Protein: 2. Changes Associated with Angel Food Cake Functionality

ABSTRACT:  The effects of sucrose on the physical properties and thermal stability of foams prepared from 10% (w/v) protein solutions of whey protein isolate (WPI), egg white protein (EWP), and their combinations (WPI/EWP) were investigated in wet foams and angel food cakes. Incorporation of 12.8 (w/v) sucrose increased EWP foam stability (drainage 1/2 life) but had little effect on the stability of WPI and WPI/EWP foams. Increased stability was not due to viscosity alone. Sucrose increased interfacial elasticity ( E  ') of EWP and decreased E' of WPI and WPI/EWP combinations, suggesting that altered interfacial properties increased stability in EWP foams. Although 25% WPI/75% EWP cakes had similar volumes as EWP cakes, cakes containing WPI had larger air cells. Changes during heating showed that EWP foams had network formation starting at 45 °C, which was not observed in WPI and WPI/EWP foams. Moreover, in batters, which are foams with additional sugar and flour, a stable foam network was observed from 25 to 85 °C for batters made from EWP foams. Batters containing WPI or WPI/EWP mixtures showed signs of destabilization starting at 25 °C. These results show that sucrose greatly improved the stability of wet EWP foams and that EWP foams form network structures that remain stable during heating. In contrast, sucrose had minimal effects on stability of WPI and WPI/EWP wet foams, and batters containing these foams showed destabilization prior to heating. Therefore, destabilization processes occurring in the wet foams and during baking account for differences in angel food cake quality.     

Survival in food systems of Lactobacillus rhamnosus R011 microentrapped in whey protein gel particles

ABSTRACT:  The aim of this study was to investigate the effect of whey protein isolate (WPI) gel microentrapment on the viability of Lactobacillus rhamnosus R011 during the production and storage of biscuits, frozen cranberry juice, and vegetable juice. Viability of microentrapped (ME) cells was compared to free cells freeze-dried in a milk-based protective solution as well as in a WPI-based solution (ungelled). During the production of biscuits and their storage for 2 wk at 23 °C, the highest stability was obtained with the cells ME in WPI gel particles. However, free cells prepared in the milk-based matrix were those that maintained the highest viability during storage of vegetable juice as well as during freezing and storage of cranberry juice. The culture prepared in a WPI-based solution had the highest drops in viable counts following the heating process of biscuits as well as during storage of vegetable juice and freezing and storage of cranberry juice. Although the WPI-based solution was not efficient in protecting free cells, it is concluded that the process of microentrapment in WPI can help in protecting the freeze-dried cells against subsequent acidic and alkaline pH conditions as well as heating and freezing of food products.     

Water vapour permeability,thermal and wetting properties of whey protein isolate based edible films

This study deals with the effect of whey protein isolate (WPI) and glycerol (GLY) used as a plasticizer on some physical properties of cast whey protein isolate (WPI) films. Films were prepared from heated (80 °C for 30 min) aqueous solutions of WPI at 7, 8, 9 and 10% (w/w), GLY (40%, w/w, of WPI) and WPI at 8% (w/w), GLY (30, 40, and 60%, w/w, of WPI). For all types of films, water vapour permeability for four relative humidity differentials (30–100%, 30–84%, 30–75%, and 30–53%), surface and thermal properties were measured. Varying the proportion of WPI and GLY in edible films had some effect on water vapour permeability, wetting and thermal properties of WPI films. A cumulative effect of both glycerol and protein content was observed on the water vapour permeability increase. Indeed film barrier properties are much better for the lowest WPI (7%) and GLY (40%) contents. GLY increases the degradation temperature and favours film surface wettability whereas protein content did not affects thermal properties of films.     

Temperature-Sensitive Microcapsules Containing Lactoferrin and Their Action Against Carnobacterium viridans on Bologna

ABSTRACT:  Lactoferrin (LF) was encapsulated in 2 types of emulsion to protect it from contact with agents like divalent cations, which interfere with its antimicrobial activity. First, paste-like microcapsules were prepared as water-in-oil (W₁/O) emulsions from mixtures of 20% w/v LF in distilled water, 20% w/v LF in 3% w/v sodium lactate or in 20 mM sodium bicarbonate, which were emulsified with an oil mixture of 22% butter fat plus 78% corn oil and 0.1% polyglycerol polyricinoleate. Second, freeze-dried double emulsion (W₁/O/W₂), powdered microcapsules were produced following emulsification of paste-like microcapsules in an external aqueous phase (W₂) consisting of a denatured whey protein isolate (WPI) solution. The release of LF from the W₁/O microcapsules was dependent on temperature and NaCl concentration. LF was not released from the W₁/O emulsion at <5.5 °C. Its release was greater from W₁/O microcapsules when suspended in 5% aqueous NaCl than in water at ≥10 °C, whereas LF release from freeze-dried microcapsules was not controlled by temperature change. Paste-like microcapsules were incorporated in edible WPI packaging film to test the antimicrobial activity of LF against a meat spoilage organism Carnobacterium viridans . The film was applied to the surface of bologna after its inoculation with the organism and stored under vacuum at 4 or 10 °C for 28 d. The growth of C. viridans was delayed at both temperatures and microencapsulated LF had greater antimicrobial activity than when unencapsulated. The temperature-sensitive property of the W₁/O microcapsules was reduced when they were incorporated into a WPI film.     

Process Lethality Prediction for Escherichia coli O157:H7 in Raw Franks During Cooking and Fully Cooked Franks During Post-cook Pasteurization

ABSTRACT: Thermal inactivation D (decimal reduction time at a certain heating temperature) values of Escherichia coli O157:H7 at 55 °C to 70 °C were 21.36 to 0.031 min in raw franks and 24.91 to 0.038 min in fully cooked franks. Although statistically significant differences were found on the D values of E. coli O157:H7 between raw and fully cooked franks, the z value of E. coli O157:H7 in raw franks (5.07 °C) and fully cooked franks (5.08 °C) was not significantly different. The obtained D and z values were used to validate the process lethality of the pathogen in the raw franks that were processed according to a multistage cooking/cooling schedule or in the fully cooked franks that were pasteurized in-packages via steam. In this study, the calculated process lethality for both the cooking (process lethality = 254 min) and post-cook pasteurization (process lethality = 39 min) processes was far greater than the processing time that was needed for achieving a 7D reduction of E. coli O157:H7 during cooking and post-cook pasteurization of the franks.     

Thermal transitions and extrusion of glycerol-plasticized whey protein mixtures

ABSTRACT:  The effects of glycerol and moisture contents on the thermal transitions of whey protein isolate (WPI) powder–glycerol–water mixtures were studied. Mixtures with ratios of 100:0, 70:30, 60:40, and 50:50 WPI:glycerol on a dry basis (db) were preconditioned to 0.34 ± 0.01 (25.4 ± 0.4 °C) and 0.48 ± 0.02 (25.9 ± 2.2 °C) water activity. Differential scanning calorimetry (DSC) showed the existence of an endothermic peak starting at 148.3 ± 0.7 °C for 100% WPI preconditioned to a water activity of 0.34 ± 0.01. The onset temperature of this peak decreased with addition and increase of glycerol content, as well as with the increase in water activity from 0.34 ± 0.01 to 0.48 ± 0.02. An additional endothermic transition, important for extruding the mixtures into flexible sheets, occurred in mixtures containing 50% glycerol db, preconditioned to 0.48 ± 0.02 water activity. The onset temperature of the peak was 146 ± 2.0 °C. Whey protein-based sheets containing 45.8%, 48.8%, and 51.9% glycerol db were obtained using a Haake–Leistritz corotating twin-screw extruder. All samples were obtained at a screw speed of 250 rpm and a final barrel-temperature profile of 20, 20, 20, 80, 110, and 130 °C. Melt temperature at the time of sheet formation was 143 to 150 °C. Average thickness of the sheets was 1.31 ± 0.02 mm. Samples with 45.8% glycerol db had significantly higher tensile strength (TS) than samples with higher glycerol contents. Also, as glycerol concentration increased, sheet elastic modulus (EM) decreased significantly ( P ≤ 0.05). Extrusion of whey protein-based sheets is an important step toward extrusion of thinner edible films for food wraps, layers, or pouches.     

Whey protein-okra polysaccharide fraction blend edible films: tensile properties, water vapor permeability and oxygen permeability

BACKGROUND: A hot‐buffer‐soluble‐solid fraction (HBSS) and an alkaline‐soluble‐solid fraction (ASS) of okra polysaccharides (OKP) were obtained using sequential extraction. These fractions were combined with whey protein isolate (WPI) and glycerol (Gly) plasticizer to form blend edible films. Effects of OKP fraction and content on tensile properties, water vapor permeability (WVP) and oxygen permeability (OP) were determined. RESULTS: HBSS film had significantly higher percent elongation (%E) and lower elastic modulus (EM), WVP and OP than ASS film. Increasing HBSS or ASS content in blend films with WPI significantly reduced film tensile strength and EM and increased film %E and WVP. OP values for WPI–HBSS blend films were significantly lower than OP for WPI or HBSS film. WPI–HBSS and WPI–ASS blend films had lower WVP and OP than WPI films with equivalent tensile properties. CONCLUSIONS: WPI–HBSS blend films have higher WVP and lower OP than WPI film or HBSS film, indicating unique interactions between WPI and HBSS. Compared to WPI film, WPI–HBSS blend films have improved flexibility, stretchability and oxygen barrier. Different HBSS and ASS compositions and structures are responsible for property differences between HBSS and ASS films and between WPI–HBSS and WPI–ASS blend films. Copyright © 2010 Society of Chemical Industry     

Whey protein film with oxygen scavenging function by incorporation of ascorbic acid

Residual O(2) in a package headspace can be removed by an O(2)-absorbing sachet, which can be harmful if swallowed by the consumer, or by a chemically-active plastic packaging film, which is difficult to recycle. An edible, O(2)-absorbing film would avoid these disadvantages. The objective of our research was to assess the O(2)-scavenging potential of an edible whey protein isolate (WPI) film incorporating ascorbic acid (AA). AA at 0.05, 0.1, or 0.2 M was added to 5% (w/w) heat-denatured WPI film-forming solutions with WPI : glycerol (Gly) ratio of 1 : 1.00, 1 : 0.80, or 1 : 0.67. The pH of solutions was then adjusted to 3.5 (below pK(a1) of AA), to stabilize AA against oxidation, before film casting. The mechanical properties, O(2) permeabilities, and thermal transitions of films were measured. Activation of the O(2)-scavenging function of the AA-incorporated films was accomplished by adjustment of the films to pH ≥ 7. O(2)-scavenging ability of AA-incorporated WPI films was determined by measuring residual O(2) in the headspace of a high-barrier container. Incorporation of AA into WPI film decreased film tensile strength and further reduced O(2) permeability at each WPI : Gly ratio. AA-containing films adjusted to pH ≥ 7 demonstrated O(2) absorption proportional to AA content, consistent with theoretical O(2)-scavenging capacity. Thermal transition measurements indicated that AA was involved in WPI structural modification and decreased the degradation temperature of WPI-based film. The demonstrated O(2)-scavenging function, improved O(2) barrier and acceptable mechanical properties of AA-incorporated films indicate potential commercial usefulness. PRACTICAL APPLICATION: Ascorbic acid-incorporated whey protein film with oxygen scavenging function can be used to extend shelf lives of a wide variety of oxygen-sensitive products by eliminating headspace oxygen as well as oxygen permeating through the packaging wall over time. Edible oxygen-scavenger film has the advantages of avoiding both accidental consumption and nonrecyclability of conventional oxygen scavenger systems.     

The Gloss of Edible Coatings as Affected by Surfactants, Lipids, Relative Humidity, and Time

ABSTRACT: Water-based whey protein isolate (WPI) coatings had the same gloss as shellac and zein coatings cast from ethanol solutions and water-based tapioca dextrin and hydroxypropyl methylcellulose (HPMC) coatings. For lipid dispersion coatings, the particle size of the dispersed phased influenced gloss values. WPI coatings had stable gloss values at 52%, 75%, and 95% relative humidity (RH). At 95% RH, shellac and zein coatings "blushed," and both dextrin and HPMC coatings became tacky. WPI and shellac films maintained a high gloss after 7.6 mo of storage at 23 °C and 75% RH and had higher gloss than whey protein concentrate (WPC) and HPMC coatings. The type and level of surfactant added to WPI coatings greatly influenced gloss.     

Properties of triticale flour protein based films

Triticale flour proteins based films were developed. Solubility in water, water vapor permeability (WVP), and mechanical properties of triticale films are presented. The effects of thermal treatments and glycerol concentration were also evaluated. WVP values were in the range 0.10-4.22 × 10⁻¹⁰ g m⁻¹ s⁻¹ Pa⁻¹. Tensile strength (TS) and percentage of elongation (%E) were in the range 2.9-0.20 MPa and 250-110% respectively. Total soluble matter (TSM), WVP, and %E decreased with the increase in the curing temperature. More plasticized films presented greater TSM, WVP, %E and lower values of TS. At a giving temperature (T) and glycerol concentration, an increase in relative humidity (RH) resulted in higher values of TSM, WVP, %E and lower TS values. It was observed that in films with the same treatments and conditioning, WVP increased with the increase in measurement temperature. Triticale proteins showed suitable film-forming capacity for the formulation of biodegradable films.     

Defatted mustard seed meal-based biopolymer film development

Edible films were developed from a defatted mustard seed meal (Sinapis alba) (DMM), a byproduct from the bio-fuel industry. Films were formed by casting DMM suspensions (3-g DMM/100-g suspension) that were treated by high-pressure homogenization (HPH, 138 MPa), ultrasound (400 W, 30 min), or gamma irradiation (10 or 20 kGy), and mixed with glycerol and soy lecithin. Rheological properties, water vapor permeability, water solubility, tensile strength (TS), percentage elongation (%E), elastic modulus (EM), color, and structural properties of film-forming suspensions or films were determined. Films were successfully produced using the HPH-processed suspension with 0.6% glycerol. Rheology results indicated the polymer network structure of the film-forming suspension was loosened by HPH, but tightened by heating at 90 °C. The ranges for the properties of WVP, WS, TS, %E, and EM of the films were 3.4-5.0 g mm/kPa h m², 30.3-34.4%, 1.3-5.5 MPa, 0.9-18.1%, 33.2-294.7 MPa, respectively. L, a, and b by CIELAB coordinates were 73.3-77.9, 0.4-3.5, and 29.5-45.7, respectively. HPH increased TS and %E of the films and decreased EM, whereas the ultrasound and the 20 kGy-irradiation treatments increased %E and decreased EM. The TS and EM decreased and E% increased with increasing glycerol and soy lecithin. DMM is a promising material to produce edible biopolymer films and coatings for food packaging.     

Physical properties of whey protein coating solutions and films containing antioxidants

ABSTRACT:  Antioxidants (ascorbyl palmitate and α-tocopherol) were incorporated into 10% (w/w) whey protein isolate (WPI) coating solution containing 6.67% (w/w) glycerol (WPI:glycerol = 6:4). Before incorporation, the antioxidants were mixed using either powder blending (Process 1) or ethanol solvent-mixing (Process 2). After the antioxidant mixtures were incorporated into heat-denatured WPI solution, viscosity and turbidity of the WPI solutions were determined. The WPI solutions were dried on a flat surface to produce WPI films. The WPI films were examined to determine transparency and oxygen-barrier properties (permeability, diffusivity, and solubility). WPI solution containing antioxidants produced by Process 1 and Process 2 did not show any difference in viscosity and turbidity, but viscosity was greater for the WPI solution with rather than without antioxidants. WPI films produced by Process 2 were more transparent than the films produced by Process 1. Oxygen permeability of Process 1 film was lower than Process 2 film. However, both the diffusivity and solubility of oxygen were statistically the same in Process 1 and Process 2 films. Both control WPI films and antioxidant-containing WPI films had very low oxygen solubility, comparable to polyethylene terephthalate films. Permeability of antioxidant-incorporated films was not enhanced compared to control WPI films.     

Starch–methylcellulose–whey protein film properties

Four % (wt/wt) aqueous solutions were prepared at corn starch:methylcellulose:whey protein isolate (CS:MC:WPI) ratios of 2:2:2, 1:2:3, 2:1:3, 2:2:0, 1:2:0 and 2:1:0. Glycerol (gly) was used as a plasticiser at CS–MC–WPI:gly ratios of 2:1, 2.5:1 and 3:1. CS–MC–WPI blend films were stronger than CS–WPI films and had lower oxygen permeability (OP) than MC–WPI films. The highest tensile strength (TS) of blend films was 8.01 ± 3.41 MPa, at CS:MC:WPI ratio of 2:2:0 and CS–MC–WPI:gly ratio of 3:1. Lowest OP value was 45.05 ± 7.24 cm³ μm m^?2 per day kPa^?1, at CS:MC:WPI ratio of 2:2:2 and CS–MC–WPI:gly ratio of 3:1. OP values were predictable based on relative amounts of components. However, TS and elastic modulus properties of the CS–MC–WPI blend films did not reflect the relative amounts of the components. All of CS–MC–WPI films were translucent indicating some degree of immiscibility among the CS, MC and WPI. These results indicate the influence of complex molecular interactions among the components.