•Physical modification using heating, freezing, or extrusion can denature protein structure.•Application of modern food processing methods can offer low temperature and low waste technologies in ...physical protein modification.•Some of these new methods need further researches to prove their effect on protein functional properties.
Today, there is a growing demand for novel technologies, such as high hydrostatic pressure, irradiation, ultrasound, filtration, supercritical carbon dioxide, plasma technology, and electrical methods, which are not based on chemicals or heat treatment for modifying ingredient functionality and extending product shelf life. Proteins are essential components in many food processes, and provide various functions in food quality and stability. They can create interfacial films that stabilize emulsions and foams as well as interact to make networks that play key roles in gel and edible film production. These properties of protein are referred to as ‘protein functionality’, because they can be modified by different processing. The common protein modification (chemical, enzymatic and physical) methods have strong effects on the structure and functionality of food proteins. Furthermore, novel technologies can modify protein structure and functional properties that will be reviewed in this study.
The aim of this study was to examine mechanical and physical properties of starch/chitosan composite film exposed to low‐pressure air and argon plasma at 600 mTorr for different duration (4, 8 and 12 ...min) and evaluate the shelf life of the chicken breast fillet packaged with plasma‐treated films. The mechanical properties of the composite films were improved significantly.
It is shown that argon plasma is more efficient in improving the tensile strength of the films and increased it from 10.59 to 22.09 Mpa after 12 min of process due to the formation of a stable cross‐linked network on the surface of the polymer, although film's stretchability, modified in air plasma, was significantly more. Solubility and hydrophilicity of the films were increased; however, no significant change in the water vapor transmission rate was observed. Oxygen permeability of films improved after both plasma treatment. Total viable count and oxidative (TBA) changes of fillets were analyzed during shelf life. The results showed that Cold plasma treatment could not prolong the shelf life of the fillets through plasma‐treated films.
Plasma treated chitosan/starch film was used for packaging of chicken breast fillet.
Nano-chitosan (NCH), nano-cellulose (NCL) and cellulose derivative are biodegradable biopolymer. Nano-chitosan or nano-cellulose at different concentrations (0.1, 0.5 and 1%) incorporated in ...carboxymethyl cellulose (CMC) film solution using casting methods. Both CMC/NCH and NCL decreased physical properties (water solubility, moisture content and moisture absorption) especially in concentration of 1%. However, these properties in CMC/NCH were significantly (p < 0.05) lower than CMC/NCL. Water vapor permeability of polymer and nanofiller decreased when nanocomposite concentration increased. Tensile strength and Elongation at break improved in nanocomposite film by increasing concentration. Thermal properties of CMC/NCH were significantly (p < 0.05) lower than CMC/NCL. Emersion of crystalline peaks in X-ray analyses certified the presence of nanofiller in polymer. However, in high content (1%) cause to create aggregation of nanofiller in CMC film. Finally antibacterial activity against five pathogens was studied and good effective inhibition on CMC/NCH was observed while CMC/NCL had no inhibitory effect. These results show that use of CMC/NCH as a biocompatible film has more advantages than CMC/NCL biopolymer.
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•Incorporation of NCH and NCL to CMC improved WVP and mechanical properties of film.•The CMC films with various contents of NCH could inhibit the pathogens tested.•CMC/NCH films had better activities compared to CMC/NCL.•The CMC nanocomposite films have a potential for application in food packaging.
In this study, survival of four probiotic strains (Lactobacillus acidophilus, L. casei, L. rhamnosus and Bifidobacterium bifidum) immobilized in edible films based on carboxymethyl cellulose (CMC) ...and physicochemical properties of films were investigated during 42 days of storage at 4 and 25 °C. Results showed a significant decrease in viability of bacterial cells during 42 days of storage at 25 °C. However, viability of L. acidophilus and L. rhamnosus were in the range of recommended levels during the storage at 4 °C (107 CFU/g). Probiotic films caused more water vapor permeability (WVP)and opacity, and less tensile strength (TS) and elongation at break (EB) compared to the control film. However, no significant physicochemical changes were observed among probiotic films containing different strains. Therefore, incorporation of some probiotic strains in edible coats and films could be their suitable carrier at refrigerated temperatures.
•Viability of L. acidophilus and L. rhamnosus were in the range of recommended levels at the end of storage at 4 °C.•Probiotic films showed less water vapor permeability (WVP) and opacity than the control film.•Addition of probiotics to edible CMC films decreased tensile strength (TS) and elongation at break (EB).
Althaea rosea flowers were used to procure the gum (ARG) needed for film preparation. Pretest studies suggested 1.5% ARG + 50% glycerol as optimum for film preparation. The reinforcement impact of 3, ...5, and 8 wt% bacterial nanocrystalline cellulose (BNC) incorporation (based on the dry weight of ARG) was investigated on the structural, mechanical, physical, thermal, optical, morphological, and barrier properties of films. The Results suggested that increasing the BNC concentration until a certain level (5 wt% BNC) could improve the latter properties. However, at higher concentration (8 wt% BNC), cellulose nanoparticles tended to agglomerate, which led to the impairment of some of those properties, especially barrier properties. According to AFM and SEM results, BNC addition increased surface roughness and coarseness. All BNC-loaded films showed better functions compared to control sample (0 wt% BNC) and the film containing 5 wt% BNC was suggested as the optimum film.
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•The films showed outstanding anti-UV properties.•Surface roughness was increased as the nanocellulose concentration increased.•BNC addition improved tensile strength and barrier properties of films.•The optimum concentration of BNC for the reinforcing of nanocomposite film was 5%.
Lipid oxidation is a problem associated with roasted peanuts which occurs during storage time and contributes to development of rancidity. Fungi can grow upon peanuts and produce carcinogenic ...byproducts such as aflatoxins. This study investigated the effect of different concentration of edible coatings including β-glucan and chitosan on shelf-life parameters of peanuts. Lipid oxidation was evaluated by peroxide value (PV), thiobarbituric acid (TBA) and anisidine value (AV). The induction time (t
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), hardness and viscosity of samples were measured using rancimat instrument, texture analyzer and rheometer, respectively. The dilution plating method was used for fungal counts and analysis of aflatoxins was performed by High-Performance Liquid Chromatography (HPLC). Lipid oxidation of samples was significantly affected by all formulations of coatings (p < 0.05). After four months of storage, β-glucan/chitosan coated (coating with both β-glucan and chitosan in coating formulation) peanuts significantly showed the least lipid oxidation values. The oil stability of peanuts was significantly affected by all formulations of coatings (p < 0.05). After four months storage, the highest level of polyunsaturated fatty acids (PUFAs) was observed in β-glucan/chitosan coated sample. Interestingly, there was a direct relationship between the viscosity of coating solutions and the hardness of peanuts. The chitosan and β-glucan/chitosan coated samples showed the highest viscosity and hardness during storage time (p < 0.05). In terms of the moisture content, fungal counts and mean total aflatoxins levels, the coated samples with 1% chitosan showed the least levels during storage time in comparison with other samples. Consequently, coating the peanuts with natural solutions can be an alternative and useful method to peanut storage.
•A new active SSPS film incorporated ZEO and MEO were developed and characterized.•Dynamic mechanical, tensile properties and WVP of these films were determined.•The SEM micrograph did not show signs ...of phase separation between the components.•MEO and specially ZEO improved the barrier properties of the SSPS films.•The results showed that SSPS could be a promising carbohydrate 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.
The bacteriocin nisin has been extensively used as potential natural preservative in the food industry. However, antimicrobial activity of nisin due to its binding with food components and ...inactivation by enzymatic degradation is reduced when it is applied in food. Encapsulation of nisin is an efficient approach to overcome the problems related to the direct application of this antimicrobial peptide in foods. In this study, nisin was encapsulated in alginate‐high methoxy pectin (HMP) microparticles, and its release studies were performed in water to determine the diffusion and the kinetic behaviour of the matrix. Results showed that the nisin content had a significant influence on encapsulation efficiency (EE), loading capacity (LC) and microparticles size. The values of EE, LC and particle mean diameter were about 47–54%, 16–21% and 57–131 μm, respectively. The nisin‐loaded microparticles showed nearly spherical structure with fold on the surface, as displayed by scanning electron micrograph. Interaction between alginate and HMP was confirmed by the changes in the intensity and wave number of the stretching vibrations of the hydroxyl and carboxyl groups in alginate‐HMP microparticles FTIR spectra. Furthermore, the addition of nisin resulted in a markedly increase in intensity of carboxylic peak at 1620 cm⁻¹, indicating the presence of nisin inside of the microparticles. The in vitro nisin release from these microparticles followed a sustained release profile consistent with a Fickian diffusion mechanism.
Antibiotic therapy is among the most important treatments against infectious diseases and has tremendously improved effects on public health. Nowadays, development in using this treatment has led us ...to the emergence and enhancement of drug-resistant pathogens which can result in some problems including treatment failure, increased mortality as well as treatment costs, reduced infection control efficiency, and spread of resistant pathogens from hospital to community. Therefore, many researches have tried to find new alternative approaches to control and prevent this problem. This study, has been revealed some possible and effective approaches such as using farming practice, natural antibiotics, nano-antibiotics, lactic acid bacteria, bacteriocin, cyclopeptid, bacteriophage, synthetic biology and predatory bacteria as alternatives for traditional antibiotics to prevent or reduce the emergence of drug resistant bacteria.
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