The soy protein isolate (SPI) antimicrobial films were made with Nisin (N), sodium lactate (NaL), EDTA (E) and their optical combination (C). The C film showed a significant (p<0.05) antimicrobial effect on three food pathogens, E. coli, Salmonella and Bacillus cereus, which inhibitory zone is 32mm, 33.33mm and 32.33mm, respectively. The addition of N and NaL to SPI film reduced its mechanical properties, that is, the tensile strength (TS) was reduced from 10.8716MPa to 8.1405MPa (N1) and 3.2715MPa (NaL3) and the elongation at break (E) was increased from 3.03% to 4.73% (N3, N4) and 11.21 % (NaL4). While the addition of EDTA and combination increased TS from 10.8716MPa to 17.0600MPa (E4) and reduced E from 3.03% to 2.36% (E1). The water vapor permeability (WVP), oxygen permeability (OP) and total color difference (ΔE) of films had changed with the addition of antimicrobial agents. The FTIR analysis showed no specific interaction between active groups of Nisin with functional group of control film. However, the intensity of peaks in the spectrum of NaL and EDTA increased, indicating interactions between NaL, EDTA and SPI. The appliction experments showed that the SPI antimicrobial film (C) did have a bacteriostatic preservation effect on the meat antibacterial preservation and extend the shelf life to 3-6 days compared with SPI film and ordinary wraps. The SPI antimicrobial film broadens the application of SPI film.
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Renewable resources have attracted some research attention as precursors for developing tailored bioactive polymers that are capable of minimizing the rate of bacterial adhesion and biofilm growth in healthcare facilities. Within the therapeutic arsenal of naturally-available alternatives that have been explored, plant secondary metabolites (PSMs), such as essential oils and herb extracts, have revealed relatively powerful broad-spectrum antibacterial activities [15,16]. Good examples of currently used PSMs are tea tree (Melaleuca alternifolia), geranium, zataria, and cinnamon oils that have shown inherent bactericidal performance in their liquid and/or vapor form toward important pathogenic microbes. Due to the presence of a large number of active molecules within a single essential oil or plant extract, their antimicrobial pathway is not fully understood and cannot be attributed to a particular mechanism . However, the pharmaceutical, cosmetic, and food industries have recently paid great attention to bioactive PSMs, by way of the usage of natural additives as a substitute for synthetic preservatives . Indeed, PSMs are a relatively low-cost renewable resource available in commercial quantities, with limited toxicity, and potentially, different biocidal mechanisms to synthetic antibiotics, which make them an appropriate precursor for “green” functional polymeric materials. On the other hand, using PSMs for surface functionalization through immobilization or synthesis of coatings without loss of functionality is challenging, in part due to the issues with solubility and volatility of these precursors. The plasma-assisted technique overcomes these challenges, allowing the fabrication of a polymerized 3D matrix from renewable precursors with control over its surface properties and chemical functionality. Under appropriate fabrication conditions, plasma-enabled synthesis may help preserve/retain the inherent antimicrobial functionality of PSMs within the solid polymer-like thin films. Plasma polymers of PSMs (PP-PSMs) have several advantages including low cytotoxicity, long-term stability, and a reduced risk of developing microbial resistance. These advantageous properties render PP-PSMs a suitable candidate for bioactive coating applications.
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72 Results & Discussion Table 4.8 shows the diffusion coefficients, rate constants and initial release rates for the diffusion and kinetic analyses. Although the release of linalool occurs faster from the extruded film, the diffusion coefficient is significantly lower than that of the melt compressed film. The differences in the film fabrication method (see Table 4.8), would suggest that the short-term release of the AM agent from samples produced by melt compression is considerably faster than that of samples produced by melt extrusion. This may be due to the more uniform distribution of AM agent in the polymer matrix (LaCoste et al., 2005) imparted by melt-mixing during extrusion. Furthermore, in the thick, non-uniform films produced by melt compression, part of the AM agent additive could be concentrated on the film surface resulting in an apparent higher calculated diffusion coefficient. The diffusion coefficient determined for the melt extruded film is of a similar order of magnitude to values obtained in a previous study (Suppakul, 2004).
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san-PVA film is confirmed by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and X-ray Dif- fraction (XRD) analysis. The Scanning Electron Microscopic (SEM) images illustrate the presence of embedded silver nanoparticles throughout the films. In addition, the formed silver nanoparticles have an average particle size of ~ 16.5 nm as observed by Transmission Electron Microscopy (TEM). The anti-microbial and anti-fungal activity of the chito- san-PVA silver nanoparticle films have demonstrated significant effects against Escherichia coli (E. coli), Pseudomo- nas, Staphylococcus, Micrococcus, Candida albicans, and Pseudomonas aeruginosa (P. aeruginosa). To improve fur- ther their therapeutic efficacy as anti-microbial agents, curcumin encapsulated chitosan-PVA silver nanocomposite films are developed which showed enormous growth inhibition of E. coli compared to curcumin and chitosan-PVA sil- ver nanoparticles film alone. Therefore, the present study clearly provides novel antimicrobial films which are poten- tially useful in preventing/treating infections.
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on nanocomposites material which prevent rancidity, the change or missing color, loss the nutrient material, dehydration, microbial growth, gas production, creating odors and dehydration. Currently, based-biopolymers nanocomposites such as PLA/nanocomposites receive focus of attention in various packaging because of increasing demand from customers and production for stable products environmentally [6,7]. Generally, active packaging has features beyond the inhibition properties and they are obtained by adding active elements and compounds in packaging system. This kind of packaging show good reaction to change of the properties of the package related to internal and external changes of the package environment and therefore it is very important in preserving freshness of food . Active anti-microbial packages made of metal nanocomposites are new generation of nanostructures packaging that are produced from direct combinations of metallic nanoparticles with a background polymer . The antimicrobial activity of a polymer is usually achieved by adding metal particles, metal oxides and organic compounds. Metals and oxidative particles are the most commonly used particles in the development of antimicrobial activity [10, 11]. Silver, copper and zinc oxide nanoparticles are the most widely used metal nanoparticles in the production of antimicrobial films . Silicon dioxide or silica is the most abundant material in the earth’s crust. This compound with a SiO 2 chemical formula is structurally similar to diamond, it is a crystalline and white material, it`s melting and boiling point is relatively high and it is found in crystalline and amorphous form in the nature. Nano Silicon Dioxide (SiO 2 ), which has high heat resistance and a melting point of 1750 ℃, can be used to improve the PLA heat resistance. Almost all researchers who have reported the mixing of inorganic silicon dioxide with PLA used it to make a block or film or sheet, rather than a fibrous or filament shape; therefor the PLA / SiO 2 nanocomposite filament should be studied. Meanwhile, nano SiO 2 has environmental protection, safe and non-toxic functions, so the PLA / nano SiO 2 composite filament has an environmentally friendly nature. On the other hand, nano SiO 2 has a very low price and hence can reduce the cost of composite filaments. Also, the nano SiO 2 color is white, so the composite filament is bright and can be colored almost with all colors .The aim of this study
. Nanocomposites are thought to be 21st Century materials and expected to be utilized more in the future. Industries tend to produce considerably thin films not only to reduce the material and production costs but also the environmental impacts of packaging. This result-oriented research helps the development of new active packaging based on the composite materials that prevents rancidity, change or loss of color, loss of nutrients, dehydration, gas production, creating odors and dehydration. As regards to the increment of the consumer demands and production of sustainable environmental products, nanocomposites based on the bio-polymers like Poly-Lactic Acid (PLA) have gained a peculiar attention in the field of foodstuff packaging [7, 8]. Generally, active packaging has features beyond the preventing properties and they are obtained by adding active elements and compounds in packaging system . Antimicrobial active packaging made of metal nanocomposites are new generation of nano structures packaging that are produced from direct combinations of metallic nanoparticles with a polymer . The antimicrobial activity of a polymer is usually achieved by adding metal particles, metal oxides and organic compounds. Metals and oxidized particles are the most commonly used particles in the development of antimicrobial activity [11, 12]. Silver, copper, and zinc oxide nanoparticles are the most widely used metal nanoparticles in the production of antimicrobial films . Zinc is one of the nanoparticles which is a kind of metal widely distributed in the nature and imperative for the function of many metalloproteinase. Nanoparticles of zinc oxide have some advantages over silver nanoparticles, including the low cost, white appearance and the ability to block ultraviolet radiation . The antimicrobial mechanism of metal nanoparticle is not specified yet. According to researchers, the antimicrobial activity of these nanoparticles may be related to induction of oxidative stress due to generation of reactive oxygen species (ROS) which may cause the degradation of the membrane structure of the cell [15-17] release of ions from the surface of nanoparticles that has been reported to cause bacterial death due to binding to cell membrane [18, 19]. Antimicrobial effect of nano-zinc oxide nanoparticles against a broad spectrum of gram-positive and gram- negative bacteria such as Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium,
The present study attempts to assess the efficacy of active packaging films incorporating natural antimicrobial agent like cinnamon essential oil (CEO) into sodium alginate- calcium formulations to extend the shelf- life of paneer at refrigeration temperature (4 ± 1 ºC). Paneer, analogous to the western cottage cheese, is characterized by a short shelf- life mainly due to spoilage by psychrotrophs, coliforms, yeasts and molds. Natural methods of preserving paneer are an improvement of food safety since there is growing concern among the population about the chemical nature of sorbates and other chemical preservatives used. Cinnamon essential oil (CEO) has been identified to possess outstanding antioxidant activity as well as high antimicrobial activity against a wide range of spoilage and pathogenic micro-organisms. Paneer samples were left untreated (C), or were treated with alginate- calcium coating incorporating 2.5% cinnamon essential oil (CP). Proximate analyses, microbial and sensory analyses of all the samples were performed at regular intervals for a period of 15 days in order to determine the storage stability of the paneer samples. Cinnamon essential oil in alginate- calcium coating treatment could efficiently maintain the quality of the paneer samples during storage better than that of the control. Edible coating also increased the shelf- life of paneer samples to 13 days from 5- 6 days of the control sample.
Cold smoked salmon is a ready to eat seafood product processed by brining fish in a 3-5% salt solution and then smoking at 37°C for 6 to 24 hr. Listeria monocytogenes (LM), a psychrotrophic and halotolerant pathogen, can survive all of these processes and is a major safety concern for smoked salmon producers. Salmine is a cationic antimicrobial peptide derived from the milt of salmon, and it has been shown to inhibit the growth of LM in vitro. Commercialization of this peptide would also add value to a waste product produced when raising salmon. The purpose of this study was to determine the anti-listeria activity of salmine in smoked salmon by measuring the viable counts of LM over time.
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Inhibition zone test on potato dextrose agar medium culture was used to determine the antimicrobial effects of prepared films against fungi Aspergillus flavus (PTCC 5004), Aspergillus parasiticus (PTCC5286) and Aspergillus parasiticus (PTCC 5018). 0.1 ml of each fungus spore suspension (104 spores per ml) were cultured in potato dextrose agar medium culture. Disc shape films with diameter of 10 mm were placed in sterile conditions at the center of plate containing medium culture. Plates were placed in the oven at 25 °C for 48 hours then composed zone diameter was measured using a caliper with 0.01 precision, composed zone diameter was considered as an index of antimicrobial activity of films. In cases that halo was not formed means there was no antimicrobial activity, instead of reporting 10 mm (primary diameter of disc), its equivalent size was considered zero. But when the antimicrobial activity was observed, with respect the disc diameter, the composed halos diameter always was more than 10 mm. To ensure the steady growth of fungus on the surface of plate, a cultured plate without film was used as control, also a plate lacking fungi was used to ensure that no fungus contamination there is.
Chitosan, (1–4)-linked 2-amino-2-deoxy-D- glucopyranose, is derived from chitin, second most abundant natural polysaccharides and is the major component of the exoskeleton of crustaceans 5 . Chitosan is hydrophilic, non-toxic, biocompatible and biodegradable polymer. It has a unique antimicrobial activity and inhibits the growth of wide variety of fungi, yeasts, and bacteria 6 . The positively charged chitosan and the negatively charged cell membrane interact to disrupt the cell wall of the microorganism 7 . Chitosan can be cross linked into matrix using chemical cross-linking agents such as glutaraldehyde and genipin, but they are highly toxic.
In last few years, Nanotechnology can be used to meet the requirements of consumers in proving food's quality and in using antimicrobial agents to increase the shelf life of foods during storage and distribution. Food industries should choose the packaging materials that are suitable for their food products along with the benefits and disadvantages of these packaging materials . Nanomaterials have broad range of applications in various fields, such as physics, chemistry, electronics, optics, materials science and biomedical sciences . Therefore, inorganic/organic composite materials are prepared with many compositions where by combining organic and inorganic materials, the result composites may have advantages of both organic and inorganic materials, thus creating various usages in many applications. Among the many inorganic materials, zinc oxide .
with in microcrystalline cellulose, further it was sup- ported by SEM-EDS results. AgNPs that are impreg- nated into MCC were estimated using TG analysis, which is found to be ~1.3%, which is very much consis- tence with SEM-EDS analysis. The fabricated silver im- pregnated MCC then combined with PLA to produce antimicrobial bionanocomposite film using solvent cast- ing process. The preliminary analysis showed that these films exhibits significant antimicrobial properties and further research in this direction is in progress.
Salleh E, Muhamadi l & Khairuddinr N. 2007. Inhibition of Bacillus subtilis and Escherichia coli by Antimicrobial Starch-Based Film incorporated with Lauric Acid and Chitosan. Proceedings of the 3 rd CIGR Section Vl International Symposium on Food and Agricultural Products: Processing and Innovation. Naples, ltaly.
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Propolis release profile from formulations was studied in 3 mL of medium, which was a solution containing 20% v/v of ethanol in water, at 37°C. The samples were prepared by the application of 40 μL (20 μL twice) of the varnishes in incisive bovine teeth, previously cut in 0.5 × 0.5 cm square pieces. After the formation of the com- pletely casted films, the teeth were placed in tubes with the same medium used before (3 mL of 20% v/v of etha- nol in water). At scheduled time intervals (30 min, each hour until eight hours, 24 h, and then, once a week until the end of the release), samples were taken and the entire medium volume (3 mL) was replaced with fresh medium to maintain sink conditions. The amount of propolis re- leased was quantified as total flavonoids content, mea- sured as quercetin) . UV/Vis spectroscopy at 425 nm was used for flavonoids quantification and the method was properly validated, according to ICH guidelines before analysis (linear equation: y = 0.106722 × +0.0229511, r 2 = 0.9970, n = 5).
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Increased use of synthetic polythene bags has led to serious ecological problems due to their total non-biodegradability. To overcome these problems, there is an urgent need to develop packaging films, which are safe and eco-friendly. One possible solution may be utilization of naturally derived materials for the development of biodegradable films. Biodegradable films are generally used for food packaging due to its edibility and safety. Biodegradable films degrade naturally. Biodegradability varies with the conditions of sunlight, moisture, oxygen and composting (Tharanathan, 2003). Biodegradation is enhanced by reducing the hydrophobic properties and increasing hydrophilic properties. Biodegradable plastics or bio-plastics are made from renewable raw materials such as starch, protein, polysaccharides, lipids, fibers etc. Among all the natural polymers, starch has been considered as one of the most promising candidate for future material, because of its attractive combination of price, abundance and renewable in addition to biodegradability. All the plant seeds and tubers contain starch, which is predominantly present as amylose and amylopectin. Plants use starch as way to store excess glucose.
Numerous studies have concentrated on incorporating common food preservatives such as organic acids, their salts and anhydrides into packaging films (see Table 2.3). Studies on benzoic or sorbic acid incorporated into packaging materials have evaluated their action against various microorganisms in laboratory media such as agar plates and/or in actual food products. The packaging films incorporated with these organic acids or anhydrides have demonstrated inhibitory effects against various spoilage and pathogenic microorganisms. Weng et al. (1999) showed that benzoic or sorbic acids incorporated into poly(ethylene-co- methacrylic acid) (PEMA) film inhibited the growth of A. niger and Penicillium sp. on solid media. Weng and Chen (1997) investigated the AM activity of benzoic acid or benzoyl chloride incorporated into ionomer films. The AM activity of these films was demonstrated by their ability to inhibit the growth of Penicillium sp. and A. niger. In an earlier study, Weng and Hotchkiss (1993) incorporated benzoic acid or benzoic anhydride into LDPE films which significantly suppressed the growth of Rhizopus stolonifer, Penicillium sp. and A. toxacarius on potato dextrose agar and on the surface of Cheddar cheese. Matche et al. (2006) examined the AM activity of benzoyl chloride incorporated into modified ethylene acrylic acid films against Penicillum sp. and A. niger sp. on solid media for 15 days with the film demonstrating inhibition against both species. Silveira et al. (2007) incorporated sorbic acid into LDPE films with the aim of preserving fresh pastry dough. It was found that 3% (w/w) sorbic acid incorporated into a 70 μm film reduced 2 and 1.5 log cycles of mesophilic and
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starch-based films coated with carvacrol also demonstrated a positive AM activity against S. cerevisiae on the solid media. The AM activity of carvacrol against S. cerevisiae increased significantly (p ≤ 0.05) with the increase in concentration in the film coating. These observations are consistent with the study of Rupika et al.  who found that polyethylene-based films containing carvacrol and/or thymol demonstrated significant inhibitory activity against S. cerevisiae using the agar disc diffusion assay. The AM activity of starch-based films coated with linalool at 1, 3 and 5% (w/w) were also found to be effective against the growth of S. cerevisiae on solid media (see Table 1). In these systems the zone of inhibition increased with the increase in linalool concentration from 1% to 5% (w/w). The data indicate that the inhibitory effect of the films containing linalool against S. cerevisiae on the solid medium is significantly less than that of the films containing thymol in all cases.
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 I. Leceta, M. Peñalba, P. Arana, P. Guerrero y K. de la Caba, «Ageing of chitosan films: Effect of storage time on structure and optical, barrier and mechanical properties,» European Polymer Journal, vol. 66, p. 170–179, 2015.  ICONTEC, «Pan. Requisitos generales,» Norma Técnica Colombiana 1363, p.
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The application of natural antioxidants and antimicrobials to edible films in pre- cooked meat products is an innovative but poorly explored option that needs further comprehension (Akcan, Estevez, & Serdaroglu, 2017). Polyphenol-rich plant extracts, such as T. arjuna, are considered as potent additives for development of bioactive edible films to prevent lipid oxidation and the microbial spoilage (Pineros-Hernandez, Medina-Jaramillo, Lopez-Cordoba, & Goyanes, 2017). The objective of this study was to develop a novel calcium alginate based bioactive edible film incorporated with T. arjuna with high antioxidant and antimicrobial potential, and study its effects on lipid oxidative stability, microbial quality and sensory properties during refrigerated storage of chevon sausages used as a model system.
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Organic acids including their salts and esters are the most extensively studied AM agents for the feasibility to combine them with packaging films. The inhibitory action of organic acids is to acidify the environment of the microorganism in order to suppress its growth. However, this action is only effective against bacteria which normally cannot survive at a pH lower than 4. Mildly lowering the environmental pH is ineffective against most yeast and mould species because they can survive at a pH as low as 1.6. Unfortunately, producing such acidic conditions to inhibit yeast and mould in food is not practical. Another possible mechanism of the AM action of organic acids is the “weak acid theory”. Most organic acids used as AM agents are weak lipophilic organic acids or weak fatty acids and can form equilibrium between the undissociated acids and their charged ions. While the pH of a food is low, the proportion of undissociated acids increases but in acidic aqueous foods, salts of organic acids such as sorbates and benzoates can react with water and produce acid forms. Only the undissociated acids can diffuse through lipid cell walls. Longer chain fatty acids, that are lipophilic, can pass the membrane better than short chain fatty acids. As a result, the shorter chain fatty acids need generally to be at a higher concentration to inhibit microorganism (Stratford and Eklund, 2003).
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