Antimicrobials hydrocolloid

Free silver ions are the active components of antimicrobial silvers, and it has been shown that as little as one part per million of elemental silver in solution is an effective antimicrobial. Materials such as polymers, charcoal, and hydrocolloids when formulated with silver not only aid wound management and healing but also regulate its release into the wound environment and surrounding tissues. Silver ions kill micro-organisms by inhibiting cellular respiration and cellular function. " It is known that their mode of action is exerted by binding cysteine residues on the cell walls of yeasts such as C. albicans thereby... 

A Preliminary Study on Antimicrobial Edible Films from Pectin and Other Food Hydrocolloids by Extrusion Method... 

Antimicrobial Edible films were prepared from natural fiber of pectin and other food hydrocolloids for food packaging or wrapping by extrusion followed by compression or blown film method. Microscopic analysis revealed a well mixed integrated structure of extruded pellets and an even distribution of the synthetic hydrocolloid in the biopolymers. The resultant composite films possess the mechanical properties that are comparable to films cast from most natural hydrocolloids that consumed as foods or components in processed foods. The inclusion of polyethylene oxide) alters the textures of the resultant composite films and therefore, demonstrating a new technique for the modification of film properties. The composite films were produced in mild processing conditions, thus, the films are able to protect the bioactivity of the incorporated nisin, as shown by the inhibition of Listeria monocytogenes bacterial growth by a liquid incubation method. 

Extrusion is a cost effective manufacturing process. Extrusion is popularly used in large scale production of food, plastics and composite materials. Most widely used thermoplastics are processed by extrusion method. Many biopolymers and their composite materials with petroleum-based polymers can also be extruded. These include pectin/starch/poly(vinyl alcohol) (Fishman et al. 2004), poly(lactic acid)/sugar beet pulp (Liu et al. 2005c), and starch/poly(hydroxyl ester ether) (Otey et al. 1980), etc. In this study, composite films of pectin, soybean flour protein and an edible synthetic hydrocolloid, poly(ethylene oxide), were extruded using a twin-screw extruder, palletized and then processed into films by compression molding process or blown film extrusion. The films were analyzed for mechanical and structural properties, as well as antimicrobial activity. 

The current study provides a new type of edible, antimicrobial food packaging or wrapping films from food-grade natural fibers or hydrocolloid. Besides film casting, the films can also be produced by compression, extrusion blown methods. The inclusion of PEO hydrocolloid in natural fiber formulations makes films tougher and caused less permanent deformation when the films were subjected to an external force. Since the extrusion and compression were performed in mild conditions, nisin can be incorporated into films without diminishing its antimicrobial activity. 

Zinoviadou, K.G., Koutsoumanis, K.P., Biliaderis, C.G. Physical and thermo-mechanical properties of whey protein isolate films containing antimicrobials, and their effect against spoilage flora of fresh beef. Food Hydrocolloids 24, 49-59 (2010)... 

Sekiguchi S., Miura Y., Kaneko H., Nishimura S.I., Nishi N., Iwase M., Tokura S., Molecular weight dependency of antimicrobial activity by chitosan oligomers, in Food Hydrocolloids Structures, Properties and Functions, Eds. Nishinari K. and Doi E., Plenum Press, New York, 1993, pp. 71-76. 

Perdones, A., Vargas, M., Atares, L. Chiralt, A. (2014). Physical, antioxidant and antimicrobial properties of chitosan-cinnamon leaf oil films as affected by oleic acid. Food Hydrocolloids, 36, 256-64. 

Echeverria I, Eisenberg P, Mauri AN (2014) Nanocomposites fi 1ms based on soy proteins and montmorillonite processed by casting. J Membr Sci 449 15-26 Espitia PJP, Du W-X, Avena-Bustillos R de J, Soares N de FF, McHugh TH (2014). Edible films from pectin Physical-mechanical and antimicrobial properties—a review. Food Hydrocolloids 35 287-296... 

Bonilla J, Fortunati E, Atares L, Chlralt A, Kemy JM (2014). Physical, structural and antimicrobial properties of poly vinyl alcohol-chitosan biodegradable films. Food Hydrocolloid, 35,463-470. 

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