Development and evaluation of an edible antimicrobial film based on yam starch and chitosan

Abstract

Edible antimicrobial films are an innovation within the biodegradable active packaging concept. They have been developed in order to reduce and/or inhibit the growth of microorganisms on the surface of foods. This study developed an edible antimicrobial film based on yam starch (Dioscorea alata) and chitosan and investigated its antimicrobial efficiency on Salmonella enteritidis. A solution of yam starch (4%) and glycerol (2%) was gelatinized in a viscoamilograph and chitosan added at concentrations of 1%, 3% and 5%. Films with and without chitosan were produced by the cast method. To evaluate the antimicrobial activity of the films, two suspensions of S. enteritidis were used in BHI medium, corresponding to counts of 2 ¥ 10 8 and 1.1 ¥ 10 6 CFU/ml. The suspensions (50 ml) were poured into flasks. The films were cut into 5 ¥ 5 and 5 ¥ 10 cm rectangles to be used at ratios of 1 : 1 (1 cm 2 /ml microorganism suspension) and 2 : 1 (2 cm 2 /ml). The film 30 mm thick on average. As a control, pure chitosan at an amount corresponding to that contained in the 3% and 5% films (5 ¥ 10 cm) was added to flasks containing the microorganism suspension. Also, flasks containing only a suspension of S. enteritidis were used as control. The suspensions, in flasks, were kept at 37°C in a waterbath with agitation. Suspension aliquots were removed every hour for reading the optic density (OD 595 ) and plating onto PCA medium. The results showed that chitosan has a bactericidal effect upon S. enteritidis. Films treated with chitosan at different concentrations showed similar antimicrobial efficiency, in addition to being dependent on diffusion. The chitosan-treated films caused a reduction of one to two log cycles in the number of microorganisms, whereas the pure chitosan presented a reduction of four to six log cycles compared with the control and starch film. The films showed good flexibility.

Effect of antioxidant and optimal antimicrobial mixtures of carvacrol, grape seed extract and chitosan on different spoilage microorganisms and their application as coatings on different food matrices

“…Several researchers reported concentrations of chitosan solutions between 1% and 2% w/v for the development of chitosan films (Pranoto, Rakshit, & Salokhe, 2005;Durango et al, 2006). Therefore, the percentage of chitosan for optimization was restricted between 60% (1.2% w/v) and 70% (1.4% w/v).…”

Selection of biopolymers to develop a biodegradable and ediblefilm for packaging of luncheon chicken meat slices

“…As a result of solvent evaporation, biopolymer increased with the result that hydrogen bonds were formed and basic film structure was formed. The addition of plasticizing agent such as PEG and glycerol into the film reduced the intermolecular forces and increased thermo stability of the polymeric chains, resulting in a better flexibility (Durango et al, 2006). Then, film solution was cooled to 40°C and poured into glass petri dish of 8 inch diameter.…”

“…Coating materials that are currently in use include polysaccharides (chitin, starch, cellulose derivatives and gums), proteins (soy, milk, gelatin, corn zein, wheat gluten) and lipids (oils, waxes, resins) (Sanchéz-Gonzáles et al, 2010). Durango et al (2006) stated that polysaccharides have been used for edible films most frequently because of their excellent film forming properties derived from cellulose, starch, alginate and their mixtures.…”

Effect of Medicinal Plant Extract Incorporated Carrageenan Based Films on Shelf-Life of Chicken Breast Meat

“…Polysaccharides have been used for edible films most frequently because of their excellent film-forming properties derived from cellulose, starch, alginate, and their mixtures (Durango et al, 2006 …”