| Abstract
| - To develop biodegradable packaging that both acts as a moisture barrier and as antimicrobial activity,nisin and stearic acid were incorporated into a hydroxy propyl methyl cellulose (HPMC) based film.Fifteen percent (w/w HPMC) of stearic acid improved film moisture barrier. However, film mechanicalresistance and film antimicrobial activity on Listeria monocytogenes and Staphylococcus aureuspathogenic strains were both reduced. This lower film inhibitory activity was due to interactions betweennisin and stearic acid. The molecular interaction was modeled, and an equation was developed tocalculate the nisin concentration needed to be incorporated into the film matrix to obtain a desiredresidual antimicrobial activity. Because the molecular interactions were pH dependent, the impact ofthe pH of the film-forming solution on film inhibitory activity was investigated. Adjusting the pH to 3totally avoided stearic acid and nisin interaction, inducing a high film inhibitory activity. Keywords: Carbohydrate edible packaging; polypeptide nisin; fatty acid; electrostatic interactions
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