Optimizing the viability of lactic acid bacteria incorporated into chitosan films

Abstract

Cells entrapment in polymeric matrices is a strategy employed to maintain viability. Chitosan has functional properties that make it suitable for making films containing microorganisms. Using a Plackett Burman and Response Surface design, seven factors were evaluated and the components of the chitosan biofilm were combined for optimizing the viability of lactic acid bacteria incorporated into the matrix. A viability of 39.32% was maintained in the factor screening stage, with the type of chitosan and the type of organic acid having the greatest effect. The concentration of cells and the type of carbohydrate used had no effect on viability. After optimizing the factors, 106 CFU mL-1 of lactic acid bacteria were incorporated into films with the composition of 1.5% low molecular weight chitosan, 1.5% lactic acid, pH 4.5, 0.1 M lactose and stored under 90% RH conditions. Films made under these conditions maintained 90.75% of cell viability after 7 days of storage. Our results demonstrate that the antimicrobial effect of chitosan does not greatly affect the viability of BALs in short storage periods.