Introduction.

There are reports of the use of biofilms as a support for the incorporation of beneficial microorganisms, however, there are scarce the reports where the antimicrobial capacity of biofilms containing lactic acid bacteria (LAB) is evaluated.

Objective.

Optimize the components of an edible biofilm based on chitosan to preserve the viability and antifungal capacity of the LAB Lactobacillus plantarum CDBB-B-1091 for 28 days.

Methods.

Through a design Plackett-Burman of 8 treatments, two levels of 7 factors (componente) were evaluated (glucose, lactose, glycerol, starch, relative humidity, pH, BAL concentration). Of the factors that showed effect, the concentration was optimized using the response surface methodology based on a Box-Benhken arrangement.

Results.

It was found that cell concentration (A), starch concentration (B) and glucose concentration (C) are the most determining biofilm components to maintain viability and antifungal ability against the phytopathogenic fungus Colletotrichum gloeosporioides. Optimal values were obtained by response surface analysis to maintain the viability of the bacteria for 28 days, the values being 7.009164 log CFU/g film for factor A, 1.997712% for B and 0.10750016 M for factor C. According to ANOVA the concentration of cells being the most influential factor. However, for the antifungal capacity it was only possible to obtain 100% inhibition with freshly made films, for this day the optimal values of 8.9004 log (CFU/g) for factor A, 2.0% for B and 0.0850143 M for C.

Conclusion.

The antifungal capacity of the biofilms containing BAL was decreasing as the storage of the biofilms passed. Even with the above, regression models are proposed to predict the viability values and the antifungal capacity of biofilms containing the bacterium Lactobacillus plantarum CDBB-B-1091.

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