Bay Leaves Extracts as Active Additive for Food Protective Coatings

Ethanolic extracts of bay leaves were obtained using the Soxhlet method (extraction yield of 22.3 +/- 1.2%) and further analyzed through different methods, thus determining the chemical composition with gas chromatography, phenolic content with the Folin-Ciocalteu technique (11.8 +/- 0.4% wt.) and antioxidant power with the radical 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) method (75.06%). Furthermore, its effect on the growth of two bacteria, Escherichia coli and Bacillus cereus, and on two yeasts, Candida glabrata and Saccharomyces cerevisiae, was determined, showing a minimum inhibitory concentration of 0.65 mg/mL on the growth of B. cereus. Finally, edible films were prepared using different polymers (carboxymethyl cellulose, gum Arabic, polyvinyl pyrrolidone, and polyvinyl alcohol) containing 0, 5, 10, or 15% wt. of bay leaf extract as troubleshooting for perishable fruits, specifically for cultivated strawberry. The prepared composites presented reduced water vapor permeabilities (up to 4.3 x 10(-7) gPa-1m(-1)h(-1)), high specific transparencies (approximate to 30%/mm), as well as the effective blocking of ultraviolet radiation (>99.9%). In vivo tests showed that the most suitable treatment for strawberry protection was the impregnation with a composite comprising polyvinyl alcohol and a 15% wt. bay leaf extract, resulting in a noteworthy reduction in mass loss (22% after 6 days). It can be asserted that food packaging with the designed composites would be an effective alternative for the reduction in postharvest losses.

Automated summary

The ethanolic extract of bay leaves was obtained, and its chemical composition, phenolic content, and antioxidant power were analyzed. The extract also showed inhibitory effects on certain bacteria and yeasts. Edible films were prepared using different polymers and tested for their ability to protect strawberries.