Antimicrobial activity and physicochemical characterization of a potato starch-based film containing acetonic and methanolic extracts of Hibiscus sabdariffa for use in sausage

In this study, acetone and methanol extracts of Hibiscus sabdariffa were obtained and used to supplement films made with potato starch and glycerol as plasticizers. Antimicrobial tests were carried out on the extracts and films, and the growth of Listeria monocytogenes was evaluated in film-coated sausage. The physicochemical properties of the processed films were evaluated. In in vitro tests, the acetonic extract produced greater inhibition halos than did the methanolic extract, with Escherichia coli being the most sensitive bacterial strain assayed. In the antimicrobial tests of the films, the most significant effect was observed for the films containing acetonic extract. When coated onto sausages, a more significant inhibitory effect against L. monocytogenes was observed when the sausage was vacuum-packed. The addition of extracts produced noticeable changes in the films, with those containing methanolic extracts exhibiting major changes. The glass transition temperature of the films was lower when methanolic extract was added than when acetonic extract Furthermore, the fracture tension was more greatly affected in the films containing methanolic extract. The permeability of the films containing methanolic extract was lower than that of the other films. These films also exhibited antimicrobial activity, and the addition of extracts modified their physicochemical properties.