ANALYSIS OF PLANT EXTRACTS WITH ANTIBACTERIAL EFFECTS AND THEIR APPLICATION IN EDIBLE ALGINATE-PECTIN FILMS

Abstract

The existing potential risks for consumers from the synthetic antimicrobial additives and the aspiration towards reduction of the possibilities for emergence of microbial resistance reinforce the trends of searching for alternative solutions to protect foods from microbial contamination. One of these solutions is the use of natural plant antibacterial compounds. The aim of this study was to examine the antibacterial activity of extracts derived from sour cherry (Prunus cerasus), St. John's Wort (Hypericum perforatum), clove (Syzygium aromaticum) and smoke tree (Cotinus coggygria). The total content of phenols was highest in the extract from smoke tree (31.80 mg GAE / mL) and clove (23.12 mg GAE / mL). All extracts had an inhibiting effect on the tested microorganisms (Staphylococcus aureus ATCC 43300 and Escherichia coli ATCC 25922). The largest inhibition zones were observed in the extracts from St. John’s Wort and smoke tree. A very good result was obtained through the combination of extracts from St. John’s Wort and clove (39 mm for Staphylococcus aureus and 20 mm for Escherichia coli). The extracts from smoke tree and the combination of St. John’s Wort and clove extracts preserved their high degree of antibacterial activity when they were included in edible alginate-pectin films. The films obtained in this way may be used in packaging to help reduce the microbial population on the surface of food products.