Physical and antibacterial properties of alginate-based edible film incorporated with garlic oil

Antibacterial alginate-based edible film has been studied by incorporation of garlic oil as a natural antibacterial agent. Initially, 0.1% v/v garlic oil was tested in in vitro experiments against some food pathogenic bacteria. The presence of 0.1% v/v garlic oil in the nutrient broth decreased viable cell counts for Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus cereus by 2.28, 1.24, 4.31 and 5.61 log cycles, respectively after 24 h incubation. Meanwhile, an increased cell population occurred on all accompanying controls. Antimicrobial alginate films were prepared by incorporating garlic oil up to 0.4% v/v. They were characterized for antibacterial activity, mechanical and physical properties. The edible film exhibited antibacterial activity against Staphylococcus aureus and B. cereus among bacteria tested by using agar diffusion assay. Tensile strength and elongation at break were significantly (p < 0.05) changed by incorporation of garlic oil at 0.3% and 0.4% v/v, respectively. Water vapor permeability decreased significantly (p < 0.05) with 0.41% v/v garlic oil incorporation, whereas total color difference remained same until 0.4% v/v. These results revealed that garlic off has a good potential to be incorporated into alginate to make antimicrobial edible film or coating for various food applications. (C) 2004 Published by Elsevier Ltd.