Effect of Nisin on the properties of edible films prepared by gum ghatti

In order to increase the antibacterial ability of gum ghatti ( GG) film, lactic acid streptococcus ( Nisin) was selected as a natural antibacterial agent in the test, and its minimum inhibitory concentration ( MIC) and antibacterial ability were determined.The effect of Nisin on the antibacterial properties, physical properties, mechanical properties and microstructure were determined and analyzed.As a result, Nisin had better ability in inhibiting Staphylococcus aureus and Bacillus subtilis ( gram positive bacteria) than that of Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa bacteria ( gram negative bacteria) .The antibacterial effect of GG film on Staphylococcus aureus, Bacillus subtilis, Bacillus subtilis and Pseudomonas aeruginosa increased with the increase of Nisin, but not obvious effect was observed on Escherichia coli. The thickness, surface hydrophobicity and water vapor permeability ( WVP) values of films decreased with increasing Nisin concentration. Nisin concentration had significantly effect on tensile stress.However, Nisin concentration had little effect on the elongation at break of GG film ( p > 0.05) . The results will provide theoretical basis for the application of GG edible film in food storage and preservation.