Preparation Of Edible Antimicrobial Film And Its Application In The Cheese Storage

Research and development of safe, non-toxic and even pure natural edible antimicrobial film is a key technical problem in the cheese industry.This paper is mainly based on sodium caseinate,chitosan and glycerol as base material for preparing edible film, the single factor experiment was carried out with the 3 kinds of substrate as the factors and the adding amount as the change level.the result showed that:(1) Increasing the amount of sodium caseinate and chitosan could increase the mechanical strength of edible film, and the increase of the amount of glycerol could significantly increase the elongation at break of edible film. Considering the strength and elongation characteristics of edible film, the levels of sodium caseinate, chitosan and glycerol were determined by 3%-5%, 1%-2%and 2%-3%, respectively.(2) Design orthogonal test with the 3 factors 3 levels was carried out. The results showed that the film forming substrate to edible film of water soluble, elongation at break, tensile strength and Young’s modulus of significant sequence were:chitosan> glycerol> caseinate sodium. The edible film with good comprehensive performance was obtained wih 5% sodium caseinate aqueous solution,2% chitosan acetic acid solution and 2% glycerol.The water solubility of the film was 35.8%,the elongation at break was 75.4%,the tensile strength was 10.58MPa and the elastic modulus was 13.47Mpa.(3) Using response surface analysis method, using chitosan and natamycin and lysozyme as variables, to surface smear cheese samples of edible film liquid light absorption value as the measure of inhibitory effect index, and ultimately determine the natamycin 0.07g/100mL base fluid, lysozyme 1.0g/100mL base fluid, ultimately determined natamycin and Lysozyme 0.07g and 1 g per 1 OOmL base liquid respectively. Under these conditions, the inhibitory effect is best.(4) With sodium caseinate-chitosan film, sodium caseinate-chitosan natamycin film, sodium caseinate-chitosan-lysozyme film and sodium caseinate-chitosan-natamycin/ lysozyme film wrapped cheese samples, in the surface of inoculated bacteria and storage experiment. The results showed that sodium caseinate-chitosan-natamycin antibacterial film of inoculation with E.coli, yeasts and molds the cheese had obvious effect of growth inhibition; sodium caseinate-chitosan-lysozyme antibacterial film, sodium caseinate-chitosan natamycin/lysozyme antibacterial film of inoculated with Staphylococcus aureus cheese showed a certain antibacterial;sodium caseinate-chitosan antibacterial film, sodium caseinate-chitosan natamycin antibacterial film, sodium caseinate-chitosan natamycin/ lysozyme antibacterial film of inoculation with Pseudomonas cheese had bacteriostatic action.