73D-8 |
Preparation and diffusion rate of nisin-incorporated antimicrobial film |
D. S. CHA1, H. J. Park1, and D. K. Cooksey2. (1) Graduate School of Biotechnology, Korea Univ., 5Ka Anam-Dong, Sungbuk-Ku, Seoul, 136-701, South Korea, (2) Dept. of Packaging Science, Clemson Univ., 228 Pool Agricultural Center, Clemson, SC 29634-0370 The antibiotic nisin consists of more than one polypeptide with a low molecular weight. Nisin is heat-stable but degraded by proteolytic enzymes in the human intestinal tract. Since nisin is being used in a wide range as a food antimicrobial agent in many countries. Its incorporation into biodegradable films may have a great potential in active packaging system. Our objectives were a) to manufacture the nisin-incorporated biopolymer films by heat press and casting method b) to determine the release rate of nisin from the films. Two film-forming methods, a heat-press and a casting method, were used. The heat press method: Components of antimicrobial film were mixed in a mortar and pestle, weighed onto an aluminum plates, heat pressed using a Carver press (model 2629) for 1 min at 100°É and 1,500 Ib/in2. Nisin was added to the film mixtures, K-carrageenan, methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) with polyethylene (PE), during the mixing stage using a mortar and pestle. A control mixture (without an antibacterial compound) was made using PE. The casting method: A MC/HPMC coating film solution was applied to the surface of PE using a thin-layer chromatography (TLC) plate coater set at a thickness of 0.75mm. Detection of nisin activity: The agar well diffusion method was used to detect the nisin activity against Micrococcus luteus NCIB8166 (ATCC 10240). Both heat press and casting methods with nisin formed excellent films and exhibited strong inhibition of Micrococcus luteus. The cast films exhibited larger inhibitory zones, as compared to the heat press films, when the same levels of nisin were incorporated. Release rate of nisin from MC was faster than that of K-carrageenan or HPMC. Nisin incorporated films have a great potential to be used as an antimicrobial film in a food system.
Session 73D, Food Packaging
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