89D-6 |
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E. PONCE-ALQUICIRA1, B. Quintero-Salazar, E. J. Vernon-Carter3, and I. Guerrero-Legarreta. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) IPH, Univ. Autonoma Metropolitana-Iztapalapa Antimicrobial food packaging plays an important role in reducing the risk of pathogen development, and extending the self life of minimally processed foods. However, release of active antimicrobials from films need to be studied to develop suitable food packaging materials. The objective of this work was to study the addition of various levels of pediocin in protein films with different hydrophobic characteristics: (a) water soluble whey protein isolate (WPI) and (b) corn zein (CZ) ethanol-soluble, and to evaluate pediocin release to water and antimicrobial activity against L. innocua. CZ and WPI protein film forming solutions, were added with 0, 16666, 33333, or 50000 UA/mL freeze dried pediocin obtained from Pediococcus parvulus, and casted. Film sections of 28 mm2 were immersed in water to measure bacteriocin release, and in a L. innocua suspension (108 CFU/mL) with agitation at 100 rpm, 10° C for 24 h. Pediocin release was measured by the diffusion agar method using L. innocua as indicator; reduction of Listeria population (PALCAM-Listeria selective agar) was reported as antimicrobial activity. Pediocin release was only detected in CZ films and completed at approximately 15 min of agitation for all pediocin levels. WPI films produced a modest, but significant (P≤0.05) decrease (<0.5 log cycles) in Listeria population. While, CZ films decreased 2.5, 3.4, and 3.5 log cycles for 16666, 33333, and 50000 UA pediocin/mL, respectively. The cationic nature of the pediocin probably promoted electrostatic interactions with WPI proteins, which attach the bacteriocin into the film matrix and restrain antimicrobial activity. Conversely, the hydrophobic nature of CZ did not interact with pediocin thus allowing bacteriocin release. Nature of protein films may interfere with the antimicrobial activity of bacteriocins and reduce their effectiveness.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |