83B-11 |
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E. PONCE-ALQUICIRA, Departamento de Biotecnologia, Universidad Autonoma Metropolitana, Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Mexico D.F., 09340, Mexico, I. Guerrero-Legarreta, B. Quintero-Salazar, Biotecnología, Mexico D.F., 09340, Mexico, and J. Vernon-Carter, IB-IPH. Microbial growth is one of the most critical factors in food quality. Bacteriocins such as pediocin, can be incorporated into edible films as natural antimicrobial agents. However, antimicrobial activity could be diminished due to bacteriocin denaturation during film formation, or as a result of bacteriocin binding to the film matrix. The objective of this work was to incorporate pediocin into zein based films and to measure the effect of pediocin concentration on film antimicrobial activity, as well as pediocin release rate from the films. Concentrations from 0 to 7.5 mg/mL of freeze-dried pediocin produced by Pediococcus parvulus were incorporated to zein solutions using glycerol as plasticizer, films were prepared by the casting method. Antibacterial activity was measured by placing film portions in peptone water previously inoculated with L. innocua (10-6- 10-7 cfu/mL). Listeria populations were analyzed from 0 to 8 h. The amount of pediocin released from films into phosphate buffer (50mM, pH7) as test media, was analyzed by the agar well diffusion method, using Listeria innocua as indicator; after incubation (30ºC, 24h) the diameter of inhibition zones was measured and pediocin concentration estimated using a standard assay curve. Antibacterial activity of zein films increased with pediocin concentration as Listeria population decreased in 3 and 5 log cycles when 2.5 and 7.5 mg/mL of pediocin, respectively were incorporated into the film. Eighty percent of pediocin was released after five hours to the media, independently of pediocin concentration. Release pediocin and antimicrobial activity were highly correlated. Addition of 2.5 mg/mL pediocin to the film solution was enough to inhibit of L. innocua, this concentration could be taken as a reference for future studies.
Session 83B, Food Packaging: Applications of edible coatings, antimicrobial films, and sensors in food packaging
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