Bioatividade de quitosana produzida por Mucor rouxii no controle de Listeria monocytogenes em produto cÃrneo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In last years consumers has demanded for safe foods, especially regarding their microbiological contamination, being still worrying with the damages posed by microbial foodborne diseases, as well as the side effects related to the use abusive use of synthetic additives added to foods, particularly to meat products. In this perspective, the study of new natural and non toxic food additives looking for the replacement of synthetic preservatives has received special attention for researchers all over the world. Chitosan, a natural polymer, biodegradable, highly abundant and non toxic, has been highlighted as potential antimicrobial for use in natural food conservation systems for researches all over the world. Among many meat products-contaminating microorganisms, the high physiological resistance of Listeria monocytogenes and capability of surviving and multiplying in foods stored under refrigeration makes it a threat for the health of consumers and a worrying for the industry of meat products, mainly in ready-to-eat ones. The objective of this study was to evaluate the growth profile and chitosan production by Mucor rouxii UCP 064 grown in yam bean (Pachyrhizus erosus L. Urban) medium, as well to assess the anti-L. monocytogenes efficacy of the obtained chitosan in order to a possible application in foods. The production of chitosan was carried out by submerse of M. rouxii in yam bean media at 28 ÂC, in an orbital shaker at 150 rpm, for 96 houurs. During the cultivation aliquots werw collected every 24 hours for biomass, chitosan production, pH, glucose and total nitrogen determination. The polysaccharide was extracted by alkali-acid treatment and chitosan characterized by infrared spectroscopy and viscosity. Higher value of biomass of M. rouxii (16.9g.L-1) and best yield the chitosan (62 mg.g-1) was found after 48 hours of cultivation. Residual glucose and nitrogen in the growth media were 4.1 and 0.02 g.L-1, respectively, after 96 h. Obtained chitosan presented 85% of degree of deacetylation and 2.60 x 104 g.mol-1 of molecular weight. MIC and MBC values of chitosan against L. monocytogenes ATCC 7664 were, respectively, 2.5 and 5.0 μg.mL-1. The addition of 5 mg.g-1 of chitosan from M. rouxii significantly reduced counts L. monocytogenes. These results show the biotechonological potential of yam bean medium for chitosan from fungi as natural antimicrobial to control L. monocytogenes in foods

ASSUNTO(S)

nutricao quitosana antilisterial antilisterial meat products chitosan produtos cÃrneo

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