Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.14/2726
Título: Antimicrobial effects of chitosans and chitooligosaccharides, upon Staphylococcus aureus and Escherichia coli, in food model systems
Autor: Fernandes, João C.
Tavaria, Freni K.
Soares, José C.
Ramos, Óscar S.
Monteiro, M. João
Pintado, Manuela E.
Malcata, F. Xavier
Palavras-chave: Bactericidal
Molecular weight
Juice
Milk
Gram-positive
Gram-negative
Data: 2008
Editora: Elsevier
Citação: "Food Microbiology". ISSN 0740-0020. 25: 7 (2008) 922– 928
Resumo: The objective of this study was to elucidate the controversial relationship between the molecular weight (MW) of chitosans and their antibacterial activity (upon different inoculum levels, at several concentrations). The influence of food components on the activity was also ascertained, as well as acceptance by a sensory panel. All the compounds tested exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. This activity was shown to be closely dependent on the inoculum level, MW and concentration used. Within 4 h at 10³ cells/mL, all five compounds, at every concentration (0.5%, 0.25% and 0.1%, w/v), proved to be bactericidal; for higher inocula, 0.1% (w/v) was only bacteriostatic; at 107 or 105 cells/mL, and independently of the inoculum level, 0.25% (w/v) of any chitooligosaccharide (COS) mixture was sufficient to reduce the E. coli initial population by at least 3 log cycles; COS never exhibited bactericidal action over S. aureus, unlike high and medium MW chitosans—which, at 0.5% (w/v), presented a bactericidal effect even against 107 cells/mL. When incorporated in liquid food matrices, medium and high MW chitosans maintained their activity, for both matrices and bacteria, although a slower activity was noticeable in milk; however, COS lost their activity upon both bacteria in milk after 4–8 h. Furthermore, addition of chitosans to apple juice led to several unpleasant off-flavors, such as astringency and after taste—which increased in magnitude with MW.
URI: http://hdl.handle.net/10400.14/2726
Versão do Editor: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WFP-4SK62VM-1&_user=2460358&_coverDate=10%2F31%2F2008&_alid=1490227552&_rdoc=2&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=6800&_sort=r&_st=13&_docanchor=&view=c&_ct=2&_acct=C000057417&_version=1&_urlVersion=0&_userid=2460358&md5=9f669ae2d8f9a651b4096e802080f335&searchtype=a
Aparece nas colecções:ESB - Artigos em revistas internacionais com Arbitragem / Papers in international journals with Peer-review

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