Antimicrobial effects of chitosans and chitooligosaccharides, upon Staphylococcus aureus and Escherichia coli, in food model systems
Antimicrobial effects of chitosans and chitooligosaccharides, upon Staphylococcus aureus and Escherichia coli, in food model systems
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DOI：
10.1016/j.fm.2008.05.003
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发表时间：
2008-10-01
影响因子：
5.3
通讯作者：
Malcata, F. Xavier
中科院分区：
文献类型：
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作者：
Fernandes, Joao C.;Tavaria, Freni K.;Malcata, F. Xavier
本研究的目的是阐明壳聚糖的分子量 (MW) 与其抗菌活性（不同接种水平、多种浓度）之间存在争议的关系。食物成分对活动的影响也得到了确定，并得到了感官小组的认可。所有测试的化合物均表现出对金黄色葡萄球菌和大肠杆菌的抗菌活性。该活性与接种量、分子量和使用浓度密切相关。在 10(3) 个细胞/mL 的 4 小时内，所有五种化合物在每个浓度（0.5%、0.25% 和 0.1%，w/v）下均被证明具有杀菌作用；对于较高级的接种物，0.1% (w/v) 仅具有抑菌作用：在 10(7) 或 10(5) 个细胞/mL 下，并且与接种物水平无关，0.25% (w/v) 的任何壳寡糖 (COS) 混合物足以将大肠杆菌初始种群减少至少 3 个对数周期； COS 从未表现出对金黄色葡萄球菌的杀菌作用，与高和中 MW 壳聚糖不同，高和中 MW 壳聚糖即使在 0.5% (w/v) 下，甚至对 10(7) 个细胞/mL 也具有杀菌作用。当掺入液体食品基质中时，中和高 MW 壳聚糖对基质和细菌都保持其活性，尽管在牛奶中活性较慢，但 COS 在 4-8 后对牛奶中的两种细菌都失去了活性。 h.此外，在苹果汁中添加壳聚糖会导致一些令人不快的异味，例如涩味和后味，MW (C) 2008 Elsevier Ltd. 保留所有权利。
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 10(3) 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 10(7) or 10(5) 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 10(7) 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 (C) 2008 Elsevier Ltd. All rights reserved.