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首页> 外文期刊>Food microbiology >Antimicrobial effects of chitosans and chitooligosaccharides, upon Staphylococcus aureus and Escherichia coli, in food model systems
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Antimicrobial effects of chitosans and chitooligosaccharides, upon Staphylococcus aureus and Escherichia coli, in food model systems

机译：食品模型系统中壳聚糖和壳寡糖对金黄色葡萄球菌和大肠杆菌的抗菌作用

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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 4h 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.
机译：这项研究的目的是阐明壳聚糖的分子量（MW）与它们的抗菌活性之间的争议关系（在不同浓度下，接种量不同）。还确定了食物成分对活性的影响，以及感觉小组的认可。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。已证明该活性与接种物水平，分子量和所用浓度密切相关。在10到3个细胞/毫升的情况下，在4小时内，所有浓度（0.5％，0.25％和0.1％，w / v）的所有五种化合物均具有杀菌作用。对于较高的接种量，0.1％（w / v）仅具有抑菌作用。以10〜7或10〜5个细胞/ mL的浓度，与接种量无关，0.25％（w / v）的任何壳寡糖（COS）混合物足以使大肠杆菌的初始种群减少至少3个对数周期；与高分子量和中等分子量的壳聚糖不同，COS从未对金黄色葡萄球菌具有杀菌作用，后者的含量为0.5％（w / v），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，中等和高分子量的壳聚糖对基质和细菌均保持其活性，尽管牛奶中的活性明显降低；但是，COS在4-8小时后对牛奶中的两种细菌失去活性。此外，向苹果汁中添加脱乙酰壳多糖会导致几种令人不愉快的异味，例如涩味和余味，随MW的增加而增加。

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