对羟基苯甲酸酯衍生物的抗菌活性及其发展趋势

介绍了新型高效食品防腐剂对羟基苯甲酸酯衍生物的抗菌活性，阐述了对羟基苯甲酸酯衍生物的生产现状和在食品工业应用研究的发展趋势。     

三种苯甲酸类抗菌剂的活性-结构关系研究

对苯甲酸钠、苯甲酸甲酯及苯甲酸苄酯三种物质的抗菌性能进行了实验比较研究,发现苯甲酸甲酯比苯甲酸苄酯具有更强的抗菌强度和抗代谢能力,而苯甲酸盐类的抗菌性较强,但受介质pH的限制。同时,基于量子化学理论,采用CNDO算法,重点从分子结构的角度对三者的活性进行分析,对实验结果加以确证。     

山梨酸对禽肉的保鲜研究

山梨酸为不饱和六碳酸。里无色针状结晶或白色结晶粉末，无味，对光、热稳定，易溶于乙醇、乙醚，具有抑制霉菌和较高的抗菌活性。山梨酸比目前常用的防腐剂苯甲酸、对羟基苯甲酸酯的毒性小，日允许量值为25mg／kg，为苯甲酸的5倍、羟基苯甲酸酯的2．5倍。     

量子化学在食品防腐剂构效关系中的应用

本文对食品防腐剂的抗菌效果与防腐剂分子构象、电荷密度及分布、电荷转移及代谢转化等量子化学参数间的关系进行了讨论。对一些防腐剂的抗菌活性与其分子性质参数间进行了相关分析。结果表明防腐剂分子的前沿轨道能差是决定抗菌性能的一个极为重要的参数。防腐剂的抗菌强度与最高占有轨道能量呈正比。而抗微生物代谢性能则与最低空轨道能量呈反比。     

量子化学在食品防腐剂构效关系中的应用

本文对食品防腐剂的抗菌效果与防腐剂分子构象、电行密度及分布、电行转移及代谢转化等量子化学参数间的关系进行了讨论．对一些防腐剂的抗菌活性与其分子性质参数间进行了相关分析．结果表明防腐剂分子的前沿轨道能差是决定抗菌性能的一个极为重要的参数．防腐剂的抗菌强度与最高占有轨道能量呈正比．而抗微生物代谢性能则与最低空轨道能量呈反比．     

肉桂醛,酸类化合物抗菌活性的特征及其与化学结构关系的研究

本文对肉桂醛、酸及其衍生物的抑菌效果进行了测定，对其量子化学参数进行了计算，并对这类化合物抗菌活性分子化学结构之间的关系进行了相关分析。结果表明，该类化合物抑菌率ＥＦＰＯ、ＥＬＵＭＯ和ＥＨＯＭＤ的相关系数分别为－０．７８１４、０．７３２８和０．６３１８。该类化合物的抗菌活性中心原子可能是碳基氧、α－碳、β－碳，由这些原子组成的不饱和羰基共轭体系可能是抗菌剂的活性功能率。     

对羟基苯甲酸酯类化合物抗菌活性的定量构效关系探讨

基于定量结构-活性关系(QSAR)研究对羟基苯甲酸酯类化合物性质具有重要意义。本文采用量子化学密度泛函理论(DFT)和逐步回归分析法研究了具有抗菌活性的11种对羟基苯甲酸酯类化合物的定量构效关系。在B3LYP/6-31G*水平上计算了对羟基苯甲酸酯类化合物的相关量子化学参数,得到在最稳定构型下分子结构参数,通过多元逐步回归分析筛选出对羟基苯甲酸酯类化合物影响抗大肠杆菌活性的主要因素并建立定量构效关系方程,采用留一法分析模型的稳定性及预测能力。结果表明对羟基苯甲酸酯类化合物抗大肠杆菌活性与最低空轨道能量(ELUMO)及偶极距(μ)呈正相关关系,QSAR模型表明化合物的最低空轨道能量、偶极距和极化率是影响对羟基苯甲酸酯类化合物抗菌活性的主要因素,ELUMO和μ越大,抗菌活性越大,所得QSAR模型对该类化合物抗菌活性有较好的预测效果。     

对羟基苯甲酸壳聚糖酯的制备、表征和抗菌活性

壳聚糖经氨基保护、与对乙酰氧基苯甲酰氯发生酯化、再水合肼去保护合成得到了对羟基苯甲酸壳聚糖酯。在适宜的反应条件下，对羟基苯甲酸壳聚糖酯酯化度可达130％、得率80％以上。产物经IR分析，酸与壳聚糖之间生成了酯，该酯溶解性略优于对羟基苯甲酸庚酯，而醇溶性显著提高：对大肠杆菌和金黄色葡萄球菌抗菌试验表明，该酯抗菌活性大于对羟基苯甲酸庚酯，更优于壳聚糖。     

对羟基苯甲酸酯衍生物的理化性质及其在食品中的应用

介绍了新型高效食品防腐剂对羟基苯甲酸酯衍生物的结构通式和产品特性，同时阐述了对羟基苯甲酸酯衍生物在食品工业领域的应用和发展前景。     

对羟基苯甲酸酯衍生物的使用安全性和复配效果

介绍了新型高效食品防腐剂对羟基苯甲酸酯衍生物在食品工业中的使用安全性和复配增效效果，同时阐述了对羟基苯甲酸酯衍生物的研究发展趋势。     

乳酸菌抗菌肽抗菌机理的研究进展——乳酸菌抗菌肽抗菌机理

乳酸菌抗茵肽是乳酸菌代谢过程产生的一类具有活性的多肽或蛋白质物质,可抑制或杀死食品中的病原茵或腐败菌。近几年,乳酸茵对其他细菌的拮抗作用的机理研究得最多的是乳酸菌抗茵肽,在食品行业中具有广泛的应用前景,这是由于乳酸茵抗茵肽被认为是一种“天然”的食品添加剂而容易被接受。对乳酸菌抗菌肽作用机理的研究可为其在食品安全生产加工业中的应用奠定了基础。本文综述了乳酸菌抗茵肽的分类及作用机制的最新研究进展。     

Antimicrobial activity of enterococci strains isolated from white cheese

Twelve strains of enterococci isolated from white cheese samples obtained from different regions of Turkey were screened for their antimicrobial activity against some Gram-positive and Gram-negative food-borne pathogens and contaminating bacteria, also against themselves and some other lactic acid bacteria (LAB), including some species of lactococci, lactobacilli and Leuconostoc . Antimicrobial activity was confirmed for all 12 strains, including six Enterococcus faecium , two Enterococcus faecalis and four Enterococcus durans . Antimicrobial agents produced by these enterococci exhibited a spectrum of activity, which is mainly directed against food-borne pathogens, specially Listeria monocytogenes and Bacillus cereus and some other Bacillus spp. and also some enterococci. Tested LAB was insensitive to inhibitory agents produced by them.     

Antimicrobial proteinaceous compounds obtained from bifidobacteria: from production to their application

Antimicrobial proteinaceous compounds such as bacteriocins or bacteriocin-like compounds produced by bifidobacteria are largely unknown but have been found to have potent antimicrobial activities toward closely related bacteria and undesirable harmful microorganisms. They are useful in the fields of food preservation or safety, health care, and pharmaceutical applications. The inhibition activity of these substances has been reported to be strain-dependent. Binding to the epithelial cell on the gastrointestinal surfaces is one of the important factors of resident microflora to colonize the intestine. Certain Bifidobacterium strains are able to produce substances that compete and prevent pathogenic bacteria from adhering to the receptors on epithelial cells of intestinal surfaces. The potential probiotic effects of bifidobacteria is well known in the human ecosystem and their production of antimicrobial peptides can contribute to elucidate the precise mechanisms by which bifidobacteria can dominate the intestinal microbiota and achieve their probiotic function. This paper presents a review of the antimicrobial proteinaceous compounds produced by various Bifidobacterium strains, the attempts made to purify them, their characterization, identification and useful applications.     

Antimicrobial properties of chitosan and mode of action: a state of the art review

Owing to its high biodegradability, and nontoxicity and antimicrobial properties, chitosan is widely-used as an antimicrobial agent either alone or blended with other natural polymers. To broaden chitosan's antimicrobial applicability, comprehensive knowledge of its activity is necessary. The paper reviews the current trend of investigation on antimicrobial activities of chitosan and its mode of action. Chitosan-mediated inhibition is affected by several factors can be classified into four types as intrinsic, environmental, microorganism and physical state, according to their respective roles. In this review, different physical states are comparatively discussed. Mode of antimicrobial action is discussed in parts of the active compound (chitosan) and the target (microorganisms) collectively and independently in same complex. Finally, the general antimicrobial applications of chitosan and perspectives about future studies in this field are considered.     

抗菌肽功能特性与作用机制的研究进展

抗菌肽是核糖体合成的天然抗生素,是多细胞生物体免疫系统的一部分。抗菌肽的来源广泛,氨基酸的组成和结构差异很大,具有快速杀伤以及广谱的抗菌活性。随着抗菌肽种类越来越多,对其抗菌机制及构效关系的研究成为学者们关注的热点。文章系统地阐述了抗菌肽的来源和功能特性、抑菌机制以及构效关系。     

Migration of Antimicrobial Silver from Composites of Polylactide with Silver Zeolites

ABSTRACT: Silver ion migration and antimicrobial activity of PLA (polylactic acid-polylactide)/silver zeolite composites were investigated. Films prepared by solution-casting/solvent evaporation, or by melt-mixing/compression molding were compared. Silver migration to food simulants and TSB (tryptone soy broth) was quantified at different temperatures. Antimicrobial activity against Staphylococcus aureus and Escherichia coli was measured following the Japanese Industrial Standard JIS Z 2801. All types of PLA/silver zeolite composites released Ag⁺ ions. A more intense ionic exchange with the zeolites and a significant, but low, antimicrobial activity in solution were found in cast films. To attain antimicrobial effects, however, migrated ions ought to be in the range of the legal limit of 0.05 mg Ag⁺/kg food stated by the European Food Safety Agency (EFSA). Silver migration and antimicrobial activity were sensitive to the methodology chosen to process the PLA films, the ionic strength of the medium, and the ion motility in the polymer matrix. Practical Application: Silver exchanged zeolites incorporated in food contact polymers are gaining importance as antimicrobial agents. Migration of silver ions from polymer matrices, however, is legally restricted. Therefore a compromise between silver migration and antimicrobial activity needs to be critically analyzed to validate novel materials in food packaging applications.     

Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing microorganisms

The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged and interacts with positively charged lysozyme by electrostatic attraction. Application of the lysozyme-containing starch particles to environments contaminated with microbes, may lead to hydrolysis of the starch by microbial enzymes. As a result, lysozyme is released in the environment where it inhibits microbial growth. In this study, first bacteria were screened for amylase production and lysozyme sensitivity. Then, the bacteria were mixed with empty gel particles (i.e., without lysozyme) in a Nutrient Broth liquid medium to test whether the bacteria that can produce amylase are also able to degrade oxidized starch gel. Subsequently the amylase-producing lysozyme sensitive bacteria, Bacillus licheniformis 7558 and Bacillus subtilis 168, were selected for further quantification of the antimicrobial activity of the gel-lysozyme particles after incubation with these bacteria in Nutrient Broth liquid suspensions. The results prove that the starch microgel has a potential as antimicrobial carrier targeting amylase-producing and lysozyme-sensitive bacteria. The controlled antimicrobial delivery for inactivating undesired microorganisms may find applications in food related systems, where amylase-producing bacteria may be abundantly present.     

油菜抗菌肽基因BnCRP1的克隆表达和活性分析

通过生物信息学的方法,充分利用甘蓝型油菜组织转录组测序数据和已有的抗菌肽数据库,筛选获得一个核苷酸长度为102 bp,编码34个氨基酸长度的新型抗菌肽基因BnCRP1,BnCRP1抗菌肽序列中有9个半胱氨酸,半胱氨酸含量超过27%,是一种新型的植物来源的半胱氨酸富集类抗菌肽(Cystin rich protein CRPs),在抗菌肽分类中属于打结素类抗菌肽(Knottin-like Peptides)。抑菌活性检测结果表明抗菌肽BnCRP1对细菌和真菌都具有较强的抑菌活性。拟南芥离体叶片涂抹接菌实验证实,BnCRP1能够显著增强植物对腐生营养型真菌核盘菌的抗性,能够作为生防制剂用于菌核病的防治中,还可以作为一个新基因源用于植物基因工程,以培育抗病转基因植物。本研究为利用生物信息手段和基因工程技术大规模鉴定新植物来源抗菌肽提供参考。     

鲫鱼鱼鳞抗菌多肽的制备纯化及其抑菌活性

以鲫鱼鱼鳞为原料,对其预处理后采用柠檬酸浸提酶解等工艺得到鱼鳞抗菌多肽粗酶解液,经透析后,再依次经Sephadex G-15、Sephadex G-50凝胶过滤层析和纤维素DEAE-52阴离子交换层析对其进行分离纯化,最后得到具有较强抑菌活性的鲫鱼鱼鳞抗菌多肽,并对其进行分子质量分析以及对多种细菌、霉菌的抑菌活性和最小抑菌浓度（minimal inhibitory concentration,MIC）测定。结果表明：经分离纯化后得到的具有抑菌活性的蛋白组分AcIII,十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示为单一条带,表明其已达到电泳级纯,其分子质量约为20.1 kDa,抑菌活性测定结果表明鲫鱼鱼鳞抗菌多肽具有很好的广谱抗菌活性,对金黄色葡萄球菌、枯草芽孢杆菌、白色葡萄球菌、副溶血性弧菌、假单胞菌和希瓦氏菌的MIC为16 μg/mL,对大肠杆菌和沙门氏菌的MIC为32 μg/mL。     

海洋生物抗菌肽研究进展及其在生物防治中的应用前景

抗菌肽是一种具有抗菌活性的生物短肽,广泛存在于生物界中。本文综述了抗菌肽的几种类型及作用机理,介绍了海洋生物抗菌肽的研究状况、存在的主要问题及其在生物防治中的应用前景。