复配精油抑菌剂的制备及其对鲜切猪肉的抑菌作用

通过水蒸气蒸馏法提取肉桂精油(cinnamon essential oil, CEO)、紫苏精油(perilla essential oil, PEO)和牛至精油(oregano essential oil, OEO),采用微量二倍稀释法测定单一植物精油的最小抑菌浓度(minimal inhibitory concentration, MIC),用棋盘稀释法计算复配精油的分级抑菌浓度指数,并探究复配精油的抑菌效果及对鲜切猪肉的保鲜抑菌作用。结果表明,3种精油对大肠杆菌及金黄色葡萄球菌均有抑菌作用,抑菌能力的大小表现为肉桂精油>紫苏精油>牛至精油;精油复配后存在协同或相加现象,其中,肉桂-紫苏精油复配剂对2种供试菌种的抑菌效果显著优于肉桂-牛至精油复配剂和紫苏-牛至精油复配剂。肉桂-紫苏精油复配在一定程度上能有效抑制鲜切猪肉水分及蛋白质含量的损耗,抑制微生物生长并保持鲜猪肉的色泽,证明肉桂-紫苏精油复配剂对鲜切猪肉具有一定的保鲜抑菌作用。     

紫薯色素与防腐剂复配抑菌作用研究

用酸化乙醇[1.5mol/L盐酸∶95％乙醇(v/v) =15∶85]溶剂对紫薯色素进行提取,并用AB-8大孔树脂纯化,纯化后的花色苷经过减压浓缩(40℃)可得到紫甘薯花色苷浓缩液(200.02mg/L).将紫甘薯花色苷浓缩液冷冻干燥后,做抑菌试验,对大肠杆菌的最小抑菌浓度(MIC)为5mg/mL.根据GB2760-2011《食品添加剂使用标准》,用不同浓度的食品防腐剂山梨酸钾、苯甲酸钠对大肠杆菌做抑菌试验的单因素分析.在单因素试验的基础上,将紫薯色素作为抑菌物质与食品防腐剂山梨酸钾、苯甲酸钠进行复配,应用Design-expert 7.1.6响应面软件技术,以复配物抑制大肠杆菌抑菌圈直径为指标利用响应面法对复配比进行优化.结果表明,复配物最佳抑菌配比为:山梨酸钾0.51 mg/mL,苯甲酸钠0.30mg/mL,紫薯色素7.04mg/mL.在此条件下得到的理论抑菌圈直径为18.1mm,实验得实际抑菌圈直径为18.0mm,与理论预测值非常接近,具有应用价值.     

壳聚糖的结构及抑菌作用

本文综述了壳聚糖的结构,并对壳聚糖抑菌性能进行了介绍.     

多功能复配液应用于纸质文物保护

将纳米氧化镁、羟乙基纤维素、聚氧化乙烯和纳米二氧化钛复配制备具有脱酸、加固和抗菌功能的多功能复配液,并将其应用在纸质文物的脱酸和修复方面。结果表明,经过复配液处理后,纸张表面pH值从3.69提升至8.75,碱残留达到0.620 mol/kg,纸张抗张强度由421 N/m提升至546 N/m;再经热老化后,纸张表面pH值仍能达到8.21,碱残留达到0.600 mol/kg,抗张强度仍能保持在521 N/m,从而起到了持续保护的作用。复配液处理后的纸张具有一定的抑菌效果,抑菌圈直径达到28 mm。     

壳聚糖、溶菌酶和牛至油对大豆分离蛋白膜抑菌效果的影响

采用双倍稀释法研究壳聚糖、溶菌酶和牛至油对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度。采用抑菌圈法研究添加天然抑菌剂壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉的抑菌效果。结果表明,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉均有抑制作用。对大肠杆菌和金黄色葡萄球菌抑制效果为:牛至油>壳聚糖>溶菌酶。对酿酒酵母的抑制效果为:壳聚糖>牛至油>溶菌酶;对黑曲霉的抑制效果为:牛至油>壳聚糖>溶菌酶。因此,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜具有较好的抑菌效果和应用前景。     

几种植物提取液的抑真菌特性及复配研究

从39 种植物中筛选抑菌作用显著的3 种材料为丁香、肉桂、山奈。用其提取液进行复配实验,确定植物提取液的最佳配比。采用二倍稀释法测定丁香、肉桂、山奈及其复配液对黑曲霉、米曲霉、黑根霉、生香酵母菌的最小抑菌浓度(MIC),并进一步研究复配液对温度、pH 值、紫外光照射的稳定性。结果表明：提取液的最佳配比为5:3:2(V/V)。复配液对供试菌的最小抑菌浓度均为1.25%,与丁香效果大致相同,比肉桂和山奈单独作用有明显增强,并且温度、pH 值、紫外光照射对复配液的稳定性影响不显著。     

微生物源溶菌酶的抑菌及抗炎活性

为研究微生物源溶菌酶对14 种供试菌的体外抑菌活性及对脂多糖（lipopolysaccharide,LPS）诱导的小鼠巨噬细胞RAW264.7 细胞炎症的抑制作用,该文采用二倍稀释法测定微生物源溶菌酶对供试菌的最小抑菌浓度（minimum inhibitory concentration,MIC）,评价其体外抑菌活性,通过构建LPS 诱导的小鼠巨噬细胞RAW264.7 炎症模型,以细胞中一氧化氮（nitric oxide,NO）及肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）的分泌量为指标,评价微生物源溶菌酶的抗炎活性。结果表明,微生物源溶菌酶对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、沙门氏菌、单增李斯特菌、耐热芽孢杆菌、酿酒酵母、酪丁酸梭菌、产黄青霉、黑曲霉和根霉11 种菌均表现出良好的抑菌效果,具有较强的广谱抑菌性;在试验浓度范围内,对保加利亚乳杆菌、嗜热链球菌、乳酸乳球菌乳亚种3 种益生菌无抑制效果,反而具有生长促进效果。微生物源溶菌酶对LPS 诱导的小鼠巨噬细胞RAW264.7 炎症模型表现出明显的抗炎作用,可显著降低NO 及TNF-α 的分泌,且与微生物源溶菌酶的作用浓度呈正相关。在试验浓度范围内,与模型组相比NO 分泌量最高可降低57.92%,TNF-α 分泌量最高可降低36.75%。微生物源溶菌酶具有良好的抑菌和抗炎活性,为其作为食品添加剂在抑制腐败菌生长、促进益生菌增殖等方面应用提供了理论基础。     

仙人掌浸提液抑菌作用的研究

用二种不同的溶剂浸提仙人掌茎中的有效成分 ,对其进行抑菌作用、最低抑菌浓度及其热稳定性的研究。结果表明 :两种浸提液对多种供试微生物均有较明显的抑制作用 ,但对黑曲霉的抑制效果不明显 ;仙人掌的 95%乙醇浸提液的抑菌效果优于水浸提液。仙人掌乙醇浸提液的最小抑菌质量浓度分别为 :变形杆菌、大肠杆菌 0 .1 2 5g/ml,枯草芽孢杆菌、蜡状芽孢杆菌、金黄色葡萄球菌、青霉 0 .2 5g/ml,赤酵母、啤酒酵母 0 .50 g/ml。而且 ,其热稳定性好 ,经 1 2 1℃、30 min湿热灭菌处理仍具有较强的抗菌效力。      

仙人掌浸提液抑菌作用的研究

用二种不同的溶剂浸提仙人掌茎中的有效成分 ,对其进行抑菌作用、最低抑菌浓度及其热稳定性的研究。结果表明 :两种浸提液对多种供试微生物均有较明显的抑制作用 ,但对黑曲霉的抑制效果不明显 ;仙人掌的 95%乙醇浸提液的抑菌效果优于水浸提液。仙人掌乙醇浸提液的最小抑菌质量浓度分别为 :变形杆菌、大肠杆菌 0 .1 2 5g/ml,枯草芽孢杆菌、蜡状芽孢杆菌、金黄色葡萄球菌、青霉 0 .2 5g/ml,赤酵母、啤酒酵母 0 .50 g/ml。而且 ,其热稳定性好 ,经 1 2 1℃、30 min湿热灭菌处理仍具有较强的抗菌效力。     

香辛料提取物对肉制品中常见致病菌的抑菌作用

研究27 种植物香辛料的抑菌作用,并比较其醇提取液的抑菌效果。得到抑菌作用较强的乌梅、丁香、甘草3 种原料。再进行复配抑菌实验,经大量实验确定,乌梅、丁香、甘草3 种提取液复配抑菌效果最好的配比。通过测定抑菌圈和最小抑菌浓度(MIC),比较乌梅和复配液的抑菌效果。结果表明,丁香、乌梅、甘草提取液1:8:1(V/V)复配液的抑菌作用优于乌梅的抑菌作用。同时,研究表明,复配提取液的抑菌作用受温度的影响较不明显。     

壳聚糖/Ag+复合抗菌剂整理莫代尔织物

为提高Modal织物的抗菌性能,本文采用有机和无机复合的方式,制备了新型壳聚糖/ Ag+复合抗菌整理剂,并将其用于Modal织物的抗菌整理。先用单因素实验探讨两种抗菌剂单独整理Modal织物时的适用浓度范围。再用正交实验优化复合抗菌整理工艺条件,结果表明：复合抗菌剂抗菌效果明显优于单独采用壳聚糖或银离子的抗菌效果。经0.8g/L的壳聚糖、0.8mg/L的Ag+在PH为6.5的条件下整理后,Modal织物的抗菌率可达93%以上,洗涤50次以后抗菌率没有明显下降,对断裂强力和白度的损伤较小,Modal织物的抗皱性能还有所提高。     

Antibacterial action of chitosan

The antibacterial action of chitosan hydroglutamate (CH), chitosan lactate (CL) and chitosan derived from fungal mycelia was examined against both gram‐negative and gram‐positive bacteria. Plate counts indicated inactivation rates of one‐ to five‐log‐cycles within one hour. Fungal chitosan had significantly less antibiotic effect than CH and CL. The antibacterial action of CH and CL was very similar and shown to be concentration dependent with 0.1 mg/mL more effective than 2.0 and 5.0 mg/mL. When CH (or CL) and polygalacturonate were added to cell suspensions, death was prevented, possibly indicating that chitosan complexed with polygalacturonate could not penetrate the cell or disrupt the membrane. Leakage of intracellular components caused by chitosan was determined by exposing lactose‐induced Escherichia coli to chitosan with assay for ß‐galactosidase activity indicating that cell permeabilization occurred more extensively at the low chitosan concentrations. Microscopic examination showed that chitosan caused cell agglutination at pH 5.8. Injury to chitosan‐exposed Staphylococcus aureus MF‐31 could not be demonstrated using the criterion that sublethally stressed cells have increased sensitivity to high levels of sodium chloride.     

壳聚糖的抗菌活性研究

以大肠杆菌和金黄色葡萄球菌为实验菌,研究壳聚糖的抗菌活性.结果表明:分子量大的壳聚糖对大肠杆菌和金黄色葡萄球菌都有较强的抑菌作用.梯度稀释结果显示,两种壳聚糖的MIC均为:0.05%抑制大肠杆菌,0.025%抑制金黄色葡萄球菌.研究壳聚搪的抑菌机理时发现,当壳聚糖形成纳米粒子时其抑菌能力丧失,推测抑菌作用可能与壳聚糖上氨基的质子,化有密切关系.壳聚糖抑菌可能是因为壳聚糖上的氨基(NH2 )与细菌细胞壁中带负电荷的磷壁酸或脂多糖结合,并螯合Mg2 、Ca2 等阳离子,从而改变细胞壁的通透性,起到押菌作用.     

壳聚糖复合涂膜的微观形貌变化及其对红桔的保鲜效果

对采后水果进行涂膜是延长其贮藏期的新型保鲜技术。试验将红桔分别在纯壳聚糖涂膜液(CS)和壳聚糖/纳米金刚石(CS/ND)复合涂膜液(纳米金刚石质量分数为2%)中分别浸泡浸泡2~3 min后晾干,置于温度为(10±3)℃,湿度为(65±10)%的环境中贮藏,并与商业保鲜剂(FA)处理组和未处理组(CK)进行对照。定期测定红桔的失重率、抗坏血酸含量、可溶性固体含量、可滴定酸含量、内部二氧化碳浓度以及腐烂个数,并采用扫描电镜(SEM)观测果皮的微观形貌变化。结果表明,CS/ND涂膜使红桔的腐烂率在整个贮藏期间均显著降低,但CS涂膜仅在前7 d有效。CS/ND涂膜组的抗坏血酸和可溶性固形物含量在贮藏前期较高,可滴定酸含量则在整个贮藏期间均可维持较高水平,且CS和CS/ND涂膜组内部CO2浓度均高于其余2组。说明复合涂膜能有效地延长果实的贮藏期,保持较好的果实品质。随贮藏时间的延长,涂膜表面均出现微孔。在涂膜中添加纳米金刚石可提高涂膜稳定性,延缓微孔的出现,从而保鲜效果更持久。     

Antibacterial effects of chitosan solution against Legionella pneumophila, Escherichia coli, and Staphylococcus aureus

Chitosan has been shown to have antibacterial activities on the growth of a wide variety of bacteria. Chitosan solution has been sold commercially for use as an antibacterial agent. Chitosan solution contains not only chitosan but also organic acids as solvents and desalted Japan Sea Proper Water (dJSPW). We aimed to clarify whether chitosan solution has antibacterial activity against bacteria invading bath water, and then to explore the causative factor among these ingredients. The antibacterial activity of full-strength chitosan solution and of 10(2)- and 10(4)-fold chitosan solution diluted with purified water was studied against Legionella pneumophila serogroups 1 (L. pneumophila SG1) and 6 (L. pneumophila SG6), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) for 7 days at 37 degrees C. To clarify the causative factor in the antibacterial activity against E. coli, the antibacterial activities of the full-strength and diluted chitosan solutions for 24 h were examined. L. pneumophila SG1 and SG6, and E. coli could not survive in the chitosan solution or in the 10(2)-fold dilute solution for over a day at 37 degrees C. The cells of S. aureus were found to have decreased more than 2.46 log cfu/ml after 1 day of incubation, not only in the chitosan solutions, but also in phosphate buffer solution as a control. No inhibitory effect of dJSPW on the growth of the bacteria was observed. The antibacterial activity of the chitosan solution was lower compared with those of the organic acids solutions, and it increased with decreasing pH value. We observed the antibacterial activity of chitosan solution against L. pneumophila SG1 and SG6, and E. coli, suggesting it may be due to the decreased pH value derived from organic acids rather than from chitosan itself or dJSPW.     

Antibacterial activity of chitosan against Aeromonas hydrophila

The effect of chitosan on growth and production of haemolysin by Aeromonas hydrophila was investigated as well as the effects of temperature, pH, salts and irradiation on the antibacterial activity of chitosan. It was found that chitosan affected growth and haemolysin production of A. hydrophila in varying degrees compared to the control. Growth and haemolysin production were clearly suppressed at 0.04% of chitosan. Suppression was more effective at pH 6.0 than at pH 7.0. The bactericidal effects of chitosan increased with increasing temperature and decreasing pH. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Sodium ions at concentrations of 10 and 25 mM also reduced chitosan's activity. Irradiation of chitosan at 150 kGy under dry condition was effective in slightly increasing its activity.     

苎麻织物的壳聚糖抗菌整理

采用天然抗菌整理剂壳聚糖对苎麻织物进行抗菌整理,经试验得到优化工艺条件:壳聚糖浓度6%、多元羧酸浓度6%、催化剂浓度4%、焙烘条件160℃×3.5 min.整理后苎麻织物的抗菌性能明显改善,经20次洗涤后,仍具有良好的耐洗性.     

Antibacterial activity of N-alkylated disaccharide chitosan derivatives

Antibacterial activity of the water-soluble N-alkylated disaccharide chitosan derivatives against Escherichia coli and Staphylococcus aureus was investigated. It was found that the antibacterial activity of chitosan derivatives was affected by the degree of substitution (DS) with disaccharide and the kind of disaccharide present in the molecule. Regardless the kind of disaccharide linked to the chitosan molecule, a DS of 30-40%, in general, exhibited the most pronounced antibacterial activity against both test organisms. E. coli and S. aureus were most susceptible to cellobiose chitosan derivative DS 30-40% and maltose chitosan derivative DS 30-40%, respectively, among the various chitosan derivatives examined. Although the disaccharide chitosan derivatives showed less antibacterial activity than the native chitosan at pH 6.0, the derivatives exhibited a higher activity than native chitosan at pH 7.0. Antibacterial activity of the chitosan derivatives (DS 30-40%) against E. coli increased as the pH increased from 5.0 and reached a maximum around the pH of 7.0-7.5. The effect of pH on the antibacterial activity of chitosan derivatives against S. aureus was not as pronounced as that observed with E. coli. Population reduction of E. coli or S. aureus in nutrient broth increased markedly upon increasing the concentration of chitosan derivatives from 0 to 500 ppm. No marked increase in population reduction was noted with further increase in the concentration of chitosan derivatives even up to 2000 ppm.     

丁香油、百里酚复合壳聚糖处理对桃采后褐腐病菌的抑制作用

为了进一步提高壳聚糖用于涂膜时的综合抗菌能力,采用滤纸片法及菌丝扩展法测定并对比了丁香油和百里酚对桃采后致病褐腐菌的抗菌能力及用微孔板法测定了它们的最小抑菌浓度,并将丁香油、百里酚复合壳聚糖对桃果进行涂膜,测量果体经过涂膜和接菌后的病斑扩展。结果表明丁香油和百里酚都具有较好的抗褐腐菌能力,百里酚强于丁香油,复合壳聚糖涂膜时二者都可以提高壳聚糖总体抗菌能力且复合百里酚效果较好。二者具有作为壳聚糖涂膜保鲜添加剂的应用潜力。     

Antibacterial activity of shrimp chitosan against Escherichia coli

The effects of cell age, reaction temperature, pH value, and salts on the inhibitory activity of shrimp chitosan (98% deacetylated) against Escherichia coli were investigated. The age of a bacterial culture affected its susceptibility to chitosan, with cells in the late exponential phase being most sensitive to chitosan. Higher temperature (25 and 37 degrees C) and acidic pH increased the bactericidal effects of chitosan. Sodium ions (100 mM Na+) might complex with chitosan and accordingly reduce chitosan's activity against E. coli. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Chitosan also caused leakage of glucose and lactate dehydrogenase from E. coli cells. These data support the hypothesis that the mechanism of chitosan antibacterial action involves a cross-linkage between the polycations of chitosan and the anions on the bacterial surface that changes the membrane permeability.