玉米须提取物对食品腐败菌及致病菌抑制作用的研究

首次以玉米须提取物对七种常见的食品腐败菌及致病菌进行抑菌试验,发现玉米须的乙醇提取物的效果最好,其最低抑菌浓度（ＭＩＣ）为３．０ｇ／１００ｇ。此外,对食品加工条件（如杀菌方式等）及食品介质（如ｐＨ）对玉米须提取物抑菌活性的影响也作了研究。结果表明。玉米须提取物在常规食品杀菌条件（ＵＨＴ）及中酸到酸性环境下抑菌活性稳定,因而可做为潜在的食品防腐剂。     

红黑二丸中甾醇类物质的抑菌活性

采用牛津杯法和菌饼法分别测定红黑二丸甾醇类物质对细菌和霉菌的抑菌活性,并测定其最低抑菌浓度(MIC)。结果表明：红黑二丸甾醇类物质对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、沙门氏菌、志贺氏菌、黑曲霉和橘青霉均有一定的抑制效果,当甾醇质量浓度为7.0mg/mL时,对金黄色葡萄球菌的抑制效果最好,其抑菌直径大于9mm。红黑二丸甾醇类物质对金黄色葡萄球菌的抑制作用最强,其MIC值为0.5mg/mL。不同质量浓度红黑二丸甾醇类物质对细菌的药效持久性随着时间的延长呈下降趋势,且质量浓度越高,抑菌作用越明显。     

天然植物型抑菌剂的配制及抗菌性能评价

对豆蔻、肉桂、百里香、意大利蜡菊、贯叶连翘、甘草和迷迭香7种香辛料用无水乙醇进行提取,并测定各种提取液对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphyloccocus aureus)、副溶血性弧菌(Vibrio parahaemolyticus)和鼠伤寒沙门氏菌(Salmonella typhimurium)的最小抑菌浓度(minimum inhibitory concentration,MIC)。结果表明,豆蔻提取液的MIC大于0.5%(V/V),肉桂提取液对大肠杆菌和金黄色葡萄球菌的MIC为0.2%(V/V),其余香辛料提取液的MIC均为0.5%(V/V)。根据各种香辛料提取液的MIC,选择除豆蔻以外的6种香辛料作为原材料配制一种天然植物型抑菌剂,其抗菌性能评价试验表明,所配制的天然植物型抑菌剂对6种参试菌均具有显著的抑菌效果,其抑菌率达到99.99%。在对草莓的保鲜试验中,天然植物型抑菌剂显示了较好的保鲜效果,它能有效地将草莓的保鲜期从7 d之内延长至10 d。     

响应面试验优化海蓬子外种皮水溶性多糖提取工艺及其抗菌活性

对海蓬子外种皮多糖提取工艺进行研究,以干枯的海蓬子外种皮为原料,水提醇沉法获得多糖,考察提取时间、提取温度、料液比对多糖提取量的影响,通过单因素试验和响应面法对影响海蓬子外种皮多糖提取量的主要因素进行分析优化,微孔-平板法测定粗多糖对金黄色葡萄球菌、大肠杆菌的最小抑菌浓度（minimal inhibitoryconcentration,MIC）。结果表明：影响海蓬子外种皮多糖提取量工艺的因素按主次顺序排列为提取温度＞料液比＞提取时间;确定海蓬子外种皮多糖水提取的最佳工艺条件为提取温度87 ℃、提取时间5 h、料液比1∶57（g/mL）,在该条件下,海蓬子外种皮多糖的提取量为（13.03±0.63） mg/g,与预测值12.42 mg/g接近,粗多糖对金黄色葡萄球菌、大肠杆菌的MIC值分别为50、100 mg/mL,由此表明,响应面模型与实际情况拟合良好,能较好地预测海蓬子外种皮多糖的提取量,海蓬子外种皮粗多糖对金黄色葡萄球菌、大肠杆菌抑制作用。     

枸杞提取液的活性成分分析及其抑菌性、抗氧化性

以酒泉枸杞为研究对象,测定其提取液中枸杞多糖、甜菜碱、总酚3种活性成分的含量及不同浓度枸杞提取液的抑菌和抗氧化活性。结果表明:枸杞提取液对鼠伤寒沙门氏菌(Salmonella typhimurium)、大肠埃希氏菌(Escherichia coli)、铜绿假单胞菌(Pseudomonas aeruginosa)和金黄色葡萄球菌(Staphylococcus aureus)有抑制作用,抑菌能力随着枸杞提取液浓度的提高而增强,提取液含量为2.5%时,对大肠埃希氏菌的抑制率超过50%,含量为5.0%时,对鼠伤寒沙门氏菌、铜绿假单胞菌和金黄色葡萄球菌的抑制率超过50%。通过测定POV值和还原能力得出,枸杞提取液具有抗氧化性:添加5.0%提取液,与添加0.1%BHA猪油的POV值相差不大,添加7.5%提取液,猪油POV值略低于0.1%BHA。吸光度越大,抗氧化性越强,枸杞提取液含量范围为1~10 mg/mL时,A_{700 nm}吸光度范围为0.2760~0.8949。由此可知,枸杞提取物具有较强的抑菌和抗氧化能力。     

杜仲雄花正丁醇提取物抑菌活性研究

为探讨杜仲雄花正丁醇提取物的抑菌活性,以大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、炭疽杆菌、根霉、青霉和黑曲霉为供试菌种,采用打孔法和倍比稀释法,检测杜仲雄花正丁醇粗提物及经过硅胶柱分离得到的7种不同极性提取物对真菌和细菌的抑菌活性,并确定最小抑菌浓度(MIC),分析粗提物及7种分离产物的活性。结果显示,杜仲雄花正丁醇粗取物对金黄色葡萄球菌和炭疽杆菌具有较好的抑菌作用,MIC分别为0.007 8g/mL和0.015 6g/mL;杜仲雄花正丁醇粗提物对枯草芽孢杆菌、大肠杆菌、根霉、黑曲霉和青霉没有抑制作用。然而经过硅胶柱进一步分离发现,经过分级提取的样品4和样品5对黑曲霉出现了抑制作用,对金黄色葡萄球菌、炭疽杆菌、和枯草芽孢杆菌等革兰氏阳性菌的抑制作用明显增强。说明杜仲雄花正丁醇粗提物经过硅胶柱的分离能够得到对不同菌株的特异抑菌物质,这为寻找不同菌种的抑菌活性物质提供了参考依据。     

Antibacterial Activity of Two Bell Pepper Extracts: Capsicum annuum L. and Capsicum frutescens

This study was conducted to determine extracts of fruit used as food ingredients and in traditional medicine for antibacterial activities. The effect of Capsicum annuum and Capsicum frutescens methanol and aqueous extracts on selected bacteria (Staphylococcus aureus, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa, Escherichia coli, and Shigella dysenteriae) were investigated. Both extracts were found to be effective against Vibrio cholerae, Staphylococcus aureus, and Salmonella typhimurium, while methanol extracts showed the greatest effect. The extract from Capsicum annuum showed a higher antibacterial activity than the one from Capsicum frutescens. The minimal inhibitory concentrations of methanol and aqueous extracts were 0.20 mg mL^?1 and 0.25 mg mL^?1, respectively. Minimal bactericidal concentrations values of both extracts ranged from 1 to 2.5 mg mL^?1. Phytochemical assay revealed the presence of alkaloids, flavonoids, polyphenols, and sterols. Thus, Capsicum fruits may serve as a source of natural bactericidal agents to be used in food and medicinal systems.     

薤白抗菌物质的提取工艺

为优化薤白中抗菌物质的提取工艺条件,采用单因素试验和响应面分析方法,以水为提取剂,以金黄色葡萄球菌抑菌圈直径为响应值,确定最佳的薤白抗菌物质的水浸提条件：加水量为薤白浆液体积的2倍,32℃提取4次,每次3h。此条件下得到的抗菌物质抗菌性较好,进行金黄色葡萄球菌的抑菌实验,得到抑菌圈直径达到13.98mm。证明薤白具有抑菌活性,所提取的抗菌物质可以作为天然食品防腐剂。     

黄花菜多糖的提取、结构性质及抑菌活性

采用水提醇沉法,通过单因素试验和正交试验研究黄花菜粗多糖（crude polysaccharides from Hemerocalliscitrina Baroni,CPH）的提取工艺,并利用Sevag法和H2O2氧化法提纯制备黄花菜精制多糖（deproteinizedpolysaccharides from Hemerocallis citrina Baroni,DPH）,通过理化检验和紫外光谱、红外光谱、高效液相色谱分析,考察DPH的性质与结构,同时还研究DPH对铜绿假单胞菌、大肠杆菌、金黄色葡萄球菌、白假丝酵母、黑曲霉的抑制作用。正交试验结果表明,CPH最优提取条件为浸提温度75 ℃、浸提时间3 h、液固比20∶1（mL/g）、浸提2 次。在此条件下,CPH提取率为28.36%。理化性质、光谱与色谱特征表明,DPH是一种具有α-型吡喃糖苷结构的水溶性杂多糖,是由L-鼠李糖、D-木糖、L-阿拉伯糖、D-甘露糖、D-葡萄糖和D-半乳糖组成,且可能是一种与蛋白质或多肽以共价键结合的糖复合物。抑菌实验结果表明,DPH对金黄色葡萄球菌、铜绿假单胞菌、大肠杆菌具有明显的抑制作用,相应的最小抑菌质量浓度分别为10、10、25 mg/mL。     

山竹果皮中黄酮化合物抑菌特性研究

本论文通过抑菌实验和稳定性实验,研究了山竹果皮中黄酮化合物对食品加工、储存中常见腐败菌种(金黄色葡萄球菌、大肠杆菌、四联球菌、沙门氏菌、志贺球菌)的抑菌特性。抑菌实验表明:山竹果皮中黄酮化合物对五种菌种的抑菌效果大小顺序为:金黄色葡萄球菌>大肠杆菌>志贺球菌>四联球菌>沙门氏菌。山竹黄酮提取液对金黄色葡萄球菌、大肠杆菌、志贺球菌的最低抑菌浓度(MIC)为0.76mg/mL,对四联球菌、沙门氏菌的最低抑菌浓度(MIC)为1.33mg/mL。稳定性实验表明:黄酮提取液抑菌活性随着温度的升高呈先上升后下降的趋势,但影响不大;酸碱处理后都表现出一定的抑菌活性,在偏酸性条件下,抑菌效果达到最好,在pH>10时抑菌活性减弱;15W紫外光照射对抑菌活性都有所降低,可避光保存。     

Orange Essential Oils Antimicrobial Activities against Salmonella spp.

ABSTRACT:  Seven citrus essential oils (EOs) were screened by disc diffusion assay for their antibacterial activity against 11 serotypes/strains of Salmonella . The 3 most active oils were selected to determine the minimal inhibitory concentration (MIC) against the same Salmonella . Orange terpenes, single-folded d-limonene, and orange essence terpenes all exhibited inhibitory activity against the Salmonella spp. on the disc diffusion assay. EOs were stabilized in broth by the addition of 0.15% (w/v) agar for performance of the MIC tests. Orange terpenes and d-limonene both had MICs of 1%. The most active compound, terpenes from orange essence, produced an MIC that ranged from 0.125% to 0.5% against the 11 Salmonella tested. Gas chromatography-mass spectrometry (GC/MS) analysis revealed that this orange essence oil was composed principally of d-limonene, 94%, and myrcene at about 3%. EOs from citrus offer the potential for all natural antimicrobials for use in improving the safety of organic or all natural foods.     

Antimicrobial Activities of Cynara scolymus L. Leaf, Head, and Stem Extracts

ABSTRACT: Successive chloroform, ethanol, and ethyl acetate partitions of extracts from Cynara scolymus L. leaf, head, and stem were tested for their antimicrobial activity against 15 microbial species, including 7 foodborne bacterial pathogens, Bacillus subtilis, Staphylococcus aureus, Agrobacterium tumefaciens, Micrococcus luteus, Escherichia coli, Salmonella typhimurium , and Pseudomonas aeruginosa , 4 yeasts, Candida albicans, Candida lusitaniae, Saccharomyces cerevisiae , and Saccharomyces carlsbergensis , and 4 molds, Aspergillus niger, Penicillium oxalicum, Mucor mucedo , and Cladosporium cucumerinum using the disk diffusion assay technique. The leaf extract was found to be most effective against all of the tested organisms, followed by the head and stem extracts, and the ethanol fraction showed the most significant antimicrobial activity against all of the tests among 3 soluble fractions of extract, followed by the chloroform and ethyl acetate fractions. The minimum inhibitory concentrations (MICs) of extracts determined by the agar and broth dilution method ranged from 1.25 to 10.0 mg/mL. The MIC of ethanol fraction of leaf extracts was the lowest by comparison with the other 2 extracts. The MIC for fungi was at or below 2.5 mg/mL and for bacteria was at or above 2.5 mg/mL.     

蜂胶提取液的抑菌作用研究

采用水、95%乙醇及与超声波的综合作用从原蜂胶中提取蜂胶液,将得到的蜂胶提取液稀释成0.8%、0.4%、0.2%、0.1%,并分别对蜡样芽孢杆菌、大肠杆菌、金黄色葡萄球菌、沙门氏菌、黑曲霉五种菌进行抑菌圈直径和最小抑制浓度(MIC)的测定。结果表明,超声波作用于95%的乙醇蜂胶液的方法提取效果最好,提取率为27.3%。不同提取方法得到的蜂胶提取液的抑菌作用存在差异,以超声波和乙醇提取的蜂胶液对受试菌作用最强。蜂胶提取液对大肠杆菌的抑制作用最强,其次是沙门氏菌和蜡样芽孢杆菌,最差的是黑曲霉。     

Antimicrobial activity of several herb and spice extracts in culture medium and in vacuum-packaged pork

Extracts prepared from honeysuckle, Scutellaria, Forsythia suspensa (Thunb), cinnamon, and rosemary with 75% ethanol and from clove oil dissolved in 75% ethanol were applied to inoculated agar media to observe their inhibitory effects on the growth of Escherichia coli, Pseudomonas fluorescens, and Lactobacillus plantarum. All the extracts suppressed the growth of these bacteria; Scutellaria exhibited the strongest effect against E. coli. An orthogonal test revealed that the most effective antimicrobial composite extracts were equal-volume mixtures of 0.125 g/ml Scutellaria + 0.5 g/ml honeysuckle + 0.125 g/ml Forsythia + 0.25 g/ml cinnamon and 0.25 g/ml cinnamon + 0.125 g/ml rosemary + 0.25% clove oil. These mixed extracts also produced strong antimicrobial effects in vacuum-packaged fresh pork, with 1.81- to 2.32-log reductions in microbial counts compared with the control when stored for up to 28 days. The sensory panel detected minimal differences in surface color and off-odors between meat samples treated with herb-spice extracts and the control. These results indicate that combined herb and spice extracts can be used as natural antimicrobials for food preservation.     

Efficacy of Antimicrobials Extracted from Organic Pecan Shell for Inhibiting the Growth of Listeria spp.

Growers and processors of USDA certified organic foods are in need of suitable organic antimicrobials. The purpose of the research reported here was to develop and test natural antimicrobials derived from an all‐natural by‐product, organic pecan shells. Unroasted and roasted organic pecan shells were subjected to solvent free extraction to produce antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. The solvent free extracts of pecan shells inhibited Listeria strains at MICs as low as 0.38%. The antimicrobial effectiveness tests on a poultry skin model exhibited nearly a 2 log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts also produced greater than a 4 log reduction of the indigenous spoilage bacteria on the chicken skin. Thus, the pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing.     

白刺果实提取物的体外抑菌活性研究

探讨白刺果实提取物的体外抑菌活性,以期为白刺果实的综合利用及天然食品防腐剂的开发提供依据。用石油醚、氯仿、乙酸乙酯和正丁醇分别对白刺果实95%乙醇提取物进行萃取,纸片法测定各萃取部分对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、酵母菌、青霉、根霉和黑曲霉7种常见的食源性污染菌的抑菌效果,并通过倍比稀释法测定乙酸乙酯部分对其中3种细菌的最低抑菌浓度。结果表明:白刺果实乙酸乙酯部分、乙醇部分和氯仿部分对3种供试细菌均有抑菌作用,其中乙酸乙酯部分抑菌效果最好,且乙酸乙酯部分对3种细菌的抑制强弱顺序为:枯草芽孢杆菌>大肠杆菌>金黄色葡萄球菌;其中乙酸乙酯部分对枯草芽孢杆菌和金黄色葡萄球菌的最低抑菌浓度(MIC)均为25mg/mL,对大肠杆菌的MIC是50mg/mL。各萃取部分对供试真菌均无明显抑制作用。     

响应面法优化碱蓬根总生物碱的提取工艺及其抑菌活性

为优化碱蓬根总生物碱的提取工艺,并研究其抑菌活性,以碱蓬根为原料,在单因素实验基础上,采用响应面法确定碱蓬根总生物碱的最佳提取条件,管碟法及两倍稀释法检测碱蓬根总生物碱提取物对三种常见致病菌(大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌)的抑制效果。结果表明,当料液比为1:25 g/mL,乙醇浓度86%,提取温度78 ℃,提取时间2.1 h时,总生物碱得率最高为0.521%±0.04%。碱蓬根总生物碱对大肠杆菌及金黄色葡萄球菌有一定的抑菌效果,最低抑菌浓度为0.4 mg/mL,对枯草芽孢杆菌无抑菌性。该提取工艺高效可行,可用于碱蓬根中总生物碱的提取,同时提取物具有一定的抑菌性。     

微波辐射预处理提取花叶滇苦菜总黄酮工艺及其乙酸乙酯萃取物的抑菌活性研究

为了探讨微波辐射预处理提取花叶滇苦菜总黄酮的工艺优化及其总黄酮提取液乙酸乙酯萃取物的抑菌活性,在单因素实验基础上,采用正交试验定总黄酮提取最佳工艺;参照CLSI标准测定乙酸乙酯萃取物对铜绿假单胞菌(ATCC9027)、铜绿假单胞菌耐药菌(PA1)、金黄色葡萄球(ATCC29213)、金黄色葡萄球菌耐药菌(SA1)、大肠杆菌(ATCC25922)等5种细菌的抑菌活性。结果表明,花叶滇苦菜地上部分总黄酮提取的最佳工艺为:微波辐射时间为120 s,微波功率为350 W,乙醇浓度为60%,水浴温度70℃,料液比1:40 g/mL,水浴时间为60 min,此时,黄酮得率为38.328 mg/g。地下部分总黄酮提取的最佳工艺为:微波辐射时间为90 s,微波辐射功率为490 W,乙醇浓度为70%,料液比1:30 g/mL,水浴温度为80℃,水浴时间为90 min,其黄酮得率为7.232 mg/g。乙酸乙酯萃取物具备一定抑菌活性,对金黄色葡萄球菌耐药菌的MIC分别为4(地上部分)和8 mg/mL(地下部分)。当浓度低于16 mg/mL时,对铜绿假单胞菌、铜绿假单胞菌耐药菌和大肠杆菌均无抑制作用。微波辐射预处理对花叶滇苦菜总黄酮的提取具有指导意义,总黄酮提取液乙酸乙酯萃取物对金黄色葡萄球菌具有一定的抑制作用。     

非洲山毛豆种子提取物对病原菌的抑制作用研究

以非洲山毛豆种子为研究对象,分别以水、乙醇水溶液为溶剂,从山毛豆中提取活性成分,用管碟法探讨了其对六种供试菌的抑菌作用。实验结果表明,山毛豆水提物对大肠杆菌、金黄色葡萄球菌、沙门氏菌的MIC均为50%;当提取剂为30%乙醇,山毛豆提取物对大肠杆菌、金黄色葡萄球菌的MIC为25%,对沙门氏菌的MIC为50%。其水提物、醇/水提取物对黑曲霉、荔枝炭疽、尖孢镰刀菌的抑制作用不明显,对供试细菌在高浓度下呈现较好的抑菌效果。另外,山毛豆抑菌活性成分抑菌pH范围广而且热稳定性强。     

茶多酚对肉源腐败菌和致病菌的抑制效果

研究了茶多酚对肉源荧光假单胞菌、鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌的抑制效果。设计不同浓度茶多酚溶液(0.0%、0.5%、1.0%、2.0%、2.5%),采用滤纸片法评判抑制效果。结果表明,茶多酚溶液(0.5%、1.0%、2.0%、2.5%)对荧光假单胞菌有极显著的抑制效果(P<0.01),常用的防腐剂山梨酸钾(1.0%)对其抑制效果却不显著(P>0.05)。茶多酚溶液(1.0%、2.0%、2.5%)和山梨酸钾溶液(1.0%)对鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌有极显著的抑制效果(P<0.01),茶多酚溶液(0.5%)对鼠伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌无显著的抑制效果(P>0.05)。通过茶多酚溶液的浓度与4种菌抑菌圈直径的直线相关图可以看出,茶多酚溶液的浓度与鼠伤寒沙门氏菌抑菌圈直径的相关系数最大,荧光假单胞菌次之,其次是金黄色葡萄球菌、大肠杆菌。