车前草提取物抗菌活性的研究

采用滤纸片扩散法对车前草的60%vol﹑70%vol﹑80%vol﹑90%vol乙醇提取物及石油醚﹑氯仿﹑正丁醇和水相萃取物对4种细菌和13种真菌进行抗菌活性研究。结果表明:车前草粗提物对金黄色葡萄球菌、大肠杆菌、青霉和假丝酵母等常见食物致病菌的抑制作用显著,对常见植物病原菌苹果腐烂病菌、黄瓜枯萎病菌、烟草赤星、草莓镰刀菌、番茄灰霉等的抑制作用也较好。     

石榴皮抗菌活性及其在食品保鲜中的应用研究进展

石榴皮具有很好的抗氧化和广谱的抗菌活性,可以阻止食品的腐烂变质,在食品保鲜中具有较高的应用价值。文中对近10年来石榴皮提取物的抗菌活性及在食品防腐保鲜中的应用研究进行了论述,展望了其应用前景。     

Antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model

The microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against Escherichia coli O157:H7, Salmonella enterica serovar Enteritidis, Listeria monocytogenes, and Staphylococcus aureus. The mixed culture (approximately 6.0 log CFU/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts. After incubation at 35 degrees C for 0, 1, 3, and 5 days, proper dilution of each sample was spiral plated on each selective agar. Viable cell counts were performed after incubation at 35 degrees C for 24 to 36 h. Green, jasmine, and black tea exhibited an approximately 5.0 log suppression of S. aureus compared with the control from days 1 to 5. Green and jasmine tea also suppressed the growth of L. monocytogenes by approximately 3.0 log CFU/ml on day 5. In contrast, no tea extracts inactivated E. coli O157:H7 and Salmonella Enteritidis. Based on the result in liquid medium, green and jasmine teas of 0.1% (vol/wt) were individually evaluated for their antimicrobial activity against L. monocytogenes and S. aureus in a food model (ground beef) stored at 7 degrees C for 0, 1, 3, 5, and 7 days. Viable cell counts of total bacteria, L. monocytogenes, and S. aureus in ground beef were not significantly different among green and jasmine tea and the control.     

响应面优化纤维素酶法提取茶花多糖工艺及其抗氧化活性研究

目的:优化纤维素酶提取茶花多糖的工艺,并评价其抗氧化活性。方法:以茶花多糖得率为响应值,在单因素实验基础上,以液料比、酶解温度、酶解时间、酶添加量为实验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件;采用自由基清除能力体系评价茶花多糖的抗氧化活性。结果:通过二次回归模型响应面分析,影响茶花多糖得率的因素按主次顺序排列为:酶解时间>酶解温度>液料比>酶添加量;确定纤维素酶酶解茶花多糖最佳工艺条件为纤维素酶添加量5.0 mg/m L、液料比9∶1 m L/g、酶解温度48℃、酶解时间71 min,在此条件下茶花多糖得率为15.28%,模型方程理论预测值为15.91%,两者相对误差小于5%。茶花多糖具有较强的抗氧化活性,对DPPH和O-2·自由基的半数抑制浓度分别为0.974、1.342 mg/m L,但与维生素C比较,抗氧化活性较弱。结论:采用响应面法优化得到了茶花多糖的最佳提取工艺,该工艺方便可行,得到的多糖具有较强的抗氧化活性。      

油菜花粉和茶花花粉中重金属含量的分布特征研究

目的 考察2种蜂花粉产品中7种重金属(类金属)元素含量的分布特征。方法 采用微波消解-电感耦合等离子体质谱法对所采集的蜂花粉样品中铬、锰、砷、铜、镍、镉和铅等7种元素含量进行分析测定,通过统计分析考察2种蜂花粉中各元素含量是否有显著性差异。结果 2种蜂花粉均存在重金属污染问题,但重金属污染水平存在差异。锰、镍、铜等3种元素在所采集的油菜花粉样品和茶花花粉样品中的含量差异具有显著统计意义(P < 0.05);铬、砷、镉和铅等4种元素含量在该2种蜂花粉中差异不显著(P > 0.05)。结论 油菜花粉和茶花花粉中部分元素含量差异有统计意义,对于具有较高重金属污染风险的花粉种类应加强监管,将样品来源地环境无机污染物引起的重金属污染问题纳入到生产规范标准制修订的考量之中。     

乳酸菌的抑菌活性及在肉品保鲜中的应用

乳酸菌以其天然、强抗菌性及安全可靠等优势,逐步成为取代传统食品保鲜技术的关键技术之一.综述了乳酸菌的抑菌活性及其在肉品保鲜中的应用与发展趋势,为研究开发新型食品保鲜技术提供依据.     

RFID技术及其在食品安全领域中的应用

RFID是一种非接触式自动识别技术,主要通过射频信号自动识别目标对象并获取相关信息,在食品安全质量追溯、运输环境全程监控等方面有着极大的应用潜力。从RFID技术的原理、国内外食品安全领域的应用现状及前景展望等作简要阐述。     

微波法提取山茶花红色素的工艺研究

应用微波技术进行正交试验设计和Duncan法检验,确立了山茶花红色素的最佳提取条件。结果表明,用1:8(g/mL)的95%乙醇水溶液,微波功率684W,提取时间110s,提取次数3次,提取效率较好。在此条件下色素的提取率为84．7%,产率为2．7%。与溶剂浸提法相比,微波法提取每次提取时间由常规浸提的2h减小为110s,提取率从81．8%增加到84．7%。     

磷脂的表面活性及其在食品中的应用

综述了磷脂的表面活性的各种表现形式及其在食品中的应用。     

姜黄提取物的抗氧化及抗菌活性研究

以猪油的过氧化物值为指标,抗氧化能力由强到弱依次为姜黄素类化合物〉姜黄素〉挥发油。挥发油的抗菌能力比较强,对大肠杆菌、枯草芽孢杆菌、青霉、酵母菌均有抑制作用;姜黄素类化合物只对青霉有抑制作用;姜黄素对四种菌均无抑制作用。     

Antibacterial activity and mechanism of the ethanol extracts from Sonchus brachyotus DC.

Sonchus brachyotus DC. (S. brachyotus) is considered a vegetable, and rarely considered to be medicinal. However, S. brachyotus is used as a kind of traditional folk herb in Europe. Pharmacological studies are necessary in order to provide a scientific basis to substantiate their use. This study investigated the antimicrobial effect and mechanism of action of the ethanol extract from S. brachyotus. Ethanol extract from S. brachyotus exhibited antimicrobial activity against Escherichia coli, Enterobacter cloacae, Klebsiella pneumonia, Salmonella enteric, Staphylococcus aureus, and Micrococcus luteus; this is especially so in the case of E. coli. This study investigated the novel antibacterial mechanism of ethanol extract from S. brachyotus that shows an apoptosis-like response in E. coli. At all the tested concentration, it was found that ethanol extract from S. brachyotus–treated E. coli cells displayed various apoptotic markers, such as membrane damage, reactive oxygen species accumulation, and membrane depolarization. Expression of caspases protein, which mediates a bacterial apoptosis–like response, was also increased by ethanol extract from S. brachyotus. In order to evaluate the influence of caspases on the appearance of other apoptotic markers, phosphatidylserine exposure and DNA fragmentation were detected and compared with untreated and with ethanol extract from S. brachyotus. These characteristics were detected in E. coli cells, but not in untreated, with ethanol extract from S. brachyotus. In conclusion, the data obtained demonstrated that ethanol extract from S. brachyotus induces an apoptosis-like response in E. coli that associates with caspase-like protein.     

Antioxidant and antimicrobial activity of Satureja montana L. extracts

BACKGROUND: This study aimed to evaluate the antioxidant and antimicrobial activity of extracts (aqueous, ethanolic and essential oil) from Satureja montana and to characterise the chemical composition of its essential oil. RESULTS: Satureja montana L. essential oil had relatively high antimicrobial activities against the seven species of bacteria tested. In contrast, aqueous extracts did not reveal antibacterial activity, and the ethanol extract was not effective against Salmonella typhimurium. The major volatile constituents of the essential oil were carvacrol (306 g L^?1), thymol (141 g L^?1), and carvacrol methyl ether (63 g L^?1). The strongest antioxidant capacity was obtained with the hot water extracts of S. montana, whereas the plant essential oil revealed the highest phenolic content. CONCLUSION: The findings indicate that the bioactive extracts of S. montana have strong potential for use as natural antimicrobials and antioxidants in the preservation of processed food. Copyright © 2011 Society of Chemical Industry     

植物源食品防腐剂抑菌机理和效果及在食品保鲜中的应用

植物源天然食品防腐剂因其安全性高、抗菌性强以及来源广泛等优点,已成为食品防腐保鲜研究的热点。系统地介绍了几类天然植物源防腐剂种类、抑菌效果、抑茵机理及在食品贮藏保鲜中的应用。植物源防腐剂主要包括蛋白类、肽类、多糖类、黄酮类、多酚类、萜类、精油及植物自身成分的酶解产物等。目前从植物中提取有效成分作为天然防腐剂已经取得了一定的成果,但仍存在一定的问题,如防腐剂成分的鉴定、量效关系、不同防腐物质间协同增效作用效果及机理、风险分析等方面的问题。提出了天然食品防腐剂研究、开发及应用方面的建议。     

Antibacterial activity of a chitooligosaccharide mixture prepared by cellulase digestion of shrimp chitosan and its application to milk preservation

The antibacterial activity of a chitooligosaccharide mixture prepared by digestion of shrimp chitosan with cellulase at 50 degrees C for 14 h was evaluated. Sugars with 1 to 8 degrees of polymer (DP) were found in this chitooligosaccharide mixture, and the weight percentage of sugars with DP > or = 6 was 44.3%. Minimal lethal concentrations of this mixture against Aeromonas hydrophila, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, Shigella dysenteriae, Staphylococcus aureus, Vibrio cholerae, and Vibrio parahaemolyticus in nutrient broth were 5 to 29 ppm, which were much lower than those of the chitosan reactant (50 to 1,000 ppm). The antibacterial activity of this mixture in the sterilized milk against E. coli O157, L. monocytogenes, Salmonella Typhimurium, and S. aureus was much stronger at 4 degrees C than at 37 degrees C. When raw milk was supplemented with either 0.24% or 0.48% (wt/vol) of this oligosaccharide mixture and stored at 4 degrees C for 12 days, its mesophilic and psychrotrophic counts were reduced by at least 3 log cycles, and there was very little change in pH. In addition, this mixture retarded the growth of Salmonella species and caused quicker reduction of Staphylococcus species in raw milk. Accordingly, the shelf life of raw milk at 4 degrees C was extended by at least 4 days.     

植物多酚的抑菌活性及其在食品保鲜中的应用

植物多酚是一种植物次生代谢物, 其结构多样, 具有多种生物活性。植物多酚的抑菌活性是其重要活性之一, 并在食品中得到了广泛的应用。本文主要综述了植物多酚的组成、性质, 抑菌机制以及在食品保鲜中的应用。     

国槐种子蛋白质提取工艺优化及其抗氧化活性

以国槐种子为原料,在单因素实验的基础上采用Box-Behnken（BB）和响应面确定国槐种子蛋白质的提取工艺,并建立国槐蛋白质提取工艺的数学模型,同时探讨蛋白质对DPPH和ABTS自由基的清除能力。结果表明,国槐种子蛋白质提取的最优工艺为pH8.2缓冲液包含0.82 mol/L的NaCl,超声提取29 min,料液比1∶31（g/mL）,此条件下,国槐种子蛋白质的提取量为139.25 mg/g,理论预测值为139.36 mg/g,两者误差为0.08%,实验结果真实可靠。抗氧化实验表明,国槐种子蛋白质的质量浓度为38.04μg/mL时,对DPPH和ABTS自由基的清除率分别为29.44%和90.82%。国槐种子中含有较丰富的蛋白质,并对DPPH和ABTS自由基有清除作用,可以作为潜在天然抗氧化剂。      

Antibacterial activity of Osmunda japonica (Thunb) polysaccharides and its effect on tomato quality maintenance during storage

Tomatoes are rich in nutrients, yet they have a short shelf life and are prone to decay due to bacterial invasion. Polysaccharides extracted from Osmunda japonica (Thunb) were briefly characterised. The inhibitory effect of polysaccharides on nine kinds of common spoilage and pathogenic bacteria in tomatoes stored postharvest was studied, and the polysaccharides had broad-spectrum antibacterial and antifungal activities against many tested strains. The minimum inhibitory concentrations (MICs) and the minimum bactericidal (fungicidal) concentrations (MBCs) were determined, and the lowest MBC against Bacillus cereus was 0.15 g L⁻¹. Various concentrations of an O. japonica (Thunb) polysaccharide (OP) solution were sprayed onto ordinary preservation paper, which then distinctly maintained tomato freshness. OP delayed vitamin C (VC) and titratable acid decreases and increased respiratory intensity in a dose-dependent manner, reducing malondialdehyde accumulation. The tomatoes could be stored for 30 day at 25 ± 1 °C. OP has potential as a safe, nontoxic natural plant preservative.     

红曲防腐效应及其应用开发

食品发酵微生物及其代谢产物具有一定的抑菌功效,由于其安全性成为发展食品级安全生物拮抗的热点,并且成为寻找开发天然防腐剂的重要源泉。红曲是我国传统发酵食品,其天然防腐作用已有报道。红曲霉发酵体系中含有抑菌成分,固态或液态发酵方式均可生产红曲防腐剂。食品添加剂的发展方向是天然、安全、高效,开发食品级安全的天然红曲防腐剂具有广阔应用前景。基因改组技术能够通过细胞融合、传达分离、高通量筛选,将来源于出发菌群各菌株的优势基因集中于一个后代菌,采用基因组改组技术选育成功高活力红曲,为开发高活力红曲防腐剂奠定了基础。本文对红曲防腐剂的抑菌防腐效应、红曲防腐剂的生产工艺及应用作一简单综述,并探索高活力红曲防腐剂的研发策略。     

多维度食品安全评估指数体系模型的构建及应用

目的:通过食品安全评价指数体系来评价地区食品安全状况。方法:在构建的指数体系中,综合考虑影响食品安全的各种因素,如地市规模、食品种类、检测项目危害、生产地等,并采用多种数据来源对模型进行支撑。结果:利用2021年广西食品安全评价抽检数据进行实证,分别使用经典大样本估计法和经验贝叶斯估计法进行模型计算后,发现基于食品种类的安全指数的评估结果与简单合格率评估结果存在一定差异,但两种算法均显示餐饮食品的安全情况显著低于其他食品大类。此外,使用贝叶斯估计方法有效解决了合格率为100%或数值普遍接近时的计算问题。结论:该模型可以实现从地区、食品种类、地区和食品种类等多角度、不同层次计算得到食品安全指数结果。