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吴丹 《中外食品工业信息》2011,(9):34-34
乳品是消费者每天都需要摄入的东西,但因消费者自身原因会在摄入后产生不适的状况.加之最近频繁爆出乳品安全问题,让消费者对乳品的选择有了一些担忧.所以纯奶制品的销售额一直不太稳定,这给纯奶企业与经销商的投资带来了不利因素。但如果不是纯奶制品的乳品.例如果奶、花生奶等,却一直没有在销售业绩上出现下滑征兆。 相似文献
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为快速、准确地计数活性乳酸菌制品中的乳酸菌,用CO2烛缸法代替现行国家标准GB/T16347-1996活性乳酸菌饮料中乳酸菌微生物检验方法中的有氧培养法,CO2烛缸法操作简便,计算准确可靠,在菌种对比实验中,CO2烛缸法的乳酸菌计数结果是国家标准方法的8倍,在试样的对比实验中,CO2烛缸法的乳酸菌计数结果是国家标准方法的20倍,CO2烛缸法较目前国家标准方法更能真实施反映活性乳酸菌制品中乳酸菌的数量。 相似文献
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目的利用定量PCR(quantitativePCR,qPCR)技术检测杀菌型产品中乳酸菌,并与标签标示相比较,查探产品中各类菌种的异同性及数量。方法以市售的发酵乳及含乳饮料作为研究对象,设计可区分产品中常见的6种乳酸菌特异性引物及探针,利用qPCR技术对方法的特异性、灵敏度进行验证,并建立标准扩增曲线;利用模拟样品对方法进行检验,最后对市场上购买的实际样品进行检测。结果除去干酪乳杆菌,其他5种引物都能特异性扩增出其目标菌,并且对其他的乳酸菌均无扩增现象;DNA检测的灵敏度可达到2~4pg;单一标准菌种扩增曲线线性较好,相关系数r2值在0.954~0.992之间;对模拟样品的检测,与平板法差异性比较,P值均大于0.05,无显著性差异。对市售样品进行检测,产品中标记的干酪乳杆菌、双歧杆菌和嗜热链球菌与检测结果存在不匹配现象。结论本研究建立的qPCR方法可快速、准确地对产品中德氏乳杆菌保加利亚亚种、嗜热链球菌、乳酸乳球菌、嗜酸乳杆菌、双歧杆菌的鉴定和定量的分析。 相似文献
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目的建立一种使用流式细胞仪检测酸奶中乳酸菌含量的快速检测方法。方法吸取稀释后样品匀液100μL加入20 mL试管中,30 min内使用流式细胞仪检测。经过光电倍增器过滤和检测,荧光脉冲的密度和高度被记录下来并被换算为细菌的个数。结果与国标法相比,仪器检测时间约缩短了3 d,试验结果表明流式细胞仪检测结果与国标结果 R值均在1以下。结论流流式细胞仪法与国标平皿菌落计数法的结果具有很高的一致性。采用流式细胞仪对酸奶中的乳酸菌进行快速检测,培养时间为由48 h缩短至13 min,大大提高了检测速度,对于乳制品生产企业来说,意义重大。 相似文献
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目的建立一种简单、准确的检测牛乳中抗生素残留的方法-乳酸菌发酵法。方法以接种量和温度为变量,优化发酵条件;以青霉素为目标抗生素,建立检测方法;以发酵4 h未凝乳的样品中抗生素最低浓度为检测限,测定本方法对20种抗生素的检测限;对比本方法和GB/T 4789.27方法检测111个商品乳样品中抗生素残留检出率,验证本方法的准确性。结果建立了乳酸菌发酵法检测乳中抗生素残留的具体方法;确定了本方法对8类20种抗生素的检测限,其中4类12种抗生素的检测限低于其在牛乳中的最大残留限量(MRL);本方法和GB/T 4789.27方法检测111个商品乳样品抗生素残留检出率分别为9.0%和11.7%。结论本方法操作简单,结果准确,适合企业及基层检测单位作为初筛方法检测牛乳中的抗生素残留。 相似文献
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具抗氧化活性乳酸菌的筛选 总被引:6,自引:0,他引:6
以体外过氧化氢耐受能力为指标,从发酵食品中筛选出2株能够耐受1mmol/L浓度过氧化氢的乳酸菌,两株细菌的耐过氧化氢能力与L. rhamnosusGG的耐过氧化氢能力相当。研究了两株乳酸菌完整细胞和无细胞提取物的DPPH自由基和羟自由基清除能力。结果表明,菌体浓度为109mL-1的L1001完整细胞和无细胞提取物的DPPH自由基清除率分别为36.2%和37.9%,同样浓度的F12完整细胞和无细胞提取物对DPPH自由基的清除率分别为24.4%和27.0%;清除羟自由基实验表明,细胞浓度为109mL-1的细胞清除羟自由基能力与同体积的浓度为1mmol/L抗坏血酸相当,L1001的羟自由基清除能力优于F12。利用API鉴定系统L1001菌株被鉴定为植物乳杆菌Lactobacillus plantarum L1001。 相似文献
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乳酸菌抗氧化活性的研究进展 总被引:13,自引:2,他引:13
介绍了乳酸菌的抗氧化活性、可能机制及其研究进展。在体外实验中,乳酸菌及其无细胞提取物能清除机体羟自由基(HO)、过氧化氢(H2O2)、二苯代苦味肼基自由基(DPPH);可抑制脂质过氧化、螯合金属离子,具有总还原能力及SOD酶活性。并介绍了乳酸菌抗氧化活性的体内实验结果。 相似文献
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《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(10):1678-1687
Humans can be exposed to N-nitroso compounds (NOCs) due to many environmental sources, as well as endogenous formation. The main nitrosamine found in food products and also synthesised in vivo by intestinal microbiota is N-nitrosodimethylamine (NDMA). It can cause cancer of the stomach, kidney and colon. The effect of four probiotic Lactobacillus strains on NDMA was studied under different culture conditions (24 h in MRS, 168 h in modified MRS N, and 168 h in phosphate buffer). HPLC and GC-TEA methods were used for NDMA determination in supernatants. The influence of lactic acid bacteria on NDMA genotoxicity was investigated by means of the comet assay. Additionally, the effect of NDMA (2–100 µg ml–1) on the growth and survival of the probiotic strains was studied. The results indicate that the bacteria decreased NDMA concentration by up to 50%, depending on the culture conditions, time of incubation, NDMA concentration, pH and bacterial strain. Lb. brevis 0945 lowered the concentration and genotoxicity of NDMA most effectively by up to 50%. This could be due to either adsorption or metabolism. The growth and survival of the bacteria was not affected by any of the tested NDMA concentrations. 相似文献
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论述了乳酸菌的生物拮抗作用,包括对致病菌和乳酸菌之间的拮抗。并简要论述了产生拮抗作用的可能因素或机理,为乳酸菌进一步开发提供一种理论依据。 相似文献
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以猕猴桃为原料,以pH值和感官评价作为检测指标,依次经过菌种筛选、单因素试验及正交试验确定猕猴桃乳酸菌饮料的最佳工艺条件,并分析该饮料在保藏期期间总酚酸、维生素C以及乳酸菌含量的变化情况。结果表明,适用于猕猴桃乳酸菌饮料的最佳菌种为植物乳杆菌(Lactobacillus plantarum),最佳发酵工艺条件为初始pH值5.0,加糖量10%,料液比1∶1(g∶mL),接种量106 CFU/g,发酵温度37 ℃,发酵时间28 h。在此最佳工艺条件下,产品总酚酸含量174.89 mg/100 g,维生素C 46.84 mg/100 g,pH值4.27,可溶性固形物18%,活菌数对数值9.96,微生物指标符合相关标准。 相似文献
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Spray-drying of bacteriocin-producing lactic acid bacteria. 总被引:1,自引:0,他引:1
Cell survival, cellular damage, and antagonistic activity were investigated after spray-drying of four bacteriocin-producing strains of lactic acid bacteria: Lactococcus lactis subsp. lactis 140, isolated from natural whey culture and producing a narrow-inhibitory spectrum bacteriocin); L. lactis subsp. lactis G35, isolated from pizza dough and producing nisin; Lactobacillus curvatus 32Y and Lactobacillus sp. 8Z, isolated from dry sausages. Trials were performed with bacteria suspended in skimmed milk or directly grown in whey. Three air temperatures at the inlet of the drier (160, 180, and 200 degrees C) and three flow rates (10, 13, and 17 ml/min) were assayed. Cell viability and bacteriocin activity of the dried materials were determined immediately after the process and after 5, 15, 30, and 60 days of storage at 4 degrees C. There was no significant difference between the two feeding suspensions in cell survival, always decreasing with the increase of inlet-air temperature. No loss of bacteriocin activity was detected in reconstituted powders, nor was any loss of ability to produce bacteriocin found after drying. Investigations of sensitivity to NaCl revealed only temporary damage to dried bacteria. During storage for 2 months at 4 degrees C, all samples, but mainly the lactococcal strains, displayed a gradual decrease in cell survival. Bacteriocin activity remained at the same level, allowing powders to be considered as effective biopreservatives. 相似文献
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《食品与发酵工业》2015,(10):40-44
将3株乳酸菌(A1-5、ATCC19434、DSM7134)的活菌、热灭活菌分别作用于棒曲霉素,作用不同时间后用HPLC对其脱除效果进行检测。结果表明,3株乳酸菌对棒曲霉素均有脱除作用,A1-5菌株作用10 h效果最好,脱除率为52.86%;ATCC19434菌株作用48 h时效果最好,脱除率为74.28%;DSM7134菌株作用48 h脱除效果最好,脱除率为58.96%。在相同作用时间下,同一菌株的活菌比热灭活菌的脱除效果好,说明这3株乳酸菌对棒曲霉素既有吸附作用亦有代谢降解作用,均可用于棒曲霉素的脱除。ATCC19434菌株吸附脱除效果最佳,A1-5菌株则代谢降解能力最强,进一步对A1-5菌株进行鉴定,明确其为植物乳杆菌。 相似文献
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Prolyl-dipeptidyl-peptidase activity was detected in cell extracts of 21 lactic acid bacteria tested. Using disc electrophoresis and various substrates it was possible to distinguish it from proline iminopeptidase and proline endopeptidase. Generally the activity was high and was greater than that of proline iminopeptidase of proline endopeptidase at neutral pH and at 25 degrees C. 相似文献