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从117株泡菜和婴儿粪便源中筛选高产共轭亚油酸(CLA)的乳酸菌,对其进行功能性和安全性评价。采用紫外分光光度法初筛得到27株CLA转化率大于8%的菌株,通过GC-Q-TOFMS验证其CLA异构体组成,最终获得8株CLA转化率在10%以上,同时发酵液中c9,t11-CLA、t10,c12-CLA异构体质量浓度高于20 μg/mL乳酸菌。对这8株菌进行自凝集、疏水性、黏附性能、胃肠道耐受能力、抑菌活性、安全性等体外特性评价。结果表明,植物乳杆菌NCU001044、NCU006007整体表现优异,自凝集率皆大于60%,具有中度疏水能力,且黏附率分别为8.81%,9.10%。两株菌在pH 2.5酸性条件下存活率分别为95.68%,84.63%,在质量分数为0.3%的胆盐中存活率均高于65%。安全性方面,两株菌对青霉素、苄卡西林、四环素、红霉素中性敏感或敏感,无溶血活性。本研究筛选到具有高效生物转化有益CLA异构体能力的植物乳杆菌2株,这2株菌具有良好的胃肠道定植能力,以及酸、胆盐耐受力,对致病菌表现出较高的抑制作用,可进一步投入发酵产品及功能性微生态制剂的开发。 相似文献
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共轭亚油酸(conjugatedlinoleicacid简称CLA)是一种具有多种生理活性的天然脂肪酸。用气相色谱法对十八株乳酸菌产共轭亚油酸的能力进行比较,发现十四株乳酸菌具有明显的产共轭亚油酸的能力,其中德氏乳杆菌保加利亚亚种(L.delbrueckiisubsp.bulgaricus)a2的产量最高,为4.06μg/mL,并且在MRS培养基的基础上确定了乳酸菌产共轭亚油酸的最佳碳源为果糖,氮源为硫酸铵。 相似文献
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产共轭亚油酸乳酸菌的选育及培养基的确定 总被引:9,自引:0,他引:9
共轭亚油酸(conjugatedlinoleicacid简称CLA)是一种具有多种生理活性的天然脂肪酸。用气相色谱法对十八株乳酸菌产共轭亚油酸的能力进行比较,发现十四株乳酸菌具有明显的产共轭亚油酸的能力,其中德氏乳杆菌保加利亚亚种(L.delbrueckiisubsp.bulgaricus)a2的产量最高,为4.06μg/mL,并且在MRS培养基的基础上确定了乳酸菌产共轭亚油酸的最佳碳源为果糖,氮源为硫酸铵。 相似文献
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共轭亚油酸(conjugated linoleic acid, CLA)是十八碳二烯酸的异构体。通过食物摄入的CLA不能达到每日推荐摄入量,而CLA又具有减肥、抗癌、抗Ⅱ型糖尿病等多种生理功能,故CLA逐渐成为研究热点。与化学合成CLA相比,微生物合成CLA更具有优势。乳酸菌(lactic acid bacteria, LAB)具有安全性和益生功能,利用乳酸菌合成CLA是一个理想的途径。目前已发现多种产CLA乳酸菌,人们使用乳酸菌发酵油酸、牛乳、植物油合成CLA,并取得了良好的效果。亚油酸异构酶(linoleate isomerase, LAI)对乳酸菌合成CLA起重要作用,但其对乳酸菌合成CLA的作用机理还不明确。一些学者对乳酸菌合成CLA的中间产物进行了研究,发现乳酸菌合成CLA有多种中间产物。乳酸菌合成CLA的代谢机制目前尚不清楚。乳酸菌合成CLA对食品工业有重要意义,也为功能性食品的开发提供了新机遇。本文主要对CLA的生理功能、产CLA乳酸菌、乳酸菌合成CLA的底物、乳酸菌合成CLA的途径进行了概述。 相似文献
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从传统泡菜和生牛乳中筛选出一株乳酸菌ZS2058能生物合成共轭亚油酸,经API系统鉴定为植物乳杆菌(Lactobacillusplantarum).该菌株在MRS培养基中将质量分数11.6%的亚油酸(1.024mg/mL)转化为共轭亚油酸,经气相色谱分析证实c9,t11 18∶2占75.9%,t10,c12 18∶2占24.1%. 相似文献
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选择3种大孔树脂AB-8、HZ-802、HZ-841吸附固定化Thermomyces lanuginosus脂肪酶液,用AB-8树脂固定化的脂肪酶比酶活最高,达到37451U/g。用此脂肪酶催化生产CLA甘油酯,发现其对底物甘油酯种类没有特异选择性。在CLA乙酯与食用油(甘油酯)摩尔比为3:1,酶加量为7%,反应温度为60℃的条件下催化酯交换反应,CLA转酯化率可以达到47%以上。以AB-8弱极性大孔树脂固定化的脂肪酶有较高稳定性,连续反应8批以后,CLA转酯化率仍可以达到42%。 相似文献
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Chemical, physical, and sensory properties of dairy products enriched with conjugated linoleic acid 总被引:2,自引:0,他引:2
Jones EL Shingfield KJ Kohen C Jones AK Lupoli B Grandison AS Beever DE Williams CM Calder PC Yaqoob P 《Journal of dairy science》2005,88(8):2923-2937
Recent studies have illustrated the effects of cis-9,trans-11 conjugated linoleic acid (CLA) on human health. Ruminant-derived meat, milk and dairy products are the predominant sources of cis-9,trans-11 CLA in the human diet. This study evaluated the processing properties, texture, storage characteristics, and organoleptic properties of UHT milk, Caerphilly cheese, and butter produced from a milk enriched to a level of cis-9,trans-11 CLA that has been shown to have biological effects in humans. Forty-nine early-lactation Holstein-British Friesian cows were fed total mixed rations containing 0 (control) or 45 g/kg (on dry matter basis) of a mixture (1:2 wt/wt) of fish oil and sunflower oil during two consecutive 7-d periods to produce a control and CLA-enhanced milk, respectively. Milk produced from cows fed the control and fish and sunflower oil diets contained 0.54 and 4.68 g of total CLA/100 g of fatty acids, respectively. Enrichment of CLA in raw milk from the fish and sunflower oil diet was also accompanied by substantial increases in trans C18:1 levels, lowered C18:0, cis-C18:1, and total saturated fatty acid concentrations, and small increases in n-3 polyunsatu-rated fatty acid content. The CLA-enriched milk was used for the manufacture of UHT milk, butter, and cheese. Both the CLA-enhanced butter and cheese were less firm than control products. Although the sensory profiles of the CLA-enriched milk, butter, and cheese differed from those of the control products with respect to some attributes, the overall impression and flavor did not differ. In conclusion, it is feasible to produce CLA-enriched dairy products with acceptable storage and sensory characteristics. 相似文献
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Milk naturally enriched in conjugated linoleic acid (CLA) and trans-vaccenic acid (TVA) was ultra high temperature (UHT)-treated at 125–145 °C for 2–20 s and stored at 4 and 25 °C for up to 120 d. The oxidative stability of treated enriched milk was evaluated in terms of changes on the contents of CLA and TVA, dissolved oxygen, hydroperoxides, thiobarbituric acid reactive substance (TBARS) and formation of volatiles. After UHT treatment, more than 78% of CLA and 87% of TVA remained. After 15 d of storage at 25 °C, the CLA and TVA were relatively stable with values in the range of 67–75 and 63–73%, respectively. During storage, CLA oxidized faster than TVA, independently of the UHT treatment and storage conditions. Heptanal was the most abundant volatile resulting from UHT processing and a potential suitable marker for heat treatment of milk rich in CLA and TVA. 相似文献
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生物法转化合成共轭亚油酸,产物中异构体组成单一,具有很好的应用前景。通过一株植物乳杆菌(Lactobacillus plantarum)合成共轭亚油酸的培养基成分进行优化,确定最优的培养基组成:葡萄糖20g/L,酵母浸出物40g/L,硫酸镁0.5g/L,硫酸锰0.5g/L,乙酸钠2g/L,磷酸氢二钾1g/L。优化后,共轭亚油酸产量达到0.259g/L,相比优化前(0.0455g/L)有了较大的提升。 相似文献
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乳酸菌发酵生产共轭亚油酸 总被引:5,自引:0,他引:5
以盐生植物紫花苜蓿籽油为底物,用嗜酸乳酸杆菌(Lactobacillus acidophilus)1.1854催化紫花苜蓿籽油中的亚油酸转化为共轭亚油酸(CLA)。通过单因素实验,分析了发酵过程中pH、预培养、苜蓿籽油的浓度和乳酸菌菌液浓度对生产共轭亚油酸的影响。实验结果表明,预培养时加入一定量的苜蓿籽油可提高CLA转化率,发酵pH6.4,苜蓿籽油浓度0.05%,菌浓度2.5%时CLA转化率较高。 相似文献
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以固定化亚油酸异构酶和亚油酸(LA)为原料,在考察超临界CO2(SC-CO2)处理对酶稳定性影响的基础上,采用单因素试验和响应面法研究SC-CO2中LA质量浓度、反应温度、压力、反应时间对共轭亚油酸(CLA)合成的影响。结果表明:固定化亚油酸异构酶在SC-CO2压力小于30MPa,处理温度低于40℃,处理时间小于2 h时,相对酶活较高,具有较好的稳定性;响应面法优化CLA合成条件为LA质量浓度0.05 g/mL,反应温度36℃,压力30 MPa,反应时间1.5 h;在此条件下,CLA的含量为60.58 mg/g;固定化亚油酸异构酶重复使用3次,CLA保持较高的含量。 相似文献