洋甘菊多糖的分离纯化、性质结构及抗氧化活性分析

对热回流提取得到的洋甘菊多糖进行了分离纯化,并对得到的多糖的性质结构及抗氧化活性进行分析。经处理后的洋甘菊多糖先后利用DEAE-Sepharose和Sephadex G-100柱色谱分离纯化得到了2种均一多糖(MCP-1-1和MCP-2-1);经测定2种均一多糖总糖含量分别为82.23%、84.09%,糖醛酸含量分别为4.11%、5.38%,蛋白质含量分别为0.58%、1.05%,溶解度分别为98.36%、98.44%,分子质量分别为30902、7244 Da;单糖组成实验结果表明MCP-1-1是由鼠李糖(Rha)、葡萄糖醛酸(GlcA)、半乳糖(Gal)、葡萄糖(Glc)、木糖(Xyl)和阿拉伯糖(Ara)6种单糖组成,MCP-2-1是由GlcA、Gal、Glc、GalA、Xyl和Ara六种单糖组成,2种均一多糖均是不含三螺旋结构的酸性多糖,均含有吡喃环和β-糖苷键,MCP-1-1含有α-糖苷键;2种均一多糖具有良好的热稳定性。体外清除自由基试验结果显示MCP-1-1和MCP-2-1对DPPH自由基和·OH均有清除作用,而且清除能力与均一多糖的质量浓度正相关,MCP-2-1对2种自由基的清除能力明显高于MCP-1-1。研究结果表明,分离纯化得到的洋甘菊多糖可作为天然抗氧化剂,用于食品和化妆品中。     

比较基因组揭示广西酸菜乳杆菌碳水化合物活性酶谱

微生物中的碳水化合物活性酶(carbohydrate active enzymes,CAZymes)具有降解植物组织的作用,相对于真菌,目前对于乳杆菌的CAZymes研究还比较少.该研究从广西酸菜中筛选获得了3株产CAZymes的乳杆菌,并通过二代测序技术比较其编码基因.16S rRNA测序结果表明3株乳杆菌分别是La...     

铁皮石斛酶解多糖对姜黄素乳液功能性质的影响

通过酶解法获得低分子质量铁皮石斛多糖,并通过添加该多糖,用于改善乳清蛋白稳定的姜黄素乳液的功能性质.以铁皮石斛酶解多糖/乳清蛋白作为乳化系统制备荷载姜黄素的乳液,评估乳液的物理稳定性和乳液对姜黄素的保护作用;探讨荷载姜黄素的乳液抑制癌细胞的效果及乳液中的姜黄素在模拟胃肠道环境中的释放情况.结果表明,酶解降低了多糖的黏性...     

远志多糖对力竭运动小鼠体内抗疲劳和体外抗氧化作用研究

为了探讨远志多糖的体内、外活性,采用力竭运动动物模型,给予受试动物低、中、高剂量(0.10、0.20、0.40 mg/g·d)远志多糖后,分别测定各组动物负重游泳时间、肝糖原、肌糖原、乳酸、尿素氮含量及乳酸脱氢酶的活力和体外抗氧化活性.结果表明,与空白对照组相较,低、中、高剂量的远志多糖分别延长小鼠的负重游泳时间96....     

Nutrient digestibility and endogenous protein losses in the foregut and small intestine of weaned dairy calves fed calf starters with conventional or enzyme-treated soybean meal

The aims of this experiment were (1) to compare the effects of a soybean meal with an enzymatic treatment (ESBM) to reduce the concentration of antinutritional factors versus a standard soybean meal (SBM) on foregut and small intestine digestion in weaned dairy calves and (2) to estimate the endogenous losses of crude protein (CP) in the small intestine. Our hypothesis was that a diet containing ESBM instead of SBM would improve ruminal and small intestine digestion and absorption of nutrients. A T-cannula was placed in the duodenum, and a second T-cannula was installed in the distal ileum of 12 Holstein calves at approximately 3 wk of age. Calves were weaned on d 42, and on d 50 they were assigned randomly to a quadruplicated 3 × 3 Latin square with 10-d periods. Digesta samples were collected on d 7 and 8 from the ileum and d 9 and 10 from the duodenum. The diets were fed for ad libitum intake and consisted of a calf starter (CS) of 20% CP with SBM as the main source of protein (CTRL), and an isonitrogenous CS with an ESBM instead of SBM (ENZT). A third diet with a low content of CP (10%) and no soy protein was fed to estimate endogenous N losses and digestibilities of test ingredients. Flows and digestibilities of nutrients were compared between CTRL and ENZT and their test ingredients (SBM vs. ESBM, respectively). Duodenal net flows of CP and total AA as well as ruminal microbial protein synthesis per kilogram of digested CP were greater, and flow of nonprotein N and CP true (corrected by endogenous and microbial flows) foregut digestibility were lower with ENZT than CTRL. The apparent small intestine digestibilities of CP and total AA were greater for ESBM than SBM, but there were no differences between the CTRL and ENZT diets. We observed no differences in digestibilities at the duodenum or ileum of starch or NDF, but true small intestine digestibilities of CP and all AA were greater with ENZT than CTRL. Total endogenous protein losses in the small intestine estimated from calves fed the low-CP with no soy protein diet were 37 ± 1.5 g of CP and 29 ± 1.4 g of AA/kg of DMI. These values may be considered the basal endogenous losses as they are similar to values obtained with the regression method, which estimates N losses when dietary N is null. Our results indicated that the inclusion of an ESBM improved the efficiency of ruminal microbial protein synthesis per digested kilogram of organic matter and CP, and increased CP and AA absorption in the small intestine despite a greater proportion of undigested dietary protein entering the duodenum.     

野化白云黄茶闷黄过程中的品质成分变化及其菌种分离鉴定

为了掌握野化白云茶树鲜叶加工成黄茶加工过程的影响因素,该研究对比分析了野化白云茶加工的黄茶、烘青绿茶、半烘半炒绿茶的主要品质成分;分析了野化白云茶鲜叶加工黄茶过程中的依工艺阶段取8个茶样（茶青、杀青叶、揉捻叶、再炒叶（除水叶）、闷黄24 h、闷黄48 h、闷黄72 h、毛茶）可培养菌种的变化。野化白云茶与烘青绿茶、半烘半炒绿茶比较,除氨基酸、咖啡碱含量略有下降外,水浸出物含量分别高出4.80%、7.11%,可溶性糖含量分别高出0.41%、0.36%,茶多酚含量、儿茶素总含量呈下降趋势,酯型儿茶素总量下降21.62 mg/g、19.08 mg/g,EGCG下降9.99 mg/g、6.98 mg/g,GCG下降14.23 mg/g、13.80 mg/g,以上成分变化均差异显著（p<0.05）;非酯型儿茶素组分中除C减小2.49 mg/g、1.75 mg/g（p<0.05）外,其余非酯型儿茶素组分和总含量变化差异不显（p>0.05）;闷黄24 h,酵母菌数量明显,至72 h霉菌成优势菌种（3.5×105 CFU/g）;分离鉴出8株微生物,包括1株拟盘多毛孢属,4株青霉属,1株枝孢属及2株酵母菌属,其中Penicillium exsudans菌首次从茶叶加工中和茶叶中分离并鉴定。说明闷黄使茶叶水溶性物质、可溶性糖增加,茶多酚、酯型儿茶素下降,闷黄阶段有微生物繁殖并参与黄茶品质的形成。     

传统发酵泡菜中乳酸菌种群组成及优良菌株产酸耐酸特性分析

采用传统分离纯化方法从中国北方4 个不同地区的20 份传统自然发酵泡菜样品中,分离得到435 株疑似乳酸菌,通过16SrDNA序列分析对株菌进行种属鉴定,结果显示分离到的所有菌株均为乳酸菌,其中乳杆菌属6 个种共394 株,分别为莫氏乳杆菌(Lactobacillus modestisalitolerans)、清酒乳杆...     

泸香型白酒窖泥微生物生态功能研究进展

窖泥中含有大量的功能微生物,其作为白酒生香功能微生物的繁殖载体,在泸香型白酒的生产过程中发挥了重要作用。窖泥微生物是决定浓香型白酒风格的关键因素,目前基于传统微生物技术和现代生物学技术(如以聚合酶链式反应(PCR)技术、基因组学技术、高通量测序技术)等对白酒窖泥微生物的研究,已经取得了丰富的研究成果,检测到越来越多的窖泥微生物,发现微生物多样性越来越高。本文综述了窖泥微生物群落结构的多样性、窖泥功能微生物对白酒风味的贡献、新老窖泥中无机成分的质量评价,并针对研究存在的问题提出未来研究方向:进一步发掘窖泥微生物资源,提升功能微生物的应用潜力,以期为白酒生产中遇到的实际问题提供理论指导。     

基于16S rRNA的徽派腊肉加工过程中微生物群落结构分析

为探究徽派腊肉加工过程中的微生物群落演替规律,采用高通量测序技术对不同加工阶段的徽派腊肉中微生物16S rRNA进行V3～V4区测序,比较不同加工阶段(鲜肉、腌制中期、腌制结束、成熟中期、成熟结束)腊肉中细菌群落结构组成及多样性差异.结果表明:5个加工阶段分别获得80155、80116、80174、80114、8017...     

应用高通量测序分析常温贮藏吴山贡鹅的细菌多样性

运用传统培养技术结合高通量测序技术对常温贮藏吴山贡鹅的菌群结构进行分析,研究吴山贡鹅微生物群落的变化以及导致吴山贡鹅腐败的微生物分布.结果表明:吴山贡鹅贮藏期间pH值呈现先上升后下降的趋势,菌落总数则呈现上升的趋势,贮藏末期吴山贡鹅中菌落总数、乳酸菌、大肠杆菌和假单胞菌的数量分别达到5.76、5.21、2.13、2.9...