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Search Results: 1 - 10 of 28221 matches for " 冯骉 "
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纸色谱萃取分光光度法测定γ-氨基丁酸的研究
王兢,江波,
食品科学 , 2007,
Abstract: ?对γ-氨基丁酸的定量方法(纸色谱萃取分光光度法和高效液相色谱法)进行了初步研究。分析研究了纸色谱萃取分光光度法测定γ-氨基丁酸的最佳实验条件,结果表明该方法最低检测浓度为0.0176g/l,线性测量范围为0.3~10g/l,平均回收率为99.04%,平均相对标准偏差为2.376%。与高效液相色谱法相比,纸色谱萃取分光光度法具有良好的相关性和较高的准确性和精密度,是一种简单、有效和费用低廉的方法。
电渗析在粗菊糖纯化过程中的应用
杨炼,江波,,金征宇
食品科学 , 2006,
Abstract: ?菊糖具有很高的营养价值和良好的功能性质,但由于粗菊糖含盐量高,粗蛋白多,含有大量的单、双糖,限制了其在食品工业中的应用,所以需要对粗菊糖进行纯化。鉴于已报道的一些纯化方法存在一些不足,本文讨论了电渗析对粗菊糖纯化过程的影响。在不同操作电压下,分析了粗菊糖在电渗析过程中电导率、ph、灰分,粗蛋白质含量,和糖分组成的变化。电渗析1h后,粗菊糖料液中灰分的去除率达到70%,粗蛋白质去除率达到47%,同时电渗析不会引起菊糖糖分组成的明显变化。实验证明电渗析对除去粗菊糖中的无机盐和游离氨基酸非常有效,能大大减轻后续纯化操作的压力,是粗菊糖纯化的一种经济、有效的操作。
超高压对解脂耶氏酵母脂肪酶酶活的影响
杨新颖,陈刚,杜焕梅,缪铭,
- , 2017, DOI: 10.3969/j.issn.1673-1689.2017.05.012
Abstract: 研究了超高压体系中,压力、温度、pH和保压时间对解脂耶氏酵母脂肪酶活性的影响。结果表明:在超高压作用下,解脂耶氏酵母脂肪酶的活性有所提高;经正交试验优化得到在压力450 MPa、温度45 ℃、pH 7.5、保压时间10 min条件下,脂肪酶活性最高,为同等条件下常压处理的脂肪酶活性的220%。经高压处理后,脂肪酶的最适pH 较常压条件下向碱性方向移动0.5。
The study investigated the effects of pressure,temperature,dwell time and pH on the enzyme activity of lipase Lip2 from Yarrowia lipolytica(YLLIP2) in high hydrostatic pressure(HHP) treatment. Results showed that HHP improved the activity of YLLIP2 and pressure,temperature,dwell time and pH had significant effects on the enzyme activity. Optimal parameters were found by orthogonal test to be pressure 450 MPa,temperature 45 ℃,dwell time 10 min and pH 7.5. The optimal pH was increased 0.5 in HHP
副溶血性弧菌PMA-LAMP方法的建立

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.7.032
Abstract: 副溶血性弧菌(Vibrio parahemolyticus)是一种常见的食源性致病菌,在海鲜等食物中检出率很高,食用没有煮熟的带菌食物或者腌制品,极易引起食物中毒。目前用以检测副溶血性弧菌的快速检测方法都不能区别死活菌,容易出现假阳性结果。本研究基于DNA结合染料叠氮溴化丙锭(propidium monoazide, PMA),利用荧光染料钙黄绿素(Calcein)的特性,建立了一种实时的可视化环介导等温扩增方法(Loop-mediated isothermal amplification, LAMP),并与qPCR方法进行比较。实时可视化LAMP方法的反应结果,既可以肉眼直接观测,也可以借助荧光分析设备实时监测,并对半定量分析进行初探,为之后向定量分析深入研究打下基础。实验结果表明,实时可视化PMA-LAMP方法的灵敏度可达5.0×102 CFU/mL,模拟食样灵敏度为1.9×102 CFU/mL,与PMA-qPCR方法结果一致。除去前增菌时间,整个检测过程只需2 h,且准确率高,为副溶血性弧菌快速检测的开展提供了有效的技术支持。
Vibrio parahaemolyticus is a common foodborne pathogen frequently detected in seafood, and consumption of raw, pickled, or uncooked food contaminated with V. parahaemolyticus can cause food poisoning. Nearly all current methods for rapidly detecting V. parahaemolyticus can not distinguish live cells from dead cells, resulting in false-positive results. In this study, a real-time visual loop-mediated isothermal amplification (LAMP) method was developed based on the characteristics of the DNA binding dye propidium monoazide (PMA) and fluorescent dye calcein to detect viable V. parahaemolyticus strains. This method was compared to quantitative polymerase chain reaction (qPCR). The results of real-time visual PMA-LAMP assay could be observed by the naked eye and monitored in real-time using fluorescence analysis instruments. A preliminary semi-quantitative analysis was conducted, providing a basis for in-depth quantitative analysis. The results indicated that the sensitivities of the real-time visual PMA-LAMP assay in the sensitivity experiment and artificial contamination experiment were 5.0 × 102 CFU/mL and 1.9 × 102 CFU/mL, respectively, which were consistent with the values from PMA-qPCR. The entire detection process required only 2 h, excluding the pre-enrichment step. Furthermore, the method showed high accuracy and may be an effective technical method for rapid detection of V. parahaemolyticus.
钛络合物均相催化合成聚六氢苯酐二甘醇酯
蒋平平,沈敏亮,董玉明,张晓鸣,
化工进展 , 2011,
Abstract: 以六氢苯酐和二甘醇为原料,钛络合物钛酸正四丁酯为催化剂合成聚六氢苯酐二甘醇酯。结果表明,钛酸正四丁酯催化合成聚六氢苯酐二甘醇酯的最佳反应条件为醇酸摩尔比为1.1∶1,催化剂用量为0.8%(以六氢苯酐质量计),反应温度为220℃,反应时间为5h,-0.095MPa压强下减压时间为2.5h,减压温度为220℃,酯化率大于99.0%。合成产物聚六氢苯酐二甘醇酯的数均分子量Mn为14000,重均分子量Mw为15000,分子量具有窄分布物性。
抗氧化型壁材包埋番茄红素微胶囊的研究
林蔚婷,贾承胜,夏书芹,张晓鸣,
- , 2018, DOI: 10.3969/j.issn.1673-1689.2018.01.009
Abstract: 研究了新型抗氧化性壁材制备番茄红素微胶囊的生产工艺。采用番茄红素为芯材,乳清分离蛋白与低聚木糖的美拉德反应产物(MRPs)为壁材,通过均质和喷雾干燥制得番茄红素微胶囊。优化的工艺参数为乳清分离蛋白与低聚木糖的质量比1∶2,加热时间3 h,pH 10,均质压力40 MPa。在此条件下得到的微胶囊产率和包埋效率分别为86.28%和94.11%。通过保留率的数据分析,结果表明壁材能够有效保护芯材成分,提高番茄红素微胶囊的储存稳定性。
The manuscript investigated the preparation method of lycopene microcapsule by homogenization and spray-drying technique using Maillard reaction products(MRPs) of whey protein isolate(WPI) and xyloligosaccharides as novel antioxidation wall material system. The optimum experimental parameters were as follows:the mass ratio of xyloligosaccharides to WPI 1∶2,heating time 3 h,pH 10,homogenization pressure 40 MPa. The yield and encapsulation efficiency of microencapsulated lycopene were 86.28% and 94.11%,respectively. Moreover,through analyzing of retention rate,the results indicated that wall materials could protect lycopene from oxidation,and thus improve the storage stability of lycopene
超高压体系下皱褶假丝酵母脂肪酶的水解特性
杜焕梅,缪铭,,江波,张涛
- , 2018, DOI: 10.3969/j.issn.1673-1689.2018.03.005
Abstract: 研究了压力、温度、pH、保压时间对脂肪酶活性的影响,并分析了酶的复原性,测定了不同温度和压力处理脂肪酶的动力学参数。结果表明,200 MPa时脂肪酶酶活最高,是常压的1.76倍。200 MPa时脂肪酶最适温度为40 ℃,最适pH值7.5,最佳保压时间为10 min。与常压相比,200 MPa时,40 ℃时Km值变化不大,50 ℃时Km值有所增加,而Vmax、Kcat、Kcat/Km值随压力的升高而增大。
The effects of pressure,temperature,pH and holding time on Candida rugosalipase activity were studied and the recovery of the enzyme was analyzed. We also investigated the changes of kinetics parameters of lipase under different temperature and pressure. The results showed that lipase activity was the highest under 200 MPa and almost 1.76 times of atmospheric pressure. Under this pressure,the optimum temperature and pH for lipase were 40 ℃and pH 7.5,respectively;the processing time was 10 min;the change of Km at 40 ℃ is not as obvious as 50 ℃;meanwhile the Vmax,Kcat and Kcat/Km increased significantly with the elevated pressure
棕色固氮菌过氧化物酶研究
,林永齐
微生物学报 , 1992,
Abstract:
多年冻土地区水泥稳定砂砾抗冻融耐久性模拟试验
,王秉纲
冰川冻土 , 2006,
Abstract: 通过控制试件湿度,模拟基层实际使用中的最不利湿度状况下的冻融循环试验,分析了冻融循环次数和试件湿度状况对混合料耐冻系数的影响.结果表明,耐冻系数随冻融循环次数的增加而不断减小,湿度对抗冻融耐久性评价结果有明显影响.多年冻土地区水泥稳定砂砾的抗冻融耐久性评价不宜直接采用水泥混凝土的饱水冻融试验方法,采用模拟基层的最不利湿度状况的冻融试验,以10次冻融循环时弯拉强度损失表示的耐冻系数作为指标,评价结果稳定,更符合实际使用情况.
冻土地区温度对水泥稳定砂砾收缩特性的影响
王刚,,王秉纲
公路交通科技 , 2008,
Abstract: 通过模拟冻土地区实际温度养生的水泥稳定砂砾的干燥收缩与温度收缩试验,分析了混合料的收缩特性。试验得出,模拟养生初期和早期试件的相对干缩应变的变化趋势基本相同,干缩系数变化趋势明显不同,相对失水率在65%~80%之间是干缩应变的最不利阶段。养生温度对混合料的温度收缩有明显影响,模拟了养生试件的温缩应变变化速率比标准养生大,温缩系数约为标准养生的1.5~5倍,变化趋势存在差异。0~-20℃是温度收缩的最不利温度段。冻土地区混合料收缩特性的变化主要与温度对混合料强度形成的影响有关。结果表明,加快冻土地区水泥稳定砂砾的强度形成,可以明显提高混合料的抗收缩开裂能力。
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