排序方式: 共有40条查询结果,搜索用时 31 毫秒
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Aaron Gosling Geoff W. Stevens Andrew R. Barber Sandra E. Kentish Sally L. Gras 《Food chemistry》2010
The production of prebiotic galactooligosaccharides (GOS) by the β-galactosidase catalysed conversion of lactose has become commercially important. Yet it remains a challenge to sufficiently understand the structure and activity of β-galactosidase, to increase the efficiency of transgalactosylation and GOS production and to improve the quality of GOS products in a rational way. This review covers the broad but related aspects of GOS synthesis including: the structure and reaction mechanism of β-galactosidase, factors effecting yield and productivity of GOS synthesis systems, the structure of GOS products, models for the kinetics of GOS synthesis and reactor configurations for GOS synthesis. It aims to couple recent discoveries with established knowledge to enhance understanding of the complex biochemistry of GOS synthesis. 相似文献
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This work develops a highly sensitive immunoassay sensor for use in graphene oxide sheet (GOS)-based surface plasmon resonance (SPR) chips. This sensing film, which is formed by chemically modifying a GOS surface, has covalent bonds that strongly interact with the bovine serum albumin (BSA), explaining why it has a higher sensitivity. This GOS film-based SPR chip has a BSA concentration detection limit that is 100 times higher than that of the conventional Au-film-based sensor. The affinity constants (KA) on the GOS film-based SPR chip and the conventional SPR chip for 100 μg/ml BSA are 80.82 × 106 M-1 and 15.67 × 106 M-1, respectively. Therefore, the affinity constant of the GOS film-based SPR chip is 5.2 times higher than that of the conventional chip. With respect to the protein-protein interaction, the SPR sensor capability to detect angle changes at a low concentration anti-BSA of 75.75 nM on the GOS film-based SPR chip and the conventional SPR chip is 36.1867 and 26.1759 mdeg, respectively. At a high concentration, anti-BSA of 378.78 nM on the GOS film-based SPR chip and the conventional SPR chip reveals two times increases in the SPR angle shift. Above results demonstrate that the GOS film is promising for highly sensitive clinical diagnostic applications. 相似文献
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基于虚拟化技术的进程级监控 总被引:1,自引:0,他引:1
刘钊远 《微电子学与计算机》2009,26(12)
目前虚拟环境中,虚拟机管理程序VMM和客户操作系统之间相对独立,因此,VMM只能对客户操作系统的整体运行情况进行监控.但是,当客户操作系统中一个进程因某种原因导致整个客户操作系统崩溃时,VMM显得无能为力.文中将VMM对客户操作系统的监控粒度从操作系统级提升到进程级,从而增强虚拟机的安全性和稳定性. 相似文献
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Milica Simović Ana Milivojević Marija Ćorović Katarina Banjanac Dejan Bezbradica 《International Journal of Food Science & Technology》2019,54(11):3074-3082
Whey represents a significant dairy industry by-product that has recently received due attention based on the rich nutrient composition and significant transformation potential. Hereby, we investigated a possibility of whey lactose bioconversion into prebiotic compounds, galacto-oligosaccharides (GOS) using β-galactosidase transgalactosylation activity. The results showed that whey could be successfully used for GOS synthesis, since the highest GOS concentration (around 62 g L−1) was obtained batchwise using 40% (w/w) sweet whey powder solution under optimum conditions (50°C, pH 4.5). Nevertheless, an efficient immobilized preparation using methacrylic Lifetech ECR8409 immobilization carrier was developed, enabling additional process improvement and ensuring at least 4 reaction cycles with unchanged yields and 2.5- fold enhanced productivity in comparison to the soluble enzyme. Therefore, this study provides a valuable contribution to the efficient and economical valorization of whey, which can be further on utilized as functional food and feed constituent. 相似文献
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Lamsal BP 《Journal of the science of food and agriculture》2012,92(10):2020-2028
Galactooligosaccharides are sugars composed of 3-10 molecules of galactose and glucose via a transgalactosylation reaction mediated by the enzyme β-galactosidase. Prebiotics are non-digestible food ingredients that pass through the upper digestive system relatively intact and ferment in the lower colon, producing short-chain fatty acids that support the growth of supplemented or indigenous colonic microbiota. Galactooligosaccharides and other prebiotic ingredients are increasingly being recognized as useful dietary tools for the modulation of the colonic microflora toward a healthy balance. Galactooligosaccharides compare well to other oligosaccharides in terms of their prebiotic, immunomodulation, and functional properties in foods. This review elucidates the galactooligosaccharide production process from refined lactose and/or cheese whey permeates, galactooligosaccharide market share and economic value, their health properties, and potential food applications. 相似文献
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优化并建立了半制备高效液相色谱法分离和收集、离子色谱法测定婴幼儿配方食品中低聚半乳糖的方法。本实验以乳粉、特殊医学配方奶粉和液态奶为实验对象,利用半制备高效液相色谱法分别收集婴幼儿配方食品中的二糖和三糖及聚合度(Degree of polymerization,DP)3以上的糖,再利用β-半乳糖苷酶水解收集到的聚合度3及3以上的糖组分,利用离子色谱法测定酶解后的半乳糖和葡萄糖的含量,通过计算得到样品中低聚半乳糖的含量。半制备高效液相色谱馏分固定相为Ag+色谱柱(200 mm×10 mm),流动相为100%超纯水,流速0.3 mL/min,进样量100 μL,柱温80℃;离子色谱条件固定相为Carbo Pac PA-1色谱柱(250 mm×4 mm),流动相为0.5 mol/L的氢氧化钠溶液、0.5 mol/L的乙酸钠和超纯水梯度洗脱,柱温30℃,进样量25 μL。测定的异乳糖、葡萄糖、半乳糖、1,6-β-D-半乳二糖和1,3(4)-β-D-半乳二糖线性范围在1.0~30.0 μg/mL,相关系数在0.9985~0.9999,回收率在82.80%~87.67%,相对标准偏差(Relative standard deviation,RSD)≤5%。该方法结果准确,能够满足检测要求,前处理操作简单,便于大批量样品的检测。 相似文献
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