高效液相色谱法测定盐酸精氨酸葡萄糖注射液中盐酸精氨酸的含量

目的建立测定盐酸精氨酸葡萄糖注射液中盐酸精氨酸含量的方法。方法使用高效液相色谱法,色谱条件为:Shim-Pack-CLC-NH2柱;流动相为乙腈-磷酸盐缓冲液(50:50);流速为1 ml/min;检测波长为200 nm。结果线性范围为0.04-0.2 mg/ml;相关系数R=0.999 8;回收率为99.9%(RSD=0.30%,n=9)。结论此方法重复性好,结果准确,可用于测定盐酸精氨酸葡萄糖注射液中盐酸精氨酸的含量。     

影响蔗糖旋光度的因素

旋光度是偏振光通过旋光物质时偏振光振动面旋转的角度。它是量度旋光物质对平面偏振光旋转能力的单位。对溶液旋光物质(如蔗糖溶液),旋光度α=[α]_D~(20)·(l·C)/(100),式中[α]_D~(20)表示在20℃时对于钠光的比旋光率(比旋光度)为+66.5,l 表示偏振光在溶液中通过距离,C 为100毫升溶液中所含溶质的克数。可见旋光度是与偏振光在溶液中通过的距离和浓度成正比。测知溶液旋光度就     

葡萄糖对冷冻干燥血红蛋白色素稳定性的影响

以猪血红蛋白为研究对象,研究添加5 g/100 m L的葡萄糖对冷冻干燥血红蛋白色差值和水分含量的影响,分析不同p H值、温度和NaCl浓度对血红蛋白色素稳定性的影响。结果表明:添加葡萄糖能够显著提高血红蛋白的亮度L*值和红绿度a*值,并且降低高铁血红蛋白含量(P0.05);添加葡萄糖可显著提高血红蛋白对pH值、温度、NaCl浓度的稳定性(P0.05)。当pH 7、温度低于60℃、NaCl浓度为0.6 mol/L时葡萄糖处理组中血红蛋白的稳定性最高。     

旋光法测定发酵液中2-酮基-D-葡萄糖酸

通过测定发酵液的旋光度及其葡萄糖质量浓度,计算发酵液中2- 酮基-D- 葡萄糖酸的质量浓度,并考察该方法实际应用的可行性。结果表明：对照品溶液的旋光度、2- 酮基-D- 葡萄糖酸质量浓度和葡萄糖质量浓度之间存在良好的线性关系,R2 ＞ 0.9999;该方法精密度、稳定性和重现性良好,2- 酮基-D- 葡萄糖酸的平均回收率为102.60%,RSD 为2.17%(n=5)。该方法可用于发酵液中2- 酮基-D- 葡萄糖酸的定量检测。     

发状念珠藻多糖和细胞培养液对葡萄糖浓度测定的影响

采用生物传感仪测定法和DNS法,对加入发菜多糖和发菜细胞培养发酵液的葡萄糖溶液进行了浓度测定,研究了多糖和细胞培养液对葡萄糖浓度测定的影响作用。结果表明,发菜多糖对葡萄糖浓度测定无影响。添加发菜混合营养培养液后测得葡萄糖浓度为标准葡萄糖溶液与发酵液中葡萄糖浓度之和。     

双波长分光光度法快速测定母乳替代品中钙磷比

目的建立双波长分光光度法,不经分离同时测定母乳替代品中钙、磷含量。方法常温下,pH 5.4醋酸-醋酸钠缓冲溶液中,先加入磷系列显色溶液使其反应30 min,后加入钙显色剂反应10 min,710 nm测定吸光度实现磷的测定,556 nm处利用差值吸光度完成对钙的测定。结果在上述实验条件下,磷和钙的浓度分别在0.3～1.7μg/ml,0.4～2.0μg/ml范围内与吸光度呈良好的线性关系,样品加标回收率在96.7%～112.3%之间。结论此法准确度高,方便快捷,所用仪器简单,用于母乳替代品中钙磷比测定,结果满意。     

模式体系谷氨酸-葡萄糖美拉德反应程度研究

为研究反应温度和反应时间对模式体系美拉德反应程度的影响,配制D-葡萄糖(0.02 mol/L)与L-谷氨酸(0.06 mol/L)浓度比为1∶3的美拉德反应液,分别置于10～40℃反应不同时间(10,20,30,40,50,60 d),通过测定不同条件下美拉德反应产物(MRPs)的pH值、吸光度值(A_(294nm)和A_(360nm))、挥发性成分、葡萄糖残余含量等,探讨模式体系的反应进程。结果表明,谷氨酸与葡萄糖发生美拉德反应的介质环境基本稳定,吸光度与反应温度、时间整体呈正相关,葡萄糖浓度随温度、时间变化遵循Boltzmann模型,符合动力学方程y=A_2+(A_1-A_2)/(1+exp(x-x_0)/d_x),且拟合效果较佳(R~2均大于0.90)。     

含葡萄糖培养基高温灭菌变色及其防范措施的研究

研究了葡萄糖浓度、pH值、硫酸铵及氨基酸对葡萄糖溶液高温变色的影响，结果表明pH值是葡萄糖溶液高温变色的主要因素；pH值低于5.5，并且避免与含氨离子化合物共同灭菌，可以有效防止色素的产生。     

啤酒中戊聚糖的测定——地衣酚-盐酸法

研究了地衣酚 盐酸法测定啤酒及麦汁中的戊聚糖 ,探讨了实验条件 ,建立了以双波长吸光度差值的方法测定啤酒和麦汁中的戊聚糖。当参加反应的 3 0mL的溶液中木糖的含量为 0～ 2 0 0 μg时 ,反应液吸光度的变化符合比摩尔定律 ,标样的回收率在 91 9%～ 10 6 9%之间。用此法测得的市售啤酒中戊聚糖含量在 90 6～ 2 12 1mg/L之间     

高效液相色谱法测定聚葡萄糖含量的研究

用Waters Ultrahydrogel 250(4.6×300mm)色谱柱,以水作流动相,示差折光检测,进样量20μl,在流速0.5ml/min下,直接测定样品中的可溶性膳食纤维聚葡萄糖含量和平均分子量。建立了分子量与保留时间的关系方程,用于样品中聚葡萄糖的分子量测定。聚葡萄糖浓度在0.199mg/ml～3.98mg/ml范围内与峰面积呈良好的线性关系,方法RSD小于1.00%,回收率103%～110%(RSD=1.91%)之间。结果显示,该方法是简单、准确、可靠的,适合于食品中水溶性膳食纤维聚葡萄糖含量的测定。     

Duodenal glucose increases glucose fluxes and lactose synthesis in grass silage-fed dairy cows

The effect of intestinal glucose supply on whole body rate of glucose appearance (WBGRa) and mammary utilization of glucose was studied in four lactating dairy cows. Glucose (0, 443, 963 and 2398 g/d) was continuously infused in the duodenum over 14-d periods using a Latin square design. A grass silage-based diet was formulated so that treatments were isoenergetic and isonitrogenous and contained 100 and 110% of energy and protein requirements according to INRA (1989). The WBGRa was measured by the [6,6-(2)H2]glucose dilution technique, and mammary glucose balance by arteriovenous differences and blood flow measurements. Duodenal glucose infusion increased arterial glucose concentrations linearly, whereas arterial concentrations of insulin, growth hormone, and glucagon were not changed. The WBGRa increased linearly with increasing glucose loads. The increase represented 42% of the intestinal glucose supplement. Mammary blood flow dramatically increased (up to 45%) and was associated with a significant increase of arterial insulin-like growth factor-1 concentrations. Mammary gland rate of glucose disappearance ([6,6-(2)H2]glucose measurement) increased linearly, whereas net mammary balance of glucose, lactose, and milk yields increased quadratically. Net mammary balance of glucose accounted for 60% of WBGRa, except for the greatest dose (47.6%). The decrease in milk yield with 2398 g/d of glucose may be explained by an imbalance in intracellular intermediate concentrations. The milk ratio of glucose-1-phosphate to glucose-6-phosphate decreased significantly at the greatest infusion of glucose. In conclusion, exogenous glucose supply to a grass silage-based diet increased WBGRa, mammary utilization of glucose and milk synthesis.     

Evaluation of glucose dose on intravenous glucose tolerance test traits in Holstein-Friesian heifers

Glucose metabolism in dairy and beef cattle has received considerable attention because balanced blood glucose is essential for numerous processes, such as milk production and general health. The glucose tolerance test measures the ability of an organism to regulate blood glucose levels. Glucose half-life time (GHLT) has high heritability and could serve as a potential parameter to breed for metabolic resistance. However, studies focusing on identification of an adequate glucose dose have not yet been conducted in cattle. The objective of this study was to analyze the effect of 5 different glucose doses (0.5, 1, 1.5, 2, and 3 g/kg of body weight^0.75) on intravenous glucose tolerance test (ivGTT) traits and insulin responses in nongestating heifers. A total of 150 tests were performed in 30 Holstein-Friesian heifers aged 13 to 15 mo. Blood samples were obtained every 7 min after glucose injection until min 63. Glucose traits and insulin parameters included blood serum glucose and insulin concentration at min 0 (basal concentration), min 7 to 21 (peak glucose and insulin concentration), and min 63 (last sampling) relative to glucose administration, glucose and insulin area under the curve (GAUC and IAUC), and GHLT estimated between min 14 and 42. Serum glucose and insulin concentrations were measured according to the hexokinase colorimetric method and radioimmunoassay, respectively. Generalized linear mixed model was used to test for significant differences in ivGTT traits, insulin responses, and glucose elimination rates (k) over time at different glucose doses. Maximum glucose and insulin concentrations at min 63 increased with higher glucose doses. Significantly lower GHLT were obtained at increasing glucose doses, whereas GAUC and IAUC were significantly higher at increasing doses. The k values were affected by glucose dose and by time interval. Glucose dose greatly affected most ivGTT traits, insulin responses, and glucose elimination rates. Therefore, researchers should standardize their methods to achieve repeatable results and use the same time points for GHLT calculation. Higher glucose doses (≥1.5 g/kg of body weight^0.75) triggered glucose concentrations above the glucose renal threshold during the initial 42 min, whereas the lowest glucose concentration failed to induce a maximum insulin response. Further research is necessary to determine an adequate dose inducing maximum insulin responses with minimum renal glucose losses.     

酶法制取葡萄糖的工艺研究

随着现代精细工业的发展,葡萄糖作为基料的社会用量日益增大,用途日趋广泛,制取葡萄糖的工艺研究也成为国内外不间断的课题。本文采用酶法水解与目前先进的过滤、离子交换及蒸发浓缩等下游工程技术结合,研究葡萄糖加工的工艺条件与提高产品纯度和得率的实用技术。通过实验确定最佳工艺条件为：液化时,pH6．0～6．5,温度85℃,时间40min,α-淀粉酶用量0．3％,淀粉浆浓度30％；糖化时,pH4．2～4．5,温度60℃,时间48h,糖化酶用量0．6％。     

葡萄糖/葡萄糖氧化酶抗菌纸及抗菌性研究

葡萄糖氧化酶是氧化葡萄糖的专一催化酶,具有脱氧、杀菌的功能。通过定性和定量抗菌实验方法研究了葡萄糖/葡萄糖氧化酶体系在以淀粉作为载体和不混合淀粉时施涂于纸张表面的抗菌效果。定性抗菌实验表明,葡萄糖/葡萄糖氧化酶抗菌纸具有良好的抗菌效果。而定量检测结果表明,pH等于5.5时,35℃反应10min,不添加淀粉时,葡萄糖氧化酶最小的抑菌浓度约为70U/m2,葡萄糖足量时,酶用量越高,抗菌率越好;添加0.7g/m2淀粉后,最小抑菌浓度提高到约650U/m2。淀粉对葡萄糖/葡萄糖氧化酶体系的抗菌效果有较大影响,主要原因是淀粉能够促进细菌的繁殖。     

香蕉葡萄糖浆的制备

研究用香蕉提取淀粉来制备葡萄糖浆。香蕉淀粉在抗高温α-淀粉酶的水解下可得麦芽糊精。香蕉麦芽糊精在淀粉葡萄糖苷酶和支链淀粉酶的作用下,经60℃,24h糖化后可制得葡萄糖浆。结果表明:香蕉葡萄糖浆和一般商用葡萄糖浆的化学和物理特性基本相同,但前者的颜色更清晰,适宜于食品工业的应用。     

酶促反应合成葡萄糖硬脂酸酯的研究

以Novozym435脂肪酶为催化剂,正己烷为有机溶剂,丙二醇为乳化剂,酶促合成葡萄糖硬脂酸酯.考察了脂肪酶加入量、反应温度、反应时间、底物配比、体系含水量、振荡速率对酶促酯化反应的影响,确定了酶促反应的工艺条件;同时对产物进行了定性、定量分析.研究结果表明:酶加入量为脂肪酸质量的10%,底物酸、糖的摩尔比为1:1,温度为60℃,含水量为有机溶剂的5.3%,反应时间为4.5 h,振荡速率为100r/min时,硬脂酸最大转化率可达93.40%.     

Adipose tissue insulin receptor and glucose transporter 4 expression,and blood glucose and insulin responses during glucose tolerance tests in transition Holstein cows with different body condition

Glucose uptake in tissues is mediated by insulin receptor (INSR) and glucose transporter 4 (GLUT4). The aim of this study was to examine the effect of body condition during the dry period on adipose tissue mRNA and protein expression of INSR and GLUT4, and on the dynamics of glucose and insulin following the i.v. glucose tolerance test in Holstein cows 21 d before (d ?21) and after (d 21) calving. Cows were grouped as body condition score (BCS) ≤3.0 (thin, T; n = 14), BCS = 3.25 to 3.5 (optimal, O; n = 14), and BCS ≥3.75 (overconditioned, OC; n = 14). Blood was analyzed for glucose, insulin, fatty acids, and β-hydroxybutyrate concentrations. Adipose tissue was analyzed for INSR and GLUT4 mRNA and protein concentrations. During the glucose tolerance test 0.15 g/kg of body weight glucose was infused; blood was collected at ?5, 5, 10, 20, 30, 40, 50, and 60 min, and analyzed for glucose and insulin. On d ?21 the area under the curve (AUC) of glucose was smallest in group T (1,512 ± 33.9 mg/dL × min) and largest in group OC (1,783 ± 33.9 mg/dL × min), and different between all groups. Basal insulin on d ?21 was lowest in group T (13.9 ± 2.32 µU/mL), which was different from group OC (24.9 ± 2.32 µU/mL. On d ?21 the smallest AUC 5–60 of insulin in group T (5,308 ± 1,214 µU/mL × min) differed from the largest AUC in group OC (10,867 ± 1,215 µU/mL × min). Time to reach basal concentration of insulin in group OC (113 ± 14.1 min) was longer compared with group T (45 ± 14.1). The INSR mRNA abundance on d 21 was higher compared with d ?21 in groups T (d ?21: 3.3 ± 0.44; d 21: 5.9 ± 0.44) and O (d ?21: 3.7 ± 0.45; d 21: 4.7 ± 0.45). The extent of INSR protein expression on d ?21 was highest in group T (7.3 ± 0.74 ng/mL), differing from group O (4.6 ± 0.73 ng/mL), which had the lowest expression. The amount of GLUT4 protein on d ?21 was lowest in group OC (1.2 ± 0.14 ng/mL), different from group O (1.8 ± 0.14 ng/mL), which had the highest amount, and from group T (1.5 ± 0.14 ng/mL). From d ?21 to 21, a decrease occurred in the GLUT4 protein levels in both groups T (d ?21: 1.5 ± 0.14 ng/mL; d 21: 0.8 ± 0.14 ng/mL) and O (d ?21: 1.8 ± 0.14 ng/mL; d 21: 0.8 ± 0.14 ng/mL). These results demonstrate that in obese cows adipose tissue insulin resistance develops prepartum and is related to reduced GLUT4 protein synthesis. Regarding glucose metabolism, body condition did not affect adipose tissue insulin resistance postpartum.     

葡萄糖氧化酶的生产及应用

葡萄糖氧化酶能够利用氧气将葡萄糖氧化成葡萄糖酸而有效去除氧,因而被广泛用作抗氧化剂、葡萄糖酸、尿糖试纸和生物传感器的生产。综述了葡萄糖氧化酶作为生物去氧剂的作用机理、生产工艺条件以及在食品、医药等行业的广泛应用。