葡萄酒中总糖测定方法探讨

葡萄酒国标定义为以新鲜葡萄或葡萄汁为原料,经发酵酿制而成。葡萄酒中总糖的检测方法有高效液相色谱法、直接滴定法和间接碘量法。通常实验室的常规检测方法均采用直接滴定法,该方法对样品中总糖含量、滴定操作条件、加热温度、滴定速度等都有一定要求,且存在操作人员操作熟炼与否的差异,尤其由于干红葡萄酒酒体颜色为深红色,含糖量低微,滴定时样品溶液消耗量大,滴定终点很难判定,往往影响测定结果。因此,建立一种准确、简便的比色测定方法很有必要。本文依据3,5-二硝基水杨酸与还原糖共热,可被还原成棕红色氨基化合物的原理,采用可见分光光度法测定葡萄酒中总糖含量。并对最大吸收峰、显色剂、反应时间等条件进行探索,确立了3,5-二硝基水杨酸比色法测定葡萄酒中总糖的最佳实验条件。     

当归总糖 还原糖和多糖的含量测定方法探讨

目的:测定当归中总糖、还原糖及多糖含量。方法:采用可见分光光度法,经3,5—二硝基水杨(DNS)显色测定当归中的总糖、还原糖及多糖的含量。结果:实验结果测得当归中总糖、还原糖及多糖含量分别为38.28%、12.55%、25.73%,精密度、回收率试验结果理想。结论:该方法简便、快速、准确,灵敏度高。     

黄酒中总糖的测定方法探讨

黄酒中总糖的测定一般采用GB/T13662中铁氰化钾滴定法,该法由于稀释度高,对于总糖浓度在5.0g/L以上黄酒,测定的精密度良好,但对于总糖在5.0g/L以下,特别是总糖在1.0g/L以下时,由于水解液中总糖浓度过低,滴定的精密度变差,甚至无法测定。同时由于稀释倍数较高,测定误差也较大。本法利用测定黄酒酒精度加热蒸馏阶段,同时进行样品水解,对水解液中总糖含量低的样品(总糖<2.0g/L)采用等体积法测定,节省测定时间和步骤,提高滴定精密度,具有一定推荐价值。1材料与方法1.1仪器与试剂500ml全玻蒸馏器;25ml酸式滴定管;碱性酒石酸铜甲液及乙液(试剂…     

多糖类食品总糖测定方法改进

在实际应用中,用常规CB5009.8-85法和CB5009.9-85酸水解法测定多糖类食品及饮料中总糖含量较实际偏低。为此,我们在上二法基础上进行改进,其结果较上二法为高,与实际含量接近。现报道如下。     

芦荟中糖含量的测定方法探讨

近年研究表明 ,芦荟具有抗癌、抗菌、降糖、降血脂等作用 ,并有刺激活性及增强人体的免疫功能。这些作用都与其糖含量有关。近年来植物中糖含量的研究已成为人们关注的一个热点 ,糖含量的传统分析方法是用化学法测定其中总糖和还原糖的含量 ,分析误差较大 ,不能测出各种单糖含量。本研究采用毛细管气相色谱法 ,分析芦荟中各单糖含量。现将结果报告如下。材料与方法　 (1)气相色谱仪 :美国惠普公司HP5 890型气相色谱仪 ,HP3396A型数据处理机。糖标准品 :鼠李糖、核糖、阿拉伯糖、木糖、果糖、甘露糖、半乳糖、葡萄糖均为生化试剂。试剂 :肌…     

苯酚-硫酸法测定食品总糖方法的应用和改进

食品中的总糖含量是指食品中含各种可被人类消化利用的糖类物质总和 ,在食物成份表上所列的碳水化合物均为总糖。在目前总糖的测定方法中 ,主要采用减差法和分别测定法[1 ] 将各糖类物质按单糖、双糖和多糖的检验方法转化为速原糖的方式测定。且这两种方法均操作繁琐、所用试剂多、工作量大。曾有论文专门对总糖测定进行了研究 ,并采用了 6种方法 ,测定结果均不太理想。笔者跟据文献介绍应用 ,改进了苯酚 -硫酸法测定食品中总糖[2 ] ,以下简称苯酚法。此法本来适用于分析微量样品 ,主要用于分析柱色谱法 ,纸色谱法分离组份的总糖量。还没有…     

饮用水中总铁测定方法的探讨

国家标准分析方法^〔1〕测定水中总铁的方法主要有原子吸收分光光度法和二氮杂菲光度法.原子吸收分光光度法操作简便,测定快速并可连续测定.对于没有原子吸收分光光度计的基层单位,采用二氮杂菲分光光度法也可满足测定的需要.国家标准方法中,零浓度吸光度值高,线性不理想,煮沸加热易爆沸,煮沸后剩余体积不一致.本方法用氨水代替乙酸铵缓冲溶液^〔2〕,克服了乙酸铵缓冲溶液含微量铁而使空白值过高的缺点;同时将加热方式改为沸水浴,操作步骤更简捷.经试验测定,其结果具有良好的线性,方法的精密度和准确度较好,通过与国家标准方法进行比较试验,结果满意.现报告如下.     

水产品中总汞的测定方法探讨

研究建立了一个测定水产品中总汞的三酸混合敞口消解方法，由于有效地使用了盐酸，从而增强了消解液的氧化能力，使样品中的甲基汞完全解离成无机汞而又不造成汞的损失。使用冷原子吸收光谱测定其中汞的含量．同其它方法相比，本方法快速、简便、回收率高、重现性好，可广泛地应用于各类水产品中汞的测定。     

黄酒中总糖的铁氰化钾滴定测定法

总糖含量测定方法，国家标准GB／T13662—2000都采用斐林氏容量法，该法规定样品预处理液在加入盐酸后需控制温度在68～70℃条件下加热15min进行水解，其控制的温度较苛刻，必须要微温装置。我们根据实际情况，并配制一定浓度样品溶液为例，进行试验，观察对测定结果是否有严重影响。为此选择了铁氰化钾滴定法测定黄酒中总糖含量，并对该法的样品处理、实验温度、滴定速度等做了较详细的探讨，使测定结果更加准确有效。     

Changes in intakes of total and added sugar and their contribution to energy intake in the U.S

This study was designed to document changes in total sugar intake and intake of added sugars, in the context of total energy intake and intake of nutrient categories, between the 1970s and the 1990s, and to identify major food sources contributing to those changes in intake. Data from the NHANES I and III were analyzed to obtain nationally representative information on food consumption for the civilian, non-institutionalized population of the U.S. from 1971 to 1994. In the past three decades, in addition to the increase in mean intakes of total energy, total sugar, added sugars, significant increases in the total intake of carbohydrates and the proportion of carbohydrates to the total energy intake were observed. The contribution of sugars to total carbohydrate intake decreased in both 1-18 y and 19+ y age subgroups, and the contribution of added sugars to the total energy intake did not change. Soft drinks/fluid milk/sugars and cakes, pastries, and pies remained the major food sources for intake of total sugar, total carbohydrates, and total energy during the past three decades. Carbonated soft drinks were the most significant sugar source across the entire three decades. Changes in sugar consumption over the past three decades may be a useful specific area of investigation in examining the effect of dietary patterns on chronic diseases.     

固态食品中总糖的全自动电位滴定测定法

目的采用还原糖电位滴定法测定固态食品中的总糖。方法通过精密度、加标回收率实验,系统研究了电位滴定法测定固态食品中总糖的可行性和有效性。结果还原糖电位滴定法平行测定的各种总糖相对标准偏差(RSD)范围为0.29%～1.58%,方法加标回收率范围为92.3%～103.8%。测定的总糖含量与国标方法显著相关(r=0.999 9),差异无统计学意义。结论研究结果表明电位滴定方法操作简便,具有高的准确度和精密度,适合作为固态食品总糖测定的一种新方法。     

Children's frequency of eating,total sugar intake and weight/height stature

A nationwide survey of 972 individuals ages 5 through 18 years was utilized to assess if a relationship existed between eating patterns, total sugar intake and weight/height ratios. Cross-tabulations and regression analysis were employed to test the hypothesized relations. Results indicated that there existed no general relationship between eating patterns and occurrence of obesity. The authors suggest additional analyses utilizing more homogeneous samples be undertaken before conclusions are formed concerning relationships of snack consumption and weight/height ratios.     

造船厂矽尘总尘与呼尘浓度的关系探讨

为比较中国、美国和德国粉尘采样方法测定的总尘与呼尘浓度比例关系,分析国产与美国、德国产粉尘采样器测定结果的可比性。在某造船厂的铸造车间于呼吸带高度平行采样8 d,测定总尘、呼尘浓度;分别计算总尘与呼尘浓度的比值,分析其影响因素;以方差分析、相关及回归分析对结果进行统计。结果 :(1)采用国产与美国、德国产采样器测得的总尘与呼尘浓度比值进行比较,差异无统计学意义(ANOVA-SNK检验,P>0.05)。(2)国产与美国产粉尘采样器测定的总尘与呼尘比值随着测尘距离增大而增大,但德国产仪器测定结果则反之。(3)总尘与呼尘浓度呈线性相关,只是国产仪器总尘与呼尘相关程度低于德国和美国。提示,国产仪器粉尘采样总尘、呼尘浓度比值与美国及德国的仪器具有可比性。     

饮料中微量糖的定量测定(苯酚-硫酸比色法)

目的：建立饮料中微量糖的定量测定方法。方法：用苯酚-硫酸比色法定量。结果：方法最低检出量为10μg，相对标准差为0．31％．相对偏差为0．82％，回收率为98．8％-99．1％。结论：该法作为饮料中微量糖的定量测定方法切实可行。     

The technological challenges of reducing the sugar content of foods

The reduction of sugar and energy (calories) in the diet has been a long‐standing challenge for the food industry, not only to support individuals actively seeking to limit their sugar and energy (calorie) intake but also as a response to public health policy initiatives, such as sugar taxes for the food industry and government reformulation programmes. In recent years, responding to this challenge has become more difficult for food manufacturers and formulators, as consumers are increasingly seeking products formulated using a limited range of natural, clean‐label ingredients. Zero‐calorie high‐potency sweeteners with improved taste performance are a partial solution, but a greater challenge is the replacement of the bulking, browning and other properties that sucrose, glucose and fructose provide in many solid food products. This article describes advances in high‐potency sweeteners and in bulk, low‐calorie sugar replacement ingredients that can offer effective solutions to the challenges encountered in developing great‐tasting, sugar‐ and calorie‐reduced food products for today’s consumers.     

广西姜黄总黄酮的提取及与铁离子螯合的研究

目的:以姜黄为植物资源,进行姜黄植物总黄酮的提取及含量测定和与铁离子的螯合的研究。方法:以95%为提取溶剂,水浴提取姜黄中的总黄酮;建立以芦丁标准品为显色剂,分光光度法测定姜黄总黄酮含量的分析方法,以及利用普鲁士兰法测定其黄酮还原Fe3+的能力。结果:测得样品中总黄酮的含量为0.02 mg/ml。结论:姜黄中含有一定量总黄酮,姜黄总黄酮对Fe3+具有较强的还原能力。     

Effect of storage temperatures on opacity and total nitrogen content of cholera vaccine

Fluid cholera vaccine was examined for its stability at 4–8°C, 20–25°C and 37°C with regard to the number of organisms present and the total nitrogen content. Ten batches of fluid cholera vaccine manufactured at the Central Research Institute, Kasauli, India were taken for the study. The number of organisms was determined at weekly intervals for the first month and at monthly intervals for the next 11 months. The percentage loss in the number of organisms after one year averaged 6.5 at 4–8°C, 20.6 at 20–25°C and 21.5 at 37°C. The maximum loss in number of organisms took place during the first six months at these temperatures, in the following six months the number of organisms remained almost constant even at 37°C. The total nitrogen content of the vaccine remained virtually unaltered during the same period. From this study it was concluded that the number of organisms and the total nitrogen content does not reflect the antigenicity nor potency of the vaccine.     

赤芍总苷质量标准研究

目的:制订赤芍总苷(TPG)制备工艺质量控制标准.方法:采用薄层色谱法(TLC)鉴别,紫外分光光度法(UV)定性检测芍药苷,用高效液相色谱法(HPLC)测定赤芍总苷中芍药苷含量.结果:TLC、UV定性方法简便、灵敏、专属性强;HPLC法准确、可靠、重现性好,平均回收率为100%,RSD为1.96%.结论:建立的方法可控制赤芍总苷质量.