柿果成熟过程中总酚和缩合单宁含量的变化

本实验通过Folin-Ciocalteu法、香草醛-盐酸法测定不同类型12 个柿品种果实生长发育进程中总酚和缩合单宁含量的变化,并运用正交试验法对香草醛-盐酸法进行优化。结果表明：香草醛-盐酸法优化参数为：显色液为2.0 g/100 mL香草醛甲醇与15%盐酸甲醇液,显色0.5 h。柿果实的生长发育进程中,总酚和缩合单宁含量变化规律相似,花后35～50 d达到最高水平,随后逐渐降低,但不同类型柿间总含量及变化幅度存在着较大的差异;其中,日本完全甜柿（J-PCNA）、中国完全甜柿（C-PCNA）、不完全甜柿（PVNA）、不完全涩柿（PVA）、完全涩柿（PCA）同类型各品种间总酚和缩合单宁变化趋势相似,含量相近,总酚、缩合单宁含量基本符合规律PCA＞C-PCNA＞PVA＞PVNA＞J-PCNA。     

云南及其他产区赤霞珠干红葡萄酒总酚和原花青素含量的测定与分析

采用福林-肖卡法和优化铁盐催化比色法分别对来自云南迪庆高海拔产区与山东、河北等低海拔产区的7个赤霞珠单品种干红葡萄酒样品进行了总酚和原花青素含量的测定与分析,研究高原地区葡萄酒的一些基本特征以及产地和环境因素(如紫外线,海拔高度)对葡萄酒中总酚和原花青素含量的影响。结果表明,来自云南迪庆产区的迪庆2#样品总酚和原花青素含量最高,分别为3313 mg/L和12.90 mg/mL,迪庆1#样品除与河北怀来1#的总酚含量差异不显著外,与其他样品均差异显著。由此得出,产地对葡萄酒总酚和原花青素含量影响显著,且环境因素如高海拔造成的紫外线辐射增强能促进酿酒葡萄的次生代谢,从而导致葡萄酒中总酚和原花青素含量的增加。     

不同产地新鲜紫色马铃薯中花色苷及总酚的含量测定

目的:建立新鲜紫色马铃薯中主要功能性物质——花色苷和总酚的含量测定方法,用于不同产地来源的紫色马铃薯品种的质量评价。方法:采用pH示差法、福林酚比色法分别对不同产地的新鲜紫色马铃薯中花色苷与总酚的含量进行测定。结果:通过建立的含量测定方法测得内蒙产的花色苷含量为13.68 mg/100g,总酚含量108.29 mg/100g;山东产的花色苷含量6.15 mg/100g,总酚含量100.15 mg/100g。结论:采用pH示差法、福林酚比色法测定马铃薯中花色苷与总酚的含量结果可靠、重复性好,适合新鲜紫色马铃薯中这两类功能物质的含量测定,可为紫色马铃薯的品质评价提供依据。     

单一pH法、pH示差法和差减法央速测定干红葡萄酒中总花色苷含量的比较

为了寻求快速、经济地测定干红葡萄酒中总花色苷含量的方法,采用单－pH法、pH示差法和差减法对比分析3种方法测定数据的差异性。结果表明,3种方法测定的吸光度与浓度间均具有良好的线性关系,其相关系数R分别为0．9977、0．9988和0．9984,测定结果没有显著性差异（p〈0．05）。3种方法均能用于干红葡萄酒总花色苷含量的快速测定．     

不同品种桑椹抗氧化能力及其与Vc、花色苷和总酚含量的关系

对19个不同品种桑椹的Vc、花色苷、总酚和总抗氧化能力及相关性进行了分析.结果发现,不同品种桑椹的Vc、花色苷和总酚含量及总抗氧化能力变幅和变异系数较大,存在显著的基因型差异;桑椹总抗氧化能力与花色苷和总酚含量之间存在显著性的相关性(P<0.01),与Vc并没有明显的相关性(P>0.05).19种桑椹可聚合成4大类,第4类的"粤诱34"、"2120"和"7403"都是优良的桑椹品种.     

分光光度法测定山茱萸及其保健酒中三萜酸的含量

以熊果酸为标准品,5%香草醛.冰醋酸、高氯酸为显色剂,用紫外-可见分光光度法在538nm处测定山茱萸及其保健酒中三萜酸的含量.结果表明,熊果酸的线性范围为26.4～158.4ttg,回归方程为A=0.0071C-0.0941(R2=0.9994),平均回收率为98.94%,RSD为2.31%(n=5);山茱萸及其保健酒中三萜酸含量分别为2.511%、2.091%.该方法简便、快捷、重复性好,适合于山茱萸及其保健酒中三萜酸的含量测定.     

5种柚汁中主要抗氧化成分含量及其抗氧化能力的比较

采用高效液相色谱法测定了5种柚汁中黄酮类物质、VC的含量.并用FRAP、DPPH及ABTS三种方法对其抗氧化能力做出评价.通过比较,得出佛柚汁中的柚皮苷含量、VC含量和总酚含量均为最高;除胡柚汁外,其他柚汁均未检测到橙皮苷和新橙皮苷;佛柚汁的抗氧化能力最强.酚类物质和VC则是柚汁中最主要的抗氧化物质.     

QUANTITATIVE DETERMINATION OF FAT, PROTEIN AND CARBOHYDRATES OF SOY PRODUCTS WITH INFRARED ATTENUATED TOTAL REFLECTANCE

Attenuated total reflectance (ATR), offering a possible rapid method for quantitative measurements of major nutritional components in food materials (fat, protein, carbohydrate), was employed to evaluate the composition of a variety of soy products. Using a sample cell developed in this laboratory, different sample particle sizes and forces applied to a mounted sample were investigated to determine if variations of this type would improve the accuracy and precision of the quantitative ATR technique. Correlations of 0.96 for fat and 0.94 for protein were achieved between a chemical analysis and the infrared technique using a baseline absorbance (A') calculation and 120 mesh samples at 40 lb force. Errors assignable to various aspects of the ATR technique are discussed.     

染料产品中游离甲醛含量测定的不确定度评估

根据GB/T 23973-2009《染料产品中甲醛的测定》的操作规程,将染料样品中的游离甲醛制备于水溶液中,通过乙酰丙酮显色,显色液采用分光光度计进行比色测定样品中的甲醛含量。通过对标液标准曲线制作、样品制备、重复测试等不确定分量进行分析,并对各分量进行评估,确定测试过程产生的不确定度为0.974%,进而得出样品的扩展不确定度为3.696 mg/kg。     

紫外分光光度法测定柑桔皮中总黄酮的含量

建立以芦丁为标准品的柑桔皮黄酮类含量测定方法,采用3种紫外-可见分光光度法对不同条件处理下的柑桔皮中总黄酮含量进行了测定和比较分析。研究表明,3种分光光度测定方法中,黄酮含量以硝酸铝显色法（345nm）为最高,直接测定法（270nm）次之,氯化铝显色法（415nm）最低;经过HPLC检测后,选定氯化铝（275nm）为显色系统的含量测定方法。回归方程为：Y=28.891X＋0.0002,相关系数r=1,平均加样回收率为99.3%,RSD=1.84%（n=5）,经不脱脂超声处理过的柑桔皮中所得黄酮含量为3.09%。该法操作简便,结果准确,重复性好,为柑桔皮中黄酮含量的测定提供了一种切实可行的途径。     

QUANTITATIVE DETERMINATION OF METMYOGLOBIN AND TOTAL PIGMENT IN AN INTACT MEAT SAMPLE USING REFLECTANCE SPECTROPHOTOMETRY

SUMMARY— A technique for determining the relative quantities of oxymyoglobin, metmyoglobin and total pigment concentration at the surface of on intact meat sample was developed. A Beck-man DK-2 spectrophotometer with reflectance attachment was used and spectra were recorded on the R_A scale. The sample port of the spectrophotometer was modified so that a uniform and high intensity light beam measuring 0.5 × 0.6 cm reached the surface being evaluated. A sample holder was constructed so that known proportions of oxygenated and oxidized meat could be exposed to the light beam. A family of curves representing varying known amounts of metmyoglobin and oxymyoglobin were obtained. The height of the peak at 632 nm (ΔR_A632) was directly related to the amount of metmyoglobin at the surface of the meat sample. For 100% oxymyoglobin, ΔR_A632 was at a minimum and equal to R_A750. For 100% metmyoglobin, ΔR_A632 was at a maximum and the height of the response depended upon the amount of total pigment present. A linear relation was obtained when ΔR_A362 was plotted against percent metmyoglobin or against total pigment determined by the Hornsey (1956) method. The method requires making two readings of the meat samples at a single wave length. One reading of the sample followed by one reading of the same sample after oxidation with K₃ Fe(CN)₆ provides a quantitative evaluation of the metmyoglobin concentration and the total heme pigment concentration. The accuracy of the method may be improved by making multiple readings.     

纳豆咀嚼片中总异黄酮的含量测定

建立测定纳豆咀嚼片中总异黄酮含量的方法-紫外分光光度计法,以染料木素作为对照品,利用染料木素与氢氧化钠产生反应,并在275 nm波长处产生最大吸收峰的特性,用紫外分光光度法测定纳豆咀嚼片中总异黄酮含量.测定结果:纳豆咀嚼片中总异黄酮的含量为325μg/片,加样回收率为98.3%.     

DETECTION AND QUANTITATIVE DETERMINATION OF PAPAIN IN BEER

We have investigated an ultra-sensitive method for the quantitative determination of proteolytic enzymes in biological media by means of a chromogenic substrate (Hide Powder Azure), and adapted it to the determination of papain in beer. At pH 6 and in presence of EDTA and cysteine hydrochloride, the hydrolysis of this substrate at 37° C. by papain for 90 min. allows the rapid determination of an activity of less than I tyrosine unit/ml./min. This makes it possible to control the survival of papain in beer before, during and after pasteurization and during storage.     

超声波辅助提取松籽油及其脂肪酸的检测

研究超声波功率、时间、料液比以及提取次数对松籽油提取率的影响,得出最佳提取条件为超声波功率为160W,超声波处理20min,料液比为1∶7,超声波处理4次.并通过气相色谱-质谱联用法测定其中皮诺敛酸(Pinolenic acid)的含量.     

DETERMINATION OF TOTAL BROMINE AND OF BROMATE IN BARLEY AND MALT

Published methods for determining total bromine were found to be unsatisfactory or to require modification. Bromate may be determined directly on an aqueous extract of barley using an iodometric amplification reaction. Total bromine may be determined by the same reaction after ashing the sample in an oxygen combustion flask and oxidizing the bromide formed with hypochlorite to bromate.     

全最小二乘法在红外光谱法同时测定多组分混合物中的应用

利用全最小二乘法，对丙酮中所含红外光谱重叠严重的苯及甲苯所测数据，自编程序，在计算机上进行处理，所得结果相对误差均小于６％，优于最小二乘法．