衰减全反射傅里叶红外光谱在纤维鉴别中的应用

比较了纤维素纤维的衰减全反射红外光谱法(ATR)和溴化钾压片法测试的红外光谱图,两种制样方法得到的红外光谱图特征峰位置一致,特征谱带明显.用ATR测试了不同种类的纺织纤维的红外光谱,得到了常见纤维的衰减全反射红外光谱图,为单一纤维的定性鉴别奠定了基础.探讨了差谱分析技术在二组分混纺织物定性分析上的应用,分析了两种未知成分样品的衰减全反射红外光谱,在有效确定某一组分为参比光谱的基础上,利用差谱分析技术,能快速、有效地进行二组分混纺织物的定性分析.     

FTIR技术在婴幼儿奶粉品质检测中的应用

运用傅里叶变换红外光谱(FTIR)技术,采集50多种婴幼儿奶粉样品的红外谱图,对奶粉中蛋白质、脂肪、糖类等主要营养成分进行分析。婴幼儿奶粉的红外谱图中,蛋白质的特征峰在1 657 cm~(-1)和1 543 cm~(-1)左右处,脂肪的特征峰在2 926 cm~(-1)和1 747 cm~(-1)左右处,糖类的特征峰在1 200~900 cm~(-1)处,含量不同时对应吸收峰的强度存在差异。结果表明,同一品牌不同阶段婴幼儿奶粉中各营养物质的吸收峰强度差异明显,即质量分数差别较为明显,可直接通过红外谱图区分;而不同品牌相同阶段婴幼儿奶粉中各营养物质的质量分数差别不太明显,但二阶导数谱图差异较为显著,可间接区分。可见,FTIR技术可方便快捷地对婴幼儿奶粉品质进行检测。     

运用傅里叶变换红外光谱鉴别茅台酒

基于红外光谱技术的3种不同处理手段运用于茅台酒的真伪鉴别,实验中真伪茅台酒在一维红外谱图上首先体现出了明显的差异,特别是在1 200 cm~(-1)~1 800 cm~(-1)波段,真伪茅台酒在1 730 cm~(-1)的酯类特征吸收峰以及1 592 cm~(-1)处的羧酸特征吸收峰有明显的不同;在二阶导数谱图上,真伪茅台酒的酯类和酸类物质的红外吸收峰的峰位和峰强明显不同,这也符合一维谱图的分析结果;另外,二维相关红外光谱是通过对样品施加热扰动来对茅台酒的真伪进行鉴别,在印证了一维谱图、二阶导数谱图的鉴别结果的基础上,更加体现出了操作简便、谱图清晰与可视性强等特点。     

红外光谱差减技术在纺织品定性分析中的应用

介绍了傅里叶红外光谱仪及其衰减全反射附件的工作原理和优缺点.不同的纤维具有不同的化学基团和不同的分子结构,因而在红外光谱中会出现不同的特征吸收.对已知纤维的红外光谱图与未知纤维的红外光谱图进行比较,就可以对纤维的种类进行定性.对含有多组分纤维的混纺织物,由于其各组分特征基团之间存在相互干扰,分子内基团的红外吸收会受到邻近基团及整个分子其他部分的影响,所以各纤维原有的特征吸收峰会在一定范围内波动,使得原有纤维特征峰的选择变得不容易,这也是目前红外光谱仪不能大量有效应用在纤维定性分析上的主要原因之一.文章依据红外光谱吸光度的加和性原理,尝试利用红外光谱的差减技术解决这一难题.     

天麻醇提物对灰树花发酵菌丝体多糖及β-葡聚糖合成量的影响

在灰树花液体深层发酵体系中添加天麻醇提物,考察天麻醇提物对灰树花发酵菌丝体生物量、菌丝体多糖及β-葡聚糖含量的影响,并进一步研究起显著促进作用的关键特征成分;同时,采用高效液相色谱法对7 g/L天麻醇提物中的特征成分进行定量分析,研究了对灰树花菌丝体生物量、菌丝体多糖及β-葡聚糖起促进作用的关键特征成分及优化添加量。结果表明,适当浓度的天麻醇提物能够显著提高灰树花菌丝体生物量、菌丝体多糖及β-葡聚糖的含量,在其质量浓度为7g/L时,菌丝体干重、菌丝体多糖及β-葡聚糖含量均达到最大值,分别为1.708 g/L、5. 974%和2. 055 mg/g,与不添加天麻醇提物相比分别增加了0. 36、1. 29和1. 44倍(P<0. 05)。天麻醇提物中的特征成分分别为天麻素5. 837 5 mg/g,对羟基苯甲醇1.107 2 mg/g,对羟基苯甲醛0.660 1 mg/g,对灰树花菌丝体生物量、菌丝体多糖及β-葡聚糖起促进作用的关键特征成分均为对羟基苯甲醛,其.优化添加量分别为100、250、150 mg/L。     

板蓝根抗氧化成分的提取及活性分析

采用95%乙醇提取板蓝根,并用石油醚、氯仿和正丁醇依次萃取,醇提后药渣通过水提醇沉法制备粗多糖。采用铁氰化钾还原反应、超氧阴离子自由基和1,1-二苯基-2-三硝基苯肼(DPPH)自由基三种抗氧化模型,比较上述极性部位的抗氧化活性,并考察抗氧化活性与总糖含量的关系。结果表明,板蓝根不同极性部位的抗氧化活性差异较大,与总糖含量相关性较小。其中,氯仿萃取物对超氧阴离子自由基和DPPH自由基的清除率最高,IC50值分别为3.38、0.19mg/mL,是从板蓝根中筛选非多糖类天然抗氧化剂的重要部位。醇提后药渣通过水提醇沉法制得的粗多糖部位总糖含量最高,为18.66%。板蓝根所具有的抗氧化活性可能是该药发挥解"内毒"作用的重要机制。     

基于光谱分析的葡萄酒品质鉴别技术初探

该文对同一品种酿酒葡萄酿制的不同档次干红葡萄酒进行了拉曼光谱分析、紫外可见光谱扫描、傅立叶红外吸收光谱分析,并分析光谱扫描图谱、数据与葡萄酒品质间的相关性.结果表明紫外可见光谱扫描(200nm～800nm)的光谱图及其参数与葡萄酒品质的相关性和重现性最好,进一步的技术细化后可以作为葡萄酒品质鉴定的一种辅助手段.采用萃取物的拉曼光谱谱图及拉曼峰参数与葡萄酒品质也有一定的相关性,但提供的信息量较少;红外光谱由于上样量难于准确控制以及结果分析较为复杂,在应用中受到较大限制.     

灵山和邕宁产两面针衰减全反射傅里叶变换红外光谱研究

目的 利用衰减全反射傅里叶变换红外光谱法对灵山、邕宁两地产两面针的根皮与木部进行研究,探讨其光谱特征和主要生物活性物质含量的关系,为快速鉴定不同产地两面针样品提供依据.方法 采用衰减全反射傅里叶变换红外光谱法(ATR-FT-IR)分别对上述两地的两面针的根皮与木部进行研究,对比其红外光谱及其二阶导数光谱的差异.结果 ATR-FT-IR能有效鉴别不同产地的两面针药材样品.结论 利用ATR-FT-IR技术可以快速、简便地鉴定两面针药材,两面针中主要活性物质生物碱的含量与红外光谱信号强度成正相关.     

基于红外光谱的木棉与棉定量分析

为了进行红外光谱定量分析纤维含量的研究,测试了不同比例木棉/棉混合物的红外光谱图,探讨了红外光谱定量分析木棉/棉混纺比的方法。研究表明,1732cm-1和1242cm-1处特征吸收峰面积与木棉含量的线性关系明显,1732cm-1处最佳。以1732cm-1处的特征吸收峰面积对木棉/棉混纺试样的木棉含量作了定量分析,得出了线性关系较好的标准曲线。用本法对未知样品的木棉含量进行测定,得到了较好的结果。     

中国三个产地蛇纹石玉的地质背景及宝石学特征

辽宁省岫岩县、山东省泰安县和青海省祁连县是中国市场上蛇纹石玉最主要的三个产地,不同产地的矿床特征及所产蛇纹石玉在外观、化学成分和红外光谱等方面存在较大差异。本文综合前人的研究成果,从地层、构造、矿体、形成时期、成因等角度对三个产地蛇纹石玉矿床的地质特征进行了归纳总结;通过收集三个产地蛇纹石玉的常规宝石学特征、电子探针分析数据及红外光谱测试数据,对这三个产地蛇纹石玉的基本宝石学性质、化学成分和红外光谱图进行了对比分析,总结了三个产地蛇纹石玉的鉴别特征。三个产地的蛇纹石玉在颜色、光泽、透明度、内含物等方面表现出不同的特征,在化学成分、微量元素、红外光谱特征方面也有明显的差异,这些鉴别特征在一定程度上都可以辅助判断产地。此外,蛇纹石玉的颜色与Fe元素有关,Fe含量越大,绿色越深。     

板蓝根分散片的试制及工艺研究

目的试制板蓝根分散片。方法在多项质量指标控制下,对处方、工艺条件等进行优化。结果处方选择羧甲基淀粉钠(CMS-Na)18%、羟丙基纤维素(HPC)28%;压片压力30kN、制粒16目筛;崩解时间70s,分散均匀,稳定性好。结论处方合理、工艺可行。     

Determination of BHA and BHT in Denyarated Mashed Potatoes

The extraction step in BHA (butylated hydroxyanisole) or BHT (butylated hydroxytoluene) analysis of potato granules, unless precautions are taken, leads to a recovery of only 10–50%. This study showed that BHA (BHT) is retained in granules by retrograded starch and, mostly, its amylose moiety. No satisfactory IB covery was obtained using solvents of increasing dielectric constant unless the granules were first hydrated with water. A rapid antioxidant extraction procedure, based on the hydration principle and suitable for quality control labs, is described. Comparative data were acquired for the content of BHA (BHT) in potato granules analyzed by differential pulse voltammetry (using a glassy carbon electrode) and gas-liquid chromatography.     

Rapid small‐scale starch isolation using a combination of ultrasonic sonication and sucrose density separation

The proposed rapid small‐scale starch isolation technique in the laboratory was a combination of dry grinding of grain, suspension of the resulting flour in extraction buffer, application of ultrasonic sonication, then separation by sucrose density centrifugation. Light microscopy of separated fractions showed intact starch granules in the pellet and proteins and damaged starch in the top layer. The extraction method yielded 61% starch from sorghum and 63% from maize. The isolated starch showed lower starch damage and proteins content than by the conventional method. The gelatinization enthalpy of isolated starch was slightly higher than by wet grinding conventional method. In addition to low amount of starting flour (100 mg) the new starch isolation method was performed in less than 2 h from dry grinded seed to dried starch. Thus, it could be a useful method for cereal chemists and plant genetists.     

LIPIDS OF WHEAT, CORN AND POTATO STARCH

The lipid constituents from wheat, corn and potato starches were analyzed, as was the composition of nonstarch compounds present in these lipid extracts. The lipids were extracted from starch granules using n- propanol-water (3:1, v/v) via cold and hot extraction into surface and internal lipid fractions, respectively; fatty acid profiles of the fractions so obtained were then carried out. The content of surface lipids was greatest from potato and wheat starches, whereas cornstarch was characterized as having the highest relative percentage of internal lipids. Hot extraction resulted in an increase in the lipid content for all extracts, and of the starches investigated, the lipids from cornstarch contained the highest percentage of polyunsaturated fatty acids. Unlike that of wheat starch, it was noted that the fatty acid, C20: 1 (n-9), could only be extracted from corn and potato starch granules by the hot extraction technique. Lysophosphatidylcholine (LPC) and some phenolics were found to bind to wheat starch granules, but not to those of corn and potato. Using HPLC-UV-DAD analysis, five phenolic compounds were detected in the lipids extracted from wheat starch by hot extraction. Maxima from UV-DAD spectra of the compounds were observed at a wavelength of 337.4 or 332.7 nm, and are characteristic of phenolic acids or their derivatives.     

不同基因型烟草腺毛主要分泌物差异分析

为明确不同基因型烟草腺毛分泌物的成分差异,筛选高腺毛分泌物基因型的烟草种质,本研究基于气相色谱-质谱联用仪（GC/MS）,对不同基因型的12个烟草品种的鲜烟叶腺毛主要分泌物进行鉴定分析,结果表明:在12份检测品种烟叶中,西柏三烯二醇（CBT-diols）是西柏烷二萜的主要物质形式,且其在烤烟品种中含量相对较高;所有检测品种中均含有α-西柏三烯二醇（α-CBT-diols）和β-西柏三烯二醇（β-CBT-diols）,两者比值变化范围为1.58~2.32;所有检测品种中共检测出5个蔗糖酯类型,可依据蔗糖酯类型的有无和含量的多少将检测种质分为Ⅰ-Ⅱ型蔗糖酯较多和Ⅲ-V型蔗糖酯较多2个大类。总体上看,Basma、Beinhart1000-1、红花大金元、BX1、BX2这5个品种腺毛主要分泌物含量较高,可供烟草香气品质改良育种或表面活性物质提取利用。      

桂花颗粒冲剂与桂花果冻的研制

以新鲜桂花为主要原料,研制了桂花颗粒冲剂和桂花果冻2种休闲食品。结果表明,桂花总固形物最佳煮提条件:料水比1:13,煮提时间60min,煮提次数2次;桂花颗粒冲剂最佳原料配方:桂花煮膏粉、麦芽糊精、蔗糖粉质量比2:3:3;而桂花果冻的最佳原料配方为:桂花煮膏粉、蔗糖粉、柠檬酸、卡拉胶的质量比2:10:0.6:1.2,可分别制得口感好、有桂花独特香味且具有保健功能的新型桂花颗粒冲剂和桂花果冻。     

Co-crystallization of Sucrose at High Concentration in the Presence of Glucose and Fructose

ABSTRACT: Co-crystallization of sucrose from a highly concentrated sucrose syrup (≤ 7% moisture, w/w) at 131 °C with 0, 5, 10, 15, and 20% of fructose, glucose, or a mixture of fructose and glucose was investigated. The crystallization of sucrose was delayed in presence of these lower molecular weight sugars. The DSC melting endotherm of co-crystallized samples exhibited a decrease in crystalline sucrose in the sample as a function of increased level of glucose and fructose. The mechanical strength of co-crystallized granules was found to be related to the moisture content and the amount of glucose or fructose content in the sample. The samples containing 10, 15, and 20% glucose in co-crystallized product demonstrated crystallization of glucose in its monohydrate form during 1 mo of storage.     

Estimation of sucrose esters (E473) in foods using gas chromatography-mass spectrometry.

A method was developed for estimating the content in foods of the emulsifying additive E473, sucrose esters of fatty acids. The analytical approach taken to estimate the complex mixtures that comprise this additive involved, selective solvent extraction of the intact esters using a mixture of tetrahydrofuran and ethyl acetate, alkaline hydrolysis of the esters to liberate sucrose, and then GC-MS measurement of the liberated sucrose using GC-MS after acidic hydrolysis to glucose and fructose and then silylation. The method was developed to aid future estimates of intake of this food additive. The method determines the total sucrose esters content of a food sample and does not attempt to discrimination between individual sucrose esters when present as a mixture in a food sample. A single (average) factor is used to convert the liberated sucrose content into sucrose ester content. The method was applied to analysis of eight different food types (including bakery wares, sugar confectionery, dairy product, margarine, meat pies and a sauce) spiked with 0.5-1% of a mixture of three sucrose esters that spanned the hydrophilic/lipophilic balance (HLB) range 1-16. The limit of quantification was around 50 mg kg-1, which is more than adequate for these additives. The analytical recovery rate was 73-106% with an average of 91%. The precision of the method (RSD) was 6-18% (n = 3-20 for each food type) with an average RSD of 11%. The main analytical uncertainty is the conversion factor used to express sucrose ester content from the amount of sucrose liberated. The method is also applicable to sucroglycerides (E474).     

Structural and Physical Properties of Starches Isolated from Six Varieties of Millet Grown in China

This study investigated the structural and physical properties of starches extracted from six varieties of millet mainly grown in China. The amylose content of millet starches ranged from 17.6 to 28.4 g/100 g (dry weight basis, db), and a variety of waxy proso millet starch (0.38 g/100 g, db) was identified. These starches exhibited a majority of large polygonal granules with several indentations, few small spherical granules, and A-type crystallinity. Proso millet starch showed prominent paste clarity and freeze-thaw stability, whereas finger millet starch exhibited the highest solubility. Moreover, barnyard millet starch had the lowest sediment volume. The gelatinization enthalpy of proso millet starch was the highest (5.16 J/g). For non-waxy millet starch, the ratio of retrogradation (R%) was positively correlated with amylose content. Among all starches, the storage modulus (G′) was higher than the loss modulus (G″) during heating and cooling. The G′ and G″ of proso millet starch and barnyard millet starch pastes were significantly lower than other starches during cooling. The pasting properties of six millet starches significantly differed, had positive correlation with amylose content, and were affected by NaCl, sucrose, and pH values.     

不同香型区烤烟水溶性糖组分含量差异及与感官质量的关系

以2018—2019年207份C3F初烤烟叶样品为材料,研究了不同香型区域烟叶水溶性糖组分含量及其与感官品质的关系。结果表明：（1）烤烟果糖、葡萄糖、蔗糖、麦芽糖占总糖的比例均值分别为46.43%、48.15%、2.29%、3.13%。（2）清甜香型、蜜甜香型和醇甜香型区烤烟总糖、还原糖含量极显著高于焦甜焦香型、焦甜醇甜香型和清甜蜜甜香型区;（3）各香型区烤烟水溶性糖组分含量与占比特点为：清甜香型、蜜甜香型和醇甜香型果糖、葡萄糖含量高,麦芽糖含量适中,葡萄糖占比高;焦甜焦香型果糖、葡萄糖含量低,麦芽糖含量高,麦芽糖占比高;焦甜醇甜香型果糖、葡萄糖、麦芽糖含量低;清甜蜜甜香型葡萄糖、蔗糖、麦芽糖含量低,果糖含量高,果糖占比高,蔗糖占比低。（4）典型相关分析结果表明,果糖、葡萄糖、蔗糖和麦芽糖含量与烟气浓度呈负相关;果糖含量与香气质和杂气呈正相关,与劲头呈负相关;葡萄糖、蔗糖和麦芽糖含量与香型风格凸显程度呈正相关。