利用带光电二极管阵列检测的反相HPLC对ECG,EGCG和红茶中的氧化产物的分析研究

利用反相ＨＰＬＣ分析对ＥＣＧ和ＥＧＣＧ的氧化产物的色谱进行了比较。实验中有少量的ＥＧＣＧ在所设计的氧化体系中，由ＥＣＧ经所选择的化学氧化条件氧化形成。所以ＥＣＧ的氧化可能是先产生ＥＧＣＧ，随后再与ＥＧＣＧ共同被氧化或ＥＧＣＧ单独被氧化来继续其反应。用于分析洗脱红茶及多酚类的氧化产物的较为理想的ＨＰＬＣ洗脱梯度应为：试剂Ａ１％柠檬酸，自９２％至５０％，而相应的试剂Ｂ乙腈，则由８％在设计的区间内升至５０％。根据对高聚合氧化产物的重点分析，在这种洗脱梯度下仅用１５分钟便可以全部洗脱出叫做茶灰素的组分。相关研究表明多酚类的氧化反应即使在很低的温度下亦会自发地进行。     

测定黑液硫含量的新方法

用离子色谱法(IC)、X射线荧光光谱法(XRFS)和电感耦合等离子体质谱法(ICP-MS)分别测定黑液中的硫含量.测定方法:30%H2O2氧化黑液用于IC分析;直接稀释黑液用于XRFS分析;加浓HNO3或30% H2O2用湿燃烧法氧化黑液用于ICP-MS分析.这3种方法分析所得结果非常接近,而传统重量分析法测定结果比上述3种方法高出4%.     

我国造纸工业碱法制浆水污染的防治

主要介绍我国造纸工业碱法化学浆黑液及综合(中段)废水污染防治概况。指出麦草浆黑液污染治理近年虽已取得不少成绩,但它仍是造纸工业废水污染防治的难点及重点。非木材制浆企业治污工程生产运行统计结果说明,扩大碱回收单条生产线规模、提高黑液提取率不但可以产生多种效益,而且可以为中段废水达标处理,实现低成本治污创造极为有利的条件。     

Selective removal of tannins from medicinal plant extracts using a collagen fiber adsorbent

A novel adsorbent, used for the selective removal of tannins from medicinal plant extracts, was prepared from bovine skin collagen fiber. Some typical active constituents of medicinal plants were selected as probe molecules to investigate the adsorption selectivity of the collagen fiber adsorbent to tannins. In batch adsorption experiments, the extent of adsorption of condensed tannins, including larch tannin, black wattle tannin and bayberry tannin, was 100%. The extent of adsorption of tannic acid and the hydrolyzable tannins was also 100%. In contrast, for the most active constituents of medicinal plants, their amounts adsorbed by collagen fiber adsorbent were limited. For procyanidin, the common active constituents in medicinal plant extracts, its extent of adsorption was also low, although it has a similar basic structure to condensed tannins. In comparison with traditionally used polyamide adsorbent, the collagen fiber adsorbent exhibited an obvious advantage in adsorption selectivity over tannins. Therefore, this study provides a novel and effective method for selective removal of tannins from medicinal plant extracts. Copyright © 2005 Society of Chemical Industry     

洋葱中风味前体物质的气相色谱研究

采用一种新型衍生剂,并结合气相色谱,建立了一种对洋葱风味前体物质的快速灵敏的检验方法,在30min内即可完成分析。通过这种方法对洋葱中的各个前体物质进行了定性和定量研究。     

Changes in the quality parameters of seedling tea due to height and frequency of mechanical harvesting

Quality parameters of black tea change due to the use of a mechanical harvester, varying plucking round lengths and plucking heights. Compared with hand plucking, mechanically harvested teas have inferior quality as measured by volatile flavour compounds, theaflavins and caffeine. Similarly, longer plucking rounds produced inferior teas compared with shorter rounds. Raising mechanical plucking height by 2 cm from the previous plucking height caused less quality deterioration than increasing the height by 1 cm irrespective of plucking rounds.     

陕北小粒黑豆皮原花青素提取工艺及抗氧化性研究

提取陕北小粒黑豆皮中原花青素,考察乙醇浓度、提取时间、提取温度和液料比对其提取得率的影响,利用Box-Behnken设计试验,建立提取过程的数学模型及二次多项式回归方程,预测出最优提取条件,并对提取的原花青素进行抗氧化性研究。结果表明,陕北小粒黑豆皮提取原花青素的优化工艺条件为提取时间4.2h、提取温度53℃、液料比22:1(mL/g)、乙醇浓度60%,在该条件下提取得率为5.380%;原花青素对DPPH自由基、羟基自由基和超氧阴离子均具有一定的清除效果,其IC_(50)值分别为0.075,0.590,0.220mg/mL。     

黑小麦麸皮色素结构分离及鉴定

本文以黑小麦麸皮为原料,通过大孔吸附树脂纯化浸提液,采用光谱分析对该色素进行初步鉴定,层析分离色素,HPLC鉴定。结果表明:黑小麦麸皮色素为水溶性花色苷类色素,至少含有三种花色苷。本研究结果可以为黑小麦麸皮色素的结构分离及深入分析奠定基础。     

Non-structural carbohydrates in processed soft fried onion (<Emphasis Type="Italic">Allium cepa</Emphasis> L.)

The effects of curing, removal of top and root, peeling, storage of raw and peeled onion on the content of non-structural carbohydrates and the ability of onion to develop a brown colour were studied. Glucose, fructose, sucrose, 1-kestose, neokestose, nystose, 1^F--d-fructofuranosylnystose and four unknown oligofructosides were quantified using high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). Field drying affected the concentration of fructose only. Glucose, fructose and an unknown fructan decreased in concentration while the concentration of, e.g. 1-kestose, neokestose and nystose increased by removal of root and top of the onions when stored at 15 °C for one week. Peeling had minor influence on changes in non-structural carbohydrates. Storage of non-peeled (raw) onions at 5 °C and storage of mechanically damaged and peeled onion at 20 °C promoted fructan hydrolysis and browning of soft fried onion. Similar changes were produced by long-term storage of cultivars of common onion. Dry matter and fructose increased during storage of peeled onions at both 5 and 20 °C. The increase in fructose content during storage was due to a significantly decrease in the content of 1-kestose, neokestose, 1^F--d-fructofuranosylnystose, an unknown fructan and total fructans. It was concluded that the missing ability of industrially processed onions to develop a brown colour may be overcome by storage of the peeled onions for a few hours or even overnight at 5 °C.     

一种改进型黑液浓度控制方案

简要介绍了传统的C-P（浓度-压力）黑液浓度控制方案,并针对其利用蒸汽条件受限制的问题,提出了一种改进型的C-F（浓度-流量）黑液浓度控制方案。通过“步进式自寻优控制原理”搜索出C-F控制方案中最优的蒸汽压力设定值Ps,并给出了具体的控制算法,最大限度地利用了现用蒸汽条件,提高了蒸发系统的生产能力。