Competitive Cu and Cd sorption and transport in soils: a combined batch kinetics, column, and sequential extraction study

The competitive effect influenced the transport behavior of Cu and Cd contrastingly in soils, as illustrated by the experimental findings obtained from column, batch kinetics, and sequential extraction tests. Of particular interest, Cd transport behavior changed from nonequilibrium in a single-metal system to equilibrium in a binary-metal system, whereas Cu exhibited a slightly greater degree of nonequilibrium transport under competition.The equilibrium time of specific sorption (approximately 7 days) was found to be much longer than that of nonspecific sorption (approximately 30 min). While there was a competitive effect on nonspecific sorption for both Cu and Cd, the majority of rate-limited specific sorption of Cd on oxide and organic matter fractions (contributing to approximately 20% of total sorption) was dramatically displaced by Cu. Such a strong suppression of specific sorption of Cd bythe presence of Cu resulted in a shorter equilibrium time of overall sorption, which probably accounts for its equilibrium transport. In contrast, the competitive effect on rate-limited sorption and transport behavior of Cu was less significant. This study demonstrated a correlation between the competitive effect of Cu and Cd on their nonspecific and specific sorption and the corresponding significance of rate-limited sorption and nonequilibrium transport behavior.     

Effect of batch extraction conditions on extraction of polyphenols from rooibos tea (Aspalathus linearis)

The effects of extraction temperature (23, 50, 60, 70, 80 and 90°C), mass ratio of extract: dry tea leaf (5:1 and 10:1) and flow rate of water (0.1 and 0.2m³/h) on extraction of total polyphenols, flavonoids and non-flavonoid phenols from rooibos tea were determined with a single-stage batch-extraction system. Extraction of the different phenolic groups from tea leaves increased significantly with increasing temperature. The increase in total polyphenol extraction was due mainly to increasing extraction of flavonoids. Increasing mass ratio and decreasing flow rate resulted in better extraction of the different phenolic groups. The phenolic content of extract soluble solids also increased significantly with temperature. At extraction temperatures 23 and 50°C, increasing mass ratio resulted in a significant increase in total polyphenol and flavonoid content of the soluble solids. The non-flavonoid phenol content increased significantly with increasing mass ratio at temperatures above 23°C. Flow rate did not significantly affect the total phenolic and flavonoid content of soluble solids.     

苹果皮制备苹果多酚联产果胶的工艺研究

以干燥的苹果皮为原料,对其同时生产苹果多酚、果胶的新工艺进行了研究。苹果多酚采用超声波辅助提取法,确定其最优料液比1∶20(g/mL),提取温度63℃,提取液乙醇浓度60%,提取时间58min,后选用树脂法吸附分离纯化苹果皮多酚,探讨了静态、动态条件下树脂吸附、洗脱苹果皮多酚的特性及条件,在此条件下多酚的提取量高达18.29mg/g,多酚纯度达到52.56%;然后采用离子交换树脂辅助酸解法提取苹果皮果胶,确定最佳工艺条件为:树脂用量为11%,pH1.3,提取时间2.0h,提取温度75℃,料液比1∶24(g/mL),随后对果胶液超滤浓缩,冷冻干燥,此条件下果胶得率高达26.26%。从苹果皮中连续提取和分离多酚、果胶的工艺具有良好的工业化生产潜力,应用前景广阔。      

Insecticides extraction from banana leaves using a modified QuEChERS method

An analytical method employing gas chromatography (GC) with nitrogen–phosphorus detection has been developed for the simultaneous determination of eight insecticides (seven organophosphorus pesticides: ethoprophos, diazinon, chlorpyrifos-methyl, fenitrothion, malathion, chlorpyrifos and fenamiphos, and one thiadiazine: buprofezin) in banana leaves that are currently being used to feed cattle or hogs. The extraction and preconcentration of these pesticides were carried out using a modified QuEChERS procedure and the whole method was validated in terms of repeatability, linearity, precision and accuracy. Triphenylphosphate was used as internal standard. Matrix effect evaluation was also carried out using a matrix matched calibration. The developed procedure gave satisfactory recovery (89–104%) and relative standard deviation values (<9.1%) for the studied pesticides in banana leaves, while limits of detection ranged between 0.002 and 0.064 mg/kg. The method was finally applied to the determination of these pesticides in 12 treated banana leaves samples collected at different banana cultivars of the Canary Islands. Residues of chlorpyrifos were found in ten of these samples. Pesticide confirmation was carried out by GC with tandem mass spectrometry detection.     

Effect of batch extraction conditions on yield of soluble solids from rooibos tea

Extraction of soluble solids from rooibos tea (Aspalathus linearis) was investigated by single stage batch extraction. The effect of extraction temperature, extract: tea mass ratio and flow rate of water on extract concentration and yield of soluble solids was determined. Extract concentration and yield increased linearly with increase in temperature from 23 to 90°C.
Increasing the mass ratio from 5:1 to 10:1 decreased extract concentration, but increased yield. Both extract concentration and yield decreased with an increase in flow rate from 0.1 to 0.2 m³/hr. The water-soluble solid content of rooibos tea leaf was 21.74%, 75.1% of which was extracted at 90°C, mass ratio 10:1 and flow rate 0.1 m³/hr.     

葡萄酒中水分的冷冻离心提取法

为从葡萄酒中提取用于稳定氢氧同位素测定的水分,本研究开发了冷冻离心与活性炭吸附结合的方法,经该方法处理的葡萄酒样品中乙醇、色素及其他有机物接近完全去除;并且实验证明该分离方法没有引起葡萄酒样品的稳定氢氧同位素的分馏。因此用该方法提取的水分能够用于葡萄酒中水分的稳定氢氧同位素比测定。      

Collagen from porcine skin: a method of extraction and structural properties

This paper presents a study of the processing of collagen-containing raw material and its changes in the course of targeted complex processing by hydrolysis, including freeze-drying. The pH, chemical composition, penetration magnitude, and critical shear stress were determined. The dried samples were examined using Fourier-transform infrared spectroscopy, and their microstructures were characterized. The characteristic property of the product developed was determined to be the presence of a relatively homogeneous fibrillar structure that promotes the functional capacity of the proteinoid-forming fibres in the compositions of foods from different groups.     

大豆胚芽索氏提取法制油工艺条件初步研究

以石油醚(60～90℃)作为脱脂溶剂对大豆胚芽进行索氏提取,采用L9(33)正交表进行分析,以大豆胚芽出油率为指标,确定大豆胚芽制油的最佳工艺参数为:粒度30目,料液比1∶13,回流时间5h。      

Comparison of soil Pb in vitro bioaccessibility and in vivo bioavailability with Pb pools from a sequential soil extraction

In this study, 15 soils ranging in Pb content from 32 to 6330 mg kg(-1) were subjected to in vitro gastrointestinal extractions with and without added powdered milk. Before and after treatment, Pb in the soils was fractionated according to a 7-step sequential extraction procedure. A subset of five soils and Pb acetate was used for a minipig dosing study. The amount of bioaccessible Pb determined with the in vitro system ranged from 3 to 20% without powdered milk and from 11 to 56% with powdered milk. The higher bioaccessibility of Pb in the in vitro model with addition of powdered milk was related to a depletion of Pb in the organic Pb pool and indicates that soluble milk constituents compete with soil organic ligands for Pb. The absolute and relative bioavailabilities of Pb in the minipig dosing experiment were not related to bioaccessible Pb determined in any of the two in vitro systems. However, relative bioavailabilities in liver, kidney, and total uptake were highly correlated to Pb in the third fraction of the sequential extraction that is attributed to easily reducible Mn oxides. These results indicate that reductive processes in the intestine may be more relevant for Pb absorption than the initial solubilization in the acidic stomach.     

Fabric wrinkling evaluation: a method developed using digital image analysis

The textile and clothing industry has conventionally used subjective methods for the assessment of fabric wrinkling. Indeed, the fabrics were usually evaluated subjectively in reference to a set of visual standards. However, the visual assessments of the wrinkling degree, often showing inconsistencies between wrinkle judgments of observers, are severely influenced by the color and the fabric texture which may exist. In this paper, an objective method which permits an evaluation of multidirectional wrinkling of any colored fabric has been developed using digital image analysis. This method consists in capturing images of the color wrinkled fabrics and processing them in simple steps using image‐processing software. The surface roughness, density, width, length, number, and height of the wrinkles, considered as wrinkling characteristics, were extracted. Wrinkle degree was selected to use as the comparative parameter of the result evaluation from conventional and digital methods. The wrinkle grade of each fabric sample obtained through the conventional technique was statistically compared with that obtained through the digital technique developed. This study demonstrates that the results of the digital method developed for wrinkle evaluation of colored fabrics were similar to those of conventional methods of wrinkling evaluation.     

靛蓝牛仔布印染废水的中和-混凝-SBR处理工艺

采用“中和-混凝-SBR”法处理某牛仔布厂印染废水,处理能力为120 m^3/d.介绍了该处理工艺流程、特点和控制,并分析了每立方米废水的处理成本.经该法处理后,出水水质稳定,并达到污水排放一级标准.     

SBR工艺处理腈纶印染废水

介绍了采用混凝 SBR(间歇式活性污泥法)工艺处理腈纶印染废水(主要含阳离子染料)的试验过程。结果表明，在废水进水pH值为6、CODCr，为640—905mg／L、色度为6—10倍，处理量为240m63／d时，经该工艺处理，出水指标稳定，并达到纺织染整工业水污染排放标准(GB4287-1992)中的一级标准。     

超声波辅助酶法提取榛蘑多糖

目的:为了研究榛蘑中多糖的提取条件,以榛蘑多糖得率为指标,采用超声波辅助复合酶(纤维素酶、木瓜蛋白酶)法进行实验。方法:通过单因素实验研究了酶解温度、超声功率、超声时间、液料比、酶解时间、复合酶比例以及加酶量对榛蘑多糖得率的影响,在此基础上进行响应面优化实验。结果:通过单因素实验,确定了酶解温度50℃、超声功率360 W、超声时间20 min;通过响应面优化实验,确定了最佳提取条件:加酶量1.9%、复合酶比例2:1、酶解时间138 min、液料比30:1(mL/g)。结论:在此条件下,榛蘑多糖得率为40.56%。      

脱脂棉籽粕中棉籽糖提取方法的研究

棉籽糖是植物界中存在的低聚糖中含量仅次于蔗糖的低聚糖,提取主要是以甜菜糖蜜为原料,而从棉籽粕中提取棉籽糖的研究则较少.对棉籽粕中棉籽糖的浸出工艺进行了研究,通过对提取温度,乙醇溶液浓度和提取料液比等影响因素的分析,得出最佳工艺条件为:提取温度50℃,料液比为1:14(W/V),乙醇浓度为75%.在此工艺条件下,棉籽糖的浸出率为95%.提糖后的棉籽粕中游离棉酚含量由原来的0.085%降低到0.029%,低于FAO所规定的0.04%的食用标准.     

茶渣中蛋白质提取方法研究进展

中国是茶叶生产与消费大国,每年在生产茶多酚、茶饮料、速溶茶等产品的同时,产生大量的剩余残渣,这些茶渣中残留多种营养成分,其中蛋白质含量高达20%左右,绝大部分是非水溶性蛋白质的谷蛋白和醇溶性蛋白,同时研究发现茶蛋白具备降血脂、抗氧化、消除自由基及预防辐射等积极的作用;但茶蛋白结构复杂,对茶渣中茶蛋白的提取、纯化等均有一定的技术难度,本文主要针对茶蛋白提取方法(碱法提取、酶法提取、复合提取法)、茶蛋白纯化及茶蛋白的特性等进行阐述,并对存在的问题进行了讨论,以期为茶渣中蛋白质的研究提供参考。