Caffeine in Coffee: Its Removal. Why and How?

The popularity of coffee as a beverage is ever increasing despite the fact that there are reports antagonized to its consumption. Of the several factors cited, the alkaloid caffeine present in coffee can cause addiction and stimulate the central nervous system. It has an effect on the cardiovascular system with a slight increase in blood pressure and heart output. It undergoes biotransformation in the human body to form methylated derivatives of uric acid. In recent times, much effort has gone into the research on the removal of caffeine in coffee, resulting in a specialty product called decaffeinated coffee. Decaffeination methods mainly employ organic solvents or water or supercritical carbon dioxide. These methods with their attendant advantages and disadvantages are reviewed in this article.     

On-column decaffeination and HPLC analysis of epigallocatechin gallate in green tea nutraceuticals

Green tea (GT) derived epigallocatechin gallate (EGCG) is a commonly used nutraceutical for its antioxidant activity. Caffeine is the second major component and interferes with extraction of EGCG. On-column decaffeination was optimized to enable selective enrichment of EGCG, though less retained than caffeine. EGCG recovery and loss in caffeine were determined using RP-HPLC. Results indicated a significant improvement in caffeine removal and EGCG recovery. The SPE-HPLC protocol represents a model for an efficient and economic approach for improving dynamic capacity, selectivity, and sensitivity towards less retained analytes. This is particularly important for analysis of inherently complex samples of nutraceutical products.     

在柱甲基化法自动合成(S-[11C]甲基)-L-蛋氨酸和(S-[11C]甲基)-L-半胱氨酸

用PET trace回旋加速器通过核反应^14N(P,q)^11C生产^11CO2,经甲烷循环碘化法和”CH3I全自动合成系统制备^11CH3I,合成时间约为12min,未校正放化产率大于30％。采用(S-[^11C]甲基)-L-蛋氨酸(^11C-MET)半自动合成装置,使^11CH3I与前体L-同型半胱氨酸硫内酯盐酸盐的碱性溶液在Sep Pak Plus C18小柱上发生烷基化反应,并经Sep Pak Plus C18小柱分离,得^11C-MET注射液,烷基化反应时间约6min,放化产率大于85％,放化纯度大于99％,对映纯度约为90％。采用PET-CS-I型全自动合成模块,使^11CH3I与前体L-半胱氨酸发生在柱烷基化反应,并经柱分离后得到(S-[^11C]甲基)-L-半胱氨酸(^11C-CYS)注射液,烷基化反应时间约2min,未校正放化产率大于50％,放化纯度大于99％,对映纯度大于90％。制得的^11C-MET和^11C-CYS注射液可用于动物和人体研究。     

Cloning, Soluble Expression and Purification of High Yield Recombinant hGMCSF in Escherichia coli

Expression of human granulocyte macrophage colony stimulating factor (hGMCSF), a cytokine of therapeutic importance, as a thioredoxin (TRX) fusion has been investigated in Escherichia coli BL21 (DE3) codon plus cells. The expression of this protein was low when cloned under the T7 promoter without any fusion tags. High yield of GMCSF was achieved (～88 mg/L of fermentation broth) in the shake flask when the gene was fused to the E. coli TRX gene. The protein was purified using a single step Ni(2+)-NTA affinity chromatography and the column bound fusion tag was removed by on-column cleavage with enterokinase. The recombinant hGMCSF was expressed as a soluble and biologically active protein in E. coli, and upon purification, the final yield was ～44 mg/L in shake flask with a specific activity of 2.3 × 10(8) U/mg. The results of Western blot and RP-HPLC analyses, along with biological activity using the TF-1 cell line, established the identity of the purified hGMCSF. In this paper, we report the highest yield of hGMCSF expressed in E. coli. The bioreactor study shows that the yield of hGMCSF could be easily scalable with a yield of ～400 mg/L, opening up new opportunities for large scale production hGMCSF in E. coli.     

Effective Regulatory Approval Process for Food Ingredient Technologies

Most sciences and technologies related to food safety have advanced exponentially over the 40 years since passage in the U.S. of the Food Additive Amendment of 1958 to the Federal Food, Drug and Cosmetic (FD&C) Act. Effective regulatory decision making places a high premium on competent professional and administrative judgement applied to sound scientific data. This review discusses changes and lessons learned in the food safety sciences over the last 4 decades. Other segments of the safety and compliance infrastructure necessary to assure that the public receives safe and wholesome foods have not kept pace with the new scientific knowledge. The quality of foods in our marketplace can be improved only after the regulatory and legislative segments of the infrastructure, discussed in a companion symposium paper,⁸ are brought into better synchrony with the sciences.     

基于电动驱动的中心切割二维分离检测系统

设计了一种集采样、样品纯化、二维分离、在柱检测和数据采集功能于一体的中心切割二维分离检测系统,采用电动驱动二维分离全过程,运用在柱检测控制中心切割二维切换,并设计USB数据采集电路和上位机软件,实现数据的采集、存储和图谱的绘制.介绍了其分离检测原理、电渗泵及在柱检测单元的制作.利用该系统实现了复杂样品血样中6种β-阻断剂药物的高分辨率、高灵敏度分离检测,峰高、峰面积和迁移时间的相对标准偏差分别为1.6％ ～ 3.3％、1.2％～2.8％和0.7％～2.2％,检出限为3.5～12.6 μg/L.结果表明:该系统分辨率高、灵敏度高、重复性好,可用于复杂样品的在线纯化、高效分离检测.     

Current Trends in Producing Low Levels of Caffeine in Coffee Berry and Processed Coffee Powder

Caffeine is a bioactive compound present in coffee. The physiological effects of caffeine on human and animal models are well documented, and this has led the coffee industry to develop an artificially decaffeinated coffee based on solvent extraction process. An alternative to this approach would be to identify naturally occurring low caffeine lines, breeding for low caffeine coffee trait or to generate transgenic coffee with regulated caffeine pathway. This review is mainly focused on caffeine and its health effects; information on decaffeination processes; latest developments in the understanding of caffeine pathway and development of genetically engineered coffee with low caffeine.     

Supercritical CO2 decaffeination of unroasted coffee beans produces melanoidins with distinct NF-κB inhibitory activity

The supercritical CO(2)-decaffeination process causes unroasted coffee beans to turn brown. Therefore, we suspected that the decaffeinated beans contained melanoidins. Decaffeinated unroasted coffee extract absorbed light at 405 nm with a specific extinction coefficient, K(mix 405 nm), of 0.02. Membrane dialysis (molecular weight cut-off, 12 to 14 kDa) increased the K(mix 405 nm) value 15 fold. Gel filtration chromatography showed that the high-MW fraction (MW > 12 kDa) had an elution profile closer to that of melanoidins of medium-roast coffee than to the corresponding fraction of unroasted coffee, indicating the presence of melanoidins in decaffeinated unroasted beans. Using murine myoblast C2C12 cells with a stably transfected nuclear factor-κB (NF-κB) luciferase reporter gene, we found that the high-MW fraction of decaffeinated unroasted beans had an NF-κB inhibitory activity of IC(50) = 499 μg/mL, more potent than that of regular-roast coffee (IC(50) = 766 μg/mL). Our results indicate that melanoidins form during the supercritical CO(2)-decaffeination process and possess biological properties distinct from those formed during the regular roasting process. PRACTICAL APPLICATION: We discovered the roasting effect of decaffeination process, reporting the discovery of melanoidins in green (unroasted) decaf coffee beans. Our results indicated that melanoidins form during the supercritical CO2-decaffeination process and possess biological properties distinct from those formed during the regular roasting process. Our results offer new insights into the formation of bioactive coffee components during coffee decaffeination process.     

Stability of ochratoxin A (OTA) during processing and decaffeination in commercial roasted coffee beans

The fate of ochratoxin A (OTA) during the processing of artificially contaminated green coffee beans, the effect of decaffeination on the production of OTA in green and roasted coffee beans, and the effect of caffeine on the growth and OTA production by Aspergillus ochraceus were studied. The data indicated that the roasting, milling and decoction (brewing and Turkish coffee making) processes caused different percentage reductions in OTA. Decaffeinated samples showed a significantly higher concentration of OTA production than the caffeinated ones. A significantly higher percentage of OTA was reduced when the decaffeination process was performed before roasting treatment. Caffeine at 1.0 and 2.0% concentrations completely prevented OTA production and completely inhibited A. ochraceus growth in YES medium after 3-21 days.     

Highly simplified preparation of tea flavonoids from surplus tea leaves by the novel three-phase extraction and purification

A novel three-phase extraction and purification procedure was developed to prepare high-quality flavonoids from surplus tea leaves. Flavonoids were selectively extracted in ethyl acetate (EtOAc) by the EtOAc-water-leaf three-phase extraction, with 91.2% extraction efficiency, more than 50% higher than the traditional water extraction. The EtOAc extracts were purified by the EtOAc-water- montmorillonite/charcoal three-phase adsorptive purification at 98% recovery. Highly purified flavonoids were obtained with less than 1.0% caffeine. The overall flavonoid recovery reached 90.3%, more than 40% higher than traditional methods. This procedure highly simplified the processes and significantly increased the recovery of flavonoid production from tea leaves.