The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Yumin Chen - One of the best experts on this subject based on the ideXlab platform.
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supercritical co2 Decaffeination of unroasted coffee beans produces melanoidins with distinct nf κb inhibitory activity
Journal of Food Science, 2011Co-Authors: Yumin Chen, Peter H Brown, Kang Hu, Richard M Black, Ronald L Prior, Boxin OuAbstract:The supercritical CO2-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, Kmix405nm, of 0.02. Membrane dialysis (molecular weight cut-off, 12 to 14 kDa) increased the Kmix405nm 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 IC50 = 499 μg/mL, more potent than that of regular-roast coffee (IC50 = 766 μg/mL). Our results indicate that melanoidins form during the supercritical CO2-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.
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Supercritical CO2 Decaffeination of unroasted coffee beans produces melanoidins with distinct NF-κB inhibitory activity.
Journal of food science, 2011Co-Authors: Yumin Chen, Peter H Brown, Richard M Black, Ronald L Prior, Yi-fang ChuAbstract: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. 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. © 2011 Institute of Food Technologists®
Kyoung Heon Kim - One of the best experts on this subject based on the ideXlab platform.
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Extraction behaviors of caffeine and chlorophylls in supercritical Decaffeination of green tea leaves
LWT - Food Science and Technology, 2012Co-Authors: Hyong Seok Park, Kyoung Heon KimAbstract:Abstract The Decaffeination of green tea using supercritical carbon dioxide (SC-CO 2 ) was optimized by response surface methodology (RSM) for the maximal removal of caffeine, and the coextration of chlorophylls was also monitored during Decaffeination. The experimental conditions for the SC-CO 2 extraction of caffeine were set up according to the Box-Behnken design of RSM. The relationships between the extraction yield of caffeine and various parameters used for the SC-CO 2 extraction such as pressure, temperature and concentration of ethanol were studied at a fixed CO 2 flow rate. The extraction yields of caffeine and total chlorophyll were significantly influenced by extraction pressure, temperature and concentration of cosolvent, and their extraction yields behaved almost in parallel at different extraction conditions that were obtained by varying pressure, temperature and ethanol cosolvent concentration. At the optimal Decaffeination conditions such as 3.0 g of 95% (v/v) ethanol cosolvent per 100 g of CO 2 , 23 MPa, 63 °C and an extraction duration of 120 min for 10 g of green tea leaves, the extraction yields for caffeine and catechins were 96.60% (w/w) and 40.61% (w/w), respectively, and the substantial coextraction of total chlorophyll (43.09% of the total amount) was also observed during the Decaffeination process.
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Effect of Supercritical Carbon Dioxide Decaffeination on Volatile Components of Green Teas
Journal of food science, 2007Co-Authors: S.j. Lee, Kyoung Heon Kim, Myong-soon Park, Young-sang KimAbstract:Volatile components in regular and decaffeinated green teas were isolated by simultaneous steam distillation and solvent extraction (SDE), and then analyzed by GC-MS. A total of 41 compounds, including 8 alcohols, 15 terpene-type compounds, 10 carbonyls, 4 N-containing compounds, and 4 miscellaneous compounds, were found in regular and decaffeinated green teas. Among them, linalool and phenylacetaldehyde were quantitatively dominant in both regular and decaffeinated green teas. By a Decaffeination process using supercritical carbon dioxide, most volatile components decreased. The more caffeine was removed, the more volatile components were reduced in green teas. In particular, relatively nonpolar components such as terpene-type compounds gradually decreased according to the Decaffeination process. Aroma-active compounds in regular and decaffeinated green teas were also determined and compared by aroma extract dilution analysis (AEDA). Most greenish and floral flavor compounds such as hexanal, (E)-2-hexenal, and some unknown compounds disappeared or decreased after the Decaffeination process.
Ben J. Mccoy - One of the best experts on this subject based on the ideXlab platform.
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Rate Processes in Supercritical Fluid Extraction
Developments in Food Engineering, 1994Co-Authors: Ben J. MccoyAbstract:Rates of supercritical fluid (SCF) extraction with CO2 depend on (a) partitioning of the extract between the natural matrix and the fluid, (b) rate of mass transfer of extract from the interior of the matrix to the fluid, and possibly (c) solubility of the extract in the supercritical fluid. These issues are discussed and illustrated by calculations. Investigations of the Decaffeination of coffee beans demonstrate the concepts. Decaffeination was measured as a function of CO2 flow rate, temperature and pressure. Soaking the raw beans in water prior to Decaffeination enhanced the rate of extraction. The rate of Decaffeination increased with both pressure and temperature. The mathematical model describes the external and intraparticle diffusion resistances and the distribution of caffein between water and supercritical CO2. The partition coefficient for caffeine distributed between water and supercritical CO2 depends on temperature and pressure.
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Caffeine extraction rates from coffee beans with supercritical carbon dioxide
AIChE Journal, 1992Co-Authors: Hulya Peker, M.p. Srinivasan, J. M. Smith, Ben J. MccoyAbstract:The extraction of caffeine from whole coffee beans with supercritical carbon dioxide was studied in a continuous-flow extraction apparatus. Decaffeination rates were determined as a function of CO2 flow rate, temperature and pressure by continuously monitoring the caffeine in the effluent with a flame ionization detector. Soaking the raw beans in water prior to Decaffeination enhanced the rate of extraction, which increased markedly with water content. Using CO2 saturated with water also increased the rate of extraction. The rate of Decaffeination increased with pressure and temperature and was influenced by both intraparticle diffusion in the water-soaked beans and external mass transfer. A mathematical model based on a linear-driving-force approximation of mass transfer and partitioning of caffeine between the water and the supercritical CO2 describes the time-dependent process. The partition coefficient for caffeine distributed between water and supercritical CO2, the only parameter determined from the dynamic extraction rate data, increases with temperature and pressure.
Boxin Ou - One of the best experts on this subject based on the ideXlab platform.
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supercritical co2 Decaffeination of unroasted coffee beans produces melanoidins with distinct nf κb inhibitory activity
Journal of Food Science, 2011Co-Authors: Yumin Chen, Peter H Brown, Kang Hu, Richard M Black, Ronald L Prior, Boxin OuAbstract:The supercritical CO2-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, Kmix405nm, of 0.02. Membrane dialysis (molecular weight cut-off, 12 to 14 kDa) increased the Kmix405nm 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 IC50 = 499 μg/mL, more potent than that of regular-roast coffee (IC50 = 766 μg/mL). Our results indicate that melanoidins form during the supercritical CO2-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.
Young-sang Kim - One of the best experts on this subject based on the ideXlab platform.
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Effect of Supercritical Carbon Dioxide Decaffeination on Volatile Components of Green Teas
Journal of food science, 2007Co-Authors: S.j. Lee, Kyoung Heon Kim, Myong-soon Park, Young-sang KimAbstract:Volatile components in regular and decaffeinated green teas were isolated by simultaneous steam distillation and solvent extraction (SDE), and then analyzed by GC-MS. A total of 41 compounds, including 8 alcohols, 15 terpene-type compounds, 10 carbonyls, 4 N-containing compounds, and 4 miscellaneous compounds, were found in regular and decaffeinated green teas. Among them, linalool and phenylacetaldehyde were quantitatively dominant in both regular and decaffeinated green teas. By a Decaffeination process using supercritical carbon dioxide, most volatile components decreased. The more caffeine was removed, the more volatile components were reduced in green teas. In particular, relatively nonpolar components such as terpene-type compounds gradually decreased according to the Decaffeination process. Aroma-active compounds in regular and decaffeinated green teas were also determined and compared by aroma extract dilution analysis (AEDA). Most greenish and floral flavor compounds such as hexanal, (E)-2-hexenal, and some unknown compounds disappeared or decreased after the Decaffeination process.
