Abstract:Caffeoyl-, feruloyl-and dicaffeoylquinic acids (chlorogenic acids) in infusions from green and medium roasted coffee beans were identified and quantified by reverse phase HPLC with photodiode array and MS 3 detection prior to assessment of the antioxidant activity using an HPLC system with post-column on-line antioxidant detection based on 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid radical scavenging activity. Caffeoylquinic acids were the most abundant antioxidants and roasting induced isomerisatio… Show more
“…The antioxidant contributions of individual HPLC peaks were added to give the total HPLC-derived antioxidant activity. The total antioxidant capacity of the green coffee determined with the on-line HPLC system was 760 ± 2.5µmol Trolox/l and 984 ± 25.8µmol Trolox/l for the roasted coffee [117].…”
Section: Chromatographic Methodsmentioning
confidence: 96%
“…The ABTS cation radical was The antioxidant activity using a HPLC system with postcolumn on-line antioxidant detection, based on 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid radical scavenging activity. The method was applied to the determination of antioxidant content of coffee [117]. Following separation of the coffee samples on the HPLC column, the eluate was directed to a PDA (photodiode array) detector and then mixed with a stabilised solution of the ABTS cation radical and the solution was directed to a detector monitoring absorbance at 720 nm.…”
“…The antioxidant contributions of individual HPLC peaks were added to give the total HPLC-derived antioxidant activity. The total antioxidant capacity of the green coffee determined with the on-line HPLC system was 760 ± 2.5µmol Trolox/l and 984 ± 25.8µmol Trolox/l for the roasted coffee [117].…”
Section: Chromatographic Methodsmentioning
confidence: 96%
“…The ABTS cation radical was The antioxidant activity using a HPLC system with postcolumn on-line antioxidant detection, based on 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid radical scavenging activity. The method was applied to the determination of antioxidant content of coffee [117]. Following separation of the coffee samples on the HPLC column, the eluate was directed to a PDA (photodiode array) detector and then mixed with a stabilised solution of the ABTS cation radical and the solution was directed to a detector monitoring absorbance at 720 nm.…”
“…Antioxidants [34] are substances that when present at low concentrations, compared with those of the oxidizable substrate significantly delay or inhibit oxidation of that substrate [30], [32], [43]. In living system, antioxidants have played an important role in scavenging excessive free radicals [35] such as reactive oxygen species (ROS) and reactive nitrogen species (RNS) [36]- [39] which are formed during normal cellular metabolism in high concentration [33], [40].…”
Section: Introductionmentioning
confidence: 99%
“…Among those dietary species, coffee is a major source of antioxidants and is estimated to provide half of total antioxidant intake in several populations [20], [41], [42]. Thus, coffee extracts have received a lot of attention in recent years and numerous studies have proven that the biologically active components of the extracts such as chlorogenic acids (caffeoylquinic acids [29], dicaffeoylquinic acids [29], feruloylquinic acids [29], [30], [31]), [34] and pcoumaroylqunic acids [29]), melanoidns [37], [39], [44] and lipid soluble heterocyclic compounds (alkaloids) [45], [46] play significant role for its antioxidant behavior in both vitro and vivo [32].…”
Attempt has been made to look into caffeine contents and antioxidant activity of coffee grown at Wembera, Goncha, Zegie, and Burie localities of North-West Ethiopia. The caffeine content of the extracts in % w/w has been found to be 1.53 ± 0.003 for Wembera coffee, 1.41 ± 0.040 for Goncha coffee, 1.29 ± 0.033 for Zegie coffee and 0.97 ± 0.049 for Burie coffee. The antioxidant activities of the coffee extracts were measured by using ferric reducing power assay and Rancimat assay. Ferric reducing power assay was used to measure the total antioxidant power of water soluble components of coffee and is expressed as ascorbic acid equivalent antioxidant capacity in milligram per gram of the dried coffee samples. The ferric reducing power values of the extracts were 9.532 ± 0.201, 9.159 ± 0.441, 8.955 ± 0.180, 6.751 ± 0.284 for Wembera, Burie, Goncha and Zegie coffees, respectively. The Rancimat assay was also used to measure antioxidant activity of lipid soluble portions of coffee extracts using sunflower oil as the oxidizable substrate. It was found that all the coffee extracts improved the oxidative stability of sunflower oil. The protection factors were 1.36 ± 0.027, 1.31 ± 0.027, 1.26 ± 0.069 and 1.17 ± 0.015 for Wembera, Burie, Goncha and Zegie coffees respectively. Based on these results, it is suggested that Wembera coffee has the higher caffeine content and antioxidant activities than Burie, Goncha and Zegie coffee varieties.
“…Stalmach et al (2006) também verificaram que a capacidade antioxidante da bebida, preparada com grãos submetidos à torração média, foi o dobro daquela dos grãos verdes.…”
Resumo -O objetivo deste trabalho foi determinar a atividade antioxidante do café, bebida mole, in vivo e in vitro, antes e após a torração. Para a análise da atividade antioxidante in vitro, foram utilizados os métodos
In vitro and in vivo antioxidant activity of soft coffeeAbstract -The objective of this work was to determine the in vivo and in vitro antioxidant activity of soft coffee beverages, before and after roasting. For the analysis of the antioxidant activity, the methods of free radical sequestration (DPPH) and of the chelating activity of Fe 2+ ions were used. In vivo tests were performed with diabetic Zucker rats with metabolic syndrome and control Zucker rats. The animals received daily doses of coffee drinks by gavage for 30 days. After treatment, lipid peroxidation was evaluated. Roasted coffee samples had the highest percentage of free radical sequestration. Concentration in both green and roasted coffee samples was similar to that of the Trolox standard. From the roasted samples, medium roast stood out with greater Fe 2+ ion chelating activity. Green coffees showed higher quelating power than the roasted ones. The compounds in the extract decreased the lipid peroxidation in the liver and kidney which is common in cases of diabetes and metabolic syndrome. Coffee has an antioxidant activity and protects the liver and kidneys of animals from lipid peroxidation commonly present in type 2 diabetes mellitus and metabolic syndrome.
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