Biologically active compounds in roasted coffee
2011
Kreicbergs, V., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Dimins, F., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Mikelsone, V., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry | Cinkmanis, I., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Chemistry
Coffee is one of the products rich in biologically active compounds. The aim of this research work was to investigate the content of total phenols, flavonoids and caffeine in coffee available in the local markets as well as its changes depending on the brand. Eighteen coffee brands used in the research were analysed. The content of total phenols and total flavonoids was determined spectrophotometrically. The content of caffeine and polyphenols (gallic acid, catehin, caffeic acid, vanillin, chlorogenic acid, epicatehin and ferulic acid) were determined by high performance liquid chromatography. Total phenols in analysed coffee samples ranged from 1300 to 3700 mg gallic acid eqivalents (GAE) 100 gE-1, total flavonoids – from 15 to 103 mg quercetin equivalents (QE) 100 gE-1 coffee. The content of polyphenols varied in a wide range too: gallic acid from 2.5 mg to 80 mg 100 gE-1, catehin from 30 to 80 mg 100 gE-1, caffeic acid from 1200 to 2500 mg 100 gE-1, vanilin from 100 to 150 mg 100 gE-1, chlorogenic acid from 1.4 to 2.8 g 100 gE-1, epicatehin from 11 to 30 mg 100 gE-1, and ferulic acid from 23 till 120 mg 100 gE-1 coffee. The content of caffeine ranged from 0.7 till 1.5 g 100 gE-1 coffee. The highest content of caffeine, catehin, caffeic acid and ferulic acid was detected in coffee samples with a higher proportion of the Robusta coffee variety. Total phenols and total flavonoids content did not vary significantly between coffee varieties.
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