Chlorogenic acids, caffeine content and antioxidant properties of green coffee extracts: influence of green coffee bean preparation

Krystyna Pyrzyńska,Maria Paz De Peña,Magdalena Jeszka-Skowron,Aleksandra Sentkowska

doi:10.1007/s00217-016-2643-y

Krystyna Pyrzyńska, Maria Paz De Peña + Show 2 more

Open Access

https://doi.org/10.1007/s00217-016-2643-y

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Abstract

Chlorogenic acids and caffeine are important for flavor formation as well as the health effect of green coffee brews and its extracts. The content of these compounds was determined by HPLC–DAD analysis in twelve samples of coffee from Robusta and Arabica types of different geographical origin including steamed and decaffeinated coffees. Generally, Robusta coffee extracts contain twice as much caffeine as Arabica, and its content varies from 3.41 % per dry mass in Arabica type from Laos or Rwanda to 8.16 % in Robusta coffee from Indonesia. The highest concentration of 5-O-caffeoylquinic acid (5-CQA) was obtained for both coffees from Uganda. Decaffeination process does not affect the concentration of this main chlorogenic acid, but steaming of the coffee beans with hot water produced a significant decrease in the level of 5-CQA. Antioxidant activity of coffee extracts was measured by CUPRAC and F–C assays, which really measure the reducing power of the sample components. Extracts of green coffee beans from Vietnam possessed the highest antioxidant activity in both assays.

Highlights

Coffee is one of the most popular drinks nowadays all over the world
The aim of the study was to compare the content of chlorogenic acids and caffeine in green coffee Arabica and Robusta extracts due to their origin and preparation of beans
The caffeine content in green bean extracts of Coffea arabica was very similar 34.1–38.5 g kg−1, while in Coffea robusta was in the range between 3.9; 68.6 (Uganda Sc) to 81.6 g kg−1 dry mass

Summary

Introduction

Coffee is one of the most popular drinks nowadays all over the world It contains more than 700 compounds which are responsible for its aromatic and unique flavor. Green coffee bean extract shows a hypotensive effect in rats [4] and reduces visceral fat and body weight [5, 6]. These properties are connected with bioactive compounds, chlorogenic acids and their derivatives, and caffeine, theophylline and theobromine, cafestol, kahweol, tocopherols and trigonelline [7,8,9,10,11,12]

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