Antioxidant activity of coffee model systems.

Area of Science:

• Food Chemistry
• Food Analysis
• Antioxidant Research

Background:

• Coffee's health benefits are partly attributed to antioxidants like chlorogenic acid (CGA).
• Understanding how roasting affects CGA and antioxidant activity is vital for coffee quality.
• Model systems allow controlled investigation of roasting effects on coffee components.

Purpose of the Study:

• To investigate the relationship between chlorogenic acid (CGA) degradation, color formation, and antioxidant activity in roasted coffee model systems.
• To determine the role of sucrose degradation in color development during coffee roasting.
• To analyze the impact of roasting on key coffee components and their functional properties.

Main Methods:

• Preparation of coffee model systems using chlorogenic acid (CGA), N(alpha)-acetyl-1-arginine (A), sucrose (S), and cellulose (C).
• Roasting of model systems at 240°C for 4 minutes.
• Analysis using UV-visible spectrophotometry, capillary zone electrophoresis (CZE), and ABTS radical cation decolorization assay.
• Gel filtration chromatography for fractionation of selected systems.

Main Results:

• A positive, nonlinear relationship was observed between the remaining amount of CGA after roasting and the system's antioxidant activity.
• Sucrose degradation was identified as a primary contributor to color generation in the heated model systems.
• No correlation was found between the antioxidant activity and the degree of color generation in the roasted systems.

Conclusions:

• The retention of chlorogenic acid (CGA) post-roasting is a key determinant of antioxidant capacity in coffee.
• Color development during coffee roasting is mainly driven by sucrose degradation, independent of antioxidant potential.
• Model systems provide valuable insights into the complex chemical transformations occurring during coffee roasting.