Statistical correlation between flavanolic composition, colour and sensorial parameters in grape seed during ripening

Area of Science:

• Agricultural Science
• Food Chemistry
• Analytical Chemistry

Background:

• Grape seed composition changes significantly during ripening.
• Flavanols are key compounds influencing grape seed sensory properties.

Purpose of the Study:

• To correlate grape seed sensory attributes with flavanol content and color.
• To investigate the impact of ripening on seed phenolic profiles.

Main Methods:

• High-performance liquid chromatography with diode-array detection and mass spectrometry (HPLC-DAD-MS) for flavanol analysis.
• Correlation analysis with CIELab color parameters, perceived color, hardness, tannic intensity, and astringency.
• Multiple linear regression (MLR) to identify significant relationships.

Main Results:

• Flavanol content, particularly catechins and procyanidin oligomers, decreases during ripening.
• Epicatechin-(4-8)-epicatechin-3-O-gallate (B2G) and (-)-epicatechin-3-O-gallate (ECG) showed the most significant decreases.
• Sensory attributes like tannic intensity, astringency, and hardness are linked to phenolic composition changes.
• Qualitative flavanol profile, not just total content, affects sensory perception.
• CIELab color parameters strongly correlate with flavanolic compounds, especially ECG.

Conclusions:

• Grape seed ripening alters flavanol profiles, influencing sensory characteristics.
• The specific types and amounts of flavanols are crucial for determining astringency, hardness, and tannic intensity.
• Seed color is a reliable indicator of flavanol content, particularly ECG.