New method for evaluating astringency in red wine

Area of Science:

• Enology and Viticulture
• Analytical Chemistry
• Food Science

Background:

• Astringency is a key sensory attribute in red wine, crucial for quality assessment.
• Current methods like sensory analysis and the gelatin index lack reproducibility and accuracy.
• The gelatin index, relying on heterogeneous gelatin and acid hydrolysis, provides only approximate procyanidin concentration.

Purpose of the Study:

• To develop a novel, reproducible, and accurate method for quantifying red wine astringency.
• To compare the proposed method with existing techniques, including sensory analysis and the gelatin index.
• To establish a reliable measurement for procyanidin concentration related to astringency.

Main Methods:

• Development of a new precipitation method using ovalbumin as the precipitating agent.
• Utilization of tannic acid solutions as standards for calibration.
• Statistical analysis to assess reproducibility and correlation with sensory data.

Main Results:

• The proposed ovalbumin method demonstrated high reproducibility with a relative standard deviation (RSD) of 5%.
• The gelatin index method showed significantly lower reproducibility with an RSD of 12%.
• The new method exhibited a better correlation with sensory analysis compared to the gelatin index.

Conclusions:

• The ovalbumin precipitation method is a superior alternative for reproducible astringency determination in red wine.
• This method offers a more accurate assessment of procyanidin concentration, improving wine quality control.
• The findings support the adoption of this new technique for reliable wine analysis.