Page 52 - FoodFocusThailand No.229 April 2025

STRONG
STRONG QC & QA QC & QA

Analytical Techniques for Tannin

in Food and Beverages Products

Tannins are natural compounds found in plants, known for their distinctive flavor and health benefits. Tannins
can be categorized into several types. Hydrolyzable tannins break down easily under acidic conditions or
in the presence of enzymes, releasing potent antioxidants. Condensed tannins, like proanthocyanidins,
are found in fruits and beverages. It provides a dry and astringent feeling. Complex tannins are a combination
of both hydrolyzable and condensed tannins.

In tea, tannins vary depending on the type: green tea is rich light is absorbed by the substance. EA has specific light
in catechins, black tea contains theaflavins, and oolong offers absorption peaks, with the strongest occurring around 255 nm
a blend of both. These compounds help with digestion and protect and 366 nm. These results provide the information about
the body from oxidative stress. Similarly, red wine is rich in tannins chemical properties and structure of EA-containing in
like procyanidins, which help improve blood flow and lower the beverage sample.
cholesterol, supporting heart health. Tannins are also abundant 2. Chromatography Chromatography methods, including
in fruits like grapes, apples, and berries, and nuts like hazelnuts High-Performance Thin Layer Chromatography (HPTLC), are
and walnuts. These foods offer both that signature astringency commonly used to measure ellagic acid (EA) in plant extracts
and a boost of antioxidants. Even vegetables like beans and leafy and formulations. HPTLC is a more advanced form of thin-layer
greens provide tannins that help fight oxidative stress and support chromatography, providing better separation and detection
overall health. abilities. HPTLC can also identify EA in different plants by
Analysis of Tannins in Food and Beverage Products comparing the results to standard reference values. It has been
used to create “fingerprints” of polyphenolic compounds in
One type of tannin-related compound that has gained attention various plants, helping understand the chemical makeup of
for its health benefits is ellagic acid. Ellagic acid, a bioactive natural products.
compound present in plants such as strawberries, grapes, and 3. Sensory Evaluation Tannins have a direct impact on
pomegranates, is widely recognized for its antioxidant, the sensory characteristics of wine, particularly in terms of
anti-inflammatory, and potential anticancer properties. Ellagic acid astringency, bitterness, aroma, and overall mouthfeel. While
is often studied because it can help protect cells from oxidative polyphenolic compounds offer various health benefits, a high
damage and inflammation, which are associated with the tannin content can enhance bitterness and astringency,
development of chronic diseases. Analytical techniques such potentially affecting consumer acceptance.
as spectrophotometry and chromatography, notably 3.1 Astringency is characterized by dryness and puckering,
High-Performance Liquid Chromatography (HPLC), can be used primarily caused by tannins interacting with salivary proteins,
to detect and measure ellagic acid in plants. These methods allow leading to protein precipitation and reduced lubrication. Larger,
for the precise identification and quantification of ellagic acid, water-soluble tannins are perceived as more astringent, while
helping better understand its role in health and product smaller, hydrophobic tannins taste hotter and bitter. Factors like
applications. pH, tannin content, and other compounds in wine and fermented
1. Spectrophotometry To measure ellagic acid (EA) fruit products influence astringency. The Temporal Dominance
accurately, UV Spectrophotometry is commonly used. This method of Sensations (TDS) technique can be applied to analyze
involves shining light through a sample and measuring how much changes in astringency over time in food products, providing

52 FOOD FOCUS THAILAND APR 2025 a profile of dominant taste sensations at different time intervals.

24/3/2568 BE 19:41
50-53_Strong QC&QA_�������.indd 52
50-53_Strong QC&QA_�������.indd 52 24/3/2568 BE 19:41