Analysis of Tannins by UV and Titration

Introduction

In the realm of food testing, understanding the composition of various components is essential for quality control and consumer satisfaction. Tannins, a class of polyphenolic compounds, play a significant role in the flavor, color, and mouthfeel of many foods and beverages. Analyzing tannins can be achieved through various methods, and in this blog post, we'll explore two of them: UV spectroscopy and titration. These techniques are commonly used in food testing laboratories to quantify and characterize tannins, providing valuable insights for product development and quality assurance.

Understanding Tannins

Tannins are natural compounds found in various plant-based foods and beverages such as tea, wine, coffee, and fruits. They contribute to the astringency and bitterness of these products, influencing their sensory properties. Tannins also have antioxidant properties, making them an important consideration for health-conscious consumers.

Tannins are polyphenolic compounds found in foods and beverages. They matter because:

Flavor and Sensation: They contribute to taste, astringency, and mouthfeel, shaping our culinary experiences.

Health Benefits: Tannins possess antioxidants, potentially reducing chronic disease risk.

Preservation: Some tannins act as natural preservatives in foods, extending shelf life.

Medicine: They have been used for medicinal purposes, with anti-inflammatory and astringent properties.

Tanning and Leather: Historically vital in leather production.

Wine and Beverages: Central to wine aging, structure, and flavor.

Research: Studying tannins informs food development and industry innovation.

Environmental Role: Tannins influence ecosystems, nutrient cycling, and water quality.

Importance of testing

Market overview

In 2020, the global tannin market reached a value of $2.3 billion. Projections indicate that it is expected to expand to $4.0 billion by 2030, with a compound annual growth rate (CAGR) of 5.7% from 2021 to 2030.

Regulations and standards

The Food Safety and Standards Authority of India (FSSAI) has specific standards for tannins in some food products. For example, the FSSAI limits the level of tannins in tea to 200 mg/L. This is based on the Codex Alimentarius Commission's recommendation that the levels of tannins be kept to a minimum in foods that are intended for infants and young children.

The FSSAI also has standards for tannins in other food products, such as grape juice (100 mg/L) and wine (200 mg/L). These standards are designed to protect consumers from the potential negative effects of tannins, such as their astringent and bitter taste, their ability to bind to proteins and minerals, and their anti-nutrient effects.

Testing methods

Analysing tannins, which are polyphenolic compounds commonly found in plants, can be done using various methods, including UV (ultraviolet) spectroscopy and titration. These methods provide different types of information about tannin content and characteristics. Here's a brief overview of how each method works and its application in tannin analysis:

Eurofins role in analysis of Tannins by UV and Titration

Eurofins, as a leading laboratory testing and scientific services company, can play a significant role in the analysis of tannins by UV (Ultraviolet) spectroscopy and titration. Tannins are organic compounds found in various plant materials and can be analysed for a variety of purposes, including in the food and beverage industry, pharmaceuticals, and environmental research. Here's how Eurofins might be involved in such analysis:

Sample Preparation: Eurofins laboratories would start by preparing the samples containing tannins. This could involve extracting tannins from natural sources, such as plant extracts, beverages (e.g., wine, tea), or other matrices where tannins are of interest.

UV Spectroscopy Analysis:

UV-Vis Spectrophotometry: Eurofins might use UV-Vis spectrophotometry to quantify the concentration of tannins in a sample. This technique relies on the measurement of absorbance at specific wavelengths, usually in the UV range, where tannins exhibit characteristic absorption peaks.

Calibration Curve: Eurofins would likely create a calibration curve using standard tannin solutions of known concentrations. By comparing the absorbance of the sample to the calibration curve, they can determine the tannin concentration.

Titration Analysis:

Titration with Precipitation Reagents: In some cases, Eurofins may use titration techniques to analyse tannins. Tannins can be titrated using specific reagents that precipitate with tannins. The endpoint of the titration is typically indicated by a change in color or turbidity, and the volume of the titrant required is used to calculate tannin content.

Folin-Ciocalteu Assay: This is a common titration method used to estimate the total phenolic content, including tannins, in a sample. Eurofins would use a Folin-Ciocalteu reagent and standard solutions to perform this assay.

Data Analysis: Eurofins would analyse the data obtained from UV spectroscopy or titration to determine the concentration of tannins in the sample accurately.

Reporting: Eurofins would provide detailed reports to clients, including the tannin content, methodology used, and any relevant information about the analysis.

Method Development and Validation: Eurofins may also engage in method development and validation to ensure the accuracy and reliability of the tannin analysis procedures. This is especially important when working with complex matrices or unique sample types.

Consultation and Support: Eurofins can offer consultation and support to clients regarding tannin analysis, including interpretation of results, method selection, and recommendations for sample handling and storage.

Eurofins Analytical Services India, located in Bangalore, has achieved a significant milestone by receiving recognition from the US Food and Drug Administration (FDA) under the Laboratory Accreditation for Analyses of Foods (LAAF) program. This makes Eurofins the first laboratory in Asia to receive such recognition.

References

1. https://www.researchgate.net/publication/243892974_UV_spectrophotometric_method_for_polyphenolic_tannin_analysis
2. Antoine, L., Simon, C., & Pizzi, A. (2004). UV spectrophotometric method for polyphenolic tannin analysis. Journal of Applied Polymer Science, 91(4), 2729-2732. https://doi.org/10.1002/app.13481
3. Sillanpää, M., Engström, M. T., Tähtinen, P., Green, R. J., Käpylä, J., Näreaho, A., & Karonen, M. (2022). Tannins Can Have Direct Interactions with Anthelmintics: Investigations by Isothermal Titration Calorimetry. Molecules, 28(13), 5261. https://doi.org/10.3390/molecules28135261

Contact Us