OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 OENO IVAS 9 OENO IVAS 2019 9 Analysis and composition of grapes, wines, wine spirits 9 Comparison of tannin analysis by protein precipitation and normal-phase HPLC

Comparison of tannin analysis by protein precipitation and normal-phase HPLC

Abstract

Tannins are a heterogenous class of polymeric phenolics found in grapes, oak barrels and wine. In red wine tannins are primarily responsible for astringency, though they also have an important role in reacting with and stabilizing pigments. There are numerous sub-classes of tannins found in wine but they all share structural heterogeneity within each sub-class, with varied polymer composition, configuration and length. 

Numerous methodologies exist for the quantification of tannins, however, protein precipitation using bovine serum albumin has proved itself useful due to its strong correlation to the sensory perception of astringency and the basic instruments required for the method. Though the method can yield valuable insights into tannin composition, it cannot be automated easily and necessitates well-trained personnel. 

RP-HPLC analysis has been used for the quantification of low molecular phenolic compounds for a long time, but it is not suitable for the quantification of tannins. A normal-phase (NP)-HPLC method using a ternary solvent system is suggested, which is able to separate the phenolic compounds from red wine into three major fractions. Comparison with standard phenolic compounds allowed the characterization and quantification of these fractions and the results were compared to those obtained by protein precipitation.

DOI:

Publication date: June 23, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Jan-Peter Hensen, Ingrid Weilack, Fabian Weber, Andreas Schieber, James Harbertson

University of Bonn Institute of Nutritional and Food Sciences, Molecular Food Technology Endenicher Allee 19b D-53115 Bonn Germany 

Contact the author

"> 

Keywords

Tannin analysis, Protein Precipitation Assay, NP-HPLC

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

The role of molecular ecophysiology in terroir expression

Terroir is a complex concept which associates soil, climate, grape variety and cultural practices that include the training system and oenological techniques. It is a type of social construction with man at its centre. The typicality of a wine is also a social construction which is the result of an agreement among specialists vis à vis a given quality of the wine whose references are the wine’s origins (e.g. terroir) and taste.
Read More

The terroir of Carnuntum: investigation of the physiogeographic characteristics and interdisciplinary study of viticultural functions of the Carnuntum wine district, Austria

During a three-year period, the vineyards of the Carnuntum wine district are investigated for their terroir characteristics. The interdisciplinary study is aimed at the description of the physiogeographic

Read More

Influence of dehydration and maceration conditions on VOCs composition and olfactory profile of Moscato Bianco passito sweet wine

Among the Vitis vinifera L. cv. Moscato, Moscato Bianco is the oldest and most cultivated one in Europe (1). According to the OIV Focus 2015, Italy is the country with the largest cultivated area of Moscato Bianco with about 12500 hectares (2), that is used to produce well-known wines (i.e., Moscato Passito in Piedmont, Moscato di Trani in Puglia, and Moscatello di Montalcino in Tuscany), mainly obtained from partially dehydrated grapes (1). Different dehydration techniques can strongly modify the chemical compounds of oenological interest, among which Volatile Organic Compounds (VOCs) (1) that are the main responsible for the varietal sensory character of the final wine.

Read More

How can yeast modulate Divona’s aromatic profile?

Volatile thiols play a key role in the aromatic expression of white wines, contributing to notes such as passion fruit, grapefruit, and herbal nuances [1]. These compounds, present as non-volatile precursors in grapes, require enzymatic activation to be released and realize their aromatic potential.

Read More

How pressing techniques affect must composition and wine quality of Pinot blanc

This study investigates how the sensory profile of Pinot Blanc is affected from different maceration and pressing techniques. Grapes were sourced from four vineyards in the village Tramin in South Tyrol. For the experiment 200 kg of grapes from each vineyard site were hand picked the day before harvest for the commercial winery took place. Grapes were stored over night at 4°C, homogenized and processed in the experimental winery at Laimburg research centre the day after harvest. Four different pressing techniques were applied in duplicates of 100kg each.

Read More