Red wine astringency: correlations between chemical and sensory features
Astringency is a crucial sensory attribute typically described as the drying and/or puckering sensation occurring after the consumption of tannin-rich foods and beverages. In this study, thirty-seven red wines from different varieties, origins and styles were evaluated, analyzing both chemical and sensory features. Principal Component Analysis was used for dimensionality-reduction and for correlating selected chemical parameters against astringency. The results showed that tannin content was the most important chemical parameter influencing overall astringency but more clearly the dryness sub-quality, followed by pH, titratable acidity and alcohol content.
On sample preparation methods for fermentative beverage VOCs profiling by GCxGC-TOFMS
Study the influence of sample preparation methods on the volatile organic compounds (VOCs) profiling for fermentative beverages by GCxGC-TOFMS analysis. METHODS: Five common sample preparation methods were tested on pooled red wine, white wine, cider, and beer. Studied methods were DHS, Liquid-liquid extraction, mSBSE, SPE and SPME. VOCs were analyzed by GCxGC-TOFMS followed by data analysis with ChromaTOF. RESULTS: The volatile organic compounds (VOCs) profiling results were very dependent on the sample preparation methods.
Kinetic study of browning caused by laccase activity using different substrates
To our knowledge all the studies about laccase kinetics and its inhibition have been performed with substrates and conditions very different from those of real grape juice. Moreover, none of these researches really measure enzymatic browning, since they have not taken into account what happens after the oxidation of o-diphenols in o-diquinones and their subsequent polymerization to form melanins1. For that reason, the aim of this research was to develop a new model to measure the kinetics of browning caused by Botrytis cinerea laccase under conditions much closer to those of grape juice and using the substrates naturally present in it.
Adsorption capacity of phenolics compounds by polyaniline materials in model solution
The aim of this work was to study the trapping capacity of four polyaniline polymers towards phenolic compounds in wine-like model solutions. METHODS: The model wine solution was composed of 12% (v/v) and 4 g/L of tartaric acid adjusted to pH = 3.6. A series of centrifuge tubes (15 mL) were filled with 10 mL of model solution enriched with 50 mg/L of five phenolic compounds (i.e., Gallic acid, caffeic acid, (+)-catechin, (-)-epicatechin, and rutin), and treated with different doses of PANI polymer (i.e., 0, 2, 4 and 8 g/L). After the addition of the polymer, the samples were stirred using a platform shaker at room temperature (20 ºC) for 2, 8, 16 and 24 h. All treatments included three replications.