Banca de DEFESA: ELISANDRA NUNES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ELISANDRA NUNES DA SILVA
DATE: 11/09/2024
TIME: 14:00
LOCAL: Campus Bento Gonçalves IFRS
TITLE:

ION EXCHANGE RESIN IN RED WINES FOR PH REDUCTION AND PROCESS IMPROVEMENT

KEY WORDS:

ion exchange resin; stable wine; guard potential

PAGES: 91
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Tecnologia de Alimentos
SPECIALTY: Tecnologia das Bebidas
SUMMARY:

In the oenological field, there are several discussions on how a process can help reduce time and investment while increasing the quality of a wine, especially if it is a fine wine with aging potential. Many factors can contribute to this aspect, one of which is pH, responsible for improvements ranging from color to taste in a wine. The relationship between acidity and pH is inverse; when one is high, the other is consequently low. Currently, pH correction is mostly done by adjusting acidity through the addition of tartaric acid, which is already naturally found in grapes. However, each grape has a buffering capacity. Determining the ideal dosage for this addition requires laboratory analysis, which is not commonly done on a large scale, potentially leading to pH imbalance in the wine, altering its microbiological stability and, consequently, the correction of sulfur dioxide and tartaric stabilization. An alternative gaining ground in the oenological field is the use of ion exchange resins, capable of capturing potassium and releasing hydrogen into the solution, thereby lowering the wine's pH. Thus, the following study aims to combine the process of pH reduction in three different red wines from different regions of RS with a 20% passage through red wine resin to lower the pH and evaluate its results in the 2022 and 2023 harvests, assessing parameters of physicochemical, mineral, and sensory analyses. In the study, it was possible to evaluate that the behavior of the 2022 vintage wine was similar to that of the 2023 vintage, with some differences that could be attributed to the climate of the regions, where, in general, 2023 was a rainier year than 2022. It was observed that the pH reduction resulted in overall improvement in color, as assessed by IPT analysis, color intensity, and absorbances at 420, 520, and 620 nm, an increase in total acidity and free SO₂ present, contributing to a decrease in preservative addition when considering the relationship between pH and molecular SO₂. In terms of minerals (Mg, Cu, Zn, Ca, Na, and K), a decrease was also observed in wines treated with resin, which, in summary, demonstrates an improvement in the stability of these wines, especially for their subsequent aging. Sensory-wise, wines from both vintages did not show statistically significant differences overall. This can be considered a positive result because although there were no sensory improvements, there was also no detriment from the treatment to the wines. In conclusion, the main objective of the study was achieved, demonstrating the effectiveness of applying a technique to lower the pH of red wines.

COMMITTEE MEMBERS:
Presidente - 465.179.280-49 - VITOR MANFROI - UFRGS
Interno - 2858683 - LEONARDO CURY DA SILVA
Interno - 1356958 - EVANDRO FICAGNA
Externo à Instituição - WILLIAN DOS SANTOS TRICHES