WW JT 19-02
Dr Jose-Luis Aleixandre-Tudo
South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Stellenbosch University
The extraction of phenolic compounds during the fermentation process is influenced by many factors. Temperature, punch down and pump over frequencies, oxygen addition through aeration or micro-oxygenation, the presence or absence of skins, cold and post maceration techniques, among others, can promote significant changes in the levels and the composition of phenolic compounds in the resulting wines. The analysis of fermenting samples using conventional methods, such as spectrophotometric approaches or HPLC analysis, is nowadays not always possible due to time, personnel, facilities or budget
constraints. The use of spectroscopy with chemometrics would provide a rapid, reliable and simple way of monitoring the extraction of phenolic compounds during this process. This technique also allows for the determination of several analytes or parameters at the same time. Additionally, infrared spectroscopy is also highly suitable for on-line measurements, leading possibly to a real time fermentation monitoring system that would help winemakers in their everyday decision making. The inclusion of alerts will indicate if the obtained values are above or below the specified limits. It will thus be possible to quickly identify deviations from the ideal or projected conditions by following a batch processing strategy. The main objectives of the project would thus be firstly, to set up an on-line infrared system for the monitoring of fermentation processes and secondly to assess whether the system can distinguish between phenolic changes brought about by different winemaking techniques.