WINETECH Technical Yearbook 2020

FIGURE 2. Methodology of the thiols in red wine project.

Analysis. Dr Jeanne Brand gave a detailed description of the PM sensory method in a previous issue of WineLand (April 2016). Figure 2 better illustrates the methodology of the experiment and it can be explained as follows. The study was broken down into three parts: • Experiment 1 (single thiol effect) was designed to assess the relevance of individual thiols at different con­ centration levels in four red wine cultivars. • Experiment 2 (thiol x thiol interaction) helped us evaluate the interaction

between these thiols taking as example Pinotage as base wine. • Lastly, to determine the interaction between thiols and different red wine matrices, Experiment 3 (thiol x matrix interaction) was performed in the same four red wine cultivars as Experiment 1. In Experiment 1, to generate specific attributes for 3MH, 3MHA and 4MMP, three levels of each thiol (zero, medium and high) were considered for spiking. De- aromatised wines from various cultivars (Pinotage, Cabernet Sauvignon, Shiraz and Merlot) were used as base. Each compound was spiked individually and the resulting samples evaluated.

DR JEANNE BRAND FIGURE 1. A photographic display of the process of Projective Mapping.

wines in relation to each other by placement of samples according to their similarity/ dissimilarity on a 2D surface. At the same time, individual profiles were obtained using the descriptors given by the judges for each wine (figure 1). This cost-effective method

has been used extensively and successfully to evaluate food products and beverages. Furthermore, it gives the possibility to assess a relatively large sample set, not always possible with more traditional and expensive methods, such as Descriptive

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