Relationship between sensory and instrumental analysis of 2,4,6-trichloroanisole in wine and cork stoppers

The effect of different corks stoppers on the sensory and instrumental determination of 2,4,6-trichloroanisole (TCA) was studied in wine and cork. A relationship between both measurements was also established. Four types of cork were used to seal white wine bottles for 8 months. The stoppers were from different raw material: a high quality commercial batch (C), slabs with yellow stain (YS) and slabs with a high musty and mouldy taint (T). Spiked samples (S) were prepared from C batch by injecting 1002 ng of TCA into the cork stoppers. TCA was determined by gas chromatography with electron capture detection after headspace solid phase microextraction in bottled wine (12 per group) and after extraction with pentane in the case of corks (six per group). Seven semitrained assessors evaluated the different samples using a ranking test in 12 and six sessions for wine and cork stoppers, respectively. Wines and corks from S samples showed the highest TCA values in both sensory and instrumental measurements, the lowest values being for C samples. YS and T corks had intermediate values, although in general TCA concentration was higher in T. A slight tendency to increase the TCA content in stoppers with yellow stain compared to C samples was observed in wine. A high correlation coefficient (r=0.82) was found between sensory and instrumental analysis for wine, whereas this coefficient was much lower (r=0.56) for cork stoppers. Some hypotheses are given in order to explain these differences.