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42 WINES&VINES April 2017 BARRELS PRACTICAL WINERY & VINEYARD Sanitary Stainless Welding Inc. is the exclusive North American distributor for the Marzola product line der, soaked in model solution and analyzed by U-HPLC coupled with Fourier Transform Mass Spectrometry (FTMS). 25 Four compounds were quantified in oak extracts: QTT I, QTT II, QTT III and Glu-BA. The quantifica- tion method was validated by studying sensitivity, linearity in working range, intraday repeat- ability, interday precision, true- ness and specificity. Genetic discrimination of oak samples: Fresh leaves were used to facilitate DNA extraction. Among 46 samples analyzed in this study, 27 were assigned to Q. pe- traea (sessile oak) and 19 to Q. robur (pedunculate oak). Both spe- cies were found in some forests (Tronçais and Liffré), confirming that geographic origin is not in it- self a relevant element to discrimi- nate sessile and pedunculate oak. Triterpenoids determina- tion in oak wood samples: The method developed in this study was applied to quantify for the first time QTT I, II and III in oak. The glucosyl deriva- tive of bartogenic acid (Glu-BA) was concomitantly measured. The four considered triterpe- noids were observed in all sam- ples, and all the concentrations were measured above their limit of quantification. For each compound, the re- sults showed a wide range of con- centration with more than four orders of magnitude (0.7-1,102.5 µg/g for QTT I; 0.7-1,418.5 µg/g for QTT II; 1.2-1,408.7 µg/g for QTT III and 3.2-1,952.0 µg/g for Glu-BA). Samples with high con- tent in QTT I seemed, to a large extent, also rich in QTT II and QTT III and reciprocally. Pearson tests were realized on the 46 sam- ples and exhibited correlations between QTT I and QTT II (R² = 0.76), QTT I and QTT III (R² = 0.74), QTT II and QTT III (R² = 0.77) with p-values less than 0.1% for each pair. All these correla- tions were positive, suggesting a similar biosynthetic pathway for these compounds. In contrast, the overall rela- tion between Glu-BA and QTTs concentration appeared more complex. Pearson's test was sig- nificant (p-value less than 0.1%), but with a weak negative correla- tion (R² = 0.25 with QTT I; R² = 0.13 with QTT II, and R² = 0.20 with QTT III) sessile oak samples appeared as being rather rich in QTT I and rather poor in Glu-BA, whereas pedunculate oak sam- ples seemed to be rather poor in QTT I and rather rich in Glu-BA. No compound was species-spe- cific: All triterpenoids were pres- ent in all samples. To observe more precisely the relationship between the triter- penoids composition and the botanical species, the mean con- centration of the quantified com- p o u n d s w e r e c a l c u l a t e d f o r sessile (n = 27) and pedunculate ( n = 1 9 ) o a k s a m p l e s ( s e e "Mean Concentrations of QTT I, MEAN, MINIMAL AND MAXIMUM VALUES OBSERVED IN SESSILE AND PEDUNCULATE OAK Sessile oak (n=27) Pedunculate oak (n=19) Mean value Min. Max. Mean value Min. Max. QTT I a 413.5 ± 255.1 33.2 1,102.5 6.0 ± 2.7 0.7 22.5 QTT II a 379.5 ± 141.1 23.6 1,418.0 9.1 ± 5.0 0.7 44.1 QTT III a 543.8 ± 149.5 64.1 1,408.7 8.5 ± 3.8 1.2 28.1 Glu-BA a 24.4 ± 10.7 3.2 105.5 795.3 ± 271.3 36.0 1,952.0 TI b 1.9 ± 0.1 1.2 2.4 - 1.5 ± 0.2 - 2.2 - 0.8 a Concentrations in QTT I, QTT II, QTT III and Glu-BA were expressed in µg/g of dry wood. b TI: Triterpenoids Index (adimensional). [QTT I] + [QTT II] + [QTT III] [Glu - BA] TI = log