Využití metody UHPLC-ESI/MS/MS pro stanovení polyfenolických látek typu stilbenů
This paper deals with the determination of cis-/trans- resveratrol and piceid in the cake formed from the grape seeds by introducing and testing of the UHPLC-ESI/MS/MS method. The cake is a solid residue remaining after pressing oil from grape seeds. It is a waste product in viticulture, which can be used for the extraction (isolation) of resveratrol, or as a dietary supplement for cattle. Samples were selected from the harvests of 2012 and 2013 from two different locations in the Czech Republic: Prague-Grébovka and Mělník.
First results indicate that the concentrations of analytes are varietal dependent and affected also by the location and the year of the harvest. The highest levels of cis- and trans-resveratrol were found in the cake of Pinot Noir and Zweigeltrebe variety. The values of trans-resveratrol obtained for 2012 and 2013 in Pinot Noir variety were 17.1 ± 1.7 μg g–1 and 24.4 ± 1.6 μg g–1, respectively, in cis-resveratrol 3.3 ± 0.1 μg g–1 and 6.4 ± 0.3 μg g–1 respectively. The values of trans-resveratrol obtained for 2012 and 2013 in Zweigeltrebe variety were 15.4 ± 0.2 μg g–1 and 14.8 ± 1.5 μg g–1, respectively, in cis-resveratrol 2.1 ± 0.1 μg g–1 and 2.1 ± 0.2 μg g–1, respectively. Both varieties have grown in Mělník.
The highest content of trans-piceid was found in the cake of Hibernal variety (3.9 ± 0.2 μg g–1) from the harvest of 2013. The highest content of cis-piceid was determined in the cake of Dornfelder variety (2.5 ± 0.1 μg g–1) grown in Prague-Grébovka in 2013.