Extraction and identification by GC-MS of phenolic acids in traditional balsamic vinegar from Modena

Traditional balsamic vinegar from Modena (Aceto balsamico tradizionale di Modena, ABTM) is a typical Italian product obtained by a traditional method from grape must. As the chemical composition of this vinegar has not yet been fully investigated, the present work aims to develop a method for investigating the presence of biologically active compounds such as phenolic acids. The physico-chemical characteristics of ABTM required the development of a specific method for phenolic acid extraction. Different materials, such as diatomaceous earth cartridges for liquid–liquid extraction and polyamidic SPE cartridges, have been tested. The identification of phenolic acids in extracts of ABTM has been carried out using a GC/MS method after derivatization with bis(trimethylsilyl)trifluoroacetamide (BTSFA). The developed procedure allowed the identification in ABTM of nine phenolic acids, confirming also the presence of these natural antioxidants at the end of the process that transforms grape must into ABTM.