An investigation on molecular partition of aroma compounds in fruit matrix and brine medium of fermented table olives

Abstract

Abstract Aroma is considered as a quality index of olive products. Fermented olives aroma compounds are present both in the fruit matrix and in brine medium. The partition of aroma compounds between fruit matrix and brine medium is deeply different for the two and depends on several factors such as carbon chain length and/or branching, number of polar groups, sodium salt concentration, temperature, etc. In this work, an investigation on volatile compounds quali-quantitative partition in fruit matrix and in brine medium of Greek-style Carolea and Nocellara del Belice table olives has been assessed. Volatile compounds have been extracted by using headspace method for olive fruit and by solvent extraction and distillation for brine medium. Twenty-three volatile compounds in fruit matrix and fifteen aroma molecules in brine medium have been identified by Gas Chromatography and GC/Mass Spectrometry. Results showed that most volatile organic compounds had a major affinity for the fruit matrix depending both on the chemical characteristics of the molecules (chain length and branching, polar or no polar groups, etc.) and on the “salting out” effect due to high NaCl concentration of the brine, which brought aroma compounds to hydrophobic phase of the olive fruit. Industrial relevance The study could be potentially helpful to develop analytical methods in order to estimate the quail-quantitative composition during the fermentation process. So that it would be possible to implement automatic analytical procedures in the currently used plants for the industrial production for table olives. Furthermore, this study allow us to identify off-flavours formed by anomalous fermentation process, in order to reveal them (both in the fruit and in the brine) in premature times (just in small traces), so to obtain the fermentation process recovery.