Application of SPE for selective fractionation of essential oils constituents from plant materials

Solid-phase extraction (SPE) is simple and inexpensive sample preparation procedure which can be applied for the isolation/fractionation of essential oil compounds from wide variety of samples, such as foodstuffs, biological and environmental. Due to the complex nature of the examined matrices and frequently low concentration level of target components, analytical procedures require the use of initial sample preparation stage. The paper shows the possibility of essential oil components fractionation from different plant materials using SPE method. The results presented in this paper shows that the proposed SPE procedure allows for easy and total fractionation of essential oil constituents (especially low-molecular oxygen compounds) from the sample matrix

Isomerization of bitter acids during the brewing process

Beer is the world's oldest and most widely consumed alcoholic beverage. The transformation of bitter acids to iso-α and iso-ß-acids is recognized as the key step of beer production. The paper shows and discusses the transformation kinetics of α- and ß-acids into their iso-form. Following the performed experiments, the largest amounts of the bitter acids isomers are formed in the brewing process carried out at 80oC for more than 100 minutes. The presented data are in good agreements with the knowledge of experienced brewers who learned about the brewing process relying on sensory tests