Available online at http://journal-of-agroalimentary.ro Journal of Agroalimentary Processes and Technologies 2012, 18 (3), 229-235 Journal of Agroalimentary Processes and Technologies ___________________________________________ * Corresponding author: e-mail: tofanam@yahoo.com Optimization of ITEX/GC-MS method for beer wort volatile compounds characterisation Delia Michiu, Maria Tofană*, Sonia A. Socaci, Elena Mudura, Liana C. Salanță, Anca C. Fărcaş Univeristy of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, Mănăştur Street 3-5, Cluj-apoca, Romania Received: 10 July 2012; Accepted: 2 August 2012 ______________________________________________________________________________________ Abstract In order to characterize the Magnum hop variety volatile profile in beer wort, we determined the composition of volatile compounds during the main fermentation process of beer wort using the ITEX/GC- MS technique. An Shimadzu GC/MS-QP 2010 equipment was used for samples analysis. For a better extraction of volatile compounds by ITEX-GC-MS of the testing vial and to avoid the saturation of the detector, parameters like quantity of sample, injection volume, incubation temperature, incubation time, split ratio, scan range, start time, total flow, column temperature, column flow, were optimized. The major compounds founded in wort beer samples, during the primary fermentation, were derived from a vast array of compounds that arise from a number of sources. In this way, we founded different categories of secondary products: higher alcohols, esters, organic acids and aldehydes. The chemical constituents of the beer wort were separated and identified using the GC-MS NIST libraries. Keywords: volatile compounds, wort beer, ITEX /GC-MS, method optimization ______________________________________________________________________________________ 1. Introduction Hop cultivation began in Bavaria (Hallertau) and Bohemia (Saaz) in the 8th and 9th centuries, and because of their superior anti-bacterial properties, at some time later hops became the standard flavouring and bittering agent for beer all over Europe and the world. Today there are many varieties of hops and a number of hop products are used either alone or in combination to produce an enormous range of different hop flavours [1]. Hops are rich in flavour compounds, which give beer its typical flavour. However, the majority of these compounds are largely evaporated during boiling. Linalool is often used as an indicator for the presence of hop aroma compounds. Before wort is converted to beer by brewer’s yeast, it undergoes several process steps that influence the quality of the end-product. These process steps include mashing, lautering, boiling, trub separation and cooling. The boiling process serves many purposes, from which conversion of hop bitter substances might be the most known. However, it is equally important to control the levels of flavour constituents in wort, because they can have a major impact on the final beer flavour and the flavour stability of the beer. Due to the high temperature while boiling, the rate of several chemical reactions increases markedly [2]. During the alcoholic fermentation of wort, in addition to the major products of ethanol and carbon dioxide, the yeast Saccharomyces cerevisiae, excretes a wide range of flavour compounds including higher alcohols (also called fusel oils), esters, carbonyls, sulphur compounds, organic and fatty acids, and a number of miscellaneous compounds. The production of these compounds