Estudo da síntese de um análogo de alfa-ácido presente em lúpulo e correlação do comportamento eletroanalítico com o amargor da cerveja

Abstract

Although hops were initially used as a preservative in beer, it introduced bitterness and a pleasant taste to it, which is why its acceptance was great and thus replaced other raw materials previously used in the drink. The characteristic taste is due to essential oils and resins found in the lupulin glands. The α-acids from resins are the most interesting to the brewing industry. During boiling in the process of obtaining the beverage, α-acids are isomerized in iso-alpha-acids, conferring the typical bitter taste. The purpose of this work was to synthesize the 2,4-diacetyl-3,4-dihydroxy-5-methylcyclopent-2-anone molecule to be used how analytical standard in the quantification of hop from beer, since this standard is not found for sale. Therefore, it would be an alternative for the analysis of the α-acids, which currently has a high cost, and on the other hand, the microbreweries are in full expansion in Brazil, the analysis of α-acids would be more accessible to these companies by techniques with low cost, high accuracy and ease and speed in results. So far the molecule has not been fully synthesized. It is not yet possible to show the results obtained from bitter quantification. However, the work shows that hop extract, as well as a beer with a high degree of bitterness (IBU: 100), presented oxidative phenomena. The hops presented oxidation potential by pulse voltammetry at +1.16 V, while beer at +1.20 V. This difference occurs due to the presence of the alpha-acids being isomerized in beers. Through the mass spectrometry analysis it was possible to confirm this difference in composition between the hop extract and the beer.