BIOCHEMICAL CRITERIA OF BREWING EVALUATION OF AROMATIC HOP VARIETIES

With the expansion of the assortment of beer, brewers increasingly use different hop products of new varieties of hop, that makes it possible to obtain beer with certain profiles of taste and aroma. The comprehensive assessment of the quality of hop pellets Type 90 produced in Ukraine and European countries and that are most demand by Ukrainian beer producers were conducted. It made possible to form a database of biochemical characteristics of fine aromatic and aromatic varieties based on the absolute values of such indicators as the mass fraction of alpha-acids and beta-acids (with including their chemical composition), xanthohumol, essential oil and its components and the ratio of certain valuable hop compounds. The mass fraction of alpha-acids in hop pellets of fine aromatic varieties was ranges from 2.7% in the Hersbrucker variety to 5.3% in the Slavianka variety. A higher indicator of the content of alpha-acids was found in the pellets of the aromatic varieties Zagrava and Tradition with a range of variation of the indicator from 4.6 to 7.2% (average values are 5.9 and 6.0%, respectively). The content of beta-acids in the studied pellets ranges from 3.6% (Lublin) to 6.6% in the pellets of the Slavianka variety. The among the studied pellets in the composition of bitter substances the proportion of beta-acids is equal or exceeds the proportion of alpha-acids. As a result, they save a positive aromaticity ratio between the content of beta-acids and alpha-acids, that ranges from 0.99 (Lublin) to 1.84 (Hersbrucker). In the samples of hop pellets that was studied there is significant variability in the essential oil content with average values from 0.49 (Klone 18) to 1.64 ml/100 g in Zagrava hop pellets. The general components of essential oil of hops are hydrocarbons that are represented by monoterpenoid - myrcene and sesquiterpenoids: caryophyllene, humulene and farnesene, that collectively set up from 66.6% to 78.8% of their total amount. Biochemical criteria for brewery assessment of hop varieties of the aromatic type have been determined and scientifically substantiated. The main ones are the content and composition of bitter substances, in particular: alpha-acids and beta-acids with an indicator value in the range of 4–9%; the ratio between the number of beta- and alpha-acids is about 1; the mass fraction of cohumulone in the composition of alpha-acids is up to 28%; the amount of essential oil per 1 g of alpha-acids is within 0.20–0.25 ml in the presence of a significant amount of sesquiterpenoids. The amount of farnesene in the composition of the essential oil was within 10–20%, the content of prenylated flavonoids, in particular xanthohumol, was at least 0.4%. A new hop variety Perlyna with characteristics that requirements the specified criteria is presented. Expanding the assortment of hop products due to the formation of highly productive hop plantations of new varieties with defined characteristics is an important prerequisite for ensuring a sufficient level of competitiveness of Ukrainian hop products on the world market.