Razvoj enzimskog potencijala različitih namjenskih sorti ječma tijekom slađenja | Development of enzyme potential in different purpose barley varieties during malting

Croatian. Razvoj enzimske aktivnosti zrna ječma tijekom procesa slađenja je jedno od ključnih zbivanja kojom se osigurava zadovoljavajuća tehnološka kvaliteta slada. Brojna istraživanja su provedena na ovu temu kojima je ustanovljeno da se najbolji rezultati vezani za razvoj enzimskog potencijala zrna osiguravaju slađenjem namjenskih, jarih, dvoredih pivarskih sorti uz odgovarajući režim slađenja kojim se osiguravaju procesni uvjeti koji pogoduju aktiviranju već u zrnu prisutnih i/ili de novo sintezi enzima. Cilj ovog istraživanja bilo je ustanoviti kako s obzirom na gore postavljene zahtjeve reagiraju različite namjenske, dvorede, jare i ozime sorte ječma koje se uobičajeno koriste za proizvodnju slada u Hrvatskoj. Temeljem dobivenih rezultata ustanovljeno je aktivnost α-amilaze u svim ispitivanim sortama bila je unutar, dok je aktivnost β-amilaze u sve tri sorte bila je viša od standardnih vrjednosti za svijetli slad. Oba enzima su pokazala najvišu aktivnost zadnjeg, četvrtog dana klijanja. Proces sušenja slada značajno više smanjuje aktivnost β-amilaze (25-30%) nego α-amilaze (oko 10%). Utvrđivani su i ostali pokazatelji kvalitete polaznih ječmova, procesa mikroslađenja i gotovih sladova. Ustanovljeno je da sve tri sorte daju svijetli pivarski slad vrlo dobre kvalitete. Neki pokazatelji kvalitete slada poput topljivog dušika u sladovini i viskoznosti su imali izvrsne vrijednosti, najproblematičniji pokazatelj je bila fiabilnost. Međutim, kako je friabilnost kumulativni pokazetelj na koji utječu brojni pojedinačni faktori ovo zahtijeva dodatna istraživanja.

English. The development of enzymatic activity of barley grains during the malting process is one of the key developments which ensures satisfactory technological quality of malt. Numerous studies have been conducted on this topic, which found that the best results related to the development of enzymatic potential of grain are a result of malting purpose, spring, two-row brewing varieties. The application of appropriate malting regime that ensures process conditions favaurable for te activation of already present in the grain and/or de novo synthesis enzymes are also an important factor. The aim of this research was to establish how different purpose, two - row, spring and winter varieties of barley, which are commonly used for malt production in Croatia, react to the above requirements. Based on the obtained results, the α-amylase activity in all examined cultivars was found to be within the standard values, while the β-amylase activity in all three cultivars was higher than the standard values for light malt. Both enzymes showed the highest activity on the last, fourth day of germination. The malt drying process significantly reduced β-amylase activity (25- 30%), in comparison to the activity of α-amylase (about 10%). Other indicators of the quality of starting barley, micromalting process and finished malts were also determined. It was found that all three varieties give light malt approprite for malting, reulting with malt of very good quality. Some malt quality indicators such as soluble nitrogen in wort and viscosity had excellent values, and the most problematic indicator was fiability. However, as friability is a cumulative indicator affected by a number of individual factors this requires further research.