Kvasny Prumysl, 1993 (vol. 39), issue 6
Determination of bitter compounds from hop and hop extracts.Peer-reviewed article
J. KUBÍČEK, J. LOOS
Kvasny Prum. 1993; 39(6): 162-166 | DOI: 10.18832/kp1993011 
The results of analyses of resin fractions of bop and hop products using six different analytical methods according to Czech Standard 46 2520 and EBC Analytic, 4th Ed., 1987 are compared. Their mathematic-statistical evaluation was performed. The results prove, that it is necessary to replace the older variants of the Wollmer method, described in Czech Standard 46 2520 - Hop Analysis and in Brewing Standard 56 6604 - Hop Extract, by the more progressive Ganzlin modifications. With these new methods higher values of conductivity and those of α-acids determined by the HPLC method are obtained. The reason is on better extraction conditions of hop...
Practical application of the reaction of fermenting hopped wort with m-phenylendiamine.Peer-reviewed article
J. ŠAVEL, M. PROKOPOVÁ, D. ZDVIHALOVÁ
Kvasny Prum. 1993; 39(6): 166-169 | DOI: 10.18832/kp1993012
The test with m-phenylendiamine (m-FDA) is used for an investigation of the formation of nitrites during a fermentation. m-FDA is added into the inoculated hopped wort. During the fermentation of contaminated worts it reacts with nitrite formed and partially with some compounds of wort, too. The reaction of m-FDA with saccharides, phenols and other compounds such as ascorbic acid was proved. The m-FDA test should be performed together with the addition of an antibiotic, e.g. tetracycline hydrochloride. The quantity of the nitrite formation is given by the change of absorbance of both samples at 450 nm. This quick screening test is proper for a preliminary...