DETERMINATION OF ANTHOCYANOGENS

Abstract

Investigation of the nylon method for determining the anthocyanogen content of beer has shown that the addition of small amounts of iron or copper to the beer or to the reagents, usually, although not always, intensifies the colour and hence increases the apparent anthocyanogen content of the sample. Evidence is presented to show that the iron and particularly the copper content of beer and/or the reagents could vary enough to influence the results; hence the nylon method has been modified by the addition of iron to the reagents. An alternate method is described in which an insoluble polymer of n-vinylpyrrolidone (Agent AT) is employed as the adsorbent and the colour reaction is carried out with n-methyl-2-pyrrolidone as the solvent. This solvent will completely elute the anthocyanogens from the adsorbent. A modification of this procedure is described which can be carried out without a continuous shaking machine or a high-speed centrifuge.