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Linoleic and linolenic acid hydroperoxides in malt, mash, or wort were determined with high sensitivity and high selectivity by the chemiluminescence-high performance liquid chromatography (CL-HPLC) method using isoluminol-microperoxidase solution as a luminescing reagent. The determination limit of this method for both hydroperoxides was 0.1 iM in mash or wort. During the mashing in a laboratory mash bath, the hydroperoxides started to increase just after mashing-in, reached a maximum at 65°C, and then decreased. Though the hydroperoxides were detected in mash just before the lautering in a pilot scale brewing, they disappeared during the lautering and could not be detected during the sub sequent stages of wort production. Therefore, it was thought that the mashing process is the most important of the lipid oxidation reactions during wort production. It is also expected that the CL-HPLC method can give useful information on lipid oxidation mechanisms during wort production.

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Oxidative reactions during beer pasteurization were studied using chemiluminescence (CL) and electron spin resonance (ESR) analyses. The CL production of beer was accelerated by pasteurization and the maximum CL intensity appeared sooner than that in non-pasteurized beer. Beers pasteurized with 15-30 pasteurization units (P.U) had the same CL producing activities as the non-pasteurized beers stored at 20°C for 6-10 days. Free radicals were produced and some of them were consumed by beer oxidation during pasteurization. It seems that free radical reactions occur in beer during pasteurization and that the degree of oxidation during pasteurization generally corresponded to that of non-pasteurized beer stored at room temperature for about 1 week.