Abstract: This article determines the malt culture medium, YEPD culture medium, fermentations & Xihu beer formaldehyde content by Acetylacetone Spectrophotometric Method (ASM). Analysis the solution of formaldehyde Mechanism in fermentation. Screen low-formaldehyde mutagenesis through protoplast UV. The experiments indicate that, the logarithmic Saccharomyces cerevisiaes in 2.5% snails enzymes, hydrolysis 180 min in 30℃, protoplast rate approaches 90%, & UV-induced conditions :the ultraviolet light irradiation of 25W, Mutate 2min to make the protoplast death rate more than 80%, & the reproducibility is 5.6% in RYEPD plate. Determines the formaldehyde content of fermentation get NO.4 purpose strain. The formaldehyde content in beer lower than the ordinary one. The research in this paper offered a reliable analytical method and the researching direction of low—formaldehyde beers.
Keywords: Saccharomyces cerevisiaes; Protoplast mutagenesis; Formaldehyde
