|DUKE, STANLEY - UNIV WI--AGRONOMY
Submitted to: American Society of Brewing Chemists Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2003
Publication Date: 8/1/2003
Citation: HENSON, C.A., KARPELENIA, C.B., DUKE, S.H. ASSESSMENT OF VARIATION BETWEEN COMMERCIAL MALTS USING STANDARD AND NONSTANDARD MEASUREMENTS OF MALT QUALITY. BREWERS DIGEST. 2003. V. Abs. #.
Technical Abstract: The ability to use analytical measures of malt quality to discriminate among elite malting cultivars based on brew house performance is desirable. This study was designed to determine relationships between measurements and to determine which measurements best characterize the variation among commercially made malts. A total of 31 parameters were examined. Nine were standard malt quality parameters. Additionally, we determined work RDF values and the activities and thermostabilities of alpha-amylase, beta-amylase, limit dextrinase and alpha-glucose during starch conversion at 63 degrees F. Linear regression, used to examine the relationships between parameters, showed that RDF was positively and significantly correlated with only two parameters - % soluble/total protein (S/T) and the thermostability of alpha-glucosidase. Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were used to determine what measurements describe the variation in the malts. PCA and HCA revealed that use of the nine standard malt quality parameters plus RDF grouped the malts according to head type but did not group malts based on RDF values. PCA and HCA using all 31 parameters grouped the malts according to head type and grouped the malts according to whether they produced high or low RDF worts. The principle component that grouped the malts as high or low RDF producing malts was defined by 11 parameters and only two were standard measures of malt quality. The other nine useful measurements were beta-amylase activities at all time points during starch conversion and the thermostability ratios of all four carbohydrates.