Comparison of biochemical characteristics of three Norwegian cheese varieties using multivariate statistical analysis

Proteolysis and concentration of organic acids were studied in the Norwegia n cheeses Norvegia, Jarlsberg and Sveitser cheese. Statistical analyses wer e introduced to evaluate the results. There was no significant difference i n water soluble nitrogen as percentage of total protein nitrogen between th e cheeses, however, the free amino groups of the phosphotungstic acid solub le fractions, analysed by an o-phthaldialdehyde assay, differed significant ly. Capillary electrophoresis of the 0.5% trichloroacetic acid (TCA)- and 7 0% ethanol soluble fractions showed, as illustrated by principal component analysis, differences in the peptide profiles. However, this was not found by reverse phase chromatography of the 0.5% TCA-soluble fraction. Concentra tions of organic acids showed a significant effect of propionibacteria in J arlsberg and Sveitser. The biochemical differences appeared to reflect the differences in starter and adjunct starter cultures used for the 3 cheese t ypes.