LOX activity and different fractions of hydroxy fatty acids as well as their molecular stability in barley and malt

摘要

A great range of barley and malt samples was analysed with regard to total LOX activity and free and triglyceride-bonded hydroxy fatty acid fractions using new developed GC/MS techniques. The factors barley variety, provenience, storage time, germination, and kilning were evaluated with regard to the concentration of free and triglyceride-bonded hydroxy fatty acids. Furthermore the molecular stability of pure hydroxy fatty acid fractions concerning different pH levels and temperatures was studied in detail. This is of special importance because the role of those lipids as precursors of flavour active carbonyls in beer is still unknown.