McFarlane, W.D.

Abstract
The recognition of trans 2 nonenal as an important contributor to the 'cardboard' flavour of stale beer has led many investigators to isolate and further characterise this carbonyl from stale beer using various techniques. Although conclusive proof is not yet available, evidence supports the theories of precursor formation from an enzymatic oxidation of linoleic acid ultimately resulting in the formation of 2 nonenal and oxidation of unsaturated long chain fatty acid ethyl esters. A table listing sensory properties of 2 nonenal in various systems is given.
Keywords: beer carbonyl compound flavour 2 nonenal off flavour staling