so that the yield of the process can be improved the final purification step may be carried out by any method such as distillation and or column chromatography accordingly compounds of the 2 1 alkoxyethenyl 1 pyrroline type can be obtained by this process and may be used for the production of encapsulated 2 acetyl 1 pyrroline it has also been found that one of the compounds of this type namely 2 1 ethoxyethenyl 1 pyrroline has certain organoleptic qualities which enable it to be used on its own or in combination as a flavouring agent these organo leptic characteristics may be described as grilled fruity hazel nuts and reminiscent of those of pyrazine thus 2 1 ethoxyethenyl 1 pyrroline may be used on its own as a flavouring agent for example as a substitute for certain alkyl pyrazines the quantity to be added to a food product depends primarily on the nature of the product and on the final effect required 2 1 ethoxyethenyl 1 pyrroline may also be used in the preparation of a flavouring composition for example a flavouring composition containing up to 0 1 by weight 2 1 ethoxyethenyl 1 pyrroline which has a flavour of corn bread or potatoes the composition thus obtained may be added to the end food product in a quantity of 1 to 2 grams per kilo end product the invention is illustrated in more detail in the following examples in which parts and percentages are by weight and wherein examples 4 and 5 illustrate two processes for the production of 2 acetyl 1 pyrroline in aqueous solution examples 6 to 9 illustrate three processes for the production of.