3 Basic chemistry and process conditions for reaction flavours with particular focus on Maillard-type reactions

Maillard reaction technology is used by the flavour and food industry for the production of process/reaction flavours or generating flavour upon food processing (in-process flavour generation). Process flavours are complex building blocks that provide similar aroma and taste properties to those found in thermally treated foodstuffs such as meat, chocolate, coffee, caramel, popcorn and bread. The Maillard reaction between a reducing sugar and a food-grade nitrogen source is the principal underlying reaction, which is responsible for flavour and colour development. However, Maillard-type reactions may also give rise to undesirable molecules that need to be limited using mitigation concepts. This review provides a summary of general aspects of the Maillard reaction in flavour formation in view of reinforcing distinct desirable flavour notes. An overview of important aroma compounds of thermally treated foodstuffs and process flavours is given. In addition, the patent literature and other publications relating to reaction flavour production and their process conditions are discussed. This chapter focuses on Maillard-type reactions and only partially deals with other reactions occurring during process flavour preparation (e.g. lipid oxidation).