Enzymes and bread flavor

Enzymes used in breadmaking and their influence on bread flavor are reviewed. Components of bread flavor originate from fermentative and thermal reactions. Enzymes provide precursors for both processes, and their influence should be controlled. Enzymes are now replacing other improving additives in breadmaking, indirectly affecting bread flavor. Amylases produce reducing sugars, which are (1) fermentable substrates for fermentative microflora leading to numerous aromatic compounds, those of lower volatility remaining in bread, and (2) precursors of many components (mainly carbonyls) after reacting with amino acids in nonenzymatic browning reactions. Proteases produce peptides and amino acids, which, like sugars, participate in metabolic and thermal reactions and can occasionally be a source of bitter peptides. Lipoxygenase from soy or faba flour, used in some breadmaking processes, gives unstable products decomposing to carbonyl compounds generating off flavors in bread. In addition, the ingredients, the breadmaking process, and the baking conditions modify enzymatic activity and bread flavor.