Acrylamide in Bread. Routes for intervention?. Gareth Edwards. What is Bread?. Huge differences between types of bread across EU countries: Mainly white wheat breads in UK and France Dark rye breads in Scandinavia and Central Europe Mixed base in Germany: predominantly wholegrain products
Acrylamide in Bread Routes for intervention? Gareth Edwards
What is Bread? • Huge differences between types of bread across EU countries: • Mainly white wheat breads in UK and France • Dark rye breads in Scandinavia and Central Europe • Mixed base in Germany: predominantly wholegrain products • Wide range of sizes, shapes and baking conditions
Reaction Parameters • Predominantly reaction between asparagine and reducing sugars • Asparagine level is usually the controlling factor • Influence of raising agents, e.g., Ammonium bicarbonate? • High temperature and low moisture promote formation in crust but not in crumb.
Fermentation • Yeast fermentation of dough can help to reduce asparagine levels by >90% (depending on proof time and yeast type) • Reduced asparagine levels are closely translated into lower acrylamide formation
Distribution of Acrylamide • Highest AA concentration in the outermost layer of the crust • Moderate concentrations in lower part of crust • Very low levels in the crumb • “Lidding” of the loaf during baking can reduce AA formation by increasing moisture in the surrounding atmosphere, but • Crust quality is changed, which affects product characteristics and consumer acceptance
Toasting • Significant increase in AA levels by toasting, with clear time/temperature dependence • Bread should be toasted to light colours, and burning should be avoided
Risk/Benefit? • Lower protein (asparagine) content of bread is associated with lower acrylamide. • Choice between white bread with low AA levels and wholegrain breads with comparatively higher AA levels but additional nutritional benefits, e.g., more fibre • Overall, levels of Acrylamide (AA) in bread are at the lower end of the range