Acrylamide in Bread

1
Acrylamide in Bread

• Routes for intervention?

Gareth Edwards
2
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

3
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.

4
Fermentation

• Yeast fermentation of dough can help to reduce
  asparagine levels by gt90 (depending on proof
  time and yeast type)
• Reduced asparagine levels are closely translated
  into lower acrylamide formation

5
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

6
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

7
Effect of Toasting Time
8
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