In Britain today, around 80% of the bread we consume is manufactured using the Chorleywood Bead Process (CBP). This process, invented in 1961, enabled the use of lower-protein wheat and dramatically reduced the manufacturing time.
The Chorleywood process used a cocktail of fats, flour treatment agents, bleach, reducing agents, soya flour, emulsifiers and preservatives to speed up manufacture, and deliver a consistent product with a long shelf life. It also uses enzymes which are legally classed as processing aids so they don't need to be included on ingredient lists. The use of bleached flour was phased out in the 1990s, but the rest of the ingredients is still the same today.
And as there's no legal requirement to label unwrapped bread, even the fresh, crusty loaf you buy at the supermarket is probably made using the Chorleywood process.
Real bread campaigners believe that this mix of additives is a factor in why many people complain that bread is difficult to digest.
If you're interested in knowing more about the CBP, here are some links for further reading:
Chorleywood: The bread that changed Britain (BBC News)
Against the grain (The Guardian, 2008)
The shocking truth about bread (The Independent, 2006