Bound Phenolic Constituents as Co-passengers of Dietary Fibre
Cereal-derived dietary fibre has an important role in the health benefits of consuming whole grains. However, the known health benefits of cereal-derived dietary fibre do not occur in isolation because they are covalently bound to phenolic acids through ester and ether linkages. These bound phenolic acids have been demonstrated to have antioxidant health-promoting properties. For the health effects of their fibre content to be of benefit to consumers, whole grains have to be cooked or processed into edible and palatable forms. Different processing operations are applied to whole grains and these processes may affect the bound phenolic acids by disrupting the cell wall structure. On consumption, the phenolic acids bound to dietary fibre are generally unaffected by the digestive enzymes in the mouth, stomach and small intestine, but are metabolized by the microbiota in the colon. This chapter explores the nature of the phenolic acids bound to dietary fibre in whole grain cereals, how they are affected by processing and their potential release and bioavailability.