Improving Rice Dietary Fibre Content and Composition for Human Health

Soft textured rice is the major source of calories in the diet of most South East (SE) Asian countries. However, it is most often consumed after polishing which removes the bran and embryo and hence most of the vitamins, minerals and dietary fibre (DF) are lost. Consequently, white rice comprises over 90% starch with only trace amounts of DF and is rapidly digested in the human gastrointestinal tract, resulting in a high glycaemic index (GI). The excessive consumption of high GI foods is associated with increased risks of a range of chronic diseases including type-2 diabetes, cardiovascular disease (CVD) and some types of cancer. Furthermore, the incidence of these conditions is dramatically increasing in areas where white rice is the staple food, notably Asia, with the prevalence of diabetes in SE Asia alone predicted to reach 120 million by 2030. It is therefore necessary to develop rice lines in which high energy content is combined with low GI. This may be achieved by combining acceptable levels of resistant starch (RS) with an increased content of the cell wall derived-dietary fibre components.