Abstract
Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fibre. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behaviour in the gastro-intestinal tract and their contribution to healthy diets.