Abstract

The influence that food structure has on digestive behavior in human is discussed. The gastrointestinal tract (GIT) is a versatile multi-compartment reactor that operates on a variable solid/liquid feed but delivers more or less standardized products. The structure of food undergoes major size reduction facilitating the release of nutrients embedded in the food matrix so they may be subjected to enzymatic action and eventually absorbed. The oral step is rapid but plays an important role in reducing particle size, mixing, hydrating and lubricating the contents with saliva so that a bolus is formed and swallowed. The motility of the stomach mixes the ingested bolus with gastric juice, which contains acid and digestive enzymes inducing further reduction of particle size, remixing and phase separation. The degree of gelatinization of starch granules and of recrystallization of the released polymers is of vital importance in the breakdown to sugars because both phenomena influence the susceptibility to enzymatic degradation.