RS1 refers to starch entrapped in protein matrix, cell-wall materials, and other physical
barriers that reduce the accessibility of starch to amylolysis (Rooney and Pflugfelder 1986;
Zhang and Hamaker 1998; Ezeogu et al. 2005). A good example of RS1 is the RS in pasta,
which has been shown to result in a lower postprandial plasma-glucose response in human
subjects than the control bread made with the same ingredients (Granfeldt and Bjorck 1991). The
compact protein matrix of pasta has been proved to be responsible for its higher RS-content than
other wheat products (Fardet et al. 1998; Kim et al. 2008). Treatments that can destroy the
physical barriers in foods (e.g., grinding and protease hydrolysis) reduce the RS1 content