Resistant starch derived from processed ragi (finger millet, Eleusine coracana) flour: structural characterization

From five cycle autoclaved finger millet (ragi, Eleusine coracana) flour, resistant starch (RS) was isolated by sequential enzymatic digestion and purified by GPC and SE-HPLC methods. Its molecular weight was ~1.4x10⁶ Da. Permethylation followed by GC-MS analysis revealed the RS to be a linear α-1,4-d-glucan, probably derived from a retrograded amylose fraction of ragi starch. X-ray diffraction data showed the ragi RS to have both B and V-type diffraction patterns. The enthalpy value of ~0.7 mcal mg^-1 showed ragi RS to be thermally stable. The undigested material recovered from the ileum of rat intestine fed with processed ragi flour exhibited a close similarity in some of its properties to that of RS isolated by an in vitro method. Copyright (C) 1998 Elsevier Science Ltd.