Studies on bioaccessibility of elements were carried out by in-vitro gastrointestinal digestion simulation method combined
with neutron activation analysis (NAA) using NH4HCO3 as an alternate base to commonly used base of NaHCO3. The effect of two bases namely NaHCO3 and NH4HCO3 on the bioaccessibility of the elements namely Br, Fe, K, La, Na, Rb, Sm and Zn from wheat seeds, fresh wheatgrass and commercial
wheatgrass tablet was investigated. The bioaccessible concentrations of the elements were determined by neutron activation
analysis (NAA). The bioaccessible concentrations of samples digested using NH4HCO3 were found to be higher by 10–15% for most of the elements than that observed using NaHCO3. In the case of fresh wheatgrass, the differences were as high as 50%. The present study indicated that NH4HCO3 can be used as a base instead of NaHCO3 in in-vitro gastrointestinal digestion simulation method.