Cereal Chem 69:78-81   |  VIEW ARTICLE

Effects of Lime Treatment on the Bioavailability of Calcium in Diets of Tortillas and Beans: Bone and Plasma Composition in Rats.

S. O. Serna-Saldivar, L. W. Rooney, and L. W. Greene. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

The properties and composition of femurs and plasma of weanling rats fed (for eight weeks) regular corn, raw grains of quality protein maize (QPM) or sorghum, or tortilla-based diets supplemented with and without Ca were determined. The femurs of rats fed tortillas weighed more; were thicker and longer (P less than 0.05); contained more ash, Ca, P, and Mg; and had less moisture and organic matter (P less than 0.05) than those of rats fed raw grains. Femurs of rats fed tortillas were denser (P less than 0.05) and at least five times stronger (P less than 0.05) than those of rats fed raw grains. Among rats fed tortillas, QPM produced denser, stronger, longer, and thicker bones with more ash and Ca, followed by sorghum and regular corn tortillas. Supplementation of raw grain diets with Ca considerably improved the properties and mineral composition of the femur and serum Ca levels. These changes were not as marked when tortilla-based diets were supplemented with Ca. Serum Ca levels were approximately 30% lower for rats fed raw grains without supplemented Ca. Ca supplementation of QPM and sorghum tortillas had a marginal effect on serum Ca levels. Hypocalcemia was related to low serum albumin levels. Rats fed Ca-supplemented QPM products had the highest serum albumin levels (P less than 0.05), probably because of the improved dietary protein quality.