Abstract
The present study was conducted to evaluate the biological effectiveness of Zn released from beef meat with proteolytic digestion. Cooked beef meat was hydrolyzed with pepsin at pH 1.0 for 3.5hr, and subsequently the pH was adjusted to pH 7.6, and the suspension of the meat after pepsin digestion was further hydrolyzed for 2hr with trypsin. During the course of the peptic digestion, considerable amount of Zn in cooked meat was released into its digestion medium. Nevertheless, over half of this solubilized Zn was transferred into the undigestive residue by the subsequent tryptic digestion. The observed change of solubility of Zn seems to be caused by alterations in pH. Fractionation of the hydrolyzates with pepsin, or pepsin and trypsin, by Sephadex G-100 column chromatography, indicated that Zn in these hydrolyzates might bind to proteinaceous substances. These results allow us to speculate that the most amount of ingested Zn, being bound to protein-like substances, may be transported into intestinal lumen before absorption.
