MODIFICATION OF AN IN-VITRO METHOD FOR ESTIMATING THE BIOAVAILABILITYOF ZINC AND CALCIUM FROM FOODS

A continuous flow in-vitro method for estimating the bioavailability o f minerals and trace elements was modified. This modified method inclu des a simulated gastric digestion with pepsin, gradual pH change durin g the first 30 min of dialysis in an Amicon stirred cell, and a furthe r 2 h of continuous dialysis accompanied by intestinal digestion with pancreatin-bile extract. The percentage of continuously dialysed miner als or trace elements (dialysability) is used to express the bioavaila bility. Comparison of different in-vitro methods by using the dialysab ility of zinc and calcium from milk- and soy-based formula samples rev ealed that with the modified method the results are closer to the in-v ivo situation and could be used as a relative index for predicting the bioavailability of some minerals and trace elements.