Speciation studies on simulated gastro‐intestinal digests of foodstuffs†

The factors affecting the solubilisation of metals during digestion of food have been examined in a two‐stage model system comprising simulated gastric and intestinal juices. The solubilisation of iron, copper and zinc was examined in digests of white and wholemeal bread. Zinc solubility was principally governed by pH and the simulated digestion had little additional effect. In contrast both iron and copper solubility were markedly affected by digestion of the bread. In the case of copper the enzymolysis increased solubility appreciably at neutral pH. All of the cadmium in a simulated gastric digest of canned crab meat was associated with soluble low molecular weight species of less than 1000 daltons. Cadmium solubility resulted from the acidic conditions of the digest rather than enzymatic solubilisation of binding proteins. Ninety percent of the cadmium in the digest became rebound to the insoluble fraction on adjustment to pH7.0. Subsequent simulated intestinal digestion increased the level of soluble ...