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Zinc bioaccessibility is affected by the presence of calcium ions and degree of methylesterification in pectin-based model systems
Journal Contribution - Journal Article
Minerals are required by the human body to perform physiological functions. Mineral deficiencies, often caused by low mineral bioaccessibility in plant-based foods, are a matter of great concern all over the world. Several mineral antinutrients (e.g. pectin) may contribute to this reduced mineral bioaccessibility by formation of indigestible complexes due to mineral binding. Structural characteristics of the mineral antinutrients, as for instance the degree of methylesterification (DM) in the case of pectin, may play a role in this mineral binding phenomenon and has been evaluated before, however, only in single mineral model systems. In natural food systems, several mineral types are present together which may affect each other's bioaccessibility. Therefore, this study investigated the influence of the presence of Ca2+ on Zn2+ binding capacity and bioaccessibility in mineral-pectin model systems with different DM. The results showed that increasing Ca2+ concentration and pectin DM reduces the Zn2+ binding capacity of pectin and consequently increases Zn2+ bioaccessibility in the in vitro small intestine. Moreover, the in vitro digestion procedure with adjustment of pH only, no addition of enzymes, bile salts nor digestive fluids during simulation of gastric and small intestinal phases, was found to be most appropriate to fundamentally study the influence of pectin DM and presence of Ca2+ on Zn2+ bioaccessibility in mineral-pectin model systems.
Journal: Food Hydrocolloids
Pages: 206 - 215