Qualitative in vitro study on the degradation of mineral complexes in vegetables.

Mechanisms of degradation and absorption of mineral complexes by the human digestive system are complex and still under investigation. The elaborate matrix of vegetables, and the presence of phytates and other inhibitors make study of these mechanisms difficult. In this qualitative study, extracts from freeze-dried savoy cabbage, broccoli, kale and spinach were subjected to digestion in vitro at pH 2.0 and pH 7.5 and analysed using SEC-ICP-MS. The results suggest that low molecular weight species (peak 6), related to the iron and zinc fractions, which appeared after acidic digestion in all vegetables, except in kale, were considerably reduced after digestion at pH 7.5. Low molecular weight species (peak 9), related to the phosphorus fraction, were present in all vegetables, except in kale, after alkaline digestion. While cabbage, broccoli and spinach showed similar degradation patterns, kale showed a different degradation behaviour.