Portal de Periódicos da CAPES

Oxalate Reduces Calcium Availability in the Pads of the Prickly Pear Cactus through Formation of Calcium Oxalate Crystals

2004; American Chemical Society; Volume: 52; Issue: 5 Linguagem: Inglês

10.1021/jf035332c

1520-5118

Michele M. McConn, Paul A. Nakata,

Botany, Ecology, and Taxonomy Studies

The pads (nopales) of the prickly pear cactus are considered to be a good source of minerals and other nutrients on the basis of compositional analysis. In this study, this analysis is taken a step further by assessing the availability of selected minerals in nopales using an in vitro digestion and dialysis method. The results obtained suggest that although nopales are enriched in a number of minerals, their tissue calcium is not freely available. Microscopic analysis, energy-dispersive X-ray microanalysis, and oxalate measurements suggest that this reduction in available calcium is a result of its sequestration in the form of calcium oxalate crystals. The issue of mineral availability in plant foods is important when the dependence of many populations around the world on plant foods as their main source of minerals and other nutrients is considered. Keywords: Availability; calcium; crystals; nopales; oxalate; prickly pear