In vitro calcium bioaccessibility in raw and cooked cladodes of prickly pear cactus (Opuntia ficus-indica L. Miller)

The aim of this work was to determine the calcium bioaccessibility in Opuntia ficus indica L Miller cultivars (Milpa Alta and Atlixco) and to evaluate the effect of cooking by using an in vitro digestion and dialysis method. The studied cladodes had a high content of calcium; however, only 16 and 9% of total calcium was dialyzable in Milpa Alta and Atlixco cultivars, respectively. The calcium dialyzability of Milpa Alta could be classified as medium level (10-19%) and Atlixco at the top of the rank assigned to low food dialyzability (<10%). Our results presented a significant negative correlation, between total oxalate and ionic dialyzable calcium (r = - 0.716, P <= 0.05). Milpa Alta could be a better source of calcium due to the higher bioaccessibility of ionic dialyzable calcium and lower total oxalate/calcium ratio. The cooking process did not affect significantly intestinal calcium bioaccessibility in any of the cultivars studied. (C) 2011 Elsevier Ltd. All rights reserved.