BIOACCESSIBILITY OF CALCIUM IN CITRUS RESIDUES

Calcium (Ca) is an important mineral for healthy and it is present on the peel of citrus fruits. The aims of this study were to estimate the total calcium in residues of orange, lime and mixture (Pera orange, Hamlin orange and Tahiti lime) and its bioaccessibility using in vitro methods. We evaluated dried samples of Pera orange, Tahiti lime and mixture resulting from juice processing. For Ca determination the samples were initially mineralized with nitric acid and hydrogen peroxide using a block digester1 and after evaluated by Flame Atomic Absorption Spectrometry (FAAS). The bioaccessibility of Ca was estimated with the use of methods of solubility and dialysis2. The total calcium content in the samples were 6649 µg/g to mixture, 7734 µg/g to lime and 8016 µg/g to orange. The percentages of soluble Ca ranged from 33.3% to 40.2 %. The percentage of dialyzed Ca ranged from 19.3% to 26.2%. The soluble fractions for orange, mixture and lime were 40.16%, 39.71% and 33.34%, respectively. The dialysed fractions of Ca were 21.29%, 19.32% and 26.13% for orange, mixture and lime, respectively. We can conclude that citrus residue have a high content of calcium and present Ca bioaccessible that can be absorbed by the organism. Thus citrus residue can contribuite with necessities quantities of Ca for the organism up to 20.2% of the recommended DRI for adults.