Evaluation of the bioaccessibility of minerals from blackberries, raspberries, blueberries and strawberries

The quantification of the total concentration and an in vitro digestion method was used to evaluate the bioaccessibility of elements in berries. The results for the total concentration of Al, Ba, Ca, Cu, Fe, K, Mg, Mn and Zn show the values (expressed as concentration range): 1.2-8.3; <0.07-0.80; 82-285; 0.20-0.99; 7.3-13.3; 954-1594; 119-243; 2.2-28.7; 1.3-3.0 mg kg−1, respectively, and the bioaccessibility values are approximately 10, 74, 41, 9, 34 and 18% of the total concentration for Al, Ba, Cu, Fe, Mn and Zn, respectively. These results show that Ba has the greatest value for bioaccessibility and that almost half of Cu and Mn present in the fruit is bioaccessible, while the values for Al, Fe and Zn are much lower. It was also verified that the bioaccessibility varies with the samples, depending on their polyphenol composition. The poor bioaccessibility of Zn and Fe is expected because these elements tend to form insoluble compounds with phytates and fibers present in fruits, while Cu and Mn may form metal-phytate complexes that are more soluble in the gastrointestinal tract.