Essential inorganic ions in milk-based drinks : evaluation of bioaccessibility.

Abstract

The determination of the bioaccessible fractions of Co, Cu, Mo, Mn, Fe, Zn, Mg and Ca in milk-based drinks (dairy beverages) was carried out using in vitro digestion and quantification by ICP OES. Microwave assisted mineralization was used for sample preparation and the method allowed recoveries between 90 - 110% for all the elements, considering three different levels of analytes addition, with relative standard deviations (RSD) below 10%. The total concentration of Ca determined by the present method was in good agreement with the value declared by the manufacturer while Co was the only element that was below the limit of quantification (LOQ). The bioaccessible fractions for Ca and Mg were approximately 100% while for Cu, Zn, Mn and Fe the bioaccessibility values were 56, 48, 46, and 29%, respectively, and for Co and Mo the values were below the LOQ. Additionally, it was noticed that the bioaccessibility of these elements may vary according to the sample composition.