HR-CS FAAS based method for direct determination of total concentrations of Ca, Fe, Mg and Mn in functional apple beverages and evaluation of contributions of the bioaccessible fraction of these elements by in vitro gastrointestinal digestion and chemical

Functional apple beverages, including organic apple juices and apple juices with added species, were studied on the content of total concentrations of Ca, Fe, Mg and Mn as well as bioaccessibility of these elements and their chemical fractionation patterns. A new simplified sample preparation procedure was developed and validated for determination of Ca, Fe, Mg and Mn by high resolution-continuum source flame atomic absorption spectrometry (HR-CS FAAS). Bioaccessibility of Ca, Fe, Mg and Mn from analyzed apple beverages was assessed using in vitro simulated gastrointestinal digestion while chemical partitioning of elements species was carried out with the aid of tandem-column solid phase extraction (SPE). It was established that Ca, Mg and Mn are highly bioaccessible from functional apple beverages (>94% of total concentrations), significantly contributing to recommended daily intakes (RDIs) of these elements, i.e. up to 11%, 19% and 21% per 1 L, respectively, for Ca, Mg and Mn.