Abstract
Two methods for extracting anthocyanins and bioelements [calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe)] from black chokeberry, black currant, strawberry, and bilberry fruits were compared in this study. Correlations between the content of anthocyanins and bioelements in fruit extracts were determined using method A [extraction with hydrochloric acid (HCl)] and method B [extraction with water (H2O)]. Relationships between the content of anthocyanins and particular nutrients, as well as between Mg and Ca and between Zn and Fe, in fruit extracts obtained by method A and by method B were also established.
The mean content of anthocyanins and bioelements (Ca, Mg, Zn, Fe) was the highest in black chokeberry fruits, regardless of the extraction method used. Bilberry fruits had the lowest nutrient content, despite a high anthocyanin content. The mean content of anthocyanins and bioelements was higher in fruit extracts obtained by method A than method B. The coefficients used to recalculate method A into method B were anthocyanins, 5.1; Ca, 1.1; Mg, 1.2; and Zn, 2.2. The statistical analysis showed that the effect of a given extraction method on the content of anthocyanins and bioelements (except for Ca) in fruit extracts depended on fruit species. The correlations between the content of anthocyanins, Ca, Mg and Zn in fruit extracts obtained by method A were found to be positive and highly significant, in comparison with method B. There was no correlation between the content of anthocyanins and particular nutrients in fruit extracts obtained by method A and by method B. The Mg content of fruit extracts was highly significantly higher than the Ca content, irrespective of the extraction method applied.