Variability of the minerals content as a factor limiting health properties of birch saps
Treść / Zawartość
In this study, the content of minerals in silver birch (Betula pendula Roth.) tree saps was tested using atomic absorption spectrometry to evaluate the intraspecies variability. The mean values of zinc (2.79 - 4.49 mg dm-3), sodium (0.66 - 2.76 mg dm-3) and copper (0.02 - 0.19 mg dm-3) for tree saps collected from particular locations did not differ significantly. The mean calcium (77.83 mg dm-3) and magnesium (13.38 mg dm-3) content in the sap from trees growing in a farmyard was significantly higher than in sap from other sites, where calcium ranged between 25.85 and 41.04 mg dm-3 and magnesium varied from 5.98 to 8.00 mg dm-3. Based on the results of tree sap analyses, it can be claimed that mineral content detected in birch saps is low when compared to the dietary standards (RDA, AI), although saps from individual trees can have a copper and zinc content, owing to which birch sap can be considered as a potentially valuable source of these two minerals. However, the prospective health-promoting benefits related to the high content of zinc and copper are not explicit. According to our study, this mineral content is highly variable, both between particular trees in a single location and between distant locations. For example, in the case of copper, one liter of sap collected from neighbouring trees can contain from zero to several dozen percent of the Recommended Dietary Allowances, making it impossible to identity specific nutritional benefits.