Zróżnicowanie zawartości manganu w soku drzewnym brzozowym w profilu czasu

Abstract

Introduction. Birch tree sap is an increasingly popular food product. Its nutritional and health properties are primarily related to the high content of selected minerals. The concentration of manganese in birch sap make it one of the richest sources of this element. But the determining factor for manganese nutritional benefits is both the collection sites and the individual, from which the sap is collected. At the same time it is noted that the content of other minerals fluctuations in the time profile, which also determines the nutritional benefits. Aim. The aim of this study was to determine the time-related variability of the manganese content in birch tree sap and interpretation of the results from the nutritional benefits point of view. Material and methods. The tree sap was collected from three individuals of white birch for sixteen consecutive days (February 28-March 15, 2015). The manganese content was determined by the Electrothermal Technique of Atomic Absorption Spectrometry. Results. For the sixteen measurements, the mean manganese concentration for birch No. 1 was 0.21 ± 0.08, for birch No. 2 – 1.07 ± 0.38, and for birch No. 3 – 0.81 ± 0.16 mg/l, thus, the scattering of the time-related concentrations was similar to those previously found for other minerals. In terms of nutritional benefits, this means a variation in Adequate Intake ranging from 3.8 to 12.7%, from 15.3 to 62.5%, and from 18 to 35.3%, respectively. It was also found that concentrations of manganese in the sap of examined individuals recorded in 2015 were similar to those found for the sap taken from the same trees in the previous year. Conclusions. Taking into account the previously identified interindividual variation and differentiation between collection sites, as well as time-related variability of manganese content shown in this paper, it should be noted that the tree sap collecting procedures should take into account the use of several individuals and combining the obtained sap in order to obtain certain nutritional and health benefits.