Assessment of trace elements in Herbal and Conventional beverages consumed in Kenya

Abstract

Studies on beverage consumption have increasingly become important due to their neutraceutical role. The study was aimed at quantifying both total and labile trace elements content between herbal and conventional beverages. Forty three beverages were classified into coffee, herbal, spiced tea, plain tea chocolates/cocoa and soybean beverages. Nine elements (K, Ca, Cr, Mn, Fe, Cu, Zn Sr and Rb) were analyzed in herbal and conventional beverage samples consumed around Nairobi using TXRF-Ga internal standard method and the data on labile trace elements subjected to chemometric evaluation to group the beverage samples based on their trace element concentration.

Total K ranged from 17100 ug g-l in coffee samples to 127900 ug g' in soybean beverages. Calcium concentration ranged from 16.7 -2038 Jlg g' in spiced tea and soybean beverages. Total Cr ranged from 9.2 -15.2 ug g-l among spiced tea and plain herbal. Total Mn ranged from 21.2- 853 Ilg g-l among the soybean and plain tea beverages. Total iron concentration ranged between 67.3 - 826 ug g' among soybean and plain herbal beverages. Cu concentration ranged between 9.6 - 10.3 ug g' among the spiced tea and plain tea samples. Zn concentration ranged between 16.4 - 37.4 ug g-l among the spiced tea and plain tea samples. Total rubidium concentration ranged between 44.6 - 72.6 ug g' among the soybean beverages and coffee beverage samples.

From the PCA analysis, two principal components were identified for both macro and labile elements in beverage samples. Cluster analysis identified eight (8) groups among the 31 grouped beverage samples based on labile trace element content. A strong correlation (0.88) was identified between mn and zn. While negative correlation was identified between K and Mn (0.15) and K and Fe (0.13) relations.