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Tomato (Lycoperscion esculentum) is an annual vegetable crop of the Solanaceae family. It can be consumed as fresh food or processed in the form of pelee, concentrate, juice or ketchup. Potassium activates enzymes and regulates permeability of living membranes. The goal of this research was to determine the content of potassium in fresh tomatoes and tomato products. Tomato sampling was conducted on 3 sales places in Zagreb, including fresh grappolo tomatoes, fresh cherry tomatoes, ketchup, double concentrate (28-30 % DW) and organic tomato pelée. In order to determine the content of potassium, the grinded samples were digested with concentrated HNO3 and HClO4 in a microwave oven, potassium is determined by flamephotometer. The content of dry weight ranged from 4.2 to 30.4%. Statistically the highest potassium content was found in fresh grappolo tomatoes (7.5% K dry weight and 1783 mg K/100 g in fresh weight). Slightly lower potassium content was determined in fresh cherry tomatoes and peeled tomatoes, while in ketchup was statistically the lowest (1.97% K dry weight and 65 mg K/100 g in fresh weight). |
