The measurement of potassium (K) in the soaking water to reconstitute the dried wild mushrooms for edible by total reflection X-ray fluorescence analysis

It is known that the nutrients are lost from the foodstuff in the cooking process. As a result, it is no longer containing the original nutrients ingredients in the food. It is important to know the desirable cooking process in which food stuffs nutrients keep the value of food's nutrients with minimizing a loss. Therefore, the speed of flowing out of Potassium (K) during reconstituting process for dried wild mushrooms was calculated by measuring the amount of K in the soaking water by the total reflection X-ray fluorescence spectrometry (TXRF). The concentration of K in each soaking water after filtration was measured by a TXRF instrument of OURSTEX200TX (OURSTEX co. ltd., Osaka, Japan). The elution of K for the control dried shiitake was completed by 360 minutes after dipping into pure water. On the other hand, the mushroom samples examined were classified into 2 groups based on the K elution rate. One is the rapid K elution group and the other is the slow elution group. It was thought that any mushrooms were enough broken by dry treatment to elute K during the reconstituting treatment, and the autolysis process of fungal filament gradually processed during the examination and caused to the elution of K. The elution rate of K was calculated to 32.8% at control dried shiitake. And it was calculated to 6.2 ∼ 39.3% at each mushroom sampled. It was thought that the residual rate of K was more than 60% until 30 minutes after dipping pure water at room temperature. (author)