Comparison of the Physicochemical Properties of Hot-Air-Dried Potatoes and Burdock according to the Pretreatment Process

Abstract

This study compared the changes in the physicochemical properties and mineral content of hot-air-dried potatoes and burdock according to the pretreatment process for use as food materials for patients with kidney disease. Potatoes and burdock were pretreated with steaming and blanching (water, salt, sucrose, vinegar, ascorbic acid solution), dried with hot air, and observed for color, hardness, mineral content, and microstructure. Potatoes and burdock soaked in a low-concentration salt solution showed the least browning, and the color difference value was low, and they were most similar to the raw materials. Additionally, the degree of browning was found to be low in potatoes and burdock soaked in salt solution, and in burdock pretreated in water. The control (non-pretreated) potatoes, and those soaked with salt or sugar solutions showed maximum hardness, while those blanched or soaked in vinegar solution showed minimum hardness. The changes in mineral content showed different trends depending on the pretreatment process, but the total mineral content decreased the most when potatoes were soaked in sugar solution and when burdock was soaked in water. In addition, potatoes soaked in sugar solution and burdock soaked in water showed similar levels of bitterness, saltiness, sweetness, sourness, and umami in the taste distribution analyzed by the electronic tongue. These results show that the mineral content decreases the most when potatoes are soaked in sugar solution and when burdock roots are soaked in distilled water as pretreatment. Therefore, these are considered to be the most suitable food materials for patients with kidney disease.