Effect of drying methods on physical and chemical quality of Jerusalem artichoke tea powders during storage

Abstract

Drying method could extend the shelf life of agricultural products and was very useful for short shelf-life herbs. However, different drying methods affected the quality of dry foods in a different way. Therefore, this research aimed to study the effect of drying methods on physical and chemical quality of Jerusalem artichoke tea powders and Jerusalem artichoke tea drink based on hot air drying (80ºC), sun drying (32ºC), and freeze drying (-80ºC). The dried samples were grinded to powders and contained in a paper sachet. They were kept at room temperature (27±2ºC) for 6 months. The experimental result found that drying methods had an effect on its color. Hot air drying and sun drying gave darker Jerusalem artichoke powder than freeze drying. Drying methods had an effect on more moisture content and higher water activity (a_w) of Jerusalem artichoke powder when they are kept longer. As for Jerusalem artichoke tea, the tea from all experiments had total soluble solid and inulin-type fructans with statistical significance level (p≤0.05). Total soluble solid seemed to decrease during storage. The tea infusion from Jerusalem artichoke tea powder had inulin-type fructans ranging from 1.01 - 1.16 g/ml. In every experiment, inulin-type fructans increased in the 6^th month of the storage but there was no statistical significance level.