Effect of Initial Leaf Moisture Content on the Herbal Quality Parameter of Orthosiphon stamineus Dried Leaf During Storage

The experiment was conducted to determine the effect of short term storage of Orthosiphon stamineus herbal leaf, dried at different level of moisture content on its moisture, color property, antioxidant capacity and total phenolic content. The experimental treatments, that consisted of initial sample moisture content (7%, 10% and 13%) and storage period (10, 20, 30 and 40 days), were arranged in a random completed design (RCD) manner. The changes of moisture content and color property were analyzed by using moisture analyzer chroma meter. The measurement of total phenolic compounds was conducted according to Folin-Ciocalteu method. The study of antioxidant activity was analyzed using 1,1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging activity assay. The results showed that the initial moisture content of leaf samples significantly affected the sample moisture content of the O. stamineus dried herbal leaf during storage. Meanwhile, the storage time induces the increase of antioxidant capacity and slightly affecting the total phenolic content of stored leaves. However, the color properties such as lightness (L*) and hue (h°) were not significantly influenced by the treatment during storage. The results revealed that both storage parameters, which are initial moisture content of the stored leaves and storage time, positively affect the quality of dried herbs, although the experiment was conducted for only 40 days of storage time. It is proposed that further experiment need to be performed for longer storage periods with an extra focus to the effect on antioxidant activity.