Abstract Gambir leaf herbal tea is an innovative product made from Gambir (Uncaria gambir Roxb.), which can potentially be an export product. Considering its hygroscopic nature, moisture content is an imperative indicator for controlling the stability of Gambir leaf herbal tea quality. This research intends to investigate near-infrared spectroscopy (NIR) to estimate the moisture content of herbal tea made from Gambir leaves. We placed powdered Gambir leaf herbal tea samples in a petri dish, using 20-21 g per sample. The number of samples used was 60. We obtained the reflectance of herbal tea from Gambir leaves using NIR spectroscopy at 1000 to 2500 nm. The oven method determined the reference moisture content. A calibration model was developed using the partial least squares (PLS) regression method. Furthermore, the model acquires standard error in the calibration (SEC) and prediction (SEP) are 0.36 and 0.43, respectively. The model had a determination coefficient of prediction set (R2p) of 0.95 and Residual Predictive Deviations (RPD) of 4.38. This study proves that NIR spectroscopy is reliable in presupposing the moisture content of herbal tea made from Gambir leaves.
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