NOll Destructive Measurement of Catechin Content in GUlllbir (Um'aria gal1lbir Roxb.) Using NI R Spectroscopy

Abstract

Gambir is one of Indonesian export commodities. Catechin content is main determinant of gambir quality, In traditional market. determining of the gambir catechin content is conducted qualitatively based on experience of the assessor which led to Subjective measurement. Chemical method to determine catechin content of gambir quantitatively, This method is notefficient since it requires expensive chemical reagents. takes a long lime. and destructive. Near infrared ( IR) Spectroscopy is one of the non destructive techniques which can inform gumbir quality. The objective of this study was to demonstrate of NIR spectroscopy to measure of catechin content in gambir. Partial Least Square (PLS) method by combination pre-treatment between normalization between 0 and 1 (n0l), and first derivative Savitzky-Golay 9 points (dg1) was used to develop calibration model. Value of consistency and V-Set PRESS was used to determine the optimum number of PLS factor. The result showed that calibration model with 6 PLS factors was the best predictive models for catechin content since it provided a high accuracy as well as precise models. Model for catechin content showed the bias value - 0.10 %, SEC = 3.56 %, SEP = 3.27 %. Correlation coefficient (r) = 0.95, CY = 4.86 %, and RPD = 3.60. The result demonstrated that NIR spectroscopy might be applied to measure catechin content in gambir accurately.