Determination of Water Content and Piperine Content of Black Pepper (Piper Nigrum L.) Using Near Infrared Spectroscopy (NIRS)

Abstract

Black pepper is one of the most widely exported spice commodities by Indonesia. The main content of black pepper is piperine which affects the spiciness of black pepper and can be used to determine the quality of black pepper. Determination of the chemical content of black pepper is still carried out by chemical methods in the laboratory which takes a long time to find out the results, the test costs are expensive due to the use of tools and chemicals and requires complicated sample preparation. The purpose of this study was to determine the water content and piperine content in black pepper using the NIRS method using the PLS (Partial Least Square) and PCR (Principal Component Regression) methods. FT-NIR Spectrometer type NIRFlex N-500 with wave length of 1000-2500 was used to measure 30 samples of black paper powder.  NIRS spectrum data were pre-processed by normalization, SNV, MSC, and de-Trending methods, while the calibration methods used are PLS and PCR. The results showed that the best estimation of piperine levels was using the PLS method with the original spectrum data at a factor of 8 (r = 0.87; SEC = 0.42 %; SEP = 0.44 %; CV = 5.79 %; RPD = 1 .77 and consistency = 97.46 %), while the best estimation of the water content of black pepper was obtained using the PCR method with spectrum data using normalization pretreatment at a factor of 15 (r = 0.85; SEC = 0.32 %; SEP = 0, 29 %; CV = 2.79 %; RPD = 1.90 and consistency = 108.96 %).