Comparative Study of Hyperspectral Aquisition Technique in Total Soluble Content and pH Measurement in Honey

Transmittance and reflectance modes are the two most common technique used for investigating liquid physicochemical properties based on optical spectra. In the case of honey characterization, this research performed to show a comparison between both modes to measure honey's Total Soluble Solids and pH based on the Vis-NIR hyperspectral imaging system. The system consists of Specim FX10 hyperspectral camera with 448 bands (400-1000nm), three 200 W halogen lamps, a light diffuser, a motor slider, and a PC. Then, a Partial Least Square Regression (PLSR) algorithm applied to predict measured values based on the acquired transmittance and reflectance spectrum. Performance of each technique tested by tenfold Cross Validation, which randomly grouping the dataset into ten partitions. Samples is prepared from 28 different honey types with varied colors, placed in 5 cm diameter Petri dishes at 10 ml volume. Performance of each technique measured by R
²
and a Root Mean Square Percentage Error (RMSPE) score. Transmittance mode results in R
²
of 0.93 and 0.80, RMSPE of 1.06% and 5.36% for total soluble solid content and pH measurement. For similar measured properties, reflectance mode results in R
²
of 0.94 and 0.82, RMSPE of1.01% and 5.23%. In this research, reflectance mode performs slightly better than transmittance mode in the measurement of Total Soluble Solids and pH in honey samples.