Determination of seed content in red pepper powders by H-1 NMR and second-derivative FT-IR spectroscopy combined with statistical analyses

Abstract

This study focuses on discriminating the seed content in red pepper powders using H-1 NMR and second-derivative FT-IR Spectroscopy with canonical discriminant and multiple linear regression analyses. We used 165 test samples prepared by varying the seed content for spectroscopic analyses. The canonical discriminant functions derived from 21 peak variables were used to properly discriminate the red pepper powder samples based on their seed content with a 97.6% hit ratio. Additionally, we observed an average error of 7.0% while discriminating 42 blind samples. Multiple linear regression analysis was performed to directly determine the seed content of new samples without running a statistical program. The best regression model constructed with only two variables showed an average error of 6.2% when applied to the blind samples. These results verify the feasibility of using H-1 NMR and FT-IR Spectroscopy with statistical analyses to determine the seed content in red pepper powders.