Discriminant Analysis of the Geographical Origin of Asian Red Pepper Powders Using Second-Derivative FT-IR Spectroscopy

Abstract

This study aimed to discriminate between the geographical origins of Asian red pepper powders distributed in Korea using Fourier-transform infrared (FT-IR) spectroscopy coupled with multivariate statistical analyses. Second-derivative spectral data were obtained from a total of 105 red pepper powder samples, 86 of which were used for statistical analysis, and the remaining 19 were used for blind testing. A one-way analysis of variance (ANOVA) test confirmed that eight peak variables exhibited significant origin-dependent differences, and the canonical discriminant functions derived from these variables were used to correctly classify all the red pepper powder samples based on their origins. The applicability of the canonical discriminant functions was examined by performing a blind test wherein the origins of 19 new red pepper powder samples were correctly classified. For simplicity, the four most significant variables were selected as discriminant indicator variables, and the applicable range for each indicator variable was set for each geographical origin. By applying the indicator variable ranges, the origins of the red pepper powders of all the statistical and blind samples were correctly identified. The study findings indicate the feasibility of using FT-IR spectroscopy in combination with multivariate analysis for identifying the geographical origins of red pepper powders.

Rapid analysis technologies with chemometrics for food authenticity field: A review

“…In the study of distinguishing the geographical origin of grapes, MIR combined with PLS-DA was used to model the different geographical origins of Chardonnay grapes in South Australia, and the overall success rate in discriminating geographical origin for samples from different vintages (2014 and 2016) was 83% and 81%, respectively ( Gambetta et al, 2019 ). For vegetables, MIR was used to differentiate lentils from two countries and red chili powder from three countries at 100% accuracy ( Innamorato et al, 2019 ; Kim et al, 2021 ). Research involving the utilization of MIR for the geographical origin differentiation of animal-derived foods mainly focuses on milk and dairy products, such as goat milk and Alpine milk.…”

Food Authentication: Techniques, Trends and Emerging Approaches (Second Issue)

“…Statistical modelling was applied to develop a characteristic spectral fingerprint ("spectralprint") by selecting the most important variables, which enabled the rapid, reliable, and uncomplicated differentiation of vinegar samples depending on the starting wine. The same spectroscopic approach was employed in another study to discriminate Asian red pepper samples based on their geographical origin [6]. The four most significant peak variables from second-derivative FT-IR spectral data were selected as discriminant indicator variables, and their origin-specific ranges were set.…”