Mineral oil detection in ghee using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) in conjunction with chemometrics

Abstract

Ghee (anhydrous milk fat), being a costly product, is susceptible to adulteration by unscrupulous personnel in the market. The presence of mineral oil in ghee was examined using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) spectroscopy in conjunction with chemometrics. Spectral data in the wavenumber range 4000–500 cm−1 were collected for pure ghee, mineral oil, and pure ghee samples spiked with mineral oil at different concentrations (2 %, 4 %, 6 %, 10 %, and 15 %). Principal Component Analysis (PCA) revealed distinct clustering patterns in specific wavenumber regions (1350–950 and 1800–1600 cm−1) at 5% level of significance, effectively distinguishing pure ghee from adulterated samples. Soft Independent Modeling of Class Analogy (SIMCA) showed classification efficiency of 100 % for the samples of pure ghee and mineral oil. Developed Partial Least Square (PLS) and Principal Component Regression (PCR) models showed high R2 values (above 0.99) indicating strong predictive accuracy for mineral oil adulteration levels in ghee. Thus, using ATR-FTIR and chemometrics, detection of as low as 2 % of mineral oil in ghee is possible.