Fourier transform infrared (FTIR) spectroscopy is an appealing technology for the food industry because simple, rapid, and nondestructive measurements of chemical and physical components can be obtained. Advances in FTIR instrumentation combined with the development of powerful multivariate data analysis methods make this technology ideal for large volume, rapid screening and characterization of minor food components down to parts per billion (ppb) levels. Because of the use of FTIR techniques in quality and process control applications, the food industry is already familiar with the technology and its potential to expand to monitoring for food adulteration. The aim of this review is to compile the current research on applications of near infrared (NIR) and mid-infrared (MIR) spectroscopy for rapid authentication and detection of adulteration in food.

This study evaluated the capabilities of a handheld mid-infrared (MIR) spectrometer combined with multivariate analysis to characterize oils, monitor chemical processes occurring during oxidation, and to determine fatty acid composition. Vegetable oils (corn, peanut, sunflower, safflower, cottonseed, and canola) were stored at 65°C for 30 days to accelerate oxidation reactions. Aliquots were drawn at 5 day intervals and analyzed by benchtop and portable handheld mid-infrared devices (4,000-700 cm -1 ) and reference methods (IUPAC 2301 [1], 2302 [1]; AOCS Cd 8-58 [2]; and Shipe 1979 [3]). PLSR and soft independent modeling of class analogy (SIMCA) models were developed for oil classification and estimation of oil stability parameters. Models developed from MIR spectra obtained with a benchtop spectrometer equipped with a 3-bounce ATR device resulted in superior discriminative performances for classifying oils as compared to those obtained from handheld spectra (singlebounce ATR). Models developed from reference tests and handheld spectra showed prediction errors (SECV) of 1 meq/kg for peroxide value, 0.09% for acid value and 2% for determination of unsaturated fatty acids in different oils. Spectral regions *3,012-2,850 cm -1 (C-H stretching bands/shoulders of fatty acids), *1,740 cm -1 (C=O stretching of esters), and *1,114 cm -1 (-C-O stretching) were found to be important for prediction. Handheld-FTIR instruments combined with multivariate-analysis showed promise for determination of oil quality parameters.Portability and ease-of-use makes the handheld device a great alternative to traditional methods.