Near infrared spectroscopy as a rapid method for detecting paprika powder adulteration with corn flour

Abstract

Paprika powder is a spice of culinary importance in many homes but it's powdered form, has been targeted for fraudulent activities intended at consumer deception. Diverse methods have been used to investigate some of these adulterations but there is no report of paprika adulteration with corn flour, although it remains a suspicion. Technologies such as the near infrared spectroscopy (NIRS) possess non-invasive and rapid advantages that could be explored to monitor this type of adulteration. The study aimed to discriminate and quantify different levels of paprika powder adulterated with corn flour, using NIRS. Two authentic paprika types (DP and SP) were purchased from reputable sources in Hungary and artificially adulterated in the laboratory. Three repeats of each adulteration level (40%, 30%, 25%, 20%, 15%, 10%, 5%, 3%, 1%) were prepared and scanned with the Metri NIRS respectively, then, analysed with chemometrics: Linear discriminant analysis (LDA) and partial least squares regression (PLSR). LDA showed 100% recognition and prediction accuracies respectively when DP and SP were analyzed separately to discriminate different concentrations of paprika adulteration. LDA models with NIRS recognize corn flour adulteration with 95.55% and predict it with 95.02% accuracy irrespective of the paprika type used in this experiment. PLSR prediction of 40%, 30%, 25%, 20%, 15%, 10%, 5%, 3%, 1% corn flour adulteration yielded an R 2 CV of 0.98 (high accuracy) and a low RMSECV of 1.71 g/100g (low error). Near infrared as a non-invasive technique exhibited good potentials for paprika powder authentication when corn flour is used as an adulterant.

Detecting Low Concentrations of Nitrogen-Based Adulterants in Whey Protein Powder Using Benchtop and Handheld NIR Spectrometers and the Feasibility of Scanning through Plastic Bag

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Classification of Bee Pollen and Prediction of Sensory and Colorimetric Attributes—A Sensometric Fusion Approach by e-Nose, e-Tongue and NIR

“…This change is composition-dependent [38]; consequently, this technique is suitable for both qualitative and quantitative analysis. Major advantages of NIR spectroscopy are that it requires little to no preparation, its rapidness, safety to the analyst, non-destructiveness, and multicomponent remote analysis [39]. Most molecules in foods contain C-H, N-H, S-H, or O-H bonds, so the application of NIR spectroscopy is nearly universal.…”

Near-Infrared Spectroscopy and Aquaphotomics for Monitoring Mung Bean (Vigna radiata) Sprout Growth and Validation of Ascorbic Acid Content

“…Based on the spectral changes, it can be possible to detect differences within samples or groups of samples as the structural and chemical differences reflect back in the NIR spectra [ 28 ]. Therefore, by applying multivariate statistics, it is possible to compare different samples with each other [ 29 ]. NIRS is a correlative method, which means with this method, we may not be able to observe the exact composition of the sample, but in the possession of the physicochemical data obtained by reference conventional methods, it could be possible to build correlation models to predict the quantity of the constituents and value of physicochemical data such as pH, electrical conductivity, and vitamin content.…”