Rapid detection of green‐pea adulteration in pistachio nuts using Raman spectroscopy and chemometrics

Abstract

BACKGROUND Ground pistachio nut is prone to adulteration because of its high economic value and wide usage. Green pea is known as the main adulterant in frauds involving pistachio nuts. The present study developed a new, rapid, reliable and low‐cost methodology by using a portable Raman spectrometer in combination with chemometrics for the detection of green pea in pistachio nuts. RESULTS Three different methods of Raman spectroscopy‐based chemometrics analysis were developed for the determination of green‐pea adulteration in pistachio nuts. The first method involved the development of hierarchical cluster analysis (HCA) and principal component analysis (PCA), which differentiated authentic pistachio nuts from green pea and green pea‐adulterated samples. The best classification pattern was observed in the adulteration range of 20–80% (w/w). In addition to classification methods, partial least squares regression (PLSR) and genetic algorithm‐based inverse least squares (GILS) were also used to develop multivariate calibration models to determine quantitatively the degree of green‐pea adulteration in grounded pistachio nuts. The spectral range of 1790–283 cm−1 was used in the case of multivariate data analysis. A green‐pea adulteration level of 5–80% (w/w) was successfully identified by PLSR and GILS. The correlation coefficient of determination (R2) was determined as 0.91 and 0.94 for the PLSR and GILS analyses, respectively. CONCLUSION A Raman spectrometer combined with chemometrics has a high capability with regard to the detection of adulteration in pistachio nuts, combined with low cost, strong reliability, a high level of accuracy, rapidity of analysis, and minimum sample preparation. © 2020 Society of Chemical Industry

Rapid Screening of Mentha spicata Essential Oil and L-Menthol in Mentha piperita Essential Oil by ATR-FTIR Spectroscopy Coupled with Multivariate Analyses

“…Previous Data from several studies reported that the 4000-600 cm −1 spectral range included fingerprinting spectral information, which could be used to obtain classification patterns of authentic and counterfeit herbal samples [21]. HCA is an algorithmic approach and it provides an opportunity to observe the classification pattern of authentic and adulterated samples on 2-D dendrogram plots [22]. Dendrograms are composed of branches which include sample sets and sub-sets.…”

“…The current research used two different multivariate calibration models (PLSR and PCR) for the prediction of Mentha spicata and L-menthol contents of adulterated Menhta piperita samples. These powerful chemometrics are widely used to detect and quantify suspicious additives or adulterants in the various matrices such as foods, beverages, and essential oil for the sustainability of originality of high-valued products [22]. In the present study, research calibration and cross-validation was carried out for the samples of Mentha piperita EO (MP1, MP2, MP3), Mentha spicata EO (MS1, MS2, MS3), L-menthol (LM1, LM2, LM3) and adulterated Mentha piperita EOs at the concentration levels of 0, 1, 2, 4, 8, 16, 32, 64, 100% (v/v).…”

Nuts as a Dietary Enrichment with Selected Minerals—Content Assessment Supported by Chemometric Analysis

“…Chemometric analyses of nuts described in the literature are primarily related to data on the chromatographic fingerprint [ 61 ], interpretation of results obtained by Raman spectroscopy [ 62 ] or Fourier transform infrared spectroscopy [ 63 ], or a combination of chemometric and metabolomic techniques [ 64 ].…”

Application of Raman Spectroscopic Methods in Food Safety: A Review

“…Besides adulteration causing image loss of food products due to dishonesty and depriving consumers of vital nutrients, adulterants can be hazardous to human health as they may be toxic or induce allergies [77]. Examples of adulterations that can be detected by Raman spectroscopic methods include olive oil adulterated with rapeseed and corn oil [78], honey adulterated with fructose, glucose, inverted sugar, hydrolyzed inulin syrup, and malt must [79], pistachio nuts adulterated with green peas [80], cassava starch adulterated with wheat flour or sodium bicarbonate [77], and butter adulterated with margarine [81].…”