Chia Oil Adulteration Detection Based on Spectroscopic Measurements

Abstract

Chia oil is a valuable source of omega-3-fatty acids and other nutritional components. However, it is expensive to produce and can therefore be easily adulterated with cheaper oils to improve the profit margins. Spectroscopic methods are becoming more and more common in food fraud detection. The aim of this study was to answer following questions: Is it possible to detect chia oil adulteration by spectroscopic analysis of the oils? Is it possible to identify the adulteration oil? Is it possible to determine the amount of adulteration? Two chia oils from local markets were adulterated with three common food oils, including sunflower, rapeseed and corn oil. Subsequently, six chia oils obtained from different sites in Kenya were adulterated with sunflower oil to check the results. Raman, NIR and fluorescence spectroscopy were applied for the analysis. It was possible to detect the amount of adulterated oils by spectroscopic analysis, with a minimum R2 of 0.95 for the used partial least square regression with a maximum RMSEPrange of 10%. The adulterations of chia oils by rapeseed, sunflower and corn oil were identified by classification with a median true positive rate of 90%. The training accuracies, sensitivity and specificity of the classifications were over 90%. Chia oil B was easier to detect. The adulterated samples were identified with a precision of 97%. All of the classification methods show good results, however SVM were the best. The identification of the adulteration oil was possible; less than 5% of the adulteration oils were difficult to detect. In summary, spectroscopic analysis of chia oils might be a useful tool to identify adulterations.

Techniques for Food Authentication: Trends and Emerging Approaches

“…Nevertheless, the effective application of spectroscopic approaches in food authentication relies on the construction of suitable spectral databases and multivariate analysis. The combined techniques of Raman, near-infrared (NIR), and fluorescence spectroscopy were applied to the analysis of chia oils adulterated with sunflower oil [ 11 ]. Fourier transform mid-infrared spectroscopy with attenuated total reflection (ATR-FTMIR), coupled to multivariate analysis, was applied to discriminate doughs and 3D-printed baked snacks, enriched with edible insect ( Alphitobius diaperinus and Locusta migratoria ) powders [ 12 ].…”

Identification of adulterants (sunflower oil and soybean oil) in grapeseed oil (Vitis vinifera L.) and chia oil (Salvia hispanica L.) by FT-MIR spectroscopy and chemometric

“…Thus, their detection is increasingly difficult. Several techniques have been developed for the analysis of adulterants in edible vegetable oils, for example: highperformance liquid chromatography (HPLC) (De la Mata-Espinosa et al, 2011), nuclear magnetic resonance (RMN) (Zhang et al, 2013), gas chromatography (GC) (Ruiz-Samblás et al, 2012), fluorescence spectroscopy (Ge et al, 2014;Mburu et al, 2021), near infrared spectroscopy (Mburu et al, 2021), Raman spectroscopy (Mburu et al, 2021;Farley et al, 2016) and Mid-Infrared spectroscopy (Jiménez-Sotelo et al, 2016).…”