Use of the SAW Sensor Electronic Nose for Detecting the Adulteration of Virgin Coconut Oil with RBD Palm Kernel Olein

Abstract

An electronic nose (zNose TM ) was applied to the detection of adulteration of virgin coconut oil. The system, which is based on a surface acoustic wave sensor was used to generate a pattern of volatile compounds present in the samples. Virgin coconut oil was mixed with refined, bleached and deodorized palm kernel olein at a level of adulteration from 1 to 20% (wt/wt). Adulterant peaks were identified from the chromatogram profile and fitted to a curve using linear regression. The best relationship (R 2 = 0.91) was obtained between the peak tentatively identified as methyl dodecanoate and the percentage of palm kernel olein added. Pearson's correlation coefficients (r) of 0.92 and 0.89 were obtained between adulterant peak methyl dodecanoate and of the iodine and peroxide values, respectively. Principal component analysis (PCA) was used to differentiate between pure and adulterated samples. The PCA provided good differentiation of samples with 74% of the variation accounted for by PC 1 and 17% accounted for by PC 2. Pure samples formed a separate cluster from all of the adulterated samples.

Electronic Nose as a Tool for Monitoring the Authenticity of Food. A Review

“…zNose™ was also used to detect the adulteration of virgin coconut oil with RBD palm kernel olein at the level from 1 to 20% (w/w) (Marina et al 2010). The e-nose peaks were obtained from the sensor signal values, which represented the concentration of specific volatile compounds.…”

“…This image can be regarded as the chemical signature of an aroma of a substance. It is the graphical display of the SAW detector sensor converted into a planar format: the angular variable is the retention time and the radial variable is the SAW detector frequency (Marina et al 2010;Nurjuliana et al 2011a). Using PCA, the authors were able to differentiate lard fat adulterated with chicken at the level from 1 to 80% (w/w).…”

“…It was used to detect adulteration of palm olein (Che Man et al 2005), virgin coconut oil (Marina et al 2010), lard (Nurjuliana et al 2011a), and meat (Nurjuliana et al 2011b). The SAW is a piezoelectric sensor measuring the resonant frequency of the sensor, which is changed due to the changes in the mass caused by the adsorption or absorption of volatile compounds.…”

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

“…They are recognized as good alternatives to sensitive laboratory-based techniques in some situations [18]. Sensors like electronic noses [19][20][21] and thin film based chips [22] have been reported for identification and classification of vegetable cooking oils. Nanomaterials such as gold nanoparticles [23], quantum dots [24], and carbon-based nanomaterials [25] have been investigated in biosensing strategies to enhance target recognition, amplify the signal, and improve the sensitivity.…”

Fruit Volatile Analysis Using an Electronic Nose

“…The electronic nose used in our work (zNose, EST, Newbury Park, CA, USA), consists of ultra-fast gas chromatography coupled with a surface acoustic wave sensor (UFGC-SAW). This technology has already been tested for its ability to monitor quality of various commodities, including detection of deterioration in apple 5 ; ripeness and rot evaluation in mango 6 ; aroma profiling of thymus species 7 ; C 6 volatile compounds in grape berries 8 ; characterization of vegetable oil 9 and detection of adulterants in virgin coconut oil 10 .…”