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

An electronic nose (zNose™) 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 (R2 = 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.

[1]  Pamela J. White,et al.  Relationship of electronic nose analyses and sensory evaluation of vegetable oils during storage , 2001 .

[2]  D. Ballabio,et al.  Evaluation of different storage conditions of extra virgin olive oils with an innovative recognition tool built by means of electronic nose and electronic tongue , 2007 .

[3]  H. L. Gan,et al.  Characterisation of vegetable oils by surface acoustic wave sensing electronic nose , 2005 .

[4]  M. Namiki,et al.  Aroma constituents of roasted coconut. , 1984 .

[5]  Jun Wang,et al.  Prediction of soluble solids content, firmness and pH of pear by signals of electronic nose sensors. , 2008, Analytica chimica acta.

[6]  T. Rajamohan,et al.  Beneficial effects of virgin coconut oil on lipid parameters and in vitro LDL oxidation. , 2004, Clinical biochemistry.

[7]  Kevin L. Goodner,et al.  Comparison of Headspace GC and Electronic Sensor Techniques for Classification of Processed Orange Juices , 2000 .

[8]  Hongmei Zhang,et al.  Quality grade identification of green tea using E-nose by CA and ANN , 2008 .

[9]  J. Leffler,et al.  The Role of the Solvent in Radical Decomposition Reactions: Phenylazotriphenylmethane , 1954 .

[10]  H. L. Gan,et al.  Monitoring the storage stability of RBD palm olein using the electronic nose , 2005 .

[11]  M. Omar.  Microstructure, free amino acids and free fatty acids in Ras cheese , 1984 .

[12]  Y. Man,et al.  MONITORING THE ADULTERATION OF VIRGIN COCONUT OIL BY SELECTED VEGETABLE OILS USING DIFFERENTIAL SCANNING CALORIMETRY , 2009 .

[13]  D. Firestone,et al.  Official methods and recommended practices of the American Oil Chemists' Society , 1990 .

[14]  Chin Ping Tan,et al.  Detection of lard adulteration in RBD palm olein using an electronic nose , 2005 .

[15]  M. C. Oliveros,et al.  Electronic nose based on metal oxide semiconductor sensors and pattern recognition techniques: characterisation of vegetable oils , 2001 .

[16]  Jun Wang,et al.  Electronic nose and data analysis for detection of maize oil adulteration in sesame oil , 2006 .

[17]  J. Ventanas,et al.  An electronic nose to classify Iberian pig fats with different fatty acid composition , 2001 .

[18]  T. Rajamohan,et al.  Influence of virgin coconut oil on blood coagulation factors, lipid levels and LDL oxidation in cholesterol fed Sprague–Dawley rats , 2008 .

[19]  S. Biswas,et al.  Differentiation of vegetable oils and determination of sunflower oil oxidation using a surface acoustic wave sensing device , 2004 .

[20]  Jun Wang,et al.  Evaluation of peach quality indices using an electronic nose by MLR, QPST and BP network , 2008 .

[21]  Y. Man,et al.  Determining α-tocopherol in refined bleached and deodorized palm olein by Fourier transform infrared spectroscopy , 2005 .

[22]  Y. Man,et al.  ANALYSIS OF ADULTERATION OF VIRGIN COCONUT OIL BY PALM KERNEL OLEIN USING FOURIER TRANSFORM INFRARED SPECTROSCOPY , 2007 .

[23]  A. H. Gómez,et al.  Evaluation of tomato maturity by electronic nose , 2006 .

[24]  Pamela J. White,et al.  Oxidative stability and AromaScan analyses of corn oils with altered fatty acid content , 1999 .

[25]  J. S. Pai,et al.  Effect of heat treatments on the volatile composition of coconut oil , 1979 .

[26]  W. J. Harper,et al.  Application of an electronic nose to correlate with descriptive sensory analysis of aged Cheddar cheese , 2003 .

[27]  T. Rajamohan,et al.  Virgin coconut oil supplemented diet increases the antioxidant status in rats , 2006 .

[28]  C. S. Narayanan,et al.  Volatile aroma compounds of raw and roasted palm kernel , 1987 .

[29]  Jeroen Lammertyn,et al.  zNose technology for the classification of honey based on rapid aroma profiling , 2004 .

[30]  F. Shahidi.  Nutraceutical and Specialty Lipids and their Co-Products , 2006 .

[31]  A. G. Mathew,et al.  Identification of volatile flavor compounds in roasted coconut , 1991 .

[32]  José Pedro Santos,et al.  SAW sensor array for wine discrimination , 2005 .

[33]  Sylwia Mildner-Szkudlarz,et al.  The potential of different techniques for volatile compounds analysis coupled with PCA for the detection of the adulteration of olive oil with hazelnut oil , 2008 .

[34]  D. Nakhasi,et al.  MEDIUM CHAIN TRIACYLGLYCEROLS , 1996 .