Vegetable oils authenticity

The presence of vegetable oils of high linoleic acid content in olive oil can be detected by measuring its authenticity factor (Au) as follows ... 

In conclusion, it seems probable that, with the exception of unrefined oils and lecithin, there is no likelihood of detection of the presence of GM oils in most of the vegetable oils traded throughout the world in the foreseeable future. The only way to ensure that oils are authentic would be a complex, comprehensive and expensive scheme inspection and accreditation scheme, including the analysis of all batches of the source oilseed. This does not seem a likely possibility. 

Spangenberg, J.E. and Ogrinc, N. (2001) Authentication of vegetable oils by bulk and molecular carbon isotope analysis with emphasis on olive oil and pumpkin seed oil. J. Agric. Food Chem., 49, 1534-1540. 

Flor et al. (1993) were the first to develop criteria for the authentication of olive oil based on vegetable oil HPLC data. They observed that corn, cottonseed, soyabean, sunflower and safflower oils, to mention the most important commercial products, have large peaks for LLL, LLO and LLP but generally smaller LOO and LOP peaks (abbreviations P, palmitic O, oleic S, stearic L, linoleic Ln, linolenic Po, palmitoleic). Additional typical peaks were observed LnLL peak (ca. 7%) in soyabean and LnLO peak (ca. 7%) in rapeseed oils, respectively. Other relevant compositional pictures were observed peanut oil displays a relatively small LLL peak (ca. 3.5%) but larger LLO and LLP peaks (ca. 18.2, 5.9%, respectively). 

Because of the toxic nature of these oxidized components, the authors cautioned regular intake of encapsulated fish oils. The sale of oxidized fish oil products can be considered criminal as they pose potential health risks to the consumer. In addition to ensuring that the consumer is buying the authentic product, it must be fresh, with a clear and realistic shelf-life date indicated. The presence of vegetable oils in a fish oil is best tested for by examination of the sterol composition, as fish oils consist almost entirely of cholesterol and 24-methyl cholesterol (Paganuzzi, 1983). Analysis of the sterol fraction of the oil can often identify the oil, or at least indicate which oils might be present. 

In testing for authenticity of bovine milk fat (Luf, 1988a Younes and Soliman, 1987) the first test should be for the presence of plant sterols, this indicating the presence or absence of vegetable oils. This can be carried out by similar... 

The fats and oils standards aim to provide protection in terms of authenticity of the products covered and contain descriptions of each. They also recognize that the fatty acid composition is one of the main ways of identifying and distinguishing one oil/fat from another. Fatty acid specifications for each oil/fat are included as essential composition and quality factors and are reproduced in Tables 8.6 and 8.7. For vegetable oils, it is also recognized that other compositional factors may be used to assist in assessing authenticity—iodine... 

King, B., Sibley, I. and Zilka, S.A. (1985) Authenticity of edible vegetable oils and fats, Part VII maize oil. Leatherhead Food RA Research Reports No. 522. Leatherhead Food RA, UK. 

Stewart, C.A. and Gillatt, P.N. (1996) Authenticity of single seed vegetable oils—a survey of the UK market. J. Assoc. Public Analysts, 32, 179-214. 

TABLE 8. The Use of Sterol Composition for the Authentication of Vegetable Oils (% in Respective Fraction). 

Over the last decades, infrared (IR) vibrational sprectroscopy has been well established as a useful tool for structure elucidation and quafity control in several industrial applications. Indeed, the development of Fourier transform (FT) IR and attenuated total reflectance (ATR) techniques have also evolved allowing rapad IR measurements of organosolvent extracts of plant tissues, edible oils, and essential oils, for example (Damm et al., 2005 Lai et al., 1994 Schulz Baranska, 2007). In consequence of the strong dip>ole moment of water, IR spectroscopy applications have mostly focused on the analysis of dried or non-aqueous plant matrices and currently IR methods are widely used as a fast analytical technique for the authentication and detection of adulteration of vegetable oils. 

Lai, YW., Kemsley, EK Wilson, J. (1994). Potential of Fourier transform infrared spectroscopy for the authentication of vegetable oils. Journal of Agricultural and Food Chemistry, Vol. 42, pp.1154-1159. ISSN 0021-8561... 

The detection and quantification of tocopherols, carotenoids, and chlorophylls in vegetable oil were effectively used for authentication pnrposes. The presence of tocopherols, carotenoids, and chlorophylls influence the oxidative stability of vegetable oils and their potential health benefits. Puspitasari-Nienaber et demonstrated the application of a rapid and reliable analysis method of direct injection of C-30 RP-NPLC with electrochemical detection for the simultaneous analysis of the above mentioned substances. Aliquots of vegetable oils were dissolved in appropriate solvents and injected directly without saponification, thus preventing sample loss or component degradation. Thus the effective separation of tocopherols, carotenoids, and chlorophylls was achieved. 

Tay, A., Singh, R.K., Krishnan, S.S., and Gore, J.P. Authentication of olive oil adulterated with vegetable oils using Fourier transform infrared spectroscopy. Zeitschriftfur Lebensmittel Untersuchung und Forschung, 35, 99-103. 2002. 

Zhang, G., Ni, Y., ChnrchiU, 1., and Kokot, S. Authentication of vegetable oils on the basis of then-physico-chemical properties with the aid of chemometrics. Talanta, 70(2), 293-300. 2006. 

TAG are increasingly used in the food industry as a tool to assess the quality and authenticity of vegetable oils [118,119], particularly adulteration of olive oil with hazelnut oil [120,121]. 

Aparicio, R. and Aparicio-Rufz, R., Authentication of vegetable oils by chromatographic techniques, J. Chromatogr. A, 881, 93-104, 2000. 

PURITY CRITERIA FOR EDIBLE VEGETABLE OILS Table 8.1 Samples analysed in the main authenticity project ... 

Among the different chemometric methods, exploratory data analysis and pattern recognition are frequently used in the area of food analysis. Exploratory data analysis is focused on the possible relationships between samples and variables, while pattern recognition studies the behavior between samples and variables [95]. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) are the methods most commonly used for exploratory analysis and pattern recognition, respectively. The importance of these statistical tools has been demonstrated by the wide number of works in the field of food science where they have been applied. The majority of the applications are related to the characterization and authentication of olive oil, animal fats, marine and vegetable oils [95], wine [97], fruit juice [98], honey [99], cheese [100,101], and so on, although other important use of statistical tools is the detection of adulterants or frauds [96,102]. 

Authentication of VOO and detection of adulteration with vegetable oils or any olive oil quality upgrade. 

Maria, T. and Robert, M. 1987. Authentication of virgin ohve oils using principal component analysis of triglyceride and fatty acid profiles Part 2, detection of adulteration with other vegetable oils. Food Chem. 25 251-258. 

Lerma-Garcra, M. J. 2012. Characterization and authentication of olive and other vegetable oils. Springer Theses, pp. 228. 

In general, the desmethylsterols are useful markers to assess authenticity. Taking into account that beta-sitosterol is the most abundant sterol in the majority of oils, its value has only limited use for the authenticity assessment and differentiation of vegetable oils. 

---