– K 232
– K 270
– ΔK
In addition, sensory analysis (panel test) is compulsory, as described in previous
sections.
In addition to these parameters, one can investigate the content of chlorophylls,
fatty acid composition to assess the level of oleic acid, triacylglycerol composition
and composition and level of phenolic compounds, sterols and other minor
constituents.
For authenticity and safety purposes, parameters that can be tested include
contaminants, the level of α-tocopherol (as a possible indicator of deodorisation),
volatiles and specific phenolic compounds, monoacylglycerols and diacylglycerols
(the ratio of 1,2- to 1,3-diacylglycerols is an indicator of VOO freshness),
pigments, etc.
Several methods are also used to verify the genuineness of olive oils: these
include fatty acid composition; presence of trans-fatty acids (indicators of thermally
processed oils); fatty acids in the 2-position of the triacylglycerol (to identify oils
prepared by esterification); equivalent chain number (ECN); sterol composition
(to verify adulteration of olive oil with other vegetable oils, as certain sterols are
related to the plant of origin); content of erythrodiol, uvaol and waxes (to exclude
oils obtained by solvent treatment); content of aliphatic alcohols (indicators of olive
pomace oil added to olive oil); and level of stigmastadienes (indicators of thermally
treated oils or products that undergo bleaching process) (Boskou 2006, 2015).
Other analytical methods can also be used, some non-official methods, for
authenticity purposes. All these methods have been reviewed and explained in
details by Angerosa et al. (2006) and Lercker and Rodriguez-Estrada (2000).
It has been highlighted that the current issues related to olive oil authenticity are
mostly related to the fraudulent marketing of deodorised virgin olive oils treated with
mild conditions that are not easily detectable by instrumental methods, the addition
of VOOs obtained from a second mechanical extraction after the first pass, the
incorrect use of geographical origin declaration and the misclassification of VOO
(declassed for sensory defects of physico-chemical characteristics) that are sold as
EVOOs.
In addition to these issues, the olive variety identification is also of interest for
producers, consumers and control bodies. Some Protected Designation of Origin
(PDO) products from well-defined origins or of mono-variety EVOOs might be
perceived as oils with higher quality. Mono-variety EVOOs have been studied in the
literature, but from a practical point of view, there are two issues related to the
application of this knowledge. Olive plants require pollination, while the use of
many varieties in the field is often recommended: thus, obtaining a “pure” monovariety EVOO is difficult especially for certain cultivars. In addition, blending is one
of the most common industrial practice, used to obtain consistent product and for
economic reasons. Discrimination based on DNA methods or analysis of volatile
9 Olive (Olea europaea)
233
– K 270
– ΔK
In addition, sensory analysis (panel test) is compulsory, as described in previous
sections.
In addition to these parameters, one can investigate the content of chlorophylls,
fatty acid composition to assess the level of oleic acid, triacylglycerol composition
and composition and level of phenolic compounds, sterols and other minor
constituents.
For authenticity and safety purposes, parameters that can be tested include
contaminants, the level of α-tocopherol (as a possible indicator of deodorisation),
volatiles and specific phenolic compounds, monoacylglycerols and diacylglycerols
(the ratio of 1,2- to 1,3-diacylglycerols is an indicator of VOO freshness),
pigments, etc.
Several methods are also used to verify the genuineness of olive oils: these
include fatty acid composition; presence of trans-fatty acids (indicators of thermally
processed oils); fatty acids in the 2-position of the triacylglycerol (to identify oils
prepared by esterification); equivalent chain number (ECN); sterol composition
(to verify adulteration of olive oil with other vegetable oils, as certain sterols are
related to the plant of origin); content of erythrodiol, uvaol and waxes (to exclude
oils obtained by solvent treatment); content of aliphatic alcohols (indicators of olive
pomace oil added to olive oil); and level of stigmastadienes (indicators of thermally
treated oils or products that undergo bleaching process) (Boskou 2006, 2015).
Other analytical methods can also be used, some non-official methods, for
authenticity purposes. All these methods have been reviewed and explained in
details by Angerosa et al. (2006) and Lercker and Rodriguez-Estrada (2000).
It has been highlighted that the current issues related to olive oil authenticity are
mostly related to the fraudulent marketing of deodorised virgin olive oils treated with
mild conditions that are not easily detectable by instrumental methods, the addition
of VOOs obtained from a second mechanical extraction after the first pass, the
incorrect use of geographical origin declaration and the misclassification of VOO
(declassed for sensory defects of physico-chemical characteristics) that are sold as
EVOOs.
In addition to these issues, the olive variety identification is also of interest for
producers, consumers and control bodies. Some Protected Designation of Origin
(PDO) products from well-defined origins or of mono-variety EVOOs might be
perceived as oils with higher quality. Mono-variety EVOOs have been studied in the
literature, but from a practical point of view, there are two issues related to the
application of this knowledge. Olive plants require pollination, while the use of
many varieties in the field is often recommended: thus, obtaining a “pure” monovariety EVOO is difficult especially for certain cultivars. In addition, blending is one
of the most common industrial practice, used to obtain consistent product and for
economic reasons. Discrimination based on DNA methods or analysis of volatile
9 Olive (Olea europaea)
233