While the olive fruit can be consumed after fermentation and other treatment
aimed to reduce its strong bitterness caused by phenolic compounds, the main use of
this product worldwide is for olive oil extraction.
The majority of the oil is contained in the olive flesh, and approximately 5% is
contained in the seed. The composition of olive oil is dramatically different from the
olive drupe. Triacylglycerols represent the majority of compounds in olive oil. Other
constituents are “free” fatty acids (not bound to a glyceride molecule) and mono- and
diacylglycerols present at low concentration, together with hydrocarbons, sterols,
aliphatic alcohols, tocopherols and pigments (Boskou et al. 2006). Most of the
so-called minor constituents of olive oils are often regarded as particularly important
in terms of health properties and sensory effects of virgin olive oils (VOOs).
Tocopherols are antioxidant compounds found in appreciable amounts in olive
oil, especially α-tocopherol, found at 150–250 mg kg
À1 . Similar amounts have been
reported in EVOOs for phytosterols, with β-sitosterol representing 90–95% the total
sterolic fraction (Peri 2014). The analysis of sterols can be useful for authenticity
purposes as a tool to differentiate oils from different sources, and in fact strict limits
are applied also regarding the content of specific phytosterols in olive oils.
Oleic acid is the major fatty acid found in olive oil lipid fraction, and it is
approximately 55.0–83.0% of the total lipid content (Boskou et al. 2006; Beltrán
et al. 2004), with variations depending on the olive variety and agronomical factors.
Palmitic (7.5–20.0%), palmitoleic (0.3–3.5%), stearic (0.5–5.0%), linoleic (3.5–
21.0%) and linolenic acids are also present in appreciable amounts, while myristic,
heptadecanoic and eicosanoic acids are found in trace amounts (Boskou et al. 2006).
Fatty acid composition of olive oils is known to vary within certain limits
depending on several factors, including the olive variety, climate, altitude and
other agronomic conditions, as well as the ripening degree of the olive fruits at
harvest (Table 9.1). Established limits for fatty acid composition are included in the
International Olive Council (IOC 2013) and the Codex Alimentarius (2003) norms
as well as the European regulations (1991, 2002, 2013).
Tocopherols are found in relatively abundant concentrations in olive oils, with
α-tocopherol being the most abundant one. The range of tocopherols can vary from
approximately 50 mg/kg to above 350 mg/kg (Boskou et al. 2006; Caporaso et al.
2015a, b).
Sterols have an interest from a chemical point of view because they can be used as
genuineness indicators, due to their dependence upon genetic factors, e.g. detection
of sunflower oil added to olive oil. Limits of total sterols are set between 1000 and
2000 mg/kg. High levels are an indicator of admixture with lampante oils, while a
lower content reveals the presence of refined olive oils (a process forbidden for
virgin olive oils) (Table 9.2).
Table Olives
In addition to olive oil production, table olives are another product obtained from the
olive tree. They can be consumed as they are, after a fermentation process aimed to
lower their strong bitterness and make them edible (Montaño et al. 2010).
Table olive processing is based on either using a brine treatment or alkali treatment
9 Olive (Olea europaea)
215
aimed to reduce its strong bitterness caused by phenolic compounds, the main use of
this product worldwide is for olive oil extraction.
The majority of the oil is contained in the olive flesh, and approximately 5% is
contained in the seed. The composition of olive oil is dramatically different from the
olive drupe. Triacylglycerols represent the majority of compounds in olive oil. Other
constituents are “free” fatty acids (not bound to a glyceride molecule) and mono- and
diacylglycerols present at low concentration, together with hydrocarbons, sterols,
aliphatic alcohols, tocopherols and pigments (Boskou et al. 2006). Most of the
so-called minor constituents of olive oils are often regarded as particularly important
in terms of health properties and sensory effects of virgin olive oils (VOOs).
Tocopherols are antioxidant compounds found in appreciable amounts in olive
oil, especially α-tocopherol, found at 150–250 mg kg
À1 . Similar amounts have been
reported in EVOOs for phytosterols, with β-sitosterol representing 90–95% the total
sterolic fraction (Peri 2014). The analysis of sterols can be useful for authenticity
purposes as a tool to differentiate oils from different sources, and in fact strict limits
are applied also regarding the content of specific phytosterols in olive oils.
Oleic acid is the major fatty acid found in olive oil lipid fraction, and it is
approximately 55.0–83.0% of the total lipid content (Boskou et al. 2006; Beltrán
et al. 2004), with variations depending on the olive variety and agronomical factors.
Palmitic (7.5–20.0%), palmitoleic (0.3–3.5%), stearic (0.5–5.0%), linoleic (3.5–
21.0%) and linolenic acids are also present in appreciable amounts, while myristic,
heptadecanoic and eicosanoic acids are found in trace amounts (Boskou et al. 2006).
Fatty acid composition of olive oils is known to vary within certain limits
depending on several factors, including the olive variety, climate, altitude and
other agronomic conditions, as well as the ripening degree of the olive fruits at
harvest (Table 9.1). Established limits for fatty acid composition are included in the
International Olive Council (IOC 2013) and the Codex Alimentarius (2003) norms
as well as the European regulations (1991, 2002, 2013).
Tocopherols are found in relatively abundant concentrations in olive oils, with
α-tocopherol being the most abundant one. The range of tocopherols can vary from
approximately 50 mg/kg to above 350 mg/kg (Boskou et al. 2006; Caporaso et al.
2015a, b).
Sterols have an interest from a chemical point of view because they can be used as
genuineness indicators, due to their dependence upon genetic factors, e.g. detection
of sunflower oil added to olive oil. Limits of total sterols are set between 1000 and
2000 mg/kg. High levels are an indicator of admixture with lampante oils, while a
lower content reveals the presence of refined olive oils (a process forbidden for
virgin olive oils) (Table 9.2).
Table Olives
In addition to olive oil production, table olives are another product obtained from the
olive tree. They can be consumed as they are, after a fermentation process aimed to
lower their strong bitterness and make them edible (Montaño et al. 2010).
Table olive processing is based on either using a brine treatment or alkali treatment
9 Olive (Olea europaea)
215