in salt and spices. Additionally, other typical Italian olives are used as stuffed olives
(Ascolana-style), from a variety that gives big fruits with thick and crunchy mesocarp (Lanza 2012).
Despite the fact that the olive drupe is technically a fruit, it has very low
carbohydrate content and can be considered as sugar-free when it is in the form of
edible table olives, due to the loss of sugars during the fermentation process.
Table olives are also a “source of fibre” according to the European legislation, the
minimum limit being 3 g fibre per 100 g product. In terms of mineral content, table
olives contain a good amount of calcium, of about 100 mg per 100 g. It is important
to note that salt is always added for table olive preparation so the sodium content is
high, usually above 1.5 g/100 g. Table olives are rich in antioxidants and vitamins,
including vitamins B, A and E. The content of vitamin C is low (<1 mg/kg), but
some producers add it as a preservative, thus higher contents might be found. The
amount of phenolic compounds in table olives is higher than the one in virgin olive
oils, with concentrations ranging from 100 to 350 mg per 100 g of product. Organic
acids such as oxalic, succinic, malic, citric and lactic are found in rather low content
(4–10 g/kg, expressed as citric acid). The energy value of table olives has been
reported to be 200–250 kcal per 100 g, with a few exceptions including Majatica
olives (above 350 kcal) and Bella di Cerignola (160 kcal) (Lanza 2012).
9.3.1 Olive Oil Minor Constituents
The study of volatile and non-volatile minor compounds in olive oils has been
extensively used to evaluate their quality or to describe peculiarities of some olive
varieties (Boskou 2008). For example, some differences in the concentration of
phenolic compounds, sterols and the linoleic/oleic acid ratio have been reported
among the Spanish cultivar Arbequina compared to the Italian cultivar Coratina and
the Greek cultivar Koroneiki (Aparicio et al. 1997).
Hundreds of volatile compounds have been identified in virgin olive oils, but
similar to other food products, only a limited number of compounds exert an odour
impact. The number of odour-active compounds at the usual concentrations found in
VOOs is approximately 60 (Angerosa et al. 1996), while the number of “potent
odorants” is more limited (Guth and Grosch 1991).
Extensive research carried out over the past 20 years, mostly by Italian, Spanish
and Greek research groups, allowed to get an insight into the complex VOO volatile
composition and to understand the formation pathways of aroma compounds. Some
volatile compounds are still present in the fruit, as they originate from the lipid or
amino acid metabolism (Conde et al. 2008; Kalua et al. 2007). However, the
majority of the olive aroma derives from enzymatic oxidation of the fatty acids
linoleic and linolenic (Angerosa 2002).
VOO volatile compounds are mostly C5 and C6 molecules, the majority of which
arises from the so-called lipoxygenase pathway. This name was given because
lipoxygenase is one of the first enzymes to act, by catalysing the deoxygenation of
9 Olive (Olea europaea)
219
(Ascolana-style), from a variety that gives big fruits with thick and crunchy mesocarp (Lanza 2012).
Despite the fact that the olive drupe is technically a fruit, it has very low
carbohydrate content and can be considered as sugar-free when it is in the form of
edible table olives, due to the loss of sugars during the fermentation process.
Table olives are also a “source of fibre” according to the European legislation, the
minimum limit being 3 g fibre per 100 g product. In terms of mineral content, table
olives contain a good amount of calcium, of about 100 mg per 100 g. It is important
to note that salt is always added for table olive preparation so the sodium content is
high, usually above 1.5 g/100 g. Table olives are rich in antioxidants and vitamins,
including vitamins B, A and E. The content of vitamin C is low (<1 mg/kg), but
some producers add it as a preservative, thus higher contents might be found. The
amount of phenolic compounds in table olives is higher than the one in virgin olive
oils, with concentrations ranging from 100 to 350 mg per 100 g of product. Organic
acids such as oxalic, succinic, malic, citric and lactic are found in rather low content
(4–10 g/kg, expressed as citric acid). The energy value of table olives has been
reported to be 200–250 kcal per 100 g, with a few exceptions including Majatica
olives (above 350 kcal) and Bella di Cerignola (160 kcal) (Lanza 2012).
9.3.1 Olive Oil Minor Constituents
The study of volatile and non-volatile minor compounds in olive oils has been
extensively used to evaluate their quality or to describe peculiarities of some olive
varieties (Boskou 2008). For example, some differences in the concentration of
phenolic compounds, sterols and the linoleic/oleic acid ratio have been reported
among the Spanish cultivar Arbequina compared to the Italian cultivar Coratina and
the Greek cultivar Koroneiki (Aparicio et al. 1997).
Hundreds of volatile compounds have been identified in virgin olive oils, but
similar to other food products, only a limited number of compounds exert an odour
impact. The number of odour-active compounds at the usual concentrations found in
VOOs is approximately 60 (Angerosa et al. 1996), while the number of “potent
odorants” is more limited (Guth and Grosch 1991).
Extensive research carried out over the past 20 years, mostly by Italian, Spanish
and Greek research groups, allowed to get an insight into the complex VOO volatile
composition and to understand the formation pathways of aroma compounds. Some
volatile compounds are still present in the fruit, as they originate from the lipid or
amino acid metabolism (Conde et al. 2008; Kalua et al. 2007). However, the
majority of the olive aroma derives from enzymatic oxidation of the fatty acids
linoleic and linolenic (Angerosa 2002).
VOO volatile compounds are mostly C5 and C6 molecules, the majority of which
arises from the so-called lipoxygenase pathway. This name was given because
lipoxygenase is one of the first enzymes to act, by catalysing the deoxygenation of
9 Olive (Olea europaea)
219