Agriculture Reference
In-Depth Information
international market. That is why the IOC establishes a
commercial standard applicable to olive oil and pomace.
This standard establishes physicochemical criteria for each
of the designations of the olive oils and olive pomace men-
tioned in the International Convention, as well as quality
and purity criteria that distinguish each designation in a
manner similar to the US and EU standards. The members
of the IOC undertake to prohibit the use of any designation
other than those specified. That standard (IOC, 2009) is re-
flected in part in Table 26.7. In all the standards (USDA, EU,
and IOC), parameters are defined both for the quality and
purity that is required to meet each category of olive oil.
Among the parameters that define the quality criteria
common to the three standards (US, EU, and IOC) to be
determined are (1)
level of free acidity,
determined based on
the percentage of free fatty acids expressed as oleic acid, an
index of possible fermentation of the fruit during storage;
(2)
peroxide index,
determined in milliequivalents of active
O
2
per kilogram of oil and assesses the state of primary
oxidation of the oil; (3)
K232,
a spectrophotometric mea-
surement at 232 nm of conjugated dienes and also an index
of primary oxidation of the oil; (4)
K270,
used to evalu-
ate, spectrophotometrically (270
nm
), the conjugated trienes
and indicating the state of secondary oxidation of the oil;
and (5) the
matter, insoluble impurities in light petroleum, flash point,
and trace metals. The IOC also describes a category of vir-
gin olive oil designated “ordinary” whose acidity exceeds
3.3 (expressed as a percentage of oleic acid).
However, it is common to all standards (US, EU, and
IOC) to disallow the addition of any additives to virgin olive
oils and crude olive pomace oil. Meanwhile, for refined
olive oil, olive oil, refined olive pomace oil, and olive po-
mace oil, the addition of alpha-tocopherol is authorized for
replacing the natural tocopherol lost during refining, with
a maximum dose of 200 mg/kg of total alpha-tocopherol in
the final product (IOC, 2009).
Nutritional profile and health
The saponifiable part makes up approximately 98% of the
olive oil, consisting mainly of triglycerides (Table 26.8).
Among the fatty acids that are part of the triglycerides,
oleic acid is the most prevalent, between 56% and 84% of
that part. This is one of the differences between olive oil
and other oils, a high content of monounsaturated fatty
acids (MUFAs) from oil derived from olives. Olive oil
also contains between 3% and 21% linoleic acid, which
is the most essential fatty acid in our diet. However, the
health properties of olive oil are not only derived from its
fatty acid composition but also from the fact that within
the unsaponifiable fraction are the components responsible
for the specific characteristics of virgin olive oil, such as
color, flavor, and oxidative stability. Among them (Table
26.8) are the phenols, chlorophyll and carotenoids, vita-
min E (including
α
-tocopherol),
β
-sitosterol, and squalene
(Berm udez et al., 2004).
K coefficient,
calculated as
K
=
K268 -
[(K262
K274)/2]. The resulting products of the sec-
ondary oxidation (aldehydes and ketones) absorb wave-
lengths of 262, 268, and 274
nm
.
Virgin olive oils are also classified by their
sensory
char-
acteristics that are determined by a group of trained tasters,
according to the rules of sensory analysis (Albi and Gutier-
rez, 1991). Among the positives attributes is a fruity odor,
which is the most important since without it the oil cannot
be considered virgin. This odor is defined as a set of olfac-
tory sensations that is characteristic of the oil and depends
on the variety of the olive. It comes from healthy fresh fruit
that is green or ripe and is perceived through direct and/or
retronasal breathing. Bitterness and spiciness can also be
considered as positive attributes. Among the negative at-
tributes are fusty, musty, sour-vinegary, metallic, rancid,
burnt, hay-wood, rough, greasy, vegetable water, brine, es-
parto, muddy, grubby, cucumber, and wet wood (EU, 2008).
All of these parameters described (acidity, peroxide in-
dex,
K
232,
K
270,
+
Table 26.8.
Olive oil composition.
Compounds
Content (% or ppm)
Saponifiable fraction (98.5%)
%
Monounsaturated fatty acids
Polyunsaturated fatty acids
Saturated fatty acids
77.5
6.3
16.3
Unsaponifiable fraction (1.5%)
ppm
Terpenes
Hydrocarbons (mainly squalene)
Sterols (mainly
3,000-7,000
1,500-7,000
800-2,500
50-500
30-150
5-45
250
K,
sensory characteristics) constitute
the quality standard in accordance with current European
legislation (Table 26.7). However, the quality standard for
the US includes, in addition to those mentioned previously,
odor and color (Table 26.7). In turn, the IOC standard in-
cludes, in addition to those mentioned previously, the ap-
pearance at 20
◦
C after 24 hours, of moisture and volatile
β
-sitosterol)
Phenols
Tocopherols (
)
Chlorophylls and carotenoids
Others (cetones, esters, ethers)
α
,
β
,
δ
and
γ
Source: Civantos (2008c); Berm udez et al. (2004).
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