Unfiltered
olive oil (also known as ''cloudy olive oil'', ''veiled olive oil'', or ''olio nuovo'') is an intermediate product of
olive oil extraction
Olive oil extraction is the process of extracting the oil present in olive drupes, known as olive oil. Olive oil is produced in the mesocarp cells, and stored in a particular type of vacuole called a lipo vacuole, i.e., every cell conta ...
. It is actually the initial cloudy juice of the
olive drupes soon after crushing, separation and
decanting and before final
filtration. The oil is either filtered or stored in tanks to settle for weeks or months to allow sediments to be separated from the oil; this is known as ''racking''.
Once opened, unfiltered olive oil has a shorter life because the olive particles continue to ferment in the bottle.
Application
Although most commercially available olive oil in the world market is filtered, unfiltered olive oil is gaining increasing popularity amongst olive oil small scale producers, some chefs, and people who prefer a more "natural" aesthetic. They believe that this oil has superior sensory characteristics compared to filtered olive oil, because it is a less processed product.
Nature of cloudiness
Unfiltered olive has aspects of both a
suspension
Suspension or suspended may refer to:
Science and engineering
* Suspension (topology), in mathematics
* Suspension (dynamical systems), in mathematics
* Suspension of a ring, in mathematics
* Suspension (chemistry), small solid particles suspende ...
and an
emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...
. Plant material from olive drupes is suspended in oil due to lack of the filtering step, along with microdroplets of vegetative and non-vegetative
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
in small amounts (0.1–0.3%) forming in a water-oil emulsion. Unfiltered olive oil initially has higher levels of
phenolics that form a complex polyphenol-
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
complex
Complex commonly refers to:
* Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe
** Complex system, a system composed of many components which may interact with each ...
. This complex interacts within the suspension/emulsion system and contributes to the formation and maintenance of the physicochemical properties of this oil. However, the presence of water in unfiltered oil leads to a more rapid hydrolysis of these water-associated phenolics, and also to hydrolysis of the
triglycerides
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...
in the oil, and
enzymes present in particles of olive fruit and pit and
pathogens
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...
such as
yeasts
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...
can accelerate the rate of degradation of the quality of the oil and increase the oil
free acidity. The overall effect of filtration on olive oil durability is controversial, with different studies coming to different conclusions, and likely also depends on the specific systems used to filter the oil.
The main phenolics found in olive oil are
secoiridoids
Iridoids are a type of monoterpenoids in the general form of cyclopentanopyran, found in a wide variety of plants and some animals. They are biosynthetically derived from 8-oxogeranial. Iridoids are typically found in plants as glycosides, mo ...
,
hydroxytyrosol
Hydroxytyrosol is an organic compound with the formula . Classified as a phenylethanoid, i.e. a relative of phenethyl alcohol, Its derivatives are found in a variety of natural sources, notably olive oils and wines. The compound is colorless sol ...
, and
tyrosol
Tyrosol is an organic compound with the formula . Classified as a phenylethanoid, i.e. a derivative of phenethyl alcohol, It is found in a variety of natural sources. The compound is colorless solid. The principal source in the human diet is ol ...
, along with
caffeic,
vanillic,
p-coumaric,
syringic and
p-hydroxy benzoic acids,
3-hydroxyphenylethanol and
3,4-dihydroxyphenylethanol
Hydroxytyrosol is an organic compound with the formula . Classified as a phenylethanoid, i.e. a relative of phenethyl alcohol, Its derivatives are found in a variety of natural sources, notably olive oils and wines. The compound is colorless solid ...
.
[“Polyphenols in olive oils”. T. Gutfinger, ''Journal of the American Oil Chemists' Society'', Volume 58, Number 11, 966–968, ]
Natural cloudiness versus low-temperature cloudiness
Olive oil cloudiness resulting from sediments discussed in this article is different from the characteristic cloudiness of olive oil due to storage at low temperatures
EF This type of cloudiness is the result of congealing of triglycerides. When these oils are returned to room temperature, they become again transparent. Unfiltered olive oil has a cloudy appearance that can persist months after the oil has been returned to room temperature.
References
Further reading
*
{{DEFAULTSORT:Unfiltered Oil
Olive oil
Mediterranean cuisine