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Olive oil Production. Spanish olive oil. Obtaining virgin oils. Olive tree Typical mediterranean Slowly grow Fully productive ages: 35-100 years. Flowsheet. Olive tree Olive Transport Mill Washing Crushing Grindling Press/centrifugue pressing centrifugation decantation
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Olive oil Production Spanish olive oil
Obtaining virgin oils • Olive tree • Typical mediterranean • Slowly grow • Fully productive ages: 35-100 years
Flowsheet • Olive tree • Olive • Transport • Mill • Washing • Crushing • Grindling • Press/centrifugue • pressing • centrifugation • decantation • Virgin olive oil • Storage
1. Harvesting the fruit • Olives trees flower in spring • Change from green to black • End autumm/beginning winter harvest - picked by hand or beaten from the trees with “baras” -mechanical tree shaking methods
2. Transport to the oil mill • The olives must be free of stones • To avoid braking the skin, as this would lead the beginning of the fermentation • The olives must not be piled up high or else they will heat up and start to ferment. • Olives must be processed within 24 hours after they are harvested to obtain quality olive oil
3. Washing • On the conveyor belt the leaves are separated by an air current • They are washed with normal water after they are selected for quality
4. Grinding to prepare the paste • Grinding consists of crushing the fruit (including the pits - ?) until a paste is formed which is then beaten. Water is added if necessary.
5. Separation of solid and liquid phases (oil extraction) • Several methods, but it is essential that the temperature does not exceed 35º C • Traditional system (pressing) • Classic discontinuous plants • These are the classic plants maintained throughout the centuries. The ground paste is placed between round mats and is then pressed to squeeze out the oily liquid (mixture of oil and water). It is later left to decant, as the oil floats to the top due to density differences.
5. Separation of solid and liquid phases (oil extraction) • Continuous system (by centrifugation) • Continuous plants in 3 phases • The beaten olive paste is made more liquid by adding 1 litre of water per kilogram of paste and is taken to a horizontal centrifuge where solids are separated from the oily liquid. This liquid is then taken to a vertical centrifuge where the olive oil is separated from the fruit vegetable water. • Continuous plants in 2 phases • The process is practically the same as the one described above, with the difference that instead of adding water for the horizontal centrifugation, the vegetable water is recycled.
Advantages of the continuous system • High production capacity, which avoids having a stock of olives and therefore increases the oil's quality • Improves performance, cleanliness and hygiene • In the 2 phase plants, recycling the vegetable water means the oil has a larger quantity of polyphenols, natural protectors against oxidation
6. Storage • Walls and ceilings insulate against high temperatures and which does not add strange smells to the oil. • Temperature is between 15 and 18º C to allow the oils to mature without oxidation. • There must not be much light.
Non Virgin Oils • Refining • Due to climate conditions, the type of soil and so on, virgin oils can have several defects, such as high acidity, a strange colour or aroma, etc. which makes them unsuitable for human consumption ("lampante oils"). They have to undergo a refining process to eliminate defects.
Refining • 1. Classic alkaline refining • This has 3 phases. Each one tends to eliminate a specific process: -neutralisation-bleaching-deodorisation • 2. Physical refining • It is different from the previous method as acid water is used instead of soda to purify the oil and the temperature is higher.
Kinds of olive oils (Virgin oil) • Extra virgin olive oil: virgin olive oil which has a free acidity, expressed as oleic acid, of not more than 0.8 grams per 100 grams • Virgin olive oil: virgin olive oil which has a free acidity, expressed as oleic acid, of not more than 2 grams per 100 grams • Ordinary virgin olive oil: virgin olive oil which has a free acidity, expressed as oleic acid, of not more than 3.3 grams per 100 grams • Virgin olive oil not fit for consumption as it is, designated lampante virgin olive oil, is virgin olive oil which has a free acidity, expressed as oleic acid, of more than 3.3 grams
Kinds of oils (refined oils) • Refined olive oil is the olive oil obtained from virgin olive oils by refining methods which do not lead to alterations in the initial glyceridic structure. It has a free acidity, expressed as oleic acid, of not more than 0.3 grams per 100 grams • Olive oil is the oil consisting of a blend of refined olive oil and virgin olive oils fit for consumption as they are. It has a free acidity, expressed as oleic acid, of not more than 1 gram per 100 grams • Olive-pomace oil is the oil obtained by treating olive pomace with solvents or other physical treatments, to the exclusion of oils obtained by re esterification processes and of any mixture with oils of other kinds. It is marketed in accordance with the following designations and definitions: • Crude olive-pomace oil • Refined olive pomace oil