olive oil
First, the product description:
Olive oil is an excellent non-drying oil. It is one of the most important and oldest greases in the world. People in the coastal countries of the Mediterranean eat this oil extensively.
Olive oil is taken from the evergreen olive tree. The whole fruit contains 35% to 70% oil (dry basis), and its pulp contains more than 75% oil. The shape of olive oil is closely related to the process of oil production. High-quality olive oil can only be obtained by cold pressing and it needs to be separated from low pressure to high pressure. The olive oil obtained from the low pressure head can be consumed without being refined. The oil is yellowish-green and has a particularly mild and savory flavor and taste. And the acid value is low (usually 0.2-2.0), and it is still transparent at low temperatures (close to 10°C). Therefore, low-pressure first-grade olive oil is ideal for salad oils and cooking oils.
The color of olive oil increases with the pressure of the oil press: light yellow, yellow-green, blue-green, and blue to blue. Deep olive oil has a high acid value. When the acid value is greater than 3, the oily taste becomes thick and irritating and unfit for human consumption. The proportion of dark olive oil increased. If the relative density of light-colored oil (15°C/15°C) is greater than 0.918, it indicates that it is doped with other oils and fats. If vegetable oil contains a certain amount of olive oil, the presence of squalene in olive oil is higher to determine its presence.
Where olive oil differs from other vegetable oils, it also has a low iodine value and can remain liquid when the temperature drops to 0°C.
Olive oil contains 700mg/100g oil natural anti-oxidants - tetracosaene (squalene). Combined with low content of highly unsaturated fatty acids in olive oil, its storage stability is high.
Physicochemical constants of edible olive oil:
Relative density (d15°C15°C) 0.9090-0.9150
Refractive index (n20°CD) 1.4635-1.4731
Viscosity (E020°C) 11-13
Freezing Point (°C) 0-3
Fatty Acid Freezing Point (°C) 17.26
Kreismer value (°C) 68.5-71.6
Iodine value (g iodine/100 g oil) 75-88
Saponification value (mgKOH/g oil) 185-196
Unsaponifiable (%) <1.4
Average molecular weight of fatty acids 279-286
Fatty Acid Composition of Edible Olive Oil (%):
Saturated fatty acids 11.0-17.0
Palm oil 0.2-1.8
Oleic acid 65.8-84.9
Linoleic acid 3.3-17.7
Linolenic Acid 0.3-1.3
The high content of unsaturated fatty acids in olive oil. Use the human body to digest and absorb, so the nutritional value is higher. Olive oil is usually yellow and has a sweet taste similar to almond oil. The characteristic constants of olive kernel oil are as follows:
Relative density 0.9184-0.9191
The refractive index 1.4663-1.4671
Iodine value (g iodine/100 g oil) 86-87
Saponification value (mgKOH/g oil) 182-184
In order to obtain high-quality olive oil, not only can the fruit not be damaged during harvesting, but also the harvested fruit must be processed and oiled in time. If it cannot be treated in time, the fruit must be soaked in salt water (concentration 6%). The first and second cold press oils are used for medicine or food, and the third and fourth cold press oils and leachable oils can be used for industrial grease such as lubrication and soap making after being properly refined, but they are not allowed to be consumed. To prevent consumption, rosemary oil or other pharmaceutical agents need to be added when selling.
The residual oil in pressed cakes taken from olive oil is about 4%-15% and can be used as feed. Can also be used carbon disulfide, petroleum ether, benzene and chlorinated ethane and other solvents will be further leaching oil; olive oil leached with carbon disulfide as the sulfide olive oil, can not eat.
Olive oil is a high-grade edible oil and has a high selling price, so it is often adulterated. For identification, the following tests can be used:
1. Nitric acid test. Olive oil and nitric acid do not show a color reaction. Other oils and nitric acid are brown.
2. Freezing test. The anhydrous olive oil was still clear and transparent after being left at 2°C for 5.5 hours. If turbidity occurs for 24 hours at 5.7°C, there must be a large amount of adulterated oil in olive oil.
3. The Kresimil value of the fat was measured. The Kreismer value of pure olive oil is between 68.5-71.6°C. Otherwise doped. The Kresemer value is the temperature at which the fat gradually dissolves in a mixture of equal amounts of ethanol (92%) and amyl alcohol at a relatively high temperature, and then gradually cools down until the solution is cloudy.
4. Determination of squalene content. Besides the high squalene content in rice bran oil (300mg/100g), the content in other oils is very low. The content of olive oil is also very high, so the determination of squalene content is one of the main indicators to determine whether olive oil is pure.
Olive
The olive (Olea europaea L.) is an evergreen tree belonging to the genus Olea of ​​the family Oleaceae. It is a world-famous woody oil-and-fruit tree species. Cultivated varieties have high food value and are rich in high-quality edible vegetable oils. Oil olive oil, a famous subtropical fruit tree and an important economic forest, has a history of more than 4,000 years of cultivation. Olives are mainly distributed between latitude 45°N and latitude 37°S. The central distribution area is the Mediterranean countries, and Greece, Italy, Tunisia, and Spain are the concentrated production areas. Now all countries in the world have introduced cultivation. The olive acreage in the world has exceeded 8.8 million hectares (about 800 million olive trees).
Olive - Introduction Olive oil is a natural edible vegetable oil produced by directly cold-pressing fresh olive fruits. It is rich in nutrients and has strong anti-oxidation properties. Its products are widely used. The oil content of fresh olive oil is generally 20-30%, and its oil production is about 200 per year. More than 10,000 tons, accounting for the world's fourth largest total amount of vegetable oil, the quality of olive oil ranks first in the vegetable oil, is the world's recognized vegetable oil Queen, liquid gold.