Conventional oil extraction
The modern method of oil extraction involves supplying a lot of heat. The oilseed is first crushed, and the pulp is heated under pressure. As a result, almost all the oil is extracted.
The downside is that the oil is heated up to temperatures of 230 degree centigrade. Heating it to such high temperatures alters the properties of the oil molecules in unfavourable ways (Polycyclic Aromatic Hydrocarbons are formed at high temperatures which are carcinogenic) � and strips it off of its nutritional value.
For optimum extraction of oil, a solvent is added, in this case, hexane. The hazards of exposure to hexane are many � including dermatitis and CNS depression � depending upon the quantity of hexane inhaled or ingested.
The other option of extraction is using a method called �Expeller pressing�, which is a mechanical process of extraction using a machine called an expeller. No heat is added to the process, but heat can be produced as a result of the mechanical action on the nut � which could very well result in high temperatures that alter the chemical composition of the oil.
The case for cold pressed oils
In olden times, a long cylindrical contraption called a �ghani� was used. The oilseeds were placed inside and ground with a pestle until the oil came out. This is the simplest method for �cold-pressing� the oil out of a seed because it doesn�t involve the generation or addition of heat. The residue or the oil cake was used as fodder for cattle.
Today cold-pressed methods of extraction are the same as the expeller-pressed method, albeit in a temperature-controlled setting. According to the European Union regulations, the temperatures for cold-pressing must not exceed 27 degrees centigrade, though such criteria in India have not been established.
1) They retain healthy anti-oxidants that are otherwise destroyed by heat. These anti-oxidants fight harmful free radicals and prevent the growth of tumors.
2) Cold pressed olive oil is rich in

Conventional oil extraction
The modern method of oil extraction involves supplying a lot of heat. The oilseed is first crushed, and the pulp is heated under pressure. As a result, almost all the oil is extracted.
The downside is that the oil is heated up to temperatures of 230 degree centigrade. Heating it to such high temperatures alters the properties of the oil molecules in unfavourable ways (Polycyclic Aromatic Hydrocarbons are formed at high temperatures which are carcinogenic) � and strips it off of its nutritional value.
For optimum extraction of oil, a solvent is added, in this case, hexane. The hazards of exposure to hexane are many � including dermatitis and CNS depression � depending upon the quantity of hexane inhaled or ingested.
The other option of extraction is using a method called �Expeller pressing�, which is a mechanical process of extraction using a machine called an expeller. No heat is added to the process, but heat can be produced as a result of the mechanical action on the nut � which could very well result in high temperatures that alter the chemical composition of the oil.
The case for cold pressed oils
In olden times, a long cylindrical contraption called a �ghani� was used. The oilseeds were placed inside and ground with a pestle until the oil came out. This is the simplest method for �cold-pressing� the oil out of a seed because it doesn�t involve the generation or addition of heat. The residue or the oil cake was used as fodder for cattle.
Today cold-pressed methods of extraction are the same as the expeller-pressed method, albeit in a temperature-controlled setting. According to the European Union regulations, the temperatures for cold-pressing must not exceed 27 degrees centigrade, though such criteria in India have not been established.
1) They retain healthy anti-oxidants that are otherwise destroyed by heat. These anti-oxidants fight harmful free radicals and prevent the growth of tumors.
2) Cold pressed olive oil is rich in