1. Introduction

At present, sunflower oil production process have two kind of processing method: pressing and leaching(extraction). Pressing method is by physical pressure and get oil directly from the oil seeds. The whole process does not involve any chemical additives, to ensure product safety, health, pollution-free. The expeller method is divided into cold pressing and hot pressing. The difference of cold pressing and hot pressing is whether use high-temperature process or not. Hot pressing using a high temperature, can improve the oil yield, but destroy nutrients; cold-pressed not to use high temperature, the oil is low, but the complete nutritional ingredients.
1..1 Here have some example of hot pressing and cold pressing method.
1.1.1 Process and methods of soybean seeds pressing.
There are two ways of pressing of soybean: cold press and hot press.
(1) Soybean cold press process: Soybean---Filtering---Press(suitable moisture)
(2) Introduction of process: Will screen soybean and cleaning soybean first, then crushing soybean and add 7-8% of water to soften the seeds, send soybean to cooker, steam until about 115°C, then will press seeds.

1.1.2 Process and method of rapeseed press:

The rapeseed have two ways of pressing, cold press and hot press. To improve the oil yield and oil quality, generally the hot press is used.
(1) Cold press:Rapeseed/vegetable seeds---Screening---Squeezing---Steaming----Pressing, First, Screening the rapeseed and check the moisture content of rapeseed, if the rapeseed too dry, we need to add 2.5-3% water, later put the seeds into the expeller.
(2) Hot press: Rapeseed/vegetable seeds---Screening---Squeezing---Steaming----Pressing, Filter the rapeseed and remove the residue, and then enter the flaking machine for seeds flaking. After flaking, will go into the cooker for steaming and roasting, during steaming add 2-3% water, will start milling after the seeds become brown and the temperature is 110-120°C.
1.1.3 The process and method of peanut kernel pressing.
Hot press and cold press is suitable for peanut kernel, generally we use hot press. Hot pressing, the first crushing or flaking the peanut kernel, then placed in the steamer for 1.5-2 hours. When the cake’s temperature arrives 120°C and water content is 3%, will start normal squeezing.
Peanut----Cleaning---First milling---filter----Press two times---Crude oil----Refinery---Press third times---Crude oil after pressing----Filter----Cake after pressing.

1.2 The leaching(extraction) method is to use solvent naphtha (6#) after fully immerse oil meal raw material to high temperature (260 degrees) and extract the oil from seeds meal, after a "technology of six” (degreasing, degumming, dewatering, decoloring, deodorization, deacidification). The biggest characteristic is high oil yield and low production cost, the price is lower than squeezing method.
The extraction(LEACHING) method is widespread used in the market. Because of high oil yield and low production cost, the extraction(leaching) machine is hot sale in the worldwide.
2. The difference of pressing and extraction(leaching):
Squeezing method due to the yield is low, so the raw material for squeezing must be seeds of high oil content, and itself is probably oil crops; Due only to squeeze at the same time, the residual oil in the cake is high, so the modern enterprise in order to save resources, the pursuit of efficiency of cases will be to squeeze the oil cake with leaching rule of oil again
The extraction method applies to vast oil seeds. Especially those high nutritional value but low oil yield seeds. Due to the advantage of leaching, this method is widely used in the cooking oil industrial. Approximately 90% of the oil in the world is using extraction method.
3. Raw material
Almost all of the grain seeds can be pressed to make sunflower oil, like corn, soybean, peanut, sunflower, flaxseed, coconut, palm, rice brain, cottonseed, sesame, castor seed and so on.