Oil pressing can be divided into hot pressing and cold pressing according to whether the material is subjected to heat treatment before pressing.
The edible vegetable oil in our daily life is mostly hot pressed oil, that it, before oil pressing, first cleaning, crushed and then heated by high temperature to make oil inside have a series of changes, destroy oil cells and promote the protein denaturation, reducing the viscosity of oil, to be suitable for oil pressing from and improving oil yield.
Hot pressing is to extract oil after seeds roasting, the smell is fragrant, the color is deep, and the yield is higher.
Advantages of hot pressing process
Residues left in the product are small and easy to store. And cold pressed seeds without frying, so the smell is poor, but the color is good. Both presses are solvent-free. Hot pressing: hot steaming, frying, seeds with peel oil pressing system. First of all, put raw materials into the pot for roasting, and then through the oil press machine to extract oil, the advantages of this process is that the oil is fragrant, oil yield is high, and oil residue is low.
Disadvantages of hot pressing process
But the color of crude oil processed by high temperature is dark, partial acid value increases, so the crude oil must be refined before cooking. At the same time, high temperature pressing makes a great loss of bio active substances (vitamin E, sterols, carotenoids, etc.) in oil, resulting in a waste of resources.
Cold pressed oil is pressed without heating or under low temperature condition. The extracted oil from the low temperature, the acid value is low, generally do not need refining, after sedimentation and filtration, can directly get the finished oil.
The normal cold pressing method is processed under the condition of less than 60℃, the nutrition component is kept most intact
In recent years, with the continuous improvement of people's living standards, more and more people prefer cold pressed oil.
Advantages of cold pressing process
The cold pressed oilgenerally does not need to add additives, because it has not been destroyed, it can be stored for a long time. With relatively high market value. Cold pressed oil has pure natural characteristics, avoiding the adverse effects of traditional high temperature oil processing. In the cold pressed oil, the natural flavor and color of the oil are retained. The physiological active substances in the oil are preserved completely, and the cold pressed oil is with original flavor, which is the choice of healthy life. However, most of the oilseeds are not suitable for cold pressing, such as soybean, high erucic acid rapeseed, cottonseed, peanut, sesame and so on
Disadvantages of cold pressing process
Generally speaking, the point of cold pressing is low and the water content is unstable. The oil yield is low, only about half percent compared with hot pressing, cold pressing generally needs to crush materials, then the oil yield can be increased, sometimes also needs the two times pressing, even three times press.
Oil Pressing Machine
Various series of oil pressing machine
ZX Series Screw Oil Press Machine
This model oil press machine is a continuous spiral oil press. It is specially designed for small and medium sized enterprises to obtain more high-quality vegetable oil and cake’s needs. This machine is widely used in various kinds of oil plants and other special materials to press oil. Such as peanut, sunflower seed, rapeseed, sesame, rice bran, corn germ, cottonseed, soybean and other high oil plants to press oil. The machine adopts the international advanced technology and materials, own the characteristics of beautiful appearance, easy operation, its technical indicators have reach the advanced level of modern oil equipment.
This is the ZX series screw oil pre-press machine. It is the national approved product, which has the characteristic, such as reasonable structure, simple operation, convenient maintenance, high efficiency in production, combination of cooking and steaming , continuous long term operation. Suitable for the oil plant to one-time press the seeds which contain large oil such as cottonseed kernel, safflower seed, sunflower kernel, sesame seed, castor bean, kernel etc.
This type oil press machine is specially designed for oil companies to choose squeezing under normal temperature or low temperature pressing.
YZ Series Screw Oil Press Machine
The greatest advantage of this machine that it is one equipment with double duty: one-time pressing and pre-pressing low energy consumption; small occupation area. This equipment is the ideal oil pressing equipment for small and medium sized oil pressing plant.
ZY Series Screw Oil Press Machine
This series screw oil pre-press machine is a continuous oil expeller which is suitable for preliminary pressing – solvent extracting press or twice pressing process in small and medium sized oil plant, and used to handle with oil seeds such as rapeseed, peanut, sunflower seed, and cottonseed kernel. It has the following characteristics: high processing ability; low power consumption; low operation expense; defatted cake being loose but not crushed, easy to solvent penetration; low residual oil rate.