Difference between hot oil press and cold oil press

Physical oil pressing method of oil extraction process, that is, through the external force generated by the screw oil press machine will be oil seeds pressed and extracted from the edible oil, it is the more popular pressing method in the market, compared with other oil production methods with simple process, supporting equipment less, good oil quality, can press a variety of oil seeds and other advantages.

The process of oil extraction by pressing: Cooking - pressing - residue removal from the crude oil.

According to the different temperatures when the oil seeds are pressed, we divide the physical oil extraction process into hot pressing and cold pressing, what is the difference between the two?

Hot pressing method of oil extraction generally in the oil extraction before the oil through the cleaning, crushing, high temperature heating treatment, so that a series of internal changes in the oil: destruction of oil cells, promote protein denaturation, reduce the viscosity of oil, etc., can improve the rate of oil production.

However, the oil extracted from the high-temperature-treated oilseeds is dark in colour and the acid value increases, so the oil must be refined before consumption. At the same time, high-temperature oil extraction makes the biologically active substances (vitamin E, sterols, carotenoids, etc.) in oilseeds lose a lot in the pressing process.

Cold pressing method of oil extraction means that the oilseeds are fed into the press without heating or low temperature before pressing, and are generally processed under the environment of less than 60°C. The oil is extracted by cold pressing method, which is a method to extract oil from the oilseeds without heating or low temperature before pressing.

Cold pressed oil retains the natural flavour and colour of the oilseeds, preserves the physiological active substances in the oil intact, and has a low degree of protein denaturation, which makes it easier to comprehensively utilise the protein. However, the oil seeds used for cold pressing must be selected, otherwise the quality of cold pressed oil will be seriously affected. Moreover, the smoke point of cold pressed oil is low and the water content is unstable, which is not favourable for long-term storage.