The oil content of walnut kernel is 60% - 70%, which is higher than that of soybean, rapeseed, peanut and sesame. Walnut oil is extracted from walnut kernel. The main fatty acids are linoleic acid 54.3%, oleic acid 20.3%, linolenic acid 16.8%, and unsaturated fatty acid 87%. Linolenic acid can affect the synthesis, oxidation and excretion of cholesterol in vivo, help to prevent skin keratinization, enhance tissue regeneration and immunity.
The crude oil was obtained by pressing walnut kernel. The initial temperature of crude oil was 45 ℃, the dosage of sodium silicate was 0.15%, the concentration of alkali was 12.62%, and the precipitation time was 4H; The heating water amount was 3% - 5% (in crude oil), and the hydration time was 2 h; The optimum conditions were as follows: the dosage of activated bleaching clay (Ⅱ) was 2%, vacuum degree was 10 kPa, drying time was 1 h, decolorization temperature was 100 ℃ and time was 30 min; Under the conditions of deodorization temperature 200 ℃, vacuum degree 10KPA, deodorization time 5h, high quality high-grade cooking walnut oil can be obtained by refining. The content of unsaturated fatty acid is as high as 90%, linoleic acid is as high as 75%, and there are many unsaturated fatty acids such as linolenic acid.
Complete equipment of walnut oil peeling and cold pressing
Pressing oil is the traditional processing method in China's vast walnut producing areas. Jinan Yueheng machinery developed walnut shelling and peeling cold pressing technology on the basis of traditional walnut pressing technology, which can obtain high-quality cold pressed walnut oil and high protein walnut powder from pressed cake. The process is as follows
Technological process: Walnut raw material → cleaning → shelling → peeling → drying → crushing → conditioning → cold pressing → first pressing walnut oil
Process Description: the walnut is first transported to the vibrating cleaning screen to remove impurities, and then the metal impurities and stones are removed by magnetic separator and specific gravity stone remover.
After cleaning, the walnut was shelled, and the walnut kernel and shell were separated.
The walnut kernel is peeled by water machine, then separated by separator, and finally dried by dryer.
The dried walnut kernel is crushed by crusher, and the crushed walnut kernel is transferred to the cold press for cold pressing after conditioning.
The process is cold pressing, the residual oil is 13-20%, and the conditioning temperature can be increased. For hot pressing, the residual oil rate can be reduced to 6%, and the unique aroma of walnut can be maintained.
Main equipment: vibrating cleaning screen, magnetic separator, specific gravity stone remover, sheller, peeling machine, crusher, dryer, tempering pot, etc.
Main features: cold pressing technology, conditioning and pressing temperature controlled at 60-80 ℃, can better maintain protein. The quality of cold pressed crude oil is good and the acid value is & le; 0 (KOH) mg / g, peroxide value & le; 0 mmol / kg, color R / y < 2.5/25.
Walnut oil refining equipment
The chemical refining process is mostly used in the refining of common walnut crude oil. Because the soap residue produced in the alkali refining process takes many bioactive substances such as vitamin E away from the oil, the nutrients in the oil are reduced and the loss is considerable. Therefore, the physical refining method is adopted in the refining of walnut crude oil. The first stage is only degumming without alkali refining, In order to ensure that bioactive substances are not lost, and no chemical substances are added.
The deacidification and deodorization section is a distillation type physical process, which is equipped with our company's patented product combination deacidification and deodorization tower. The oil falls into the packing in the packing tower, disperses into oil film, flows from top to bottom, and contacts with water vapor countercurrent. Fatty acids and various volatile substances are removed by distillation under the action of vacuum and stripping steam, so as to achieve the purpose of deodorization (deacidification). The deodorization (deacidification) process is short, which not only reduces the production cost, but also helps to inhibit the formation of trans fatty acids and preserve the retention of vitamin E.
Process flow: crude oil → degumming → decolorization → filtration → deoxidization → heat exchange → heating → deacidification and deodorization → heat exchange → cooling → crystallization → crystal cultivation → filtration → product oil
Process Description: after the crude oil is preheated, add hot brine to the oil for washing, separate the soaping water, and finish degumming after one or two times of the same washing. The degummed oil enters into the decolorization process, and the activated clay is added to decolorize in the decolorization tower, and then pumped into the blade filter for filtration. The filtrate is polished and then enters the next process. After the blade filter is dried, the waste clay is discharged through vibration. The decolorizing oil pump is pumped into the gas separator for vacuum deoxidation, and then the oil-oil heat exchanger is pumped to preheat the deodorized oil for heat exchange. When the oil is heated to about 250 ℃, it enters the combined deacidification and deodorization tower for deacidification and deodorization under high vacuum, so as to remove the fatty acid, odor and other volatile substances in the oil to the maximum extent, The mixed steam of fatty acid is discharged from the top of the tower, enters the fatty acid capture system and is sold after capture. The oil is pumped from the bottom into the heat exchanger to exchange heat with the deodorized oil, and then cooled to obtain deodorized oil. The deodorized oil is cooled and crystallized in the crystallizing tank, and then transferred to the crystallization stage. The crystallized and crystallized oil is pumped into a filter to separate wax and grease to obtain the product oil.
Main equipment: centrifuge (or water washing pot), decolorizing tower, vane filter, bag filter, combined deacidification and deodorization tower, spiral plate heat exchanger, crystallizer, dewaxing filter, etc.
Process features: physical refining technology is adopted to retain the nutrients in the oil to the maximum extent.