Pure Walnut Oil CAS 8024-09-7

The pressing method is the main method of producing Pure Walnut Oil. It uses the principle of mechanical pressing to extrude the oil in the material at one time. The commonly used oil presses are screw presses and hydraulic presses. According to whether the material is heat treated before pressing, it is divided into two types: cold pressing and hot pressing. The cold pressing method is carried out in an environment below 65 °C, which is a physical method. The material is not roasted, which has no effect on the quality of oil and nutrients. The nutrients are kept intact, the color and luster are good, but the smell is poor; in foreign countries, Germany For example, the CA59GKOMET laboratory cold press developed by German IBGmonforts company is widely used in laboratory cold press oil production experiments because of its simple operation, good performance and relatively small volume. The hot pressing method is to extract the oil after roasting the seeds of oil crops. The smell is fragrant, the color is darker, the yield is higher, the residual residue is less, but the loss of nutrients is large. Both pressing methods have no solvent residues. The oil extraction rate of the pressing method is 50% to 60%, and there are disadvantages such as high residual oil rate in the cake, protein variability, high labor intensity and high cost, but this method has simple equipment and convenient operation. Since the oil yield of the cold-pressed method is lower than that of the hot-pressed method, but the nutrients are well preserved, the price of the cold-pressed oil is generally about 50% higher than that of the hot-pressed oil. Cold pressing is more suitable for the extraction of Pure Walnut Oil.

The leaching method is a method in which a certain organic solvent that can dissolve the oil is selected, and the oil in the oil is extracted by contacting with the oil (soaking or spraying). At present, n-hexane leaching is mostly used in my country, which is suitable for large-scale continuous production and has a high oil yield. The butane and propane leaching method is a mild oil production process, especially suitable for the extraction of precious oils and the development and utilization of low-denatured vegetable proteins. This method is more suitable for the large-scale production of Pure Walnut Oil. High protein utilization. In 1989, my country started the research on this technology, and it was put into practice soon, and it has been applied to large-scale production. The pre-pressing-leaching method is a method that combines the pressing method and the solvent leaching method, that is, in the pre-pressing process, the pressing conditions are relaxed, part of the oil is squeezed out first, and then solvent leaching is performed to fully dissolve the oil in the oil. It also makes delipoprotein readily available. This method combines the advantages of the pressing method and the solvent method, and is widely used in the modern oil industry. In recent years, a lot of attempts have been made to combine the solvent method with other auxiliary techniques. For example, the combination of solvent method and auxiliary methods such as microwave and ultrasonic has significantly improved oil yield and oil quality, but these methods are still in the laboratory research stage and have not been applied to large-scale production.

The water-substituting method is the method of “replacing oil with water”, which is a unique traditional oil-making process in my country, that is, adding hot water to the oil slurry to make the protein particles absorb water and swell, and use the vibration method to separate the oil with the help of its specific gravity difference. The method is simple in process, safe and reliable, but has problems such as difficulty in separation, protein denaturation, low oil yield, and subsequent treatment of wastewater. In recent years, enzyme preparations have been introduced into the water-replacement method in order to improve oil yield and protein utilization. Preliminary selection of enzymes for the extraction of Pure Walnut Oil by water enzymatic method shows that neutral protease has the best effect when single enzyme is used, and the effect of compound enzyme is obviously higher than that of single enzyme. Studies have shown that the addition of enzymes and ultrasonic treatment can improve the extraction rate of the traditional water replacement method. As a new technology of oil extraction, water enzymatic method has the advantages of high oil yield, good oil quality, light color, low production energy consumption, and is not easy to cause environmental pollution, which has attracted the attention of scholars at home and abroad. With the deepening of research, it is expected to open up a new situation in the processing of Pure Walnut Oil.

Supercritical fluid extraction technology uses supercritical fluid (mostly CO2) as the solvent, and uses the fluid in this state to have high permeability and high solubility for extraction and separation of non-polar mixtures. A modern high-tech separation technology for food processing. According to the quality characteristics of Pure Walnut Oil, the process conditions of supercritical CO2 fluid extraction of walnut oil were studied. Wu Cai’e, Yan Shijie, etc. [42] proposed that the optimal process parameters for supercritical CO2 fluid extraction of walnut oil are: particle size 30 mesh, extraction pressure 30MPa, extraction temperature 45℃, separation temperature 50℃, separation pressure 8MPa, extraction time 5h, CO2 flow rate 40L /h, under this condition, the extraction rate of walnut oil can reach 93.98%. The produced Pure Walnut Oil is clear and transparent, light yellow in color, no solvent residue, and does not require further refining. It is a high-quality edible oil product. The supercritical extraction method overcomes the defects of solvent extraction, such as heating and distillation, easy oxidation and rancidity of oil and solvent residue, etc. in the separation process, and also solves the problems of low oil yield, cumbersome refining process, and unsatisfactory color in the pressing method. However, this technology is limited by many factors such as equipment, energy consumption, food safety, etc. It is still in the laboratory stage, and its application in actual production is extremely limited.