Processing technology combining degumming with oil pressing for flaxseed

Abstract: In the present, oil pressing is still the main process for extracting oil from flaxseed in China，but it cannot achieve efficient utilization of functional materials in flaxseed, such as flaxseed gum and lignin secoisolariciresinol diglycoside (SDG). So a comprehensive process that produces multiple products from flaxseed needs to be developed. On the basis of the structural characteristics that the flaxseed gum is in the outermost layer of flaxseeds, the grinding degumming technology using high-speed rotating sand roller grind flaxseed surface is studied before in our laboratory. Model 150 flaxseed degumming machine was designed and manufactured according to this technology, it is composes of motor, sand roller, sieve, gum powder collector etc. Electronic motor is used in the machine to drive the sand roller with high-speed rotation inner the sieve to grind flaxseed, the gum powder flow out the sieve and is collected, the sand roller length and diameter is 800 and 146 mm, the cylindrical sieve diameter is 158 mm with uniform distribution of Φ1.5 mm sieve size. In this paper, the feasibility of Model 150 flaxseed degumming machine was studied. Based on that, the research work of flaxseed degumming and oil pressing co-process was carried out with the commodity flaxseed from Gansu as the research material. The results showed that: the machine was able to obtain flaxseed gum-powder successfully when flaxseed flow rate was controlled at 40 to 220 kg/h. The rate of gum-powder grinded from flaxseed was 6.5%±0.3%. The viscosity of the defatted gum-powder was (5100 ± 520) mPa?s. The oil contents of flaxseed and the degummed flaxseed were 39.30%±0.25% and 41.62%±0.22%, respectively. By using the method of adding 30% flaxseed cake to degummed flaxseed, the oil of degummed flaxseed can be screw pressed successfully. The oil yield pressed from degummed flaxseed was 34.65%±0.43%, higher than that pressed twice from flaxseed (33.94% ± 0.43%)when the flaxseed was pressed with the screw pressing machine without degumming. By the combination of degumming and screw-pressing for flaxseed processing, two benefits were achieved, they were: increase number of products and high pressed oil yield . The research results can provide reference for flaxseed processing.