Study On Rice Bran Pressing Oil Instant Stabilization Technology

China is rich in rice bran resources,accounting for about 1/3 of the world's total output.Its associated fat,protein,polysaccharide and other substances play an important role in promoting human health.However,its instability leads to the utilization rate only accounting for 1/4 of the developed countries,resulting in serious waste of resources.It is an important part of realizing high value utilization of rice bran resources to balance economic benefits and achieve stable effect of rice bran.In this study,rice bran was used as raw material to establish a scheme of rice bran conditioning press oil production.Taking the oil yield as the index,the optimal press process conditions were determined,and the stability of the obtained pressed cake was evaluated,so as to prove that the rice bran can be stabilized while the crude oil was obtained;A physical model was established to quantitatively calculate the mechanical parameters of oil pressing,which provided a mechanism description for the oil pressing process and a reliable basis for the oil pressing equipment and technology.The main results are as follows:1.Taking oil yield as index,the effects of conditioning temperature,conditioning water content,conditioning time,pressing water content and pressing temperature on rice bran oil production were studied by using self-made complete lateral compression device.The results showed that the optimal conditions of rice bran pre pressing process were as follows:conditioning temperature 135?,conditioning water content26.48%,conditioning time 3 h,pressing temperature 110?,pressing water content10-11%,The results showed that the residual oil rate of rice bran pressed cake was8.35%,the content of oryzanol,vitamin E and color were 1482.50 mg/100g,80.55mg/100g and Y57.7 R4.5,respectively;After stored at 25?for 24-72 h,the acid value of pressed rice bran increased from 28.87 mg KOH/g to 29.38 mg KOH/g,only increased by 1.7%,and the peroxide value increased from 1.39 mmol/kg to 1.45mmol/kg,which indicated that the rice bran treated by pressing reached the goal of instant pre pressing stabilization.2.Based on the stress-strain data collection of rice bran by the complete side compression device,the existence of lipid bodies in the cells before and after pressing was observed by transmission electron microscope to describe the oil production process of rice bran qualitatively.Then,the physical model of rice bran compression process was established.The model divided the compression process of rice bran into exhaust section and oil section.According to the correlation between compression index K₁,K₂and oil point(compression ratio,pressure)of the two-stage equation and pressing conditions(temperature,moisture)and conditioning conditions(temperature,moisture,time),it can be seen that the two-stage compression index K₁,K₂are highly correlated with pressing conditions,while conditioning conditions have a significant effect on oil point pressure and a negative correlation with oil rate,The results showed that the lower the pressure of oil outlet point,the better the oil outlet effect,that is,the faster the pressure rising rate of exhaust section,that is,the larger K₁,and the pressure rising rate of oil outlet section should be kept moderate.Otherwise,K₂is too small to extrude,and K₂is too high to realize solid-liquid separation,resulting in the oil being discharged together with cake residue.Under the optimal process,the predicted oil outlet point of rice bran is 6.01 MPa,which is close to the measured oil outlet point of 5.25 MPa.This study provides a feasible technical way for the establishment of rice grain oil co production processing system and the breakthrough of rice bran resource utilization dilemma,and points out the optimization direction for the improvement of rice bran press oil production efficiency and the reduction of processing power consumption from the perspective of press mechanics analysis.