Study On The Mass Transfer Law Of Oil Preparation From High Starch Base Oil Plantstiger Nuts By Leaching And The Quality Of Its Crude Oil

Cyperus esculentus belongs to Cyperaceae,Cyperus,which has high yield and broad prospects of comprehensive utilization,it is annual herbaceous.It is a new green cash crop.In 1952,China first introduced it from the Soviet Union and gradually developed its planting and processing scale.It mainly contains fat,starch,carbohydrate,protein and other nutrients.It is rich in oleic acid and linoleic acid,which has nutritional health and therapeutic effects.The higher starch content in Cyperus esculentus(27-32%)makes it different from other traditional oils.This topic takes Cyperus esculentus as the research object,extracts Cyperus esculentus oil,its nutritional component,and optimizes its extraction process.At the same time,studies the kinetics of solvent extraction process of conventional solvent extraction and extruded pretreated extruded material,and measures the extraction kinetics data of Cyperus esculentus oil,laying a foundation for further development and utilization of Cyperus esculentus oil.The effects of different oil preparation techniques on the oil quality of Cyperus esculentus were studied.The main research details and results are as follows:(1)Making the extraction rate of Cyperus esculentus oil as the index,the extraction process of Cyperus esculentus oil was optimized by response analysis method with the basis of single factor experiment.The best tiger nut oil extraction parameters were as follows:liquid-solid ratio 9:1mL/g,extraction temperature 55℃,extraction time 2.0h,stirring speed 350r/min.Under these conditions,the actual extraction rate of Cyperus esculentus oil is 97.02%,which compare to the theoretical value of 97.14%is close.(2)The effects of stirring speed,liquid-solid ratio,extraction temperature and tiger nut particle size on the relative extraction rate of Cyperus esculentus oil in conventional solvent extraction method were investigated.The relative extraction rate of Cyperus esculentus oil was conducted under different extraction conditions.The relative extraction rate of Cyperus esculentus oil increased with the increase of stirring speed,and reached the maximum value when the stirring speed was about 500r/min.In the experimental leaching time range,the relative extraction rate of Cyperus esculentus oil increased with the increase of temperature,the decrease of tiger nut particle size and the increase of liquid-solid ratio,and the influence of tiger nut particle size and liquid-solid ratio on the relative extraction rate of Cyperus esculentus oil was significant.By discriminant method,it was determined that the control step of the leaching process of Cyperus esculentus oil was controlled by internal diffusion,as well as calculated its apparent activation energy was 19.34kJ/mol.Meanwhile,the apparent rate constant of different tiger nut particle size is proportional to time,which further proves that the leaching process is controlled by internal diffusion.The influence of liquid-solid ratio on the relative extraction rate was 1.01.Linear regression analysis was carried out on the model based on the experimental data to determine each parameter in the model,and the reaction rate constant k0 was obtained.The kinetic equation of the extraction process was as follow:(3)The effects of extraction temperature,liquid-solid ratio and extruded material diameter on static solid-liquid extraction of Cyperus esculentus oil were investigated by using the extruded material pretreated by double spiral extruder as raw material.The ratio of liquid to solid was a significant factor affecting the relative extraction rate of Cyperus esculentus oil under three different extraction conditions.The washing diffusion fitting of the relative raffinate rate and time of Cyperus esculentus was carried out by using the derived cylinder model of Cyperus esculentus powder extruded material,and the fitting accuracy was higher.The average diffusion coefficients at 25℃,35℃,45℃ and 55℃ were 0.0021mm2/min,0.0026mm2/min,0.0028mm2/min and 0.0029mm2/min,respectively.The average diffusion coefficient of the expanded material is only 0.0014mm2/min when the barrel temperature is 110℃.When the barrel temperature is 120℃,the average diffusion coefficient is significantly increased to 0.0024mm2/min.When the liquid-solid ratio increases from 4:1 to 6:1,the average diffusion coefficient increases from 0.0011mm2/min to 0.0021mm2/min.The dynamic equation of solid-liquid extraction of extruded material of Cyperus esculentus was as follow:(4)Taking cold pressing,hot pressing and solvent leaching as the research object,quality detection and analysis were carried out,including the determination of characteristic indexes,quality indexes and nutritional components,and the effects of different oil production processes in regard to the quality of oil were analyzed:Compared with soybean,sesame and peanut,Cyperus esculentus has higher starch content but lower protein content,which belongs to high starch based oil.After oil extraction,extracting starch from cake has a promising application prospect.Cyperus esculentus oil was separately extracted by cold pressing,hot pressing and solvent leaching,and discover the quality of Cyperus esculentus crude oil had notable differences.The acid value(mg/g)range of the three oil samples was 0.72～1.05.The peroxide value(mmol/kg)range was 0.85～1.25;The iodine value(g/100g)range was 72.37～85.18,and the oil was non-drying.The saponification value(mg/g)range was 171.63～186.31,which was higher by leaching method than by pressing method.The content of unsaponifiable matter range is 0.41%～0.62%.The range of oleic acid and linoleic acid were the prime UFA in tiger nut oil,with contents ranging from 73.07%to 73.24%,respectively.The content of vitamin E(mg/100g)is 15.37～19.53.Cyperus esculentus oil is a high quality edible oil.The residual oil of the extracted tiger nut cake was higher than that of the extracted soybean cake.The crude protein range in cake is 6.74%～7.35%,which is significantly lower than that of common plant oil cake,while the starch range in cake is 39.31%～48.92%,which is significant higher than that of common plant oil cake,which can be extracted for comprehensive utilization of Cyperus esculentus.