Study On New Process Of Dehulling-Cold Pressing-Expansion And Physical-Chemical Property Changes During The New Process Of Double-low Rapeseed

Rape is one of the most important oil crops in china. Rapeseed contains abundant vegetable oil and protein resources. The extensive cultivation of double-low rapeseed does not only improve the nutritional value of the rapeseed oil, but also bring a promising prospect for the comprehensive utilization of rapeseed protein. For the present, the processing method of double-low rapeseed is still pre-pressing extraction mainly, which doesn't come up to the real value of double-low rapeseed, and cause unreasonable use of resources.According to the mini-pilot plant scale of value-added process of double-low rapeseed, the process of dehulling-cold pressing -expansion is confirmed as the best process of double-low rapeseed. The process diagram is double-low rapeseed→cleanning→water adjustment→dehulling→cold presseing→ expansion→ extraction. The orthogonal experiment et al is used to study the key parameters of the process. The dehulling machine rotating speed is 1500rpm, cold pressing temperature is at room temperature, expansion inlet temperature is at 95℃,water content is 8.46%,feeding motor rotating speed is 900 rpm.The capability of key machine during the pilot-plant scale process is evaluated. Cost and products quality as the evaluation factors, operation condition are confirmed: adjusting water content to 7-10%, dehulling machine rotating at 1500rpm, cold pressing at room temperature, expansion inlet temperature >90℃, water content 8-9%,feeding motor rotating speed 900 rpm. Under the condition mentioned above, dehulling rate is more than 95%, hulls contained in rapeseed kernel is less than 2%, kernels contained in hull is less than 1%, the oil content of cold pressing cake is reduced to 15%,density of expansed materials is 490kg/m3,expansion rate is 1.6, residual oil of rapeseed meal after solvent extraction is less than l%.Cold pressing oil meet the Standard of National II Rapeseed Oil. Protein content of rapeseed meal is 46%, meet the Standard of National I Low-glucosinolate Rapeseed Meal for Fodder. The processing cost is 143Yuan(RMB)/T, which is less than of pre-pressing extraction process by 20%.The effects of various stages in the new process on the biochemical quality including crude fat and fatty acid composition, protein and amino acid profile, glucosinolate, tannin, phytic acid of rapeseed are studied by means of HPLC, colorimetric method et al. The results show that the Lys reduced by 25%, essential amino acid such as sulfur amino acid, Tyr, Phe, Val reduced slightly. The new process solve the problem of severely loss of essential amino acid during pre-pressing and extraction, improves feeding efficiency of rapeseed meal.Transparent electron microscope is used to study the microstructures of rapeseed materials at various stages of the new process. The expansion of cold-pressing cake can destroy the cellular structure, break cellular wall fully. The free oil get together into oil drops, convenient for solvent extraction.The new process of dehulling-cold pressing-expansion for rapeseed is feasible. The new process can improve quality of oil and meal, reduce producing cost, increase producing capacity. The industrialization and application of the new process are promising.