Preparation Of Rapeseed Polyphenols And Protein From Rapeseed Meal

Annually, there is a production of700million tons of rapeseed meal in China.Rapeseed meal is rich in polyphenols, protein, phytic acid, polysaccharides andother active ingredients, which were not well used. Therefore, the comprehensivedevelopment and utilization of rapeseed meal have high research value. In thispaper, polyphenols and phytic acid were simultaneously extracted by acetic acidand ethanol from rapeseed meal; phytic acid was separated by alkali solutionprecipitation from the extract, obtaining the crude rapeseed phytic acid, thenpolyphenols was separated and purified through ion precipitation, acid dissolution,ehyl acetate extraction and dry from the extract, obtaining rapeseed polyphenolsproduct; In vitro antioxidant activity of rapeseed polyphenols product was sdudied;protein and polysaccharide were simultaneously extracted by dilute alkali solutionfrom the rapeseed meal from which polyphenols and phytic acid had already beenextractd, ultrafiltration was used to separated protein and polysaccharides in theextract, obtaining crude rapeseed polysaccharides; the protein retentate was driedby spray drying, finally rapeseed protein product was obtained. Research resultswere as follows:(1) The best simultaneous extraction conditions of polyphenols and phytic acidoptimized through response surface experiment were as follows: acetic acidconcentration0.7%(by mass), ethanol concentration61%(by volume), extractiontemperature48℃, extraction time80min, the ratio of liquid to solid11,2times ofextraction. Under these conditions, the extraction yield of polyphenols and phyticacid were2.358%and1.668%respectively.(2) The yield of the crude rapeseed phytic acid was1.516%; the bestconditions of polyphenols ion precipitation optimized through orthogonalexperiments were as follows: chlorinezinc as precipitant, the amount of precipitantwas1.5times of the polyphenols content, pH value6.0. Under these conditions, theprecipitation rate of rapeseed polyphenol was91.35%. The rapeseed polyphenolsproduct was pale yellow powder, its purity and yield were90.65%and1.97%respectively. Results of rapeseed polyphenols product in vitro antioxidant activityresearch were as follows: rapeseed polyphenols product had strong capacity in DPPH radical and superoxide anion radical scavenging; rapeseed polyphenolproduct inhibited the rise of peroxide value and acid value of rapeseed oil.(3) The best conditions of rapeseed protein and polysaccharides simultaneousextraction optimized through orthogonal experiments were as follows: theextraction temperature50℃, extraction time30min, the ratio of liquid to solid12,2times of extraction. Under these conditions, extraction rate of rapeseed proteinand polysaccharide was75.26%and59.13%respectively; protein andpolysaccharides in the extract were separated through ultrafiltration, the retentionrate of protein, the transmission rate and the yield of crude rapeseedpolysaccharide were respectively91.62%,65.34%and1.27%after ultrafiltrationseparation; the optimal conditions of protein spray drying process were as follows:air supply357L/h, inlet air temperature190℃, feeding pump speed9mL/min.Under these conditions, the rapeseed protein product was light in color, its yieldand purity was25.30%and91.52%respectively, the removal rate of phytic acidwas93.79%, glucosinolates and polyphenols were not detected.