【作者】 梁华；

【导师】 夏伏建； 黄凤洪；

【作者基本信息】 华中农业大学 ， 粮食油脂与植物蛋白工程， 2008， 硕士

【摘要】 菜籽是一种优质的油料和蛋白资源,先进的制油工艺是菜籽高效加工利用的基础。目前,脱皮低温压榨技术是菜籽制油工业发展的趋势。冷榨饼含油15%～20%,与蛋白体结合紧密,通常用溶剂将油脂萃取出来。现行的正己烷因对环境及人体存在危害,在工业上的使用受到限制。而且,正己烷来源于石油,是不可再生资源。对新型溶剂的开发成为近年来油脂行业关注的热点,其中,可再生溶剂和混合溶剂是各国研究的新方向。本论文以菜籽脱皮冷榨饼为原料,对油脂萃取溶剂进行了筛选,选择出了一种新型的比正己烷更安全的混合溶剂。通过响应面实验方法确定了该新型混合溶剂的萃取条件,并初步探讨了该混合溶剂萃取菜籽脱皮冷榨饼中油脂的适宜工艺。主要结果如下:1新型混合溶剂的筛选研究以菜籽脱皮冷榨饼为油脂萃取原料,比较了甲醇、无水乙醇、异丙醇、丙酮、乙酸乙酯、石油醚、正己烷等溶剂萃取油脂后的饼粕残油率、油脂中磷脂含量和萃取所得油脂的质量。结果表明,乙酸乙酯对油脂的萃取率高,而丙酮所萃取油脂的质量好且油中磷脂含量达到最低。为了改善丙酮对油脂的浸出性能和乙酸乙酯萃取油脂中的磷脂含量,同时考虑丙酮和乙酸乙酯的物理特性、安全性及来源等因素,选择丙酮和乙酸乙酯的混合溶剂作为菜籽脱皮冷榨饼的萃取溶剂。2新型混合溶剂油脂萃取条件的研究以残油率和磷脂含量为分析指标,运用响应面分析法对丙酮/乙酸乙酯混合溶剂萃取脱皮菜籽冷榨饼中油脂的实验进行了设计和优化,得到最适的萃取条件为:丙酮/乙酸乙酯配比(即溶剂配比,V/V)为2.7,混合溶剂与料比(即溶剂倍数,V/W)为7,温度25℃左右,浸提2.6小时。在此条件下的饼粕残油率为2.18%,油中磷脂含量为0.36%。并对优化方案进行了多级逆流萃取试验,结果4级逆流萃取使溶剂倍数降至2.93,饼粕残油率降至0.92%,所得油脂达到四级菜籽油国家标准。3混合溶剂萃取菜籽冷榨饼中油脂的工艺初探主要从浸出工序、湿粕脱溶工序、磷脂分离提纯工序和混合溶剂回收四个方面对混合溶剂萃取菜籽冷榨饼中油脂的工艺提出建议。建议浸出工序采用浸泡-渗漉法,湿粕脱溶工序采用离心预脱溶后真空蒸发的方法,粗磷脂分离工序采用旋液分离方法,混合溶剂回收工序采用真空蒸发方法。采用此工艺可合理降低溶剂用量、降低能耗和溶剂消耗,提高综合利用效益。更多还原

【Abstract】 Rapeseed is an important source of oil and protein with high quality, the efficient processing and utilization of which is based on the advanced extraction of fat and oil. Now, the technologies of dehulling and cold-pressing of rapeseed have become the trend of the development of extraction oil. The cake of rapeseed cold-pressed and dehulled contains 15%～20% oil, which integrates with protein and must be extracted with solvent. Extracting capabilities and physical properties of solvent were vital to oil quality. Currently, n-hexane was restricted in the usesage in industry because of its environmental and health hazards. In addition, n-hexane is from petroleum and un-renewable resource. The research and development of new solvent became the focus in oil-processing industry, in which the renewable resources and the mixture solvent are new research direction worldwide.In this study, the dehulled and cold-pressed cake of rapeseed was used as materials to select oil extracting solvents, and the selected solvent was safer than n-hexane. The extraction conditions of the new mixture solvents were determined and optimized by the response surface. The procedure of extracting and seperating oil and crude phospholipids from the cake of rapeseed dehulled and cold-pressed was primarily evaluated. The following results were obtained.1 Study on selection of new mixture solventThe effects of methanol, ethanol, isopropanol, acetone, ethyl acetate, ligroin and hexane on the residual oil rate, phospholipids’ content in the extracted oil and the quality of extracted oil were compared using the cake of dehulled and cold-pressed rapeseed. Results indicated that the lower residual oil rate was observed in the treatment with ethyl acetate and the lowest phospholipids’ content and high quality were also found in the treatment with acetone. To improve the extracting capability of acetone and decrease the phospholipids’ contents in oil extracted with ethyl acetate, the mixture solvent of acetone and ethyl ester was selected to extract oil from the cake of dehulled and cold-pressed rapeseed considering the physical parameters, safety and origin of acetone and ethyl acetate.2 Study on the extraction conditions with new mixture solventAcetone/ethyl acetate mixture solvents were adopted to extract oil and phospholipids from the cake of dehulled and cold-pressed rapeseed at the same time. Using the residual oil and phospholipids’ contents respectively as analysis indice, the extraction conditions were established by the response surface method. The optimum conditions of extraction established were that the mixture solvent-material ratio was 7, the optimum ratio of acetone-ethyl acetate was 2.7, the optimum temperature was about 25℃and the extraction time was 2.6h. The multi-level counter-flow liquid-solid extraction experiment was carried out on the basis of optimized scheme. The results showed, the mixture solvent-material ratio decreased to 2.93 and the residual oil rate of rapeseed cake decreased to 0.92%. The quality of extracted oil reached national band 4 standard (GB1536).3 Primary studies on the technology of extraction oil from cold-pressing cake of rapeseed with mixture solventTo consider four working procedures of lixiviation, wet meal desolvation, phospholipids’ isolation and the mixture solvent recovery, the suggestions were that extraction technology adopted soak-percolation method; the technology of wet meal desolvention adopted a centrifugal separation and evaporation method; Crude phospholipids were isolated by centrifugal sedimentation separation of hydrocyclone, and the mixture solvent was recovered with vacuum evaporation. This technology could decrease solvent usage reasonably, reduce consumption of energy and solvent and enhance the use efficiency.更多还原