【作者】 李丽梅；

【导师】 倪元颖；

【作者基本信息】 中国农业大学 ， 农产品加工与贮藏工程， 2004， 硕士

【摘要】 洋葱是我国栽培面积大、产量高的蔬菜之一，同时也是亚洲国家传统的药食两用植物，含有多种生理活性成分，在保健和预防、治疗慢性疾病等方面具有多种功效。含硫化合物是洋葱主要生理功效成分之一，主要存在于洋葱油中。但洋葱油在新鲜洋葱中的含量很少，大约只占鲜重的0.05％左右，日常饮食所摄入的洋葱量难以发挥出理想的生理功效，因此必须采取有效的提取手段，高效提取、富集洋葱油（含硫化合物）。 本论文将水蒸汽蒸馏提取法、同时蒸馏—萃取法和超临界CO₂流体萃取法应用于洋葱油的提取工艺中，分别以含硫化合物和洋葱油得率作为指标，进行工艺优化研究，确定了相应适宜的工艺参数。实验结果如下： 1、建立了洋葱油中含硫化合物的分析检测方法。分别采用GC-MS和GC（带有FID，DB-5毛细管柱）法对洋葱油进行了定性、定量分析，共鉴定出化合物27种，其中含硫化合物24种，洋葱油组分分离效果良好。 2、优化了水蒸汽蒸馏提取洋葱油的适宜工艺参数。分别从酶解温度、酶解时间，酶解pH、洋葱浆液与水的比例、提取时间和饱和NaCl溶液的影响等方面优化了洋葱油提取的工艺参数，其适宜参数为：酶解温度30℃，酶解时间120 min，提取时间60 min，洋葱油中含硫化合物含量可达到25.07μl／kg FW。 3、首次采用同时蒸馏—萃取法提取洋葱油并确立了适宜的工艺参数。从酶解时间、酶解温度、提取时间、溶剂用量、洋葱浆液与水的比例、NaCl溶液浓度等方面对洋葱油提取的工艺参数进行了优化，确定了同时蒸馏—萃取法提取洋葱油的适宜参数为：酶解温度为35℃，酶解时间为150min，洋葱浆液与NaCl溶液（90g／1000ml）的比例为1：2（W／V），提取时间为150 min，在上述提取条件下，SDE提取的洋葱油中含硫化合物的含量可达到45.37μl／kg FW。 4、优化了超临界CO₂萃取洋葱油的适宜工艺参数。分别研究了物料的破碎粒度、含水率、萃取压力、萃取温度、萃取时间以及夹带剂用量等因素对洋葱油得率的影响，并通过二次回归正交旋转实验，确定了洋葱油提取的适宜参数为：以粒径为0.45-0.90mm的冻干红洋葱粉为原料，加入15％（v／w）的无水乙醇作夹带剂，萃取压力为27.98 MPa，萃取温度为42.18℃，萃取时间为216.6min，洋葱油的提取率为0.483％，得到的洋葱油具有浓郁的新鲜洋葱风味。更多还原

【Abstract】 Onion (Allium cepa L.) is one of the most large-production vegetables in China, and it is also a traditional drug-food herb in Asia, because of its therapeutic effects. These effects are attributed to biologically active sulfur compounds in onion oil. However, the amount of oil in fresh onion is so little that people’s daily intake cannot have the ideal therapeutic effects. So methods of effectively extracting onion oil were studied with the aim of gaining the maximum sulfur compounds.In this dissertation onion oil was extracted by steam distillation (SD), simultaneous distillation and solvent extraction (SDE) and supercritical carbon dioxide extraction (SFE) respectively, the effects of different processing conditions and the optimal parameters were studied. The results were summarized as follows:1.Methods for qualitative and quantitative analysis of onion oil by GC-MS and GC were established respectively. Compounds in onion oil were successfully separated. And 27 compounds were identified, of which 24 compounds were sulfur compounds.2.The parameters of steam distillation for extracting onion oil were optimized. Effects of cultivar, time, temperature and pH of the action of alliinase, saturated sodium chloride solution and the ratio of the onion homogenate and water on the extraction of onion oil were studied. The results of orthogonal experiment showed that the optimal parameters were enzymatic temperature, 30℃; enzymatic time,120 min; extracting time, 60 min. Under the above condition the concentration of sulfur compounds reached 25. 07ul/kgFW.3.The optimal parameters of simultaneous distillation and solvent extraction (SDE) for onion oil were obtained for the first time. Effects of extracting time, the volume of solvent, the ratio of the onion homogenate and water and the concentration of the sodium chloride solution on the extraction of onion oil were studied. The results of orthogonal experiment showed that the optimal parameters were enzymatic temperature, 35℃; enzymatic time, 150 min; extracting time, 150 min. Under the above condition the concentration of sulfur compounds reached 45. 37 ul/kg FW.4.The parameters of supercritical carbon dioxide extraction (SFE) were optimized. Effects of particle size, coefficient of water contents, extracting pressure, extracting time, extracting temperature and the volume of co-solvent on the yield of onion oil were studied. The results of orthogonal experiment showed that the optimal parameters were extracting pressure, 27.98 MPa; extracting temperature, 42.18 ℃; extracting time, 216.6 min. Under the above condition the yield of onion oil reached 0.483%. The products had pleasant aroma characteristics of fresh onions.更多还原