超临界CO2萃取姜挥发油及GC-MS分析

正交试验法时超临界CO2提取生姜挥发油的提取条件进行研究.结果表明,最佳提取条件为:原料粒径为03mm,萃取压力25 MPa,温度40℃,CO2流量30 kg/h,萃取时间100min,所得姜精油呈浅黄色,得率由传统水蒸气蒸馏法的1%左右提高到4.38%.采用气相色谱-质谱联用技术测定最佳提取条件下所得生姜挥发油的化学成分及其相对质量分数,共分离出58种成分并鉴定出其中38种,主体呈香成分为柠檬烯、α-蒎烯、莰烯、金合欢烯、β-水芹烯、β-倍半水芹烯、姜烯等烯类.主体辣味成分为6-姜醇.     

LIPID AND AROMA COMPOSITION OF BLACK CUMIN (NIGELLA SATIVA L.) SEEDS FROM TUNISIA

The chemical composition of Tunisian Nigella sativa L. seeds was investigated. The results showed that linoleic acid (C18:2) was the major fatty acid with 65.1% of total fatty acids (TFAs) followed by oleic acid (C18:1) with 12.7% of TFAs. Neutral lipids (NLs) were mainly composed of triacylglycerols with 98.4% of total NLs. Polar lipids were mainly composed of phosphatidylcholine as the major phospholipid subclass, whereas digalactosyldiacylglycerol was the major galactolipid. Total sterols (TSs) represented 2.2% of the fixed oil and were composed of (-sitosterol as the major sterol representing 60.2% of the TSs. The results indicated that the sterols were mainly present in the esterified and in the free forms with 51.2 and 36.1%, respectively, of TS content. Finally, the aroma composition of the volatile oil from oleoresin exhibited the presence of many bioactive compounds such as p-cymene as the major component followed by ocimene, α -thujene, octen-3-ol with appreciable rates of 1,8-cineole and thymol.

PRACTICAL APPLICATIONS

The results obtained showed that Nigella sativa L. seeds were a good source of polyunsaturated fatty acids (PUFAs), phytosterols (PSs) and phospholipids (PhLs) for the human diet. These seeds could be used by the food industry for formulating functional foods enriched with PUFAs and PSs. For pharmaceutical applications, N. sativa L. conjugated sterols could be used as precursors for the hemisynthesis of many hydrosoluble steroids. Also, N. sativa L. seeds are a good source of PhLs and aroma compounds, and therefore, they could be utilized in biscuit manufacturing and in food flavoring. The presence of many bioactive compounds in N. sativa L. essential oil (p-cymene, limonene, α-pinene, linalool and thymol), known for their powerful antimicrobial function, could support the utilization of the essential oil bactericidal agents.     

超声波提取薰衣草精油的研究

采用超声波法提取薰衣草精油，并通过单因素及正交实验探讨了超声波提取薰衣草精油的最佳工艺条件。结果表明，最佳提取条件为超声频率为45kHz，超声时间为45min，超声温度为50℃，超声功率为80W时效果最佳。     

水提除蜡微波醇提蜂胶黄酮工艺的研究

采用水提除蜡微波醇提蜂胶黄酮工艺，即先水提除蜡、然后微波处理、最后室温浸提蜂胶黄酮，并通过正交试验法进行优化。得出最佳工艺为：通过水提除蜡工艺获得除蜡蜂胶，然后对除蜡蜂胶以乙醇浓度75％、液固比10：1（mL／g）、微波处理4min、室温浸提3d的条件进行提取。该工艺可以显著缩短提取时间，提高提取率。     

超临界CO2萃取鱼腥草挥发油

采用超临界CO2萃取的方法，从三白草科蕺菜属植物鱼腥草中萃取制备挥发油。通过正交实验，建立并优化了挥发油萃取工艺：萃取压力25MPa，萃取温度45℃；CO2流量30kg/h，原料粒度60目～80目，分离压力5MPa，分离温度50℃，静态萃取0．5h，动态萃取1．5h。挥发油的平均萃取率为1．73％，有效成分甲基正壬酮与癸酰乙醛的萃取率为0．0106％、0．0300％。超临界CO2萃取鱼腥草挥发油、甲基正壬酮的萃取率分别是水蒸气蒸馏方法的20倍、1．5倍，同时完全保留了水蒸气蒸馏所没有的特征成分癸酰乙醛，充分体现了超临界CO2萃取的“绿色”特性。     

索氏法提取八角籽挥发油化学成分分析

用索氏提取法以石油醚为溶剂，从广西金秀县产的大红八角和干枝八角籽中提取挥发油。通过GC—MS分析手段对这两种挥发油的主要成分进行了分析，用峰面积归一化法确定各组分的相对含量；结果从大红八角籽的挥发油中共分离出22个色谱峰鉴定了18种，占被测总含量的99、16％，其主要成分为大茴香脑（64．74％）、n-棕榈酸（14．18％）、大茴香醛（6、69％）等；而从干枝八角籽的挥发油中共分离出15个色谱峰共鉴定了11种，占被测总含量的97、62％，其主要成分为n-棕榈酸（48．70％）、大茴香脑（30．65％）等。     

双相溶剂萃取技术提取酱油渣中油脂和大豆异黄酮的研究

利用正己烷-乙醇-水构成的双相溶剂萃取技术同时从酱油渣中提取油脂和大豆异黄酮,采用正交设计方法,考察温度、时间、乙醇浓度、乙醇用量、正己烷用量对油脂和大豆异黄酮提取率的影响,并用极差分析方法对正交试验结果进行分析。确定最优的提取条件：温度60℃、乙醇浓度80％、乙醇用量0．071g／mL、正己烷用量0．1g／mL、时间2h,在此条件下,油脂提取效率为99．2％,大豆异黄酮提取效率为94．5％。     

大豆胚芽油提取工艺的研究

以大豆胚芽出油率为指标，石油醚为脱脂溶剂，通过单因素和正交试验对大豆胚芽索氏提取工艺进行了研究。结果表明：大豆胚芽制油的最佳提取工艺为：粒度30目，料液比1：13，回流时间5h。在此条件下，大豆胚芽出油率为10．50％。     

微波辅助水提葡萄籽原花青素的研究

对微波辅助从葡萄籽中提取原花青素的工艺进行了研究，在单因素和正交优化设计的实验基础上。确定了微波辅助提取葡萄籽原花青素的最佳工艺条件，即微波功率为中高火，料液比为1：18（g／mL），微波作用时间为70s，然后在沸水浴中浸提80min。微波辅助浸提法所得原花青素的提取率比单用传统水提法提高了约1倍。     

超声波辅助提取玉米中黄酮类化合物

为了开发利用玉米中黄酮类化合物,选取玉米为原料,采用超声波辅助提取技术,以乙醇溶液为溶剂,乙醇浓度、料液比、超声时间、超声功率及超声温度为主要考察因素,通过L9(34)正交实验,确定了超声波辅助提取玉米中黄酮类化合物的最佳提取工艺为:超声时间50min,乙醇浓度75%,料液比1:25,超声功率400W,此时,提取的黄酮含量为10.635 mg/g.     

COMPARISON OF MULTISTAGE EXTRACTION INSTALLATIONS WITH SEPARATION OF THE SOLID PHASE BETWEEN THE STAGES IN HOPS (HUMULUS LUPULUS L.) EXTRACTION

The multistage extraction installations using cross-flow and back-flow schemes are successful in hops extraction. Both types of extraction process have been investigated, comparing the installations in order to specify the most appropriate scheme and determine the number of stages required. A three stage extraction with separation of a part of the solid phase between the stages was carried out. The parameters of each extraction stage of a cross-flow and a back-flow installation were calculated. It was established that in the cross-flow scheme the third stage was unnecessary since a minimal part of the bitter substances was extracted in it and the extract yield was too low. Moreover in the cross-flow installations a very high extraction efficiency was achieved, (94, 67%) but with a large consumption of extracting solvent (3,24.10^?2m³/kg) whilst in the back-flow scheme the extraction efficiency was much lower (71,4%) but with a reduced solvent consumption (1,2.10^?2m³/kg). The comparison of both installations demonstrates that the back-flow scheme is not very successful and that it is advisable to use a cross-flow installation with one or at most two extraction stages. The results obtained enable the proposal of a more rational scheme of hops extraction, where a one or two stages cross-flow process with separation of a part of the solid phase results in a final granulated product, a mixture of the extract and partly extracted raw material.     

鲜罗汉果挥发性风味成分分析

利用气相色谱-质谱法(GC-MS)对鲜罗汉果挥发油化学成分进行分析鉴定,共分离出18种成分,鉴定出14个化学成分.同时分析发酵型罗汉果酒中游离氧基酸成分,游离氨基酸数量高达17种之多,总含量为27.7mg/100mL.鲜罗汉果挥发性成分和罗汉果酒中丰富的游离氨基酸赋予罗汉果酒特有的香味和浓厚感及很高的营养价值.     

SUBCRITICAL WATER EXTRACTION OF CAFFEINE FROM BLACK TEA LEAF OF IRAN

ABSTRACT

This study examines subcritical water extraction (SCWE) of caffeine from black tea leaf. The effects of various operating conditions such as water temperature (100, 125, 150 and 175C), water flow rate (1, 2 and 4 g/min), mean particle size (0.5, 1 and 2 mm) on extraction yield and rate were determined. SCWE at 175C, water flow rate of 2 g/min and mean particle size of 0.5 mm were found to be able to recover 3.82% (w/w) of caffeine present in the black tea leaf within 3 h of extraction. In comparison to the SCWE, conventional hot water extraction showed 3.30% (w/w) extraction yield. It was found also that pressure had no effect on extraction yield and rate.

PRACTICAL APPLICATIONS

Recently, subcritical water has become of great interest as an alternative solvent for extraction of natural active compounds. Subcritical water, as a green solvent, can be used in many different fields of applications. In recent years, extraction of flavors, fragrances and antioxidant components from plant materials, and hydrolysis of carbohydrates, vegetable oils and fatty acids have been widely investigated by many researchers. Using subcritical water for analytical purposes, for soil remediation and applying it as a reaction media are some other interesting fields for practical applications. Subcritical water is an excellent solvent for caffeine as well as many other organic compounds but is safer than the organic solvents that are used for caffeine extraction.     

超临界CO2萃取蛋黄油的研究

采用超临界CO2萃取技术从蛋黄粉中萃取蛋黄油，研究了超临界CO2萃取过程的试验参数，结果表明：利用正交试验设计得到超临界CO2萃取蛋黄油的最佳工艺条件为：萃取温度：35℃，萃取压力：22MPa，萃取时间：180min。