分子蒸馏技术分离纯化大蒜精油的研究

应用刮膜式分子蒸馏技术对大蒜油中的有机硫化物二烯丙基二硫醚(DADs)和二烯丙基三硫醚(DATs)进行的提纯。试验研究了温度、真空度、进料速度、刮膜转速对有效成分(DADs和DATs)分离纯度和得率的影响,在单因素试验基础上通过L_9(3~4)正交设计试验,确定了一级分子蒸馏的最佳工艺参数为:温度50℃,真空度200Pa,进料速度1.5mL/min,刮膜转速200r/min。以一级分子蒸馏所得原料进行多级蒸馏试验,通过五级分子蒸馏,最终产品中DADs和DATs的纯度和得率分别可达到85.03%和54.35%。     

大蒜挥发油提取工艺优化及GC-MS分析

目的:优化大蒜挥发油提取工艺并分析其化学成分,为大蒜的开发利用提供依据。方法:通过正交试验确定水蒸气蒸馏法提取大蒜挥发油的工艺条件,并利用GC-MS进行成分分析。结果:大蒜挥发油提取的最佳工艺为超声时间35min、浸泡温度35℃、料液比1∶4、蒸馏时间2h,挥发油的实际提取率为0.280%。从该法提取的大蒜挥发油中鉴定出了32种成分,其中含硫化合物29种,占挥发油总量的88.15%,主要为二烯丙基二硫醚(35.11%)和二烯丙基三硫醚(26.15%)等烯丙基硫醚类化合物。结论:该法工艺简单、绿色环保,制备的大蒜挥发油含硫化合物含量高,有助于提高其药用价值。     

大蒜油微胶囊的表征及在腊肠中的应用研究

以大豆分离蛋白和壳聚糖为复合壁材,以大蒜油为芯材,采用复凝聚法制备大蒜油微胶囊,并对大蒜油微胶囊的感官性状、理化性质、超微结构、成分变化及在腊肠中的应用进行研究。结果表明:大蒜油微胶囊呈黄白色、松脆状固体,具有蒜香味;水分含量低,粒度小,流动性较好;GC/MS分析显示微囊化后的大蒜油的主要成分仅损失了甲基烯丙基二硫醚,保留了大蒜油中二烯丙基单硫醚、二烯丙基二硫醚、甲基-2-丙烯基三硫醚、二烯丙基三硫醚和二烯丙基四硫醚等主要有效成分;添加了大蒜油微胶囊的腊肠具有典型的蒜香味,且蒜香柔和,其风味和口感明显优于添加大蒜泥和大蒜油的腊肠,这表明大蒜油微胶囊可代替大蒜泥或大蒜油作为调味料用于生产蒜味腊肠。     

大葱挥发油含量与化学成分的分析

采用水蒸气蒸馏法提取莱芜鸡腿葱中的挥发油 ,测知其含量为 0 0 1 % ;并用毛细管气相色谱 /质谱法定性鉴别了挥发油中的 2 5种化学成分。其中含硫有机硫化合物为 2 0种 ;主要成分有 :丙基甲基硫代硫磺酸酯 ,甲基烯丙基硫代硫磺酸酯 ,甲基丙烯基三硫醚 ,烯丙基硫醇 ,甲丙基二硫醚 ,反式甲基烯丙基二硫醚 ,二甲基三硫醚 ,二丙基二硫醚 ,反式烯丙基丙基二硫醚 ,二甲基四硫醚 ,二丙基三硫醚 ,反式烯丙基丙基三硫醚 ,顺式烯丙基丙基三硫醚 ,甲硫醇 ,丙硫醇 ,二巯基甲烷 ,2 ,5 二甲基噻吩等含硫化合物 ,还鉴定出不饱和脂肪醛 1种 (3 ,7 二甲基 2 ,6 二辛烯醛 ) ,脂肪酮 1种 (十一酮 2 ) ,萜烯类化合物 2种 (2 甲基 庚稀 2和顺式 2 ,6 二甲基 2 ,6 辛二烯 ) ,挥发性无机化合物 1种 (SO2 )。     

大蒜油的抗凝血作用

为研究大蒜油的抗凝血作用,本实验从大蒜中分离提取大蒜油,经气相色谱-质谱联用仪鉴定该大蒜油中主要成分为二烯丙基硫醚（allyl sulfide,DAS）、二烯丙基二硫醚（diallyl disulfide,DADS）和二烯丙基三硫醚（diallyl trisulfide,DATS）。体外实验结果表明大蒜油、DAS、DADS、DATS均具有部分抑制凝血酶活性功能,且抑制作用由强到弱依次为DATS＞大蒜油＞DADS＞DAS。利用Lineweaver-Burk双倒数作图法进行酶动力学分析,结果表明大蒜油、DAS、DADS、DATS对凝血酶的抑制作用属于混合性抑制（竞争性和非竞争性抑制）。分子荧光光谱分析结果表明大蒜油、DAS、DADS、DATS能与凝血酶蛋白中的发色基团相互作用导致荧光猝灭。三维分子对接分析结果显示出DATS与凝血酶结合性能良好;二维分子对接分析结果显示出DATS与凝血酶蛋白活性位点处Asp189、Gly219和Ala190形成氢键,与酶活性位点的Gly216、Ser195、Trp215形成疏水作用力,体现竞争性抑制作用,与非活性位点Gly226、Asp221A、Tyr225、Glu217、Cys191、Val213形成疏水作用,体现非竞争性抑制作用。体内实验结果表明,大蒜油、DAS、DADS、DATS分别通过正向调控大鼠凝血四项指标而直接展现出抗凝血功能,且抗凝血能力依次为DATS＞DADS＞DAS＞大蒜油。大鼠体内抗氧化实验结果表明大蒜油、DAS、DADS、DATS均只有微弱抗氧化能力,大蒜油、DAS、DADS、DATS具有的抗凝血功能应与其抗氧化能力不相关。     

SPME提取多星韭不同部位挥发油的化学成分研究

用固相微萃取技术分别提取新鲜多星韭的花、茎、叶部位的挥发性成分,同时采用气相色谱-质谱联用技术对不同部位挥发油化学成分进行分离和鉴定,并用峰面积归一化法确定各组分的相对含量。结果表明,分别从多星韭花、茎、叶挥发油分离、鉴定了30、18、19个化合物,花、茎、叶中分别有22、17、16个硫化物,硫化物占花、茎、叶挥发油总离子峰相对含量的76.20%、82.73%、78.15%。多星韭各个部位挥发油含量较高的化合物基本一致,主要是烯丙基丙基二硫醚、二烯丙基二硫醚、二丙基二硫醚、二烯丙基三硫醚、反式丙烯基丙基二硫醚、甲基烯丙基二硫醚等,但是相对百分含量有一定差异。     

含硫风味化合物及其形成原理

含硫风味化合物在食品中含量极少,呈味阈值低,但对加工肉类、加工蔬菜和乳及乳制品的贡献很大。加工肉制品中典型的含硫风味化合物是二甲基二硫,二甲基三硫化物,2-甲基-3-呋喃硫醇,2-糠基硫醇和双(2-甲基-3-呋喃基)二硫化物。乳及乳制品中典型的含硫风味化合物是甲硫醇,二甲基二硫,二甲基硫醚。加工蔬菜中典型的含硫风味化合物是二甲基二硫,硫醇,二烯丙基二硫化物,二甲基硫醚。加工肉制品中的含硫风味化合物主要是通过加工过程中发生的美拉德反应形成,乳及乳制品和加工蔬菜中的含硫风味化合物主要是由前体风味物质经酶促反应转化而来。     

顶空-固相微萃取-气质联用分析泡蒜中的挥发性成分

采用顶空-固相微萃取对泡蒜中挥发性成分进行了提取,并用气相色谱-质谱联用仪对提取出的挥发性成分进行了定性和定量分析。结果表明:从泡蒜中共鉴定出46个挥发性化合物,其中以含硫化合物为主体,共29种。泡蒜中的主要挥发性化合物有二烯丙基二硫醚(19.16%)、二烯丙基三硫醚(13.60%)、3-乙酰基-2-羟基-6-甲基-吡喃-4-酮(11.45%)、3-乙烯基-3,4-二氢-1,2-二噻烯(8.10%)、二烯丙基硫醚(4.07%)、2,4-二甲基噻唑(4.00%)、二烯丙基四硫醚(3.34%)、3-甲基-5-氨基-1,2,4-噻二唑(3.10%)。     

黄皮洋葱和紫皮洋葱挥发油化学成分分析

采用水蒸汽蒸馏萃取法提取,用气相色谱.质谱联用法结合计算机检索对黄皮和紫皮洋葱挥发油的化学成分进行分析和鉴定.结果表明,黄皮洋葱中挥发油的提取率为1.78%,鉴定出20种化合物;紫皮洋葱中挥发油的提取率为3.24%,鉴定出10种化合物.黄皮洋葱主要化学成分为酮类、烷烃类和胺类;紫皮洋葱为二甘醇、联苯、二丙基二硫醚.     

同时蒸馏-萃取法(SDE)提取葱油及工艺优化

以新鲜大葱为研究对象,采用同时蒸馏-萃取法(SDE)提取葱油,利用毛细管气相色谱/质谱法(GC/MS)鉴定出25种化合物,其中含硫化合物13种,主要成分有:烯丙基甲硫醚、甲基甲基硫代亚磺酸酯、丙基甲基硫代硫磺酸酯、反式烯丙基丙基三硫醚等;醛类3种,2-甲基-2-戊烯醛、2-丁炔二乙基乙缩醛、3-丁炔二乙基乙缩醛;酯类6种,主要成分有:2-丁烯酸甲酯、3-戊烯酸,4-甲基-2-丙烯酸酯、2-丁烯酸乙烯酯等;酸2种,乙烯丁酸和2-甲基庚酸;醇类1种,2,4-二甲基-3-戊醇。在单因素实验基础上,选取蒸馏温度、料液比、同时蒸馏-萃取时间以及水浴温度进行正交实验,确定同时蒸馏-萃取法提取葱油最佳工艺参数为:蒸馏温度95℃、料液比1∶2(g∶m L)、同时蒸馏-萃取时间3.5h、水浴温度55℃,此条件下测得含硫化合物含量可达25.15mg/g。     

超临界CO2-分子蒸馏纯化蒜油与水蒸气蒸馏法制取蒜油挥发性成分分析

采用分子蒸馏技术(MD)将超临界CO2(SFE)萃取的蒜油进行纯化,以顶空固相微萃取气质联用技术(HSSPME-GC-MS)分析蒜油中的挥发性成分,确定最佳工艺：进样速度1 滴/s,蒸馏温度60℃,刮膜转速250r/min。纯化的蒜油挥发性成分仅有4 种,二烯丙基二硫醚和二烯丙基三硫醚、2- 乙烯基-1,3- 二硫杂-4- 环己烯和3- 乙烯基-1,2- 二硫杂-5- 环己烯;与水蒸气蒸馏法制得的新鲜蒜油(F-GO)比较,SFE 法是一种理想的制取蒜油的方法;蒜油放置30d(S-GO)后有效成分含量下降,导致品质下降。     

分子蒸馏法分离提取大蒜精油

采用分子蒸馏技术,依据Box-Behnken 设计原理和响应面分析法,探讨分子蒸馏不同因素对分离、提取大蒜中大蒜精油的影响,选择最佳提取条件。结果表明：当控制系统的压力105Pa、进料速度1.2g/min、进料温度40～55℃范围内,蒸馏温度45.1℃时具有最好的二次分子蒸馏效果,大蒜精油的外观质量明显提高,平均总提取率可达0.476%,大蒜精油中水分为0.15%,纯度达99.85%。     

大蒜精油抗菌活性研究

采用琼脂扩散法及肉汤稀释法研究了大蒜精油的抗菌活性.使用GC-MS分析此精油的成分,其中二烯丙基三硫醚(49.23%)及二烯丙基二硫醚(19.35%)为最主要成分.以枯草芽孢杆菌、金黄色葡萄球菌、表皮葡萄球菌、大肠杆菌、绿脓杆菌、变形杆菌、黑曲霉和白色念珠菌为供试菌种,结果显示大蒜精油对于所选的8种菌均有一定的抗菌活性,尤对黑曲霉、白色念珠菌和表皮葡萄球菌有较好的杀灭作用.实验证明大蒜精油在食品及医药工业有广泛的应用前景.     

Odor Components of Human Breath After the Ingestion of Grated Raw Garlic

The major odor components of finely grated, raw garlic in the air of the human mouth have been studied. Immediately after garlic ingestion, tests of the mouth air of six subjects revealed two major peaks that were positively identified as being allyl mercaptan and diallyl disulfide; these findings are based on an evaluation of the fragment patterns of a GC-MS analysis and from the actual retention times of these authentic compounds. The allyl mercaptan level was higher than the level of diallyl disulfide, although both compounds smell like garlic. Our results suggest that after garlic ingestion, allyl mercaptan is the major garlic-smelling compound in human mouth air, and diallyl disulfide is secondary.     

Changes in Flavor Components of Garlic Resulting from Gamma Irradiation

Formation of diallyl disulfide, identified as a main flavor component of garlic, was gradually decreased by irradiation of 0.05-0.5 kGy, but increased slightly at higher doses of 1.0-3.0 kGy. In garlic stored for 5 months, a dose of 0.1 kGy had little influence on the amount of diallyl disulfide, but higher dose irradiation caused an apparent reduction in the amount of the component.     

大蒜素和有机溶剂对蒜氨酸酶活性及大蒜油组成的影响

大蒜油具有重要的生物活性和调味功能。本文以化学合成的蒜氨酸为原料在蒜酶的催化下制备大蒜油,研究中间产物大蒜素、萃取溶剂对蒜酶活性的影响,以及溶剂对大蒜油组成成分的影响。结果显示:大蒜素在一定程度上会抑制蒜酶的活性,但不会导致蒜酶的完全失活;有机溶剂对蒜酶的影响比较复杂,其中氯仿、二氯甲烷使蒜酶活性完全丧失,而正己烷、正戊烷对蒜酶的活性影响则不明显。采用气质联用、核磁共振二维谱表征了不同溶剂下大蒜油的组成。用氯仿、正己烷等非极性溶剂萃取大蒜素,得到的大蒜油以3-乙烯基-1,2-二硫环己-4-烯(4X)和3-乙烯基-1,2-二硫环己-5-烯(5X)为主;而用乙酸等质子溶剂萃取,则大蒜油成分以二烯丙基三硫醚(DATS)、二烯丙基二硫醚(DADS)为主。     

Alliinase-independent Inhibition of Staphylococcus aureus B33 by Heated Garlic

ABSTRACT: Heated (121 °C) garlic extract in which alliinase was inactivated before crushing exhibited complete bacteriostatic activity at 15% against Staphylococcus aureus. Garlic heated for 45 min showed the highest antibacterial activity and the relative peak areas of 4-heptenal, methyl allyl disulfide, diallyl disulfide, 2-vinyl-4H-1,3-dithiin, and diallyl trisulfide (DATS) were highest at 45 min of heating. Other than 4-heptenal, all these compounds are known to possess different degrees of antibacterial activity. DATS was thought to be the primary antibacterial compound in heated garlic extract. It was tentatively concluded that antibacterial compounds were formed from alliin unreacted by alliinase by marked heating. Diallyl compounds with more than three sulfur atoms and the oxidized form of allicin were not detected.     

Effects of pH Adjustment and Subsequent Heat Treatment on the Formation of Volatile Compounds of Garlic

Effects of pH adjustment during the blending of garlic cloves and subsequence heat treatment on the formation of volatile compounds of garlic were studied by means of gas chromatography (GC). The formation of the two isomeric cyclic compounds 3-vinyl-[4H]-l,2-dithiin and 2-vinyl-[4H]-l,3-dithiin, which were artifacts from allicin, was favored around pH 5.5. Formation of diallyl trisulfide, methyl allyl trisulfide, cis-1-propenyl allyl disulfide, isobutyl isothiocyanate, 2,4-dimethylfuran, 1,3-dithiane, aniline, methyl allyl sulfide, dimethyl disulfide and 3-methyl-2-cyclopentene-l-thione were favored in neutral or weak acidic conditions, whereas formation of diallyl disulfide, diallyl sulfide, methyl allyl disulfide, propenylthiol, propyl allyl disulfide and 1,2-epithiopropane were favored around pH 9.0.     

Effect of Milk on the Deodorization of Malodorous Breath after Garlic Ingestion

Abstract: The effect of milk and milk components on the deodorization of diallyl disulfide (DADS), allyl methyl disulfide (AMDS), allyl mercaptan (AM), allyl methyl sulfide (AMS), and methyl mercaptan (MM) in the headspace of garlic as well as in the mouth- and nose-space after garlic ingestion was investigated using selected ion flow tube-mass spectrometry (SIFT-MS). Fat-free and whole milk significantly reduced the head-, mouth-, and nose-space concentrations of all volatiles. Water was the major component in milk responsible for the deodorization of volatiles. Due to its higher fat content, whole milk was more effective than fat-free milk in the deodorization of the more hydrophobic volatiles diallyl disulfide and allyl methyl disulfide. Milk was more effective than water and 10% sodium caseinate in the deodorization of allyl methyl sulfide, a persistent garlic odor, in the mouth after garlic ingestion. Addition of milk to garlic before ingestion had a higher deodorizing effect on the volatiles in the mouth than drinking milk after consuming garlic. Practical Application: Ingesting beverages or foods with high water and/or fat content such as milk may help reduce the malodorous odor in breath after garlic ingestion and mask the garlic flavor during eating. To enhance the deodorizing effect, deodorant foods should be mixed with garlic before ingestion.