百里香精油对羊奶脱膻效果的评价及机理研究

研究百里香精油对羊奶膻味的脱除效果及作用机理。采用水蒸气蒸馏法制备百里香精油;利用气相色谱-质谱联用技术对百里香精油的挥发性风味成分进行测定;通过感官评价分析百里香精油对羊奶膻味的脱除效果;根据羊奶中致膻性脂肪成分的分析,探讨了百里香精油对羊奶脱膻作用的机理。结果表明,百里香精油中鉴定出18种挥发性成分,百里香酚(14.40%)和龙脑(28.24%)为其主要的风味成分;百里香精油的添加可有效脱除羊奶的膻味,最优添加量为0.025mL/L;百里香精油通过降低羊奶中显著致膻的癸酸、辛酸和己酸的含量而脱除羊奶的膻味。     

自组装多肽水凝胶对百里香精油的控释作用、抑菌和抗氧化效果的延长作用

为实现百里香精油的控制释放并延长其抑菌和抗氧化效果,本实验利用N-芴甲氧羰基-L-苯丙氨酸(N-FMoc-L-phenylalanine,Fmoc-F)水凝胶包埋百里香精油,对比包埋前后Fmoc-F水凝胶的结构、形态等特征,研究其对百里香精油的包埋机制、控释作用及包埋后Fmoc-F对百里香精油抑菌和抗氧化效果的延长作用。结果表明:百里香精油的加入可以加速Fmoc-F/百里香精油水凝胶(50 s)的形成,并且显著提高胶体的储能模量;Fmoc-F及Fmoc-F/百里香精油水凝胶主要通过氢键作用形成胶体,其微观结构为纤维状网络结构,且百里香精油可以使Fmoc-F水凝胶的网络结构更紧密均匀,从而提高其胶体的储能模量。Fmoc-F水凝胶对百里香精油的包埋率达93.13%。通过抑菌实验和抗氧化实验发现,在环境p H≥6.5时,Fmoc-F水凝胶可通过包埋有效抑制百里香精油的挥发,而随着环境p H值的降低,Fmoc-F水凝胶会缓慢分解,释放百里香精油,起到对百里香精油抑菌和抗氧化效果的延长作用。     

新疆阿勒泰百里香挥发油化学成分GC-MS分析及抗氧化活性测定

利用水蒸汽蒸馏法提取了新疆阿勒泰百里香挥发油,测得含量为0.31%。并采用气相色谱- 质谱联用技术对拟百里香的挥发性成分进行了分离鉴定,分离出82 种成分,共确认了其中72 种。采用峰面积归一化法确定了各成分的相对含量。同时测定了挥发油的金属螯合性、还原力和抗氧化能力,结果表明阿勒泰百里香挥发油、BHT 和百里香酚均无金属螯合性,挥发油还原能力高于百里香酚和BHT,并且抗氧化活性较好。     

超临界CO2萃取百里香精油及其萃取物抗氧化活性研究

用超临界CO2萃取技术对百里香进行萃取,得到百里香精油.探讨了萃取压力、时间、温度等因素对萃取收率的影响,并将萃取物进行了抗氧化实验.结果表明,百里香芳香油对大豆油具有较强的抗氧化作用,而且不影响大豆油的品质.     

芳香植物精油对食品常见腐败微生物抗菌活性的研究

通过测定抑菌圈直径大小了解食品常见腐败微生物对12种芳香植物精油的抗菌敏感性,进一步测定最低抑菌浓度、最小杀菌浓度分析食用芳香植物精油抗菌活性。试验表明:食品常见腐败微生物对植物精油表现出不同的敏感性,特别是枯草芽孢杆菌对植物精油抗菌敏感性最强;综合抗菌活性最好的是牛至和百里香精油,浓度达到250μL/L时表现出广谱抗菌性,但肉桂精油对真菌有更好的抗菌活性;采用棋盘稀释法进一步研究植物精油间协同增效效果,发现牛至-百里香复配表现出显著的相加效果;气-质联用仪分析了牛至、百里香和肉桂精油的主要抗菌成分香芹酚、百里香酚和反式肉桂醛等的含量。研究可为食用植物精油作为"高效、安全"的防腐保鲜剂应用于食品领域提供了理论依据。     

植物精油对食品中常见有害微生物的抑菌活性研究

通过测定抑菌圈、气相熏蒸法等体外抑菌试验研究了罗勒精油、茶树油、百里香精油、丁香精油、小茴香精油、依兰油、甘牛至精油、肉桂精油、桉叶油、芫荽籽精油、香茅油、鼠尾草油、甘松精油十三种植物精油对六种食品常见有害微生物抗菌作用。结果表明:十三种植物精油均对细菌、霉菌和酵母具有一定的抑杀能力。百里香精油和肉桂精油抗菌活性最强,均表现程度不等的抗菌活性。六种供试菌种对百里香精油、肉桂精油极敏感,抑菌圈直径均大于20 mm;当两种精油空间体积浓度达到300μL/L时,两种精油对多数供试菌表现出强抑菌效果。肉桂精油与百里香精油复配后对供试菌没有表现出强的协同增效效果,部分出现相加作用和无关作用。复配精油中肉桂精油占80%时,对供试菌效果最好。     

百里香精油的提取工艺及化学成分分析

采用超高压法提取百里香精油,考察压力、料液比、粉碎度和保压时间对百里香精油提取率的影响,用气相色谱-质谱联用技术对精油化学成分进行分析。结果表明超高压萃取百里香精油的最佳条件为:压力410MPa,料液比1∶28,粉碎度50目,保压时间4min,提取温度为室温,得到百里香精油提取量平均值为11.236mg/g。气质联用分析确认了百里香精油中的46种成分,占总峰面积的97.949%,主要成分有百里酚(43.925%)、对-聚伞花素(16.112%)等。     

草果精油的化学组成、抗氧化及抑菌活性研究

以正己烷为溶剂提取草果精油,利用气相-质谱联用技术(GC-MS)分析其化学成分,同时研究了草果精油的抗氧化和抑菌活性.结果表明,草果精油成分比较复杂,其中有23种化合物被鉴定,主要成分为香叶醇(29.42％)、橙花叔醇(9.87％)、十八碳烯酸(8.62％)等.草果精油对DPPH和ABTS自由基均显示出了较好的清除效果,EC50值分别为3.84、3.20mg/mL;不同浓度的草果精油对5种测试菌都有一定的抑菌作用,其中对大肠杆菌的抑菌效果最好,其最低抑菌浓度(MIC)为2.0mg/mL.     

乳液模板-层层自组装法制备百里香精油微胶囊

采用乳液模板-层层自组装法,以百里香精油乳液为模板、壳聚糖和海藻酸钠为壁材,制备百里香精油微胶囊(Thyme oil microcapsules,TMS)。以TMS的包埋率为指标,通过单因素和正交试验对其制备工艺进行了优化;通过马尔文激光粒度仪、扫描电镜、透射电镜以及GC-MS对百里香精油微胶囊进行了表征。结果表明,最佳制备参数为:均质压力62 MPa、均质循环6次,NaCl添加量为0.3%,pH 6,基于静电作用组装的TMS包埋率为71.13%±0.03%,平均粒径为140 nm,球形规整,能保留百里香精油的主要成分。     

地椒精油中主要成分及其作用分析

地椒为唇形科百里香属植物,其所含的精油属于天然香料,具有较高的经济价值,但很少有文献对百里香属植物精油中各种成分的作用进行详细分析。本文分析了不同地区百里香属植物精油成分的差异及其在食品中的应用,同时以陕西榆林地区的地椒为试材,利用GC-MS对各种挥发性成分的含量进行测定,得出其所含的苯、烯、酚、烷和醇类物质分别为48.54%、23.69%、13.13%、1.76%和0.5%,这些成分的存在使百里香属植物具有特殊的香气,并且在抑菌、抗氧化方面都发挥了重要作用。通过对地椒精油中各个组分作用的分析,有助于加强对地椒叶中各个挥发性成分的综合利用。     

提取方法对百里香精油化学成分和抗氧化活性的影响

本文分别采用水蒸气蒸馏法（SD）、同时蒸馏萃取法（SDE）、冷等离子体辅助提取法（CPAE）从百里香叶片中提取精油,通过气相色谱-质谱联用（GC-MS）分析了三种精油中的挥发性成分,测定其精油中的总酚、总黄酮、花青素含量,通过DPPH?、ABTS+?、总抗氧化能力三个抗氧化指标评估了其体外抗氧化性,并将精油中的主要活性成分与抗氧化能力进行相关性分析,比较得出得率更高、抗氧化性更好的提取方法。结果表明,不同提取方法在精油得率上有显著性差异（P<0.05）,SDE法的精油得率最高,达到了1.30%。经GC-MS分析,三种精油共检出了36种组分,主要成分均为2-茨醇（32.194%~32.515%）、香芹酚（17.265%~19.998%）、百里香酚（13.031%~15.202%）和α-松油醇（11.296%~12.012%）,其中,SDE法和CPAE法比SD法制备得到的精油在以上活性成分上含量更高。在总酚、总黄酮、花青素的测定结果中,SDE法制备得到的精油中总酚和花青素含量更高,分别为133.67±0.20 mg GA/g EO、0.32±0.02 mg/g EO,CPAE法制得的精油总黄酮含量最高,达到了54.82 mg Rutin/g EO。在体外抗氧化性实验中,三种精油在实验浓度范围内对各项抗氧化指标都表现出较强的抗氧化性和明显的量效关系,其中,SDE法获得的精油对于自由基的清除效果更佳,在最高实验浓度下清除率均在96%以上。通过抗氧化相关性分析发现,百里香精油的抗氧化活性与酚类等物质的含量密切相关。综上,从各项实验结果来看,SDE法是一种更为可取的提取百里香精油的方法。     

野生糙苏籽挥发油化学成分的分析

用水蒸汽蒸馏法从野生糙苏籽中提取挥发油,利用气相色谱- 质谱联用技术对其挥发油中的化学成分进行分离和结构鉴定,运用气相色谱面积归一化法确定各个成分的相对百分含量。从糙苏籽的挥发油中鉴出56 种成分,其主要成分为α- 里哪醇(13.38%)、石竹烯氧化物(11.21%)、1- 辛烯-3- 醇(8.38%)、邻苯二甲酸二异丁酯(8.22%)、亚麻酸乙酯(6.21%)等。对糙苏籽的挥发油进行了抗氧化实验和抗菌实验,结果表明糙苏籽挥发油对·OH 有明显的清除作用,糙苏籽的挥发油对实验菌株均有明显的抑制和灭活作用,特别是大肠杆菌ATCC25922 株和肺炎球菌32201 株的抑制作用表现得更为显著。     

Chemical composition and antimicrobial activity of Anzer tea essential oil

Anzer tea (Thymus praecox, subsp. caucasicus var. caucasicus) naturally grows in the eastern Black Sea region of Turkey. Anzer tea, a creeping plant with crimson‐pink flowers, is important for honey production in the region. In the present study, content, composition and antimicrobial properties of Anzer tea's essential oil were investigated. Essential oil content of dried aerial plant parts varied between 1.53% and 2.05%. Essential oil composition was studied by means of gas chromatography–mass spectrometry, and 26 components were identified. The major components were thymol (47.45%), γ‐terpinene (8.73%), p‐cymene (8.30%), terpinyl acetate (4.88%) and carvacrol (4.66%). Essential oil was also screened for its antibacterial activity. In a screen for antibacterial activity, Anzer tea essential oil had significant activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Candida albicans. Copyright © 2007 Society of Chemical Industry     

不同大蒜精油成分及生物活性对比分析

为了解白皮大蒜和紫皮大蒜精油成分及生物活性差异,采用水蒸气蒸馏法提取白皮大蒜和紫皮大蒜精油,通过气相色谱质谱联用仪(GC-MS)分析测定两种大蒜精油的可挥发性成分;用对倍稀释法研究两种大蒜精油对几种常见病原菌的抑制活性;采用小叶碟法测定两种大蒜精油对斜纹夜蛾的拒食活性;并检测白皮、紫皮大蒜精油对ABTS、DPPH和OH自由基的清除作用。结果表明:白皮大蒜精油鉴定出26种成分,占精油的95.79%;紫皮大蒜精油鉴定出22种成分,占精油的94.26%,主要杀菌物质大蒜辣素和大蒜新素在紫皮大蒜(59.34%)中的含量比白皮大蒜(50.11%)多;两种大蒜精油对实验用菌有明显抑制作用,尤其紫皮大蒜精油对枯草芽孢杆菌、白色念珠菌、热带假丝酵母菌和板栗疫病的抑制效果比白皮大蒜好;白皮大蒜和紫皮大蒜精油对斜纹夜蛾24h平均拒食率分别为52.97%和100%;白皮大蒜精油对ABTS和DPPH自由基的清除率高于紫皮大蒜精油,对OH自由基的清除率基本相当。     

竹叶精油组分构成及其抑菌活性的研究

目的研究竹叶精油的化学组分构成,并考察其体外抑菌活性。方法以食品常见腐败菌(枯草芽孢杆菌、金黄色葡萄球菌、大肠杆菌和酿酒酵母)作为供试菌,采用平板打孔法对竹叶精油的抑菌活性进行研究;并通过气相色谱-质谱联用技术对竹叶精油的组分构成进行分析鉴定。结果竹叶精油共鉴定出41个化合物,含量占挥发性成分总量的97.36%,主要成分为棕榈酸(19.35%)、植物醇(10.54%)和二十五烷(9.89%)等。竹叶精油对4种供试菌株均有抑制作用,研究发现大肠杆菌是最敏感的,其最小抑菌浓度为0.56 mg/mL。结论本研究可为竹叶精油在食品工业中的深入利用提供一定的理论技术支持。     

Chemical composition and biological activities of Algerian Thymus oils

The compositions of essential oils isolated from nine samples of three Thymus species (Thymus algeriensis, Thymus pallescens and Thymus dréatensis) were analysed by GC and GC–MS, and a total of 114 components were identified. T. pallescens collected from various regions showed a great similarity in their compositions and were characterised by carvacrol (44.4–57.7%), p-cymene (10.3–17.3%) and γ-terpinene (10.8–14.2%) as the major components for four samples; only one sample was thymol-rich (49.3%) with a small amount of carvacrol (9.0%). On the other hand, T. algeriensis showed a chemical polymorphism, even for samples from the same location, and two new chemotypes for this species were proposed. Oxygen-containing monoterpenes were the predominant class (76.3%) in T. dreatensis oil, with linalool (30.4%), thymol (20.2%) and geraniol (19.6%) as the principal constituents. The oils were screened for their possible antioxidant activities by four complementary assays, namely DPPH free radical scavenging, hydroxyl radical scavenging, inhibition of lipid peroxidation and reducing power. The two new chemotypes of T. algeriensis exhibited strong hydroxyl radical scavenging (IC₅₀ = 2.2–3.3 μg/ml), but were not or only slightly active against the other radicals and exhibited a weak reducing power. Despite their chemical similarity, T. pallescens oils sometimes produced significant differences in their antioxidant activities. The essential oils were also screened for their antimicrobial activity against five bacteria (three Gram-positive and two Gram-negative) and one yeast (Candida albicans). The tested essential oils showed antimicrobial activity against the microorganisms used, in particular against two important pathogens, C. albicans and Helicobacter pylori.     

Concentration of antioxidant polyphenols from Thymus capitatus extracts by membrane process technology

Thymus capitatus is a Mediterranean plant characterized by its antioxidant polyphenols of which the most known are the carnosic and rosmarinic acids. In this way, this study aims to concentrate these acids by membrane processes. The thyme essential oil composition was established by capillary GC-MS and 27 components were identified representing 98.93%± 1.97% of total oils. The antioxidant test for permeate and retentate of methanolic and aqueous extract were determined using 3 types of membranes. The results showed that the synthetic NF membrane is able to trap and concentrate phenolic compounds in the retentate much better than the NF commercial and UF synthetic membrane. The results of the total phenolic content (TPC) showed a significant value of the polyphenol content present in the aqueous extract with 175.53 mg Gallic Acid Equivalents (GAE)/g of extract. The spectrum of the aqueous extract of Thymus capitatus showed the presence of 3 visible peaks, the 1st one at 217 nm corresponding to the carnosic acid, the 2nd one at 277 nm for essential oils, and the last one at 326 nm attributed to the rosmarinic acid. The commercial membrane NF-DK succeeded to concentrate rosmarinic acid and can be considered as a stage towards the concentration of this product with a high added value.     

Sensory and chemical evaluation of Thymus zygis L. essential oil and compressed CO2 extracts

The effects of the extraction procedure on the sensory and chemical evaluation of Thymus zygis L. aromatic extracts obtained by hydro distillation and compressed CO₂ extraction were studied. Compressed CO₂ extractions were performed at a temperature of 313 K and 10 and 15 MPa of pressure for 60 min. Aromatic extracts were analysed by GC and GC-MS. Sensorial analysis of the aromatic extracts incorporated into a sunflower oil was carried out by a panel of 20 trained members. The main compounds of Thymus zygis essential oil obtained by Clevenger distillation are: p-cymene (13.6%), thymol (23.8%), geraniol (18.2%), and geranyl acetate (16.3%). The compositions of supercritical extracts are quite different. The detection threshold of Thymus zygis essential oil was 0.001 mg/kg sunflower oil. The preferred level of essential oil incorporation was 0.02 mg/kg sunflower oil (P<0.05). Sensorial attributes were correlated with chemical compositions and it can be concluded that extracts with higher levels of phenols and geranyl acetate were preferred.     

甘肃和新疆产区孜然精油成分的比较

采用水蒸气蒸馏法提取了甘肃和新疆两地孜然籽精油,产率分别为2.38%和2.56%,用GC-MS联机对精油进行成分分析,前者检测出31个成分,鉴定了27个成分,主要成分2-蒈烯-10-醛,占总精油含量的40.239%,其次为枯茗醛(26.144%)和3-蒈烯-10-醛(16.882%);后者检测出27个成分,鉴定23个成分,主要成分2-蒈烯-10-醛,占总精油含量的44.338%,其次为枯茗醛(30.244%)和3-蒈烯-10-醛(12.861%)。含量和成分比较结果表明,新疆精油优于甘肃精油。