百里香精油在食品中开发应用的研究进展

综述了近期外国学者对百里香精油在食品中开发应用的最新进展,以期提高我国消费者对百里香精油的认识,为百里香及其精油的开发应用提供参考。     

基于气相色谱-离子迁移谱对百里香挥发性成分的分析

采用气相色谱-离子迁移谱(GC-IMS)技术对百里香花、叶中的挥发性有机物分别进行定性分析、差异鉴别及定量检测。结果表明,百里香花、叶中共检测出72种挥发性物质,定性识别出36种挥发性成分,包括醇类8种、醛类6种、酮类6种、萜类及其衍生物6种、酯类5种、酸类3种和杂环类物质2种。百里香叶中主要存在的是一些萜类物质及其衍生物,一些酸类、杂环类物质则主要分布在百里香花朵中。同时,对百里香中主要挥发性物质百里香酚进行了定量检测,试验结果表明其在5月百里香叶中的浓度最高,故对于百里香酚的利用,应以百里香叶为主。该研究建立了百里香挥发性有机化合物的气相离子迁移指纹信息模型库,为快速、高效分析百里香挥发性化合物提供了一种新的可靠手段。     

百里香,百味融合

Thyme百里香百里香原产于地中海地区,最适宜生长在温和、易排水、阳光充裕的地方。百里香气味温和辛辣,有药味,具有薄荷、干草的香气,清新芬芳。     

百里香属植物的功能利用与成分研究进展

文章介绍了百里香属植物在植被利用、烹饪调味及食用、美容保健、药用及化学成分等领域取得的进展,并对百里香中的生物活性物质的功能和成分进行了较全面的总结,为合理有效地综合利用百里香资源提供有价值的参考。     

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。     

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.     

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。     

羟丙基-β-环糊精对百里香挥发油包合作用的研究

采用正交实验与综合评分相结合的方法优化水溶液搅拌法制备百里香挥发油-羟丙基-β-环糊精(HP-β-CD)包合物的工艺条件,运用傅立叶变换红外光谱(FT-IR)对包合物进行表征,并利用气相色谱-质谱联用(GC-MS)技术对比分析了包合前后百里香挥发油的化学成分.结果表明,水溶液搅拌法制备百里香挥发油HP-β-CD包合物的最佳工艺条件为:百里香挥发油与HP-β-CD的体积质量比为1:10(mL:g),包合温度30℃,搅拌时间2.5h,HP-β-CD的浓度5％,在此最佳工艺下,平均包合物得率与挥发油利用率分别为91.77％和81.94％,该工艺合理、稳定、可行,有效地提高了百里香挥发油的稳定性.FT-IR和GC-MS分析说明,百里香挥发油与HP-β-CD已经形成了包合物,包合前后百里香挥发油的主要化学成分基本相同,但挥发油中各组分的组成比例发生了一定程度的改变,包合对百里香挥发油的化学成分略有影响.     

响应面优化百里香多糖提取工艺及其抗氧化作用

利用响应面分析法对百里香多糖的提取工艺进行优化,在单因素试验基础上,选取提取pH、料液比、提取时间进行三因素三水平的Box-Behnken试验,Design-Expert 8.0软件进行试验数据分析,得到百里香多糖最佳提取条件,并对提取的百里香多糖进行抗氧化研究。结果显示,百里香多糖的最佳提取条件为料液比1∶40.8,提取时间10.5min,提取pH 13.4,在此条件下百里香多糖的提取率为5.45%;百里香多糖具有一定抗氧化活性。     

百里香黄酮微胶囊的制备及抑菌活性研究

利用酵母细胞制备百里香黄酮微胶囊,研究芯壁比、包埋温度以及包埋时间对百里香黄酮包埋率的影响,用Box-Behnken试验设计及响应面对百里香黄酮微胶囊的制备工艺进行分析优化。结果显示:百里香黄酮微胶囊的最佳制备条件为芯壁比3∶1,包埋时间6.5h,包埋温度36℃,百里香黄酮微胶囊包埋率平均值为(68.50±0.36)%(n=3)。百里香黄酮微胶囊具有较好的抑菌作用。     

植物精油对烟草甲触杀、熏蒸和驱避作用研究

为筛选有效的贮烟用植物精油杀虫物质,利用点滴法,锥形瓶(密闭熏蒸)法,室内测定了9种植物精油(留兰香油、艾叶油、青蒿油、茶树油、丁香油、冬青油、薄荷油、桉叶油、百里香油)对烟草甲的触杀,熏蒸和驱避活性.结果表明:9种植物精油中表现触杀作用较好的是:丁香油、冬青油、茶树油、艾叶油、百里香油;表现熏蒸作用较好的是:留兰香油...     

Inhibitory effect of thyme and basil essential oils,carvacrol, thymol,estragol, linalool and p-cymene towards Shigella sonnei and S. flexneri

There are a few reports on the antimicrobial activity of essential oils or their major constituents towards Shigella sp. The antimicrobial effect of basil and thyme essential oil and its major constituents thymol, p-cymene, estragol, linalool, and carvacrol was determined using the agar well diffusion assay. Thyme essential oil and thymol and carvacrol showed inhibition of Shigella sp. in the agar well diffusion method. The potential of thyme essential oil, thymol and carvacrol at 0.5% and 1.0% v/v for decontamination of lettuce was evaluated. A decrease of the shigellae was observed after washing with 0.5% while at 1% Shigella numbers dropped below the detection limit. However, the antimicrobial effect on a subsequent lettuce sample in the same decontamination solution was significantly decreased. In addition, application of thyme essential oil or thymol or carvacrol for decontamination is hampered by sensoric properties of the lettuce (browning, strong odour).     

Characterization of biodegradable films prepared with hake proteins and thyme oil

Hake protein biodegradable films containing different thyme oil levels (0.025, 0.05, 0.1 and 0.25 ml oil/g protein) were prepared and their physical, mechanical and antioxidant properties were studied. Dried proteins were solubilized at pH 11 with NaOH and glycerol (59% of protein content) was added as plasticizer.The addition of thyme oil levels reduced both the film thickness and water vapor permeability. Films were homogeneous and transparent with a yellowish color. The optical properties of films were not generally affected by the thyme oil addition. Any clear trend between the mechanical properties of biodegradable films and thyme oil added was observed. Hake protein films exhibited some antioxidant activity, which was improved by the addition of 0.25 ml of thyme oil/g of protein.     

Efficacy of thyme oil-alginate-based coating in reducing foodborne pathogens on fresh-cut apples

In this study, the inhibition of an alginate-based edible coating (EC) containing thyme oil (0.05%, 0.35% and 0.65%) was evaluated against Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus and Escherichia coli O157:H7 inoculated onto fresh-cut apples. To investigate the antibacterial mechanism of thyme oil, the constituent compounds of that were analysed by gas chromatography-mass spectrometry (GC-MS), and the cellular damage of pathogens was observed by scanning electron microscopy (SEM). Results showed that alginate-based EC containing thyme oil effectively inhibited the growth of pathogens on fresh-cut apples. GC-MS analysis revealed thymol (47.23%) as the major compounds in thyme oil. SEM showed that the cell membrane of foodborne pathogens was damaged by thyme oil, causing their inactivation. Treatment with alginate-based EC containing 0.05% thyme oil preserved the sensory characteristics of fresh-cut apples. Therefore, using alginate-based EC with thyme oil may represent a potential approach to preserve and enhance the safety of fresh-cut apples.     

Antimicrobial effect of spices and herbs on Shigella sonnei and Shigella flexneri

Of 17 spices and herbs tested at 1% (wt/vol) in Mueller-Hinton (MH) agar, only cloves, thyme, oregano, allspice, basil, rosemary, and marjoram showed antimicrobial effects on Shigella. The MICs of thyme, oregano, basil, and rosemary (as determined by the agar dilution method) ranged from 0.5 to 1% (wt/vol) depending on the Shigella strain used. With the use of various combinations of temperatures (12, 22, and 37 degrees C), pHs (5.0, 5.5, and 6.0), and NaCl concentrations (1, 2, 3, and 4%, wt/vol) and the inclusion or exclusion of thyme or basil at 1% (wt/vol) in an MH agar model system, it was established that basil or thyme can contribute to combination processing as a growth-inhibitory factor for Shigella spp. In the presence of basil and thyme, Shigella flexneri did not develop CFU during the 7-day incubation period for, respectively, 14 and 16 of the 18 tested combinations, while growth was noted in the corresponding temperature-pH-NaCl concentration combinations without basil or thyme. A growth-inhibitory effect on Shigella sonnei was also noted. The results of an orientation study involving the addition of basil and thyme to spaghetti sauce prior to autoclaving and S. sonnei inoculation indicated that basil and thyme contributed to the reduction of S. sonnei after 16 days at 12 degrees C but not at 4 degrees C.     

Determination ofp-cymene-2,3-diol,thymol, and carvacrol in different foodstuffs

p-Cymene-2,3-diol, carvacrol and thymol are components of thyme that exhibit antioxidant activities. The concentration of each substance was determined in different foodstuffs containing thyme extract. The stabilities ofp-cymene-2,3-diol, carvacrol and thymol were examined by heating lard containing thyme extract at temperatures from 80 °C to 160 °C.     

The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients

The objective of this study was to evaluate the efficacy of plant essential oils (EOs) in combination and to investigate the effect of food ingredients on their efficacy. The EOs assessed in combination included basil, lemon balm, marjoram, oregano, rosemary, sage and thyme. Combinations of EOs were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using the spot-on-agar test. The influence of varying concentrations of EO combinations on efficacy was also monitored using E. coli. These preliminary studies showed promising results for oregano in combination with basil, thyme or marjoram. The checkerboard method was then used to quantify the efficacy of oregano, marjoram or thyme in combination with the remainder of selected EOs. Fractional inhibitory concentrations (FIC) were calculated and interpreted as synergy, addition, indifference or antagonism. All the oregano combinations showed additive efficacy against B. cereus, and oregano combined with marjoram, thyme or basil also had an additive effect against E. coli and P. aeruginosa. The mixtures of marjoram or thyme also displayed additive effects in combination with basil, rosemary or sage against L. monocytogenes. The effect of food ingredients and pH on the antimicrobial efficacy of oregano and thyme was assessed by monitoring the lag phase and the maximum specific growth rate of L. monocytogenes grown in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1.5, 3, 6 or 12%), sunflower oil (0, 1, 5 or 10%) and TSB at pH levels of 4, 5, 6 or 7. The antimicrobial efficacy of EOs was found to be a function of ingredient manipulation. Starch and oils concentrations of 5% and 10% had a negative impact on the EO efficacy. On the contrary, the EOs were more effective at high concentrations of protein, and at pH 5, by comparison with pH 6 or 7. This study suggests that combinations of EOs could minimize application concentrations and consequently reduce any adverse sensory impact in food. However, their application for microbial control might be affected by food composition, therefore, careful selection of EOs appropriate to the sensory and compositional status of the food system is required. This work shows that EOs might be more effective against food-borne pathogens and spoilage bacteria when applied to ready to use foods containing a high protein level at acidic pH, as well as lower levels of fats or carbohydrates.     

Determination ofp-cymene-2,3-diol, thymol, and carvacrol in different foodstuffs

p-Cymene-2,3-diol, carvacrol and thymol are components of thyme that exhibit antioxidant activities. The concentration of each substance was determined in different foodstuffs containing thyme extract. The stabilities ofp-cymene-2,3-diol, carvacrol and thymol were examined by heating lard containing thyme extract at temperatures from 80 °C to 160 °C.     

Inhibitory effects of spice extracts on the growth of Aspergillus parasiticus NRRL2999 strain

 The inhibitory effects of 31 spices extracts on the growth of Aspergillus parasiticus NRRL 2999 strain were investigated in vitro. Of the 31 samples tested, thyme (wild), thyme (black), oregano and savory completely inhibited the growth of A.parasiticus at the 2% level in Czapek-Dox Agar and partially inhibited it at the 1% leves. It was also found that capers, parsley leaf, coriander, sumac, mustard (wild) and dill leaf markedly stimulated the mycelial growth. The effectiveness of the inhibitors followed the sequence: thyme (black)>oregano>savory>thyme (wild)>ajovan>rosemary. Received: 30 January 1998 / Revised version: 16 March 1998     

Effect of supplementing ewes’ diet with thyme (Thymus zygis ssp. gracilis) leaves on the lipid oxidation of cooked lamb meat

The aim of this study was to ascertain whether the inclusion of thyme leaves in the diet of pregnant sheep affects the sensorial characteristics and oxidative stability of cooked lamb meat. Thirty-six Segureña sheeps were randomly assigned into three homogeneous groups. One group was fed a basal diet as control, while the diet of the other two groups was modified by substituting 3.75% and 7.5% of the control diet with thyme leaves. TBARS, volatile compounds, and the sensory characteristics of cooked lamb meat were analysed on days 0, 2 and 4. The incorporation of thyme into the animal diet favoured the antioxidant capacity of these cooked lamb meat samples. The cooked meat of lambs from ewes fed thyme leaves showed lower TBARS, hexanal values, rancid odour and rancid flavour scores. No statistically significant differences were detected between the results obtained for the two leaf levels.