分子蒸馏法富集甜橙油特征香气成分

采用分子蒸馏法(短程分子蒸馏器)富集甜橙精油中的特征香气成分,如癸醛、辛醛、芳樟醇及巴伦西亚桔烯等,同时采用气相色谱-质谱联用法进行检测。通过各参数优化比较,最终确定分子蒸馏条件为温度30℃、压力150Pa、转速200r/min、流速8mL/min。在此条件下,各成分富集结果为辛醛(由0.46%提高到1.55%)、癸醛(由0.59%提高到9.11%)、芳樟醇(由0.71%提高到5.84%)、巴伦西亚桔烯(由0.24%提到高7.96%)。分子蒸馏技术可用于甜橙油特征香气成分的高效富集。     

Effects of pulsed electric field processing and storage on the quality and stability of single-strength orange juice

The effects of pulsed electric field (PEF) processing on microorganisms in orange juice and on the flavor and color of the juice during storage for 112 days at 4 and 22 degrees C were investigated. Single-strength orange juice was PEF processed at an electric field strength of 35 kV/cm for 59 micros and placed into sterilized glass bottles in a sanitary glove box. PEF-processed orange juice was microbiologically stable at 4 and 22 degrees C for 112 days. PEF processing resulted in significant increases in the hydrocarbons D-limonene, alpha-pinene, myrecene, and valencene (P < or = 0.05) but did not have any effect on octanal, decanal, ethyl butyrate, and linalool. The levels of hydrocarbon compounds did not change at 4 and 22 degrees C in 112 days. Octanal, decanal, ethyl butyrate, and linalool levels significantly decreased in 14 days at 4 degrees C and in 2 days at 22 degrees C. The decrease in these compounds did not have a significant effect on the sensory quality of the orange juice (P > or = 0.05). The microorganisms in PEF-processed orange juice, along with the flavor and color of the juice, remained stable at 4 degrees C for 112 days.     

Microbial inhibitory and radical scavenging activities of cold‐pressed terpeneless Valencia orange (Citrus sinensis) oil in different dispersing agents

BACKGROUND: Due to their low solubility in water, oil‐based bioactive compounds require dispersion in a surface‐active agent or appropriate solvents to ensure maximum contact with microorganisms. These combinations, however, may change their physical and/or chemical characteristics and consequently alter the desired functionality. The objective of this study was to determine the impact of selected dispersing agents, ethanol, dimethyl sulfoxide (DMSO), and Tween‐80, on cold‐pressed terpeneless (CPT) Valencia orange oil to function as a free radical scavenger and an antimicrobial food additive. RESULTS: When dissolved in ethanol or DMSO, the orange oil fraction had similar minimum inhibitory concentrations (MIC) for Listeria monocytogenes ATCC 19 115 (0.3% and 0.25% v/v respectively), which were significantly lower (P ≤ 0.5) than the MIC for Salmonella typhimurium ATCC 14 028 (1% v/v). Both ethanol and DMSO oil dispersion systems exhibited an intermediate MIC (0.75% v/v) for Lactobacillus plantarum WCFS1. The orange oil (up to 3%) in an aqueous solution of 0.1% Tween‐80 yielded no inhibitory activities against any of the test bacteria. However, the 1% natural orange oil dispersed in Tween‐80 exhibited 56.86% 2,2‐diphenyl‐1‐picryl hydrazyl (DPPH) radical inhibition versus 18.37% and 16.60% when the same level of orange oil was dissolved in DMSO or ethanol, respectively. At the same orange oil concentration, the oil/Tween‐80 suspension yielded 57.92% neutralization of hydroxyl radicals. This represents 71.37% of the mannitol antioxidant activity, which was used as a positive control. CONCLUSIONS: These findings suggest that Tween‐80 is an appropriate dispersing agent only if the antioxidant functionality is desired. If both antimicrobial and antioxidant properties are needed, the CPT Valencia orange oil should be dispersed in either DMSO or ethanol. Copyright © 2010 Society of Chemical Industry     

Influence of flavour absorption by food-packaging materials (low-density polyethylene, polycarbonate and polyethylene terephthalate) on taste perception of a model solution and orange juice

The influence of flavour absorption by low-density polyethylene (LDPE), polycarbonate (PC) and polyethylene terephthalate (PET) on taste perception of a model solution containing seven flavour compounds and orange juice in glass bottles was studied with and without pieces of the respective plastic films after dark storage at 20°C. Owing to absorption, the amount of flavour compounds in the model solution exposed to LDPE decreased substantially. From the model flavour solution valencene was almost completely absorbed by LDPE, followed to a lesser extent by decanal, hexyl acetate, octanal and nonanone. Less flavour compounds were absorbed from the model solution by PC and PET. In contrast to LDPE, valencene was absorbed in the lowest amounts and decanal in the highest. Limonene was readily absorbed from orange juice by LDPE, while myrcene, valencene, pinene and decanal were absorbed in smaller quantities. Only three flavour compounds were absorbed from orange juice by PC and PET in very small amounts: limonene, myrcene and decanal. Although the flavour content between controls and polymer-treated samples differed substantially, the loss of flavour compounds due to absorption by LDPE, PC and PET did not influence taste perception of a model solution and orange juice significantly up to 29 days of dark storage at 20°C as determined by triangular taste panel tests.     

Flavor Losses in Orange Juice during Ultrafiltration and Subsequent Evaporation

Losses of volatile compounds in orange juice during ultrafiltration and subsequent evaporation were studied. Alcohols and esters predominated in the permeate, while terpenes (d-limonene and valencene) and nonpolar aldehydes (octanal and decanal) were distributed in the retentate from the ultrafiltration (UF) system. Fractions of some flavor compounds were lost during ultrafiltration process. An aqueous phase essence was recovered from the permeate during evaporative concentration. No oil phase was observed. When whole juice was concentrated, both oil and aqueous phases were recovered. Essence recovery efficiency of individual compounds was 3 to 13% when concentrating permeate and <5% when concentrating whole juice.     

Chemical composition,antioxidative capacity and interactive antimicrobial potency of Satureja khuzestanica Jamzad essential oil and antimicrobial agents against selected food‐related microorganisms

This study aimed to determine the chemical composition, antimicrobial and antioxidative activity of Satureja khuzestanica Jamzad essential oil. The oil was analysed by GC and GC/MS. Twenty‐eight constituents were identified. The oxygenated monoterpenes (78.22%) were the principal compound group. Among them, carvacrol (53.86%) and thymol (19.84%) were the most abundant constituents. The oil exhibited an acceptable antimicrobial activity against most of the tested microorganisms. The checkerboard method was applied to determine fractional inhibitory concentration indices (FICIs) to interpret the synergetic, additive, indifference or antagonistic interactions between essential oil and each of antimicrobials (lysozyme, ciprofloxacin, fluconazole and amphotericin B) against food‐related microorganisms. The synergetic phenomenon (FICI ≤ 0.5) was observed in majority of combinations with the exception of the essential oil and lysozyme. The oil exhibited good 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity (IC₅₀ = 28.71 μg mL^?1). Also, the oil had strong antioxidative activity in β‐carotene‐linoleic acid assay relative antioxidant activity (RAA% = 95.45). This study demonstrated that the essential oil has beneficial biological properties and its simultaneous application with standard antimicrobials against food‐related microorganisms result in reduction in inhibitory doses of the antimicrobials in vitro.     

Investigation of the aroma impact volatiles in Turkish pine honey samples produced in Marmaris,Datça and Fethiye regions by SPME/GC/MS technique

The aroma impact volatiles of twenty‐four pine honey samples produced in Marmaris, Datça and Fethiye regions of Turkey were evaluated by solid phase micro extraction/gas chromatography/mass spectrometry (MS) technique and the results were evaluated by using the analysis of variance and Duncan tests. A total of eight common volatiles nonanal, nonanol, decanal, octanal, 16‐oxosalutaridine, dodecanal, nonadecane and pentadecane were detected in three regions. The total area of the common volatiles were 73.01%, 78.10% and 73.91% in Marmaris, Datça, and Fethiye regions, respectively. There were not significant differences (P < 0.05) between the common volatiles detected in pine honey samples from three different regions. The major contributers to the pine honey aroma seems to be nonanal (aldehyde, citrus, fatty, floral, green, piny), nonanol (green, sweet, oily), decanal (soap, orange peel, tallow), and octanal (fat, soap, lemon, green). Nonanal seems to be the principal volatile component in all samples having average values of 46.82% in Marmaris, 51.67% in Datça and 48.63% in Fethiye regions.     

Phenolics,Aroma Profile,and In Vitro Antioxidant Activity of Italian Dessert Passito Wine from Saracena (Italy)

A traditional sweet dessert wine from Saracena (Italy), made with nonmacerated local white grapes (Guarnaccia, Malvasia and Moscato), was analyzed for phenolics and aroma profile and antioxidant activities. The most abundant classes of phenols identified by high‐performance liquid chromatography were hydroxybenzoic acids and flavan‐3‐ols, where gallic acid showed the highest content (376.5 mg/L). The analysis by solid phase microextraction‐gas chromatography‐mass spectrometry revealed the presence of superior alcohols (from iso‐butanol and iso‐amyl alcohol up to 2‐phenylethanol) and their ethyl esters, terpenes (such as linalool), furfuryl compounds, and free fatty acids (up to palmitic acid) as the key odorants of this wine. The antioxidant activity, evaluated by different in vitro assays 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS), and β‐carotene bleaching test), showed that passito wine had a radical scavenging activity (IC₅₀ value of 0.03 v/v against DPPH·) and inhibited linoleic acid oxidation with an IC₅₀ value of 0.4 v/v after 30 min of incubation.     

Analysis of odour‐active compounds of black mangrove (Avicennia germinans L.) honey by solid‐phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The volatile compounds of Cuban black mangrove (Avicennia germinans L.) honey were analysed by solid‐phase microextraction (SPME) followed by gas chromatography–mass spectrometry and gas chromatography–olfactometry. A total of 66 compounds were positively identified in this product for the first time. Application of the aroma extract dilution analysis in a novel approach, which consisted of carrying out successively dilutions of the honey sample with a synthetic honey before the SPME, revealed 17 odour‐active areas in the flavour dilution factor range of 32–1024. On the basis of the quantitative data and odour thresholds, odour activity values (OAV; ratio of concentration to odour threshold) were calculated. Sixteen compounds showed OAVs >1, among which dimethyl sulphide, 3‐methyl butanal, 2‐methylbutanal, heptanal, octanal, phenylacetaldehyde, (Z)‐linalool oxide, (E)‐linalool oxide, nonanal, hotrienol, isophorone, lilac aldehyde A, 1‐nonanol, decanal, 4‐vinyl‐2‐methoxyphenol and (E)‐β‐damascenone showed the highest values and should be considered as the most odour‐active compounds, particularly (E)‐β‐damascenone, nonanal and decanal.     

Effect of Arabic gum,xanthan gum and orange oil on flavor release from diluted orange beverage emulsion

The influence of main emulsion components namely Arabic gum (13–20% w/w), xanthan gum (0.3–0.20% w/w) and orange oil (10–14% w/w) on semi-quantitative headspace analysis of target volatile flavor compounds released from a model orange beverage (diluted orange beverage emulsion) was evaluated by using a three-factor circumscribed central composite design (CCCD). For optimization procedure, the peak area of 13 volatile flavor compounds (i.e. ethyl acetate, α-pinene, ethyl butyrate, β-pinene, 3-carene, myrcene, limonene, γ-terpinene, octanal, decanal, linalool, neral and geranial) were considered as response variables. The response surface analysis exhibited that the significant (p < 0.05) second-order polynomial regression equations were successfully fitted for all response variables except for ethyl butyrate. A satisfactory coefficient of determination (R²) ranged from 0.831 to 0.969 (>0.8) was obtained for the response variables studied. No significant (p > 0.05) lack of fit was indicated for the reduced models except for the models fitted for limonene and linalool. This observation confirmed an accurate fitness of the reduced response surface models to the experimental data. The multiple response optimizations indicated that an orange beverage emulsion containing 15.87% (w/w) Arabic gum, 0.5% (w/w) xanthan gum and 10% (w/w) orange oil was predicted to provide the minimum overall flavor release.     

甜橙果肉粉对橙油风味物质的吸附性能研究

为探究柑橘果肉在风味吸附方面的机制,测定了甜橙果肉粉的成分构成、氮气吸附-脱附等温线,采用扫描电子显微镜（scanning electron microscope, SEM）观察了其微观结构,采用气相色谱-质谱法（gas chromatography-mass spectrometry, GC-MS）测试分析了其对橙油风味物质的吸附性能。成分分析结果表明甜橙果肉粉主要由膳食纤维（51.87%±3.12%）、蛋白质（20.47%±0.58%）、脂肪（11.33%±1.60%）、淀粉（4.06%±0.59%）构成。SEM观察结果及氮气吸附-脱附等温线分析结果表明,甜橙果肉粉复合物中存在丰富的褶皱和缝隙等不规则结构,比表面积达2.98 m2/g。GC-MS测试分析结果表明,甜橙果肉粉对橙油典型香气成分例如柠檬烯、γ-萜品烯、β-月桂烯、β-水芹烯、芳樟醇、辛醛、壬醛等有明显的吸附作用,尤其与直链脂肪醛、含氧萜类衍生物的相互作用较明显,而对α-蒎烯、桧烯等双环单萜类成分的吸附作用相对较弱。综上,甜橙果肉粉中各组成成分交联而成的褶皱和缝隙结构是其发挥风味吸附作用的重要基础,研究结果可为进一步开发利用甜橙果肉提供参考。     

Antioxidant, antihypertensive and antimicrobial properties of ovine milk caseinate hydrolyzed with a microbial protease

BACKGROUND: Bioactive peptides might be released from precursor proteins through enzymatic hydrolysis. These molecules could be potentially employed in health and food products. In this investigation, ovine milk caseinate hydrolysates obtained with a novel microbial protease derived from Bacillus sp. P7 were evaluated for antioxidant, antimicrobial, and angiotensin I‐converting enzyme (ACE)‐inhibitory activities. RESULTS: Antioxidant activity measured by the 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline)‐6‐sulfonic acid method increased with hydrolysis time up to 2 h, remaining stable for up to 4 h. Hydrolysates showed low 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging abilities, with higher activity (31%) reached after 1 h of hydrolysis. Fe²⁺‐chelating ability was maximum for 0.5 h hydrolysates (83.3%), decreasing thereafter; and the higher reducing power was observed after 1 h of hydrolysis. ACE‐inhibitory activity was observed to increase up to 2 h of hydrolysis (94% of inhibition), declining afterwards. 3 h hydrolysates were shown to inhibit the growth of Bacillus cereus, Corynebacterium fimi, Aspergillus fumigatus, and Penicillium expansum. CONCLUSION: Ovine caseinate hydrolyzed with Bacillus sp. P7 protease presented antioxidant, antihypertensive, and antimicrobial activities. Hydrolysis time was observed to affect the evaluated bioactivities. Such hydrolysates might have potential applications in the food industry. Copyright © 2011 Society of Chemical Industry     

Bioactivities of essential oil and extract of Thymus argaeus,Turkish endemic wild thyme

BACKGROUND: Thymus argaeus Boiss. & Bal. (Lamiaceae), an endemic plant species of Turkey known as wild thyme, is traditionally used as a spice and a wild tea in the Inner Anatolia region of Turkey. In this study the composition of the essential oil and the antimicrobial and antioxidant effects of the methanolic extract and essential oil of T. argaeus were determined. RESULTS: The main components of the essential oil were linalool (499 g kg^?1), α‐terpineol (150 g kg^?1), linalyl acetate (97 g kg^?1) and thymol (94 g kg^?1). The total phenolic, flavanol and flavonol contents of the extract were 83.31 ± 0.59 mg gallic acid equivalent g^?1, 6.26 ± 0.00 mg catechin equivalent g^?1 and 28.81 ± 0.21 mg rutin equivalent g^?1 respectively. The antioxidant activities of the extract and essential oil determined by the 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging method were 830.18 ± 0.42 and 20.47 ± 2.3 mg g^?1 respectively. The antimicrobial activities of the extract and essential oil against 13 bacteria and two yeasts were studied by the agar diffusion method. The micro‐organisms most sensitive to the essential oil were Aeromonas hydrophila and Pseudomonas aeruginosa, while the micro‐organism most sensitive to the extract was P. aeruginosa. CONCLUSION: Only the extract of T. argaeus could be used as a natural antioxidant, while both the extract and the essential oil could be useful as natural antimicrobial agents in food preservation. Copyright © 2009 Society of Chemical Industry     

Bioactive components,ABTS radical scavenging capacity and physical stability of orange,yellow and purple sweet potato (Ipomoea batatas) powder processed by convection‐ or vacuum‐drying methods

This study aims to investigate the antioxidant properties and physical stability of convection‐ or vacuum‐dried orange, yellow and purple sweet potato (Ipomoea batatas) powder upon room temperature storage at different relative humidity (RH) of 33%, 43%, 54% and 75% for 25 days. Both convection and vacuum‐dried samples had lower total phenolic content (TPC), anthocyanin content and antioxidant activity compared to the fresh samples. Vacuum‐dried powder retained higher antioxidant activity than convection‐dried powder. Storage of the powder at high RH of 75% resulted in apparent clump formation, which was likely attributed to the decrease of glass transition temperature (T_g). In general, purple sweet potato powder contained the highest TPC (255.0 mg GAE 100 g DW^?1) and antioxidant activity (1924.0 μmol TEAC 100 g DW^?1), while orange powder had the highest beta‐carotene content (127.2 mg 100 g DW^?1). Vacuum‐dried sweet potato powder, which has relatively higher antioxidant activity, could be a potential functional ingredient or natural colourant for the food industry.     

Chemical composition,antibacterial and antioxidant activity of the essential oils of Metaplexis japonica and their antibacterial components

The aim of this research was to determine the chemical composition, antioxidant and antibacterial properties of the essential oils from Metaplexis japonica and isolation of antibacterial constituents from the essential oils. Results showed that 63 components were identified in essential oils. Phenylethyl alcohol (77.978%), α‐terpineol (31.810%) and docosane (21.644%) were the most abundent constituents of flower oil, leaf oil and fruit oil, respectively. Based on bioactivity‐guided fractionation, three active constituents were isolated and identified as phenylethyl alcohol, α‐terpineol and β‐linalool. Both flower oil and phenylethyl alcohol showed high antibacterial performance, with inhibition zone from 25 ± 0.5 to 11 ± 0.6 mm at highest concentration, and MIC values ranging from 0.125 to 2%. In both DPPH and ABTS assay, the oils showed moderate antioxidant activity. These results indicate potential efficacy of active constituents and essential oils of M. japonica to control food‐borne pathogenic and spoilage bacteria.     

Chemical Composition,Antimicrobial, and Antioxidant Activities of Essential Oil and Ethanol Extract of Coriandrum sativum L. Leaves from Turkey

This study reports the chemical composition, antioxidant, and antimicrobial activity of the essential oil and ethanol extract of Coriandrum sativum L. leaves. Gas chromatography/mass spectrometry analysis identified 19 compounds representing 95.30% of the oil. (E)-2-decenal (29.87%), linalool (21.61%), (E)-2-dodecenal (7.03%), dodecanal (5.78%), (E)-2-undecenal (3.84%), (E)-2-tridecenal (3.56%), (E)-2-hexadecenal (2.47%), tetradecenal (2.35%), and α-pinene (1.64%) were the main components identified in the essential oil. The samples were screened for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl radical scavenging and β-caroten bleaching assay. IC₅₀ value for ethanol extract of C. sativum was determined as 74.87 ± 0.03 μg/mL. Total antioxidant activity value for C. sativum ethanol extract was 85.85 ± 0.04%. Total phenolic content for ethanol extract of the plant was determined as 14.97 ± 0.05 mg gallic acid equivalents/g dry weight. The essential oil and ethanol extract were also tested for antimicrobial activity against 28 different foodborne microorganisms, including 19 bacteria, 7 fungi, and 2 yeast species. The ethanol extract of the plant showed weak antimicrobial activities against microbial strains in both disc diffusion and minimal inhibition concentration tests. This study suggested that Coriandrum sativum L. leaves may be used as a potential source of food flavoring, and for their antioxidants and antimicrobial properties.     

三种晚熟甜橙冷磨精油挥发性及主体香气成分的比较分析

为研究重庆主栽晚熟甜橙精油的挥发性及主体香气物质的组成含量特点,采用顶空固相微萃取-气质联用技术和香气活度值(odor activity values,OAV)分析奥林达夏橙、五月红甜橙和晚熟血橙的果皮冷磨精油(cold-pressed oil,CPO)。3个品种中分别鉴定出53、54和52个挥发性物质,其中D-柠檬烯含量普遍较低;奥林达CPO醇酚类、醛酮类含量更高,五月红和晚熟血橙CPO含较高的萜类物质。OAV分析表明,3种CPO的主体香气贡献物质包括对伞花烃、癸醛、己醛、壬醛和芳樟醇等30个成分,体现柑橘香、花香、油脂香等8类主要香气属性;奥林达CPO中花香、脂香和甜香类物质OAV较高,晚熟血橙CPO中松香和木香类物质OAV较高。本地区3个晚熟甜橙冷磨油的主体香气属性各具特点,适合加工不同类型的低萜精油,提升晚熟甜橙的产品附加值。     

Hot and cold water infusion aroma profiles of Hibiscus sabdariffa: fresh compared with dried

Abstract: Calyxes from the Roselle plant (Hibiscus sabdariffa L.) were used to prepare cold (22 °C for 4 h) and hot (98 °C for 16 min) infusions/teas from both fresh and dried forms. Aroma volatiles were extracted using static headspace SPME and analyzed using GC‐MS and GC‐O with 2 different columns (DB‐5 and DB‐Wax). Totals of 28, 25, 17, and 16 volatiles were identified using GC‐MS in the dried hot extract (DHE), dried cold extract (DCE), fresh hot extract (FHE), and fresh cold extract (FCE) samples, respectively. In terms of total GC‐MS peak areas DHE ? DCE > FHE ? FCE. Nonanal, decanal, octanal, and 1‐octen‐3‐ol were among the major volatiles in all 4 beverage types. Thirteen volatiles were common to all 4 teas. Furfural and 5‐methyl furfural were detected only in dried hibiscus beverages whereas linalool and 2‐ethyl‐1‐hexanol were detected only in beverages from fresh hibiscus. In terms of aroma active volatiles, 17, 16, 13, and 10 aroma active volatiles were detected for DHE, DCE, FHE, and FCE samples, respectively. The most intense aroma volatiles were 1‐octen‐3‐one and nonanal with a group of 4 aldehydes and 3 ketones common to all samples. Dried samples contained dramatically higher levels of lipid oxidation products such as hexanal, nonanal, and decanal. In fresh hibiscus extracts, linalool (floral, citrus) and octanal (lemon, citrus) were among the highest intensity aroma compounds but linalool was not detected in any of the dried hibiscus extracts. Practical Application: Hibiscus teas/infusions are one of the highest volume specialty botanical products in international commerce. The beverage is consumed for both sensory pleasure and health attributes and is prepared a number of ways throughout the world. Although color and taste attributes have been examined, little information is known about its aroma volatiles and no other study has compared extractions from both fresh and dried as well as extraction temperature differences. This is also, apparently, the first study to identify the aroma active volatiles in hibiscus beverages using GC‐olfactometry. Manufacturers and consumers will now have a better understanding of why hibiscus teas prepared in different ways from either fresh or dried forms have a different flavor quality and intensity.     

Influence of food matrix on absorption of flavour compounds by linear low‐density polyethylene: proteins and carbohydrates

The effects of differences in food matrices on the absorption of four flavour compounds (limonene, decanal, linalool and ethyl 2‐methyl butyrate) into linear low‐density polyethylene (LLDPE) were studied using a large volume injection GC ‘in vial’ extraction method. Food components investigated included β‐lactoglobulin (β‐lg), casein, pectin, carboxymethylcellulose (CMC), lactose and saccharose. β‐lg interacted irreversibly with decanal (P < 0.01) and suppressed absorption of the latter by LLDPE by more than 50% after 14 days of exposure. Casein was capable of binding limonene and decanal (p < 0.05) by hydrophobic and covalent interactions, resulting in decreased absorption of 40% and 90%, respectively. The absorption rates of limonene, and to a leaser extent decanal, were decreased in presence of pectin and CMC. Increasing viscosity slowed down diffusion of flavour compounds from the matrix to LLDPE. An increase of absorption (p < 0.01) was observed for linalool and ethyl 2‐methyl butyrate, due to a ‘salting out’ effect caused by lactose and saccharose. The absorption of decanal was decreased (p < 0.01) after 14 days of exposure in the presence of lactose, saccharose and CMC. There might be an interactive effect between a sugar (residue) and decanal. Knowledge of the composition of a food matrix and packaging material is necessary to estimate the amount of flavour absorption. © 2000 Society of Chemical Industry     

Gas Chromatography-Mass Spectrometry Analyses for Detection and Identification of Antioxidant Constituents of Achillea tenuifolia Essential Oil

The present work was designed to study the antioxidant activity and to identify the main active components of the essential oil of Achillea tenuifolia aerial parts. Gas chromatography-mass spectrometry analyses of the essential oil showed the presence of 22 compounds. The main constituents of the oil were thymol (15%), α-pinene (10.11%), Camphene (9.41%), β-pinene (7.54%), α-terpinene (7.21%), p-cymene (4%), 1,8-cineole (2.31%), γ-terpinene (7%), linalool (10%), and carvacrol (20.43%). The antioxidant and free radical scavenging activities of Achillea tenuifolia oil was evaluated by using 2,20-diphenyl-1-picrylhydrazyl assays. The oil exhibited a considerable dose-dependent antioxidant activity. Thymol showed clearly a higher activity (IC50 = 10.04 ± 0.1 μg/ml) followed by Achillea tenuifolia essential oil (15.12 ± 0.4 μg/ml). Antioxidant activity guided fractionation of the oil was carried out by the thin layer chromatography-bioautography screening and fractionation resulted in the separation of the main antioxidant compound which was identified as thymol (80%).