梅州金柚果皮挥发油气相色谱质谱分析

为开发梅州金柚皮植物资源提供依据。用气相色谱质谱对梅州金柚柚皮挥发油的化学成分进行分离鉴定,用峰面积归一化法确定其各组分相对含量。结果表明,在梅州金柚皮挥发油中鉴定出20种化合物,占总挥发油的99.81%,其中主要成分为柠檬烯(95.82%)、β-月桂烯(2.27%)、α-蒎烯(0.71%)、圆柚酮(0.62%),这4种成分占到总成分的99.42%。梅州金柚皮具有很大的药用开发价值。     

GC-MS法分析红肉蜜柚果皮香精油的化学成分

采用水蒸气蒸馏法提取红肉蜜柚果皮香精油,得油率为1.2%.采用GC-MS联用技术首次对红肉蜜柚果皮香精油的化学成分进行分离鉴定,共分离出36个峰,鉴定出了其中的29种化合物,占峰面积的94.61%.用面积归一化法测定了各个组分的相对百分含量,其主要成分有柠檬烯(68.47%)、β-月桂烯(21.22%)、β-蒎烯(1.03%)、顺式-β-罗勒烯(0.72%)、α-芹子烯(0.24%).     

赤桉和本泌桉叶精油的化学成分研究

用水蒸气蒸馏法提取了赤桉叶和本泌桉叶精油,通过气相色谱-质谱(GC-MS)联用法分析鉴定了二者的化学成分及质量分数。赤桉叶精油共鉴定出57种化合物,占总离子流出峰面积的94.81%,主要成分为w(1,8-桉叶油素)=50.17%,其后依次是w(α-蒎烯)=8.53%、w(蓝桉醇)=5.65%、w(乙酸松油酯)=3.69%、w(α-松油醇)=3.58%;本泌桉叶精油共鉴定出45种化合物,占总离子流出峰面积的90.93%,主要成分为w(α-蒎烯)=31.00%、w(蓝桉醇)=15.34%、w(香树烯)=13.80%和w(表蓝桉醇)=4.86%。     

山苍子花蕾挥发油成分GC-MS分析

通过水蒸汽蒸馏法提取山苍子花蕾挥发油,利用GC-MS联用技术对其成分进行定性定量分析。挥发油平均收率为3.8%,从中鉴定出40种成分,占总含量的87.27%。其中14个单萜烯烃化合物,占总含量的21.90%;12个单萜氧化物,占总含量的60.44%;12个倍半萜烯烃化合物,占总含量的4.85%。含量较高的成分为桉油精(39.86%)、松油醇(15.62%)、α-蒎烯(4.96%)、α-水芹烯(4.79%)。     

气相色谱-质谱法分析山黄皮果皮挥发油成分

用水蒸气蒸馏法提取山黄皮果皮挥发油,经气相色谱-质谱联机分析,共分离出60个峰,鉴定出57种化合物,占总峰面积的99.89%。挥发油主要成分为:β-月桂烯、肉豆蔻醚、异松油烯、3-蒈烯、D-柠檬烯、(+)-2-蒈烯、β-水芹烯、α-水芹烯、石竹烯、丁子香酚甲基醚、(2E)-2,7-二甲基-2,6-辛二烯-1-醇、β-细辛脑,其质量分数分别为:51.50%、24.83%、12.82%、1.94%、1.15%、1.12%、0.55%、0.44%、0.43%、0.42%、0.38%、0.30%。     

药对厚朴-麻黄及其单味药中挥发油成分GC-MS的比较分析

采用水蒸气蒸馏法分别对药对厚朴-麻黄及单味药麻黄和厚朴的挥发油成分进行了提取,并结合GC-MS对所得样品化学成分进行了分离和结构鉴定,用气相色谱峰面积归一法测定各组分的相对质量分数。结果显示,从麻黄-厚朴、麻黄和厚朴挥发油分别鉴定出44、38和39个色谱峰,分别占挥发油总峰面积的98.42%、99.07%和99.21%。药对麻黄-厚朴中挥发油化学成分有28种来自厚朴,25种来自麻黄,新产生了6种化合物。     

贵州湄潭苦丁茶挥发性成分的GC/MS分析

研究了贵州湄潭产苦丁茶挥发油的化学成分。用水蒸气蒸馏提取贵州苦丁茶挥发油,用GC-MS分析和鉴定出化学成分,使用峰面积归一法确定其百分含量。结果表明:挥发性成分的得率分别为0.17%。从苦丁茶挥发油中鉴定出13种(占挥发油总量的81.64%)化合物,苦丁茶挥发油的主要成分是β-芳樟醇、β-月桂烯、α-松油醇、(Z)-柠檬醛、(E)橙花醇。不同地区的苦丁茶挥发油的主要成分和含量差异差较大,在其饮品开发利用中都应区别对待。     

遂溪产沙田柚果皮中挥发油成分的GC-MS分析

采用水蒸汽蒸馏法提取广东遂溪产沙田柚果皮挥发油,应用气相色谱-质谱联用技术对其化学成分进行分析和鉴定。共分离出27个组分,鉴定了其中的19种化合物,占总挥发油含量的90.58%。其主要成分D-柠檬烯(37.18%)和β-月桂烯(26.93%),占总挥发油含量的64.11%。     

蓝桉叶挥发油化学成分分析研究

采用乙醚为溶剂提取云南产蓝桉干叶的挥发油,经气相-质谱联用仪分析,得到57种组分,确定了其中54个化合物的结构,主要成分是1,8-桉叶素(68.61%),α-蒎烯(10.24%),别香橙烯(5.27%),乙酸松油酯(4.05%),香橙烯(1.45%),(-)-蓝桉醇(1.26%),α-松油醇(1.02%)等。采用峰面积归一法计算各组分的相对含量,所鉴定成分占总馏出峰面积的99.69%。     

基于保留指数的GC-TOF/MS分析小茴香籽油的香味成分

采用气相色谱-飞行时间质谱法,对小茴香籽油的香味成分进行了分析,并用峰面积归一化法计算了各香味成分的相对含量。对各色谱峰对应的质谱数据于NIST标准质谱库中进行相似度检索,结合保留指数法,共鉴定出34种成分,峰面积之和占总峰面积的99.89%。小茴香籽油的主要香味成分(峰面积相对百分比)为(E)-大茴香脑(80.405%)、柠檬烯(4.176%)、α-蒎烯(3.198%)、α-水芹烯(3.096%)、葑酮(2.107%)、月桂烯(1.024%)、β-水芹烯(0.869%)、β-蒎烯(0.541%)等。该研究为小茴香籽油的产品开发和应用提供了技术支撑。     

顶空固相微萃取分析四氢异构化啤酒花浸膏的风味成分

用顶空固相微萃取技术对三种四氢异构化啤酒花浸膏中的挥发性风味成分进行了分析比较,并用高效液相色谱法分析了样品中四氢异α-酸的质量分数。数据表明,其主要成分四氢异α-酸的质量分数很接近,但挥发性风味成分却有很大差异。其中,Ⅰ号四氢异构化啤酒花浸膏样品鉴定出的44个挥发性成分中,所含的17个酮类化合物的质量分数达到80.52%;Ⅱ号样品鉴定出39个组分,所含的5个醛类化合物的质量分数达到79.95%;Ⅲ号样品鉴定出的45个组分中,所含的14个酮类化合物、11个醇类化合物、7个烯烃类化合物和4个酯类化合物的质量分数分别为44.63%、20.87%、17.22%和6.8%。     

Effect of cultivation area and climatic conditions on volatiles of virgin olive oil

To elucidate the influence of the cultivation area and climatic conditions on volatiles of virgin olive oil from Gemlik cultivar, an investigation was carried out. Five Turkish geographical zones (Bal?kesir, Ayd?n, Manisa, Antalya and Hatay) were chosen. From these areas, fruits were collected at the same maturity stage and processed using a small experimental olive oil mill, applying identical processing conditions for all olive samples. Headspace solid‐phase microextraction (HS‐SPME) technique coupled to GC/MS was used for volatile analysis. Twenty‐seven compounds were identified and characterised, representing 96.40–98.74% of the total GC area. The major volatile representing about 50% was the (E)‐2‐hexenal. This compound was found in higher concentrations on olive oils from Antalya than from Hatay area. Hexanal was the second most abundant volatile compound and varied between 13.89 and 28.96%. Comparing the olive growing areas Hatay and Antalya, the hexanal concentration was about 29 and 14%, respectively. Generally, a significant difference in the composition of volatile compounds between the oils from the same olive cultivar and from different geographic regions was recorded. The results suggest that climatic factors, latitude and longitude affect the formation of volatiles.     

Dynamic Accumulation of Volatile Compounds Between Olive Pulps and Stones and Its Relation with the Fatty Acids Content During the Oil Extraction Process of Ouslati and Chemlali Olive Fruits

The characterization of both volatiles and fatty acids of Tunisian olive varieties (Ouslati and Chemlali) is achieved in order to understand their correlation with the aroma accumulation via the lipoxygenase (LOX) pathway. The main identified volatiles in both crushed pulps and crushed stones are hexanal, E‐(2)‐hexenal, (Z)‐3‐hexen‐1‐ol, 1‐hexanol, and hexyl acetate. With regard to their fatty acid composition, results show that both de‐stoned (DOO) and conventional (COO) olive oils contain mainly unsaturated fatty acids. The results also show that oleic acid (C18:1) is the main fatty acid in both DOO and COO. Meanwhile, linoleic acid (C18:2) is present in a relatively higher percentage (5.2% and 19.8%, respectively, for Ouslati and Chemlali DOI) than linolenic fatty acid (C18:3) (<2%). The analysis of volatiles shows that more than 80% of total LOX‐compounds from both crushed pulps and crushed stones have linolenic acid as synthesis precursor despite its lower level (2%). Moreover, the contribution of olive parts in generating aroma is much higher in crushed pulps (more than 80%) than in crushed stones, which explains the fact that DOO, extracted from crushed pulps, contains the dominant amount of volatiles. Therefore, the obtained results promote both the consumption and the marketing of DOO. Practical Applications: The aroma and the organoleptic properties of olive oil are strictly correlated with both the olives quality and the extraction techniques used. Many technologies are developed to extract olive oil with highest quality. De‐stoned olive oil extraction process is one of these technical procedures. In the present work, the characterization of volatiles in pulp and stone separately provides important information about the contribution of olive constitutive parts on the accumulation of olive oil aroma during the oil extraction process.     

Enhancement of Attraction to Sex Pheromones of Spodoptera exigua by Volatile Compounds Produced by Host Plants

We measured the effects of exposure to volatile compounds produced by host plants on the rate of capture of male Spodoptera exigua using synthetic sex pheromones. Exposure to volatile compounds stimulated strong electroantennographic responses of male S. exigua. The behavioral responses of male moths to combinations of sex pheromone and volatile compounds were tested in wind tunnel experiments. When lures were baited with synthetic sex pheromone plus benzaldehyde, phenylacetaldehyde, (Z)-3-hexenyl acetate, or linalool, respectively, the landing rate of S. exigua males was increased by 101.4%, 79.6%, 60.6%, and 34.3%, respectively, compared to sex pheromone alone. In field tests, traps baited with either pheromone + (E)-2-hexenal, pheromone + phenylacetaldehyde, pheromone + (Z)-3-hexenyl acetate, or pheromone + (Z)-3-hexenol enhanced moth catches by 38.8%, 34.6%, 24.6%, and 20.8%, respectively compared to traps baited with pheromone alone. In a second field experiment, more S. exigua males were trapped with a combination of a synthetic sex pheromone blend and several individual host plant volatiles compared to synthetic sex pheromone alone. These results suggest that some host plant volatiles enhance the orientation response of S. exigua male moths to sex pheromone sources.     

Electroantennographic and behavioral responses of the sphinx moth Manduca sexta to host plant headspace volatiles

Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae—Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae—Proboscidea parviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC–EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)- and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose–response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10–100 g), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants.     

Primary Attraction of the Fir Engraver, Scolytus ventralis

In laboratory bioassays, Porapak Q-captured and steam-distilled volatiles from the bark of host trees, Abies grandis, particularly from root-rot-infected trees, attracted 50–70% of male and female fir engravers, Scolytus ventralis. Gas chromatographic–electroantennographic detection (GC-EAD) analyses of Porapak Q-captured bark volatiles revealed 19 EAD-active compounds of which 13 (mostly monoterpenes) were identified by GC–mass spectrometry (GC-MS). In separate field experiments, multiple-funnel traps baited with two blends of these 13 synthetic volatiles released at 280 and 340 mg/ 24 hr attracted 66 and 93% of the total S. ventralis captured, respectively. The clerid predator, Thanasimus undulatus, also responded strongly to the kairomonal volatiles. Additional experiments produced no evidence for aggregation pheromones in S. ventralis. These included laboratory bioassays and GC and GC-EAD analyses of Porapak Q-captured volatiles from male- and female-infested logs or trees undergoing mass attack in the field, GC analyses and/or bioassays of extracts from female accessory glands, extracted volatiles from emerged, attacking and juvenile hormone-treated beetles of both sexes, and videotape analysis of the behavior of attacking beetles on the bark surface. We argue against the hypothesis of pheromone-mediated secondary attraction in S. ventralis and conclude that the attack dynamics of this species can be explained solely by its sensitive primary attraction response to host volatiles.     

Comparative Fingerprint Changes of Toxic Volatiles in Low PUFA Vegetable Oils Under Deep-Frying

The volatile fraction of three vegetable oils recommended for deep‐frying due to their high MUFA:PUFA ratios, namely extra‐virgin olive oil, peanut oil and canola oil, was compared before and after frying potatoes, with a particular focus on toxic volatiles. For the purpose, a headspace solid‐phase‐micro extraction technique coupled with gas chromatography and mass spectrometry was optimized, with semi‐quantification achieved using two internal standards. Significant qualitative and quantitative differences were observed, both before and after frying. From a total of 51 compounds, aldehydes were the main group formed after deep‐frying, their nature and abundance being highly associated with the initial fatty acid composition, particularly linoleic acid (r² = ?0.999, p ≤ 0.001). Globally, extra‐virgin olive oil revealed fewer formations of unsaturated aldehydes, including toxic ones, and correlated with lower amounts of degradation indicators, as polar compounds (r² = 0.998, p ≤ 0.001) and p‐anisidine value (r² = 0.991, p ≤ 0.001). Despite the similarities in total unsaturation degree between canola and peanut oils, the former presented lower amount of volatiles, including E,E‐2,4‐decadienal and acrolein, the more toxic ones. These results highlight for the pertinence of volatile analyses to evaluate and compare oil degradation under thermal and oxidative stress, while complementing other degradation indicators. Additionally, the optimized methodology allows a direct comparison of different oil matrices, supporting further developments into more general methods for volatiles quantification, enabling more efficient comparison of results between research teams.     

Identification of Volatiles That Are Used in Discrimination Between Plants Infested with Prey or Nonprey Herbivores by a Predatory Mite

Carnivorous arthropods can use herbivore-induced plant volatiles to locate their herbivorous prey. In the field, carnivores are confronted with information from plants infested with herbivores that may differ in their suitability as prey. Discrimination by the predatory mite Phytoseiulus persimilis between volatiles from lima bean plants infested with the prey herbivore Tetranychus urticae, or plants infested with the nonprey caterpillar Spodoptera exigua, depends on spider mite density. In this article, we analyzed the chemical composition of the volatile blends from T. urticae-infested lima bean plants at different densities of spider mites, and from S. exigua-infested plants. Based on the behavioral preferences of P. persimilis and the volatile profiles, we selected compounds that potentially enable the mite to discriminate between T. urticae-induced and S. exigua-induced volatiles. Subsequently, we demonstrated in Y-tube olfactometer assays that the relatively large amounts of methyl salicylate and (3E, 7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene emitted by T. urticae-infested bean plants compared to S. exigua-infested plants enable the predators to discriminate. Our data show that specific compounds from complex herbivore-induced volatile blends can play an important role in the selective foraging behavior of natural enemies of herbivorous arthropods.     

Influence of Prolonged Deep-Frying Using Various Oils on Volatile Compounds Formation of French Fries Using GC–MS,GC-O,and Sensory Evaluation

Flavor is a decisive sensory characteristic to determine the popularity of French fries (FF). To investigate the effect of prolonged deep-frying using various oils on volatiles formation of FF, the FF were prepared in the palm oil (PO), soybean oil (SO), and high-oleic rapeseed oil (RO) for 24 hours intermittent frying. The effect of oil types was found to be more significant than the frying time on the volatiles of FF indicated from the clusters of the fried FF by chemometric analysis. A total of 26 key aroma-active compounds were identified by aroma extract dilution analysis, in which aldehydes were predominant. The FF fried in SO revealed higher desirable aroma compounds, i.e., (E, E)-2,4-decadienal and it increased to maximum value at 12 hours, and left the deep-fried odor in FF. Meanwhile, a significant increase in metallic off-flavor was observed in FF fried in SO and PO at 20 hours, indicating that oil quality reduction resulted in FF with unappealing flavor. The above results showed that frying process had an optimum frying window (approximately 4–16 hours with total polar compounds content below 22.2%), and the French fries prepared in this period obtained higher flavor scores. The study will provide insights into the effect of oil types and oxidation degree on obtaining the ideal flavors for fried food.