Changes in the volatile composition of Spanish-style green table olives induced by pasteurisation treatment

Thermal treatment of pasteurisation is the most widely used stabilisation method for packed green table olives. In the present work, the influence of pasteurisation on the composition of volatile compounds in packed Spanish-style green table olives was studied. To this aim, two thermal processes (P1 = 85 °C for 7 min; P2 = 85 °C for 15 min) were evaluated by comparing the contents of volatile compounds in pasteurised olives with those in unpasteurised olives. Volatiles were analysed, both in olive juice and cover brine, by means of headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). Both pasteurisation treatments caused significant increases in diverse ethyl and methyl esters and in volatile compounds derived from several chemical reactions (lipid oxidation, Maillard reaction, degradation of carotenoids). Significant differences between samples subjected to P1 and P2 were only found for 1-octen-3-ol, pentanal and 6-methyl-5-hepten-2-one in olive juice.     

固相微萃取气质联用测定酸奶发酵过程中挥发性风味成分

将酸奶发酵过程视作一个仅与外界有能量交换的动态系统,采用顶空固相微萃取法(HS-SPME)制备样品,利用气相色谱-质谱法(GC-MS)分离分析酸奶中的挥发性风味成分。比较不同顶空萃取时间、萃取方式、萃取温度,获得最佳样品提取条件,同时优化GC-MS色谱测定条件,确定吸附温度45℃、磁力搅拌30 min、加入氯化钠量为3 g/12 g时吸附30 min为测定酸奶中挥发性成分的办法。最终测定19种风味成分,分析得出特征性成分如双乙酰、乙酸、棕榈酸等随时间变化的趋势,并通过主成分分析,采用5个向量表示酸奶发酵过程及在发酵不同阶段的特征性风味。     

The profile in polyphenols and volatile compounds in alcoholic beverages from different cultivars of mulberry

Abstract: Mulberry fruits have different chemical compositions because of cultivar variation. In this study, polyphenol profile and volatile composition of alcoholic beverages produced from different mulberries of Da 10, Hongguo 2 hao, and Hongguo 1 hao were investigated. Statistically significant differences were detected in the chemical composition of the analyzed alcoholic beverage samples. The beverage of Da 10 possessed the highest content of total phenols, total flavonoids, and total anthocyanins, which was determined by spectrophotometry analysis, contrarily Hongguo 1 hao beverage showing the lowest. Phenolic acids and flavonols were analyzed by high performance liquid chromatography analysis. Protocatechuic acid was the main phenolic acid in all analyzed alcoholic beverage samples, and its concentration ranged from 8.20 mg L^?1 (Hongguo 1 hao beverage) to 29.98 mg L^?1 (Da 10 beverage). High level of flavonols was found in both Da 10 and Hongguo 2 hao beverage samples, whereas Hongguo 1 hao beverage sample was characterized with lower level of flavonols. Furthermore, volatile compounds were analyzed by solid phase microextraction‐gas chromatography mass spectrometry analysis. The amount of esters varied widely among the 3 alcoholic beverage samples. The concentration of aliphatic alcohols in Hongguo 2 hao and 1 hao beverage samples was higher than Da 10 sample, whereas Da 10 beverage sample contained more aromatic alcohols than the others. Hongguo 1 beverage sample showed the highest concentration of acetic acid. This study demonstrated that quantitative differences of phenolic compounds and volatile compounds among cultivars were significant, which highly affected the quality of alcoholic beverage from mulberry. Practical Application: Mulberry fruits had different chemical compositions because of cultivar variation. The analyzed Da 10 cultivar of mulberry appeared to be a good raw material for alcoholic beverage‐making because of its high level of total sugar and acidity. This study demonstrated that alcoholic beverages from mulberry contain high amounts of polyphenols. These bioactive compounds may act synergistically to promote health, and reduce risk factors of chronic diseases.     

Evaluation of volatile compounds and antioxidant capacity of some commercial rums from Dominican republic

Some Dominican ‘heavy’ rums, of a single brand, available commercially and labelled as 8, 15, 18, 21 and 25 year‐old have been evaluated and compared. Headspace solid‐phase microextraction (HS‐SPME) coupled to gas chromatography–mass spectrometry (GC–MS) was used to analyse volatile compounds and crocin kinetic competition test to evaluate their antioxidant capacity. The alcohols and esters profiles of rums labelled as 21‐ and 25 year‐old were similar. The alcohols and fatty acids profiles of rums labelled as 15 and 18 year‐old were similar. The esters profile of rums labelled as 8 and 15 year‐old was similar. Significant differences were found for aldehydes and volatile phenols between all the rum samples. The antioxidant capacity resulted significantly higher in the older rums (21 and 25 year‐old) than in the younger ones (8, 15 and 18 year‐old).     

SPME/GC/MS法检测蒜薹中的挥发性成分

采用两种萃取头（50/30μm DVB/CAR/PDMS和100μm PDMS）,利用顶空固相微萃取（SPME）-气质联用（GC/MS）分析四个大蒜主产地蒜薹中的挥发性成分。研究结果表明,100μm PDMS萃取头适合分析蒜薹中的挥发性成分,永年、惠民、商河、广饶四个产地的蒜薹共有的含硫化合物为二烯丙基二硫醚、甲基烯丙基三硫醚、二烯丙基三硫醚、二烯丙基硫醚、3-乙烯基-1,2-二硫杂-4-环己烯、1,3-二硫酸-2-硫酮、3,4-二甲基噻吩、1,3-二噻烷,其中二烯丙基二硫醚的含量最高。进一步分析表明,蒜薹不同部位的含硫化合物含量有一定差异,蒜薹含硫化合物含量:根部>茎中部>茎上部。本研究对于促进蒜薹加工利用,拓宽蒜薹产业链具有重要意义。      

芥末油、青芥辣、冲菜的挥发性风味成分的SPME/GC/MS测定

利用固相微萃取／气相色谱／质谱(SPME／GC／MS)联用技术对芥末油、青芥辣、冲菜的挥发性风味成分进行了研究。本试验条件下，这三种样品分别鉴定出6、12、17种挥发性风味成分，主要风味物质均为具有辛辣风味的异硫氰酸烯丙酯(AITC)，相对丰度分别为73．45％、64．25％、32．74％，二硫化碳的相对丰度也较高，分别为14．37％、25．40%、51．67％。     

Effect of the type of oil on the evolution of volatile compounds of taralli during storage

Baking process leads to a huge quantity of newly formed volatile compounds, which play a major role in developing the flavor of the final product. The aim of this work was to investigate on the evolution of the volatile profile of taralli as a function of both the kind of oil used in the dough and the storage time. The volatile compounds from the taralli were extracted by headspace solid-phase microextraction and analyzed by gas-chromatography/mass spectrometry (GC/MS). Forty-four volatile compounds were identified in taralli, most of which produced by thermically induced reactions occurring during baking process, such as volatiles deriving from Maillard reaction and/or sugar degradation and lipid oxidation. The results obtained demonstrated the essential role played by the type of oil on the formation and on the release of volatile compounds. The volatile compounds significantly increased during storage and their individual levels were in most cases significantly lower in taralli made with extra virgin olive oil than in those made with refined oils. Finally, the taralli made with extra virgin olive oil, compared with those prepared with other vegetable oils, showed to be more resistant to oxidation, probably due to the presence of natural antioxidants.     

固相微萃取结合气-质分析东北大酱的挥发性成分

采用固相微萃取结合气-质联用分析东北大酱的挥发性成分,并考察了提取时间和提取温度对挥发性成分提取效果的影响。结果表明,提取时间为40 min、提取温度为60 ℃时对东北大酱的挥发性成分提取效果较好。从东北大酱中共鉴定出28种挥发性成分,相对含量占总流出物的89.02%,包括酮类3种（相对含量为53.57%）、酸类3种（相对含量13.36%）、醇类2种（相对含量13.20%）、酯类8种（相对含量3.57%）、酚类2种（相对含量2.44%）、醛类5种（相对含量1.55%）、其他类5种（相对含量1.33%）。其中苯乙醛、3-辛酮、2,3,5,6-四甲基吡嗪、愈创木酚、4-乙烯基-2-甲氧基苯酚等挥发性成分对东北大酱整体香气贡献较大。     

Effect of solvent and extraction temperatures on the antioxidant potential of traditional stoned table olives “alcaparras”

This paper reports the first approach to the antioxidant potential evaluation of traditional stoned table olives “alcaparras”. This kind of olives are largely produced and consumed in Trás-os-Montes region (Northeast of Portugal). Different solvents and temperature extraction conditions were employed in order to achieve the best method to obtain phenolic compounds and a higher antioxidant activity. The optimum method (water at boiling temperature) was applied on 10 samples from the traditional market. The total phenol content ranged between 5.58 mg gallic acid equivalents (GAE)/g and 29.88 mg GAE/g and effective concentration (EC₅₀) values were in the range 0.36-1.64 and 0.34-1.72 mg/mL for reducing power and radical scavenging effect, respectively. A significantly negative linear regression was observed between the total phenol content found in the samples and its antioxidant activity.     

Volatile aroma compounds in wines from Chinese wild/hybrid species

The volatile aroma compounds in wines produced from Chinese wild/hybrid species were investigated in comparison to wines from European grapes. Volatiles were extracted by headspace solid‐phase micro‐extraction and identified by gas‐chromatography/mass‐spectrometry. The identification of analyte was performed by a combination of the linear retention index approach with the comparison of the obtained mass spectra. A total of 98 peaks were tentatively assigned as wine aroma components, and 15 odorants can be found at concentrations above their odor threshold among the odor activity values (OAVs) of 46 compounds evaluated in all of the wines. The “OAVs’ aroma wheels” showed that the classes of aromatic series are first fruity, next herbaceous and roasty and no spicy and caramelized notes. Via principal component analysis, all the grape germplasm studied could be divided into four groups: “Jingsheng‐1,” “Cabernet Gernischt,” “Beibinghong,” and others, which exhibited distinctive aroma features, respectively. Practical applications Chinese wild grape species have many desirable properties for wine grape breeding such as possessing strong resistant genes to fungal diseases and cold condition, especially after hybridization with European grapes. As an emerging wine country, wines from Chinese wild/hybrid species have achieved much success in the last few years. The chemical content and biological properties have been studied extensively in many but there are a few studies in our knowledge about the wine tastes of these species. In this paper, the key odorants in wines produced from the Chinese grape species of V. amurensis Rupr., V. davidii Foex., and V. quinquangularis Rehd. and its hybrids were characterized in comparison to wines produced from European grapes (V. vinifera). The findings will help to the further understanding of the key aroma components in the different Chinese grapevine germplasm, and make further efforts to enrich the wine types in the marketplace.     

基于HS-SPME和GC/MS定量分析杨梅特征香气成分

杨梅为中国南方特色树种,香气独特,研究其特征香气成分具有重要意义。该研究利用液液萃取和顶空固相微萃取（HS-SPME）技术,结合GC/MS对杨梅香气进行了定性和定量研究。研究表明,利用HS-SPME-GC/MS技术可检出挥发性物质成分60种,其中萜类物质是其主要挥发性成分,含量约占40%;醇类含量22%;醛酮类19%;酸类和酯类物质少,分别为1%和3%。在萜类物质中,发现石竹烯含量最高,达1069·8μg/L。研究了杨梅特征香气,这为促进香气质量评价体系建立、果品深加工对香气的影响研究提供了理论依据。      

Characterisation of the volatile profile of coconut water from five varieties using an optimised HS-SPME-GC analysis

BACKGROUND: Coconut (Cocos nucifera L.) water is a refreshing tropical drink whose international market has recently been growing. However, little is yet known about its physicochemical composition, particularly its aroma. This study set out to characterise the volatile profile of water from five coconut varieties. RESULTS: Aroma compounds were characterised by headspace solid phase microextraction gas chromatography (HS‐SPME‐GC) analysis. An experimental design was established to optimise SPME conditions, leading to an equilibration time of 10 min followed by an extraction time of 60 min at 50 °C. Accordingly, immature coconut water from WAT (West African Tall), PB121 (MYD × WAT Hybrid), MYD (Malayan Yellow Dwarf), EGD (Equatorial Guinea Green Dwarf) and THD (Thailand Aromatic Green Dwarf) palms was analysed and described. Ketones were mainly present in the Tall and Hybrid varieties, whereas aldehydes were most abundant in the Dwarf palms. Tall coconut water was characterised by a high lactone content. THD exhibited a high ethyl octanoate level. The cluster analysis of the volatile fraction from the five coconut cultivars was found to be related to their genetic classification. CONCLUSION: The volatile compounds of immature coconut water from five varieties were characterised for the first time. Volatile profile analysis could be a useful tool for the selection of Dwarf coconut varieties, which are mainly consumed as a beverage. Copyright © 2012 Society of Chemical Industry     

水煮鹅肉汤挥发性风味成分的GC/MS分析

采用共蒸馏分离和GC／MS分析，分析了水煮鹅肉汤的挥发性风味成分，结果共鉴定出50种成分，其中大部分为饱和或不饱和的醛酮类，其余主要为酯类和烷烃，另有少量的醇和酸。对比肉类挥发性风味成分的域值，对鹅肉汤风味贡献较大的成分主要为2，4-癸二烯醛、2-癸烯醛辛烯醛、壬醛、壬烯醛、壬二烯醛等。     

应用固相微萃取气相色谱测定毛织物中的挥发性有机化合物

毛织物试样剪碎后置于饱和NaCl溶液中经40℃超声处理后,采用100μm聚二甲基硅氧烷(PDMS)作为固相微萃取技术(SPME)装置的固相涂层,通过顶空固相微萃取气相色谱(HS-SPME-GC-MSD)法测定了织物样品中的9种挥发性有机化合物(VOCs).该方法给出了相应的检测限量和适用范围,织物样品中9种VOCs的检测限量均低于0.001 mg/kg,回收率在96.8%～103.7%之间.     

Changes in volatile compounds of peanut oil during the roasting process for production of aromatic roasted peanut oil

The changes in volatile compounds composition of peanut oil during the roasting process of aromatic roasted peanut oil (ARPO) production were investigated. The analyses were performed by gas chromatography-mass spectrometry combined with headspace solid phase microextraction (HS-SPME/GC-MS). Among the volatiles identified in ARPO, the N-heterocyclic chemical class possessed the highest relative percentage area (RPA) 61.68%, followed by O-heterocyclic group with an RPA of 24.57%. Twenty pyrazines were considered to be the key contributors to the intense nutty/roasty flavor typical of ARPO. Compounds that increased significantly in concentration during the roasting process were mainly Maillard reaction products, as well as compounds derived from Strecker degradation and lipid peroxidation. The results clearly showed that the roasting process was necessary to obtain the typical nutty/roasty aroma of ARPO. PRACTICAL APPLICATION: ARPO is the traditional edible oil in China that possesses a characteristic strong nutty and roasty flavor that distinguishes it from other edible vegetable oils. During the production, the roasting process is the crucial factor for the formation of the typical roasted peanut aroma that plays an important role in sensory quality of peanut oil. In our investigation, not only the volatile changes of peanut oil pressed from relevant peanut seeds roasted at different roasting time were determined, but also the contributions of identified volatiles on the typical nutty/roasty flavor of ARPO were discussed. Our work clearly demonstrated the significant effect of roasting process on the typical flavor formation of ARPO. The results are valuable as scientific guidance for the roasting process that better satisfy demands of the peanut oil industries for better flavor.     

Freshness characterisation of whiting (Merlangius merlangus) using an SPME/GC/MS method and a statistical multivariate approach

BACKGROUND: The freshness of whiting was studied at five stages of ice storage by comparing the analysis of volatile compounds obtained through solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) with two sensory methods. RESULTS: Of the volatile compounds identified, 38 were analysed using a statistical multivariate approach and classified according to their role in the estimation of freshness during storage as markers of freshness or spoilage. Regarding the evolution of the presence or absence of individual compounds, three categories were defined. For example, the volatile compounds propanal, hexanal, 1‐penten‐3‐ol, pentanal, 2,3‐pentanedione, 1‐penten‐3‐one, heptanal, (E)‐2‐pentenal, 2,3‐octanedione, (Z)‐2‐penten‐1‐ol, 1‐pentanol, butanal, octanal, 3,5,5‐trimethyl‐2‐hexene, 1‐hexanol and 4,4‐dimethyl‐1,3‐dioxane appeared highly relevant, because they are found throughout storage and can be divided into several categories that are directly related to the quality of fish. CONCLUSION: SPME/GC/MS combined with a statistical multivariate approach may be a useful method to identify volatile compounds and characterise fish freshness during storage. Copyright © 2010 Society of Chemical Industry     

SPME-GC/MS法测定大红袍茶及茶叶蛋卤水味包中的挥发性致香成分

采用固相微萃取（SPME）提取大红袍茶提取物和大红袍茶叶蛋卤水味包提取物中的挥发性致香成分,应用气相色谱-质谱联用技术（GC-MS）对这些香气成分进行了分析,结果显示,大红袍茶叶提取物和大红袍茶叶蛋卤水味包提取物香气成分中共检测到醇、醛、酸、酯、烯、酮和含氮、氧的杂环化合物分别为27种和56种,主要挥发性特征香气成分为橙花叔醇、棕榈酸、乳酸薄荷酯、吲哚、金合欢烯、乙位紫罗兰酮、苯酚、甜橙醛、芳樟醇、二苯甲酮等,通过积分定量,这些特征香气成分的相对百分比含量在大红袍茶叶蛋卤水味包提取物中与在大红袍茶叶提取物中的分布成正相关。