Volatile flavour components of baked potato flesh. A comparison of eleven potato cultivars

Tubers of eleven cultivars of potato were baked and the flavour compounds from the flesh were isolated by headspace adsorption onto Tenax and analysed by gas chromatography‐mass spectrometry (GC‐MS). Lipid degradation and the Maillard reaction were the main sources of flavour compounds, accounting for 22–69% and 28–77%, respectively, of the total yields. Various sulfur compounds, methoxypyrazines and terpenes were also identified at lower levels. Relative aroma impact values (RAVs) were calculated by dividing compound yields by the odour threshold value. Compounds contributing most to aroma (RAV > 10 000 in at least one cultivar) were 2‐isobutyl‐3‐methoxypyrazine, 2‐isopropyl‐3‐methoxypyrazine, β‐damascenone, dimethyl trisulfide, decanal and 3‐methylbutanal. The observed differences in yields and RAVs for compounds among cultivars would be expected to result in differences in perceived flavour.     

Identification of the key odorants in raw French beans and changes during cooking

 By application of aroma extract dilution analysis (AEDA) to an extract prepared from raw French beans, 25 odour-active compounds with flavour dilution (FD) factors in the range 4–2048 were detected and subsequently identified. Among them, (Z)-3-hexenal (green, leaf-like), 1-octene-3-one (mushroom-like), 3-isobutyl-2-methoxypyrazine (earthy, beany) and (E,Z)-2,6-nonadienal (cucumber-like) showed the highest FD factors. In an extract prepared from the same amount of cooked beans, 3-isobutyl-2-methoxypyrazine was identified as the most potent odorant, followed by 1,5-(Z)-octadiene-3-one (geranium-like), 3-isopropyl-2-methoxypyrazine (earthy, beany), 3-(methylthio)propanal (methional; cooked potato), 4,5-epoxy-(E)-2-decenal (metallic) and an unknown compound (FD 256) with a smell of geranium leaves. A decrease in (Z)-3-hexenal and 1-pentene-3-one (etheral, pungent) and an increase in methional during cooking were shown to be mainly responsible for the flavour changes induced by cooking the beans. Received: 22 January 1998 / Revised version: 16 March 1998     

Identification of the key odorants in raw French beans and changes during cooking

 By application of aroma extract dilution analysis (AEDA) to an extract prepared from raw French beans, 25 odour-active compounds with flavour dilution (FD) factors in the range 4–2048 were detected and subsequently identified. Among them, (Z)-3-hexenal (green, leaf-like), 1-octene-3-one (mushroom-like), 3-isobutyl-2-methoxypyrazine (earthy, beany) and (E,Z)-2,6-nonadienal (cucumber-like) showed the highest FD factors. In an extract prepared from the same amount of cooked beans, 3-isobutyl-2-methoxypyrazine was identified as the most potent odorant, followed by 1,5-(Z)-octadiene-3-one (geranium-like), 3-isopropyl-2-methoxypyrazine (earthy, beany), 3-(methylthio)propanal (methional; cooked potato), 4,5-epoxy-(E)-2-decenal (metallic) and an unknown compound (FD 256) with a smell of geranium leaves. A decrease in (Z)-3-hexenal and 1-pentene-3-one (etheral, pungent) and an increase in methional during cooking were shown to be mainly responsible for the flavour changes induced by cooking the beans. Received: 22 January 1998 / Revised version: 16 March 1998     

Volatile profiles of aromatic and non-aromatic rice cultivars using SPME/GC–MS

Rice (Oryza sativa L.) is enjoyed by many people as a staple food because of its flavour and texture. Some cultivars, like scented rice, are preferred over others due to their distinctive aroma and flavour. The volatile profile of rice has been explored by other investigators, some of whom have also determined a corresponding aroma using GC/olfactometry. However, little research has been done to determine if different aromatic rice cultivars produce different flavour volatiles that would make them more desirable than others when cooked. In this study, seven aromatic and two non-aromatic cultivars were examined for their volatile profiles both before and after storage using solid phase microextraction (SPME) fibres in conjunction with gas chromatography/mass spectrometer (GC–MS). Ninety-three volatile compounds were identified, 64 of which had not been previously reported in rice. Differences were found in the volatile compounds of aromatic and non-aromatic rice besides 2-acetyl-1-pyrroline (2-AP). Most of the volatile compounds were present in freshly harvested rice and rice following storage, with very few new compounds being identified only after storage. Dellrose, an aromatic cultivar, and Cocodrie, a non-aromatic cultivar, had the most complex volatile profiles (over 64 volatiles). Sixteen compounds were found only in the aromatic cultivars, and some volatiles were found to be unique to specific aromatic cultivars. However, no distinctive pattern was observed that would identify a cultivar as being derived from Basmati, Khao Dawk Mali 105 (i.e. jasmine), or other sources of aroma. This study showed that there is a great diversity of volatiles in both aromatic and non-aromatic rice cultivars and, with further research, this may lead to a better understanding of the combination of compounds that gives a cultivar a unique flavour.     

Odour-active components of simulated beef flavour analysed by solid phase microextraction and gas chromatography–mass spectrometry and –olfactometry

Volatile compounds in simulated beef flavour were qualitatively evaluated and compared with flavour compounds in roasted and boiled beef analysed under the same conditions, and to beef flavours reported in the literature. Headspace extractions of aroma compounds prepared by solid phase microextraction (SPME) were analysed by gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O) using detection frequency method of analysis. A total of 70 compounds were tentatively identified by GC–MS, including 3 furans, 6 S-heterocyclic compounds, 10 N-heterocyclic compounds, 6 aldehydes, 3 alcohols, and 2 esters. Of 49 volatile compounds detected in the sniffing port of GC–O, the most odour-active included 2-methyl-3-furanthiol, δ-3-carene, α-terpinene, 2-ethyl-3,6-dimethylpyrazine, and several unidentified odourants. 2-Methyl-3-furanthiol, regarded as one of the most powerful odour-active compounds in beef, in addition to various pyrazines, appeared to contribute to the beef-like aroma in simulated beef flavour, while the presence of various terpenoids along with the lack of aldehydes and ketones in simulated beef flavour may contribute to differences between the simulated and authentic beef flavours.     

Sensory study of the character impact aroma compounds of a coffee beverage

The more potent odorants in a sample of medium-roasted Arabica coffee and in the corresponding brew were quantified. Large amounts ( >75%) of acetaldehyde, 2,3-butanedione, 2,3-pentanedione, vanillin and some furanones were extracted from the coffee brew, whereas the yields of the more unpolar compounds, such as 3-isobutyl-2-methoxypyrazine, (E)-β-damascenone and the unstable 2-furfurylthiol were low (<25%). On the basis of quantitative data an aroma model was prepared for the brew. In triangle tests, models containing the complete set of 24 odorants were compared with a model missing one or more odorants. These experiments indicated that the aroma of the brew was mainly caused by some alkylpyrazines, furanones and phenols, and by 2-furfurylthiol, methional and 3-mercapto-3-methylbutyl formate. The higher impact of both methional and the formate on the aroma of the brew and the lower aroma activity of 4-vinylguaiacol were in contrast to results obtained in a previous study for ground coffee of the same provenance and roast degree. Received: 13 December 1999 / Revised version: 31 January 2000     

Improvement of soy-sauce flavour by genome shuffling in Candida versatilis to improve salt stress resistance

Genome shuffling of Candida versatilis was applied to improve the soy-sauce flavour by further increasing salt stress resistance. A mutant S3-5, with a stronger resistance to salt, was isolated after three rounds of genome shuffling. It is found that S3-5 improved stress tolerance to higher potassium chloride and lithium chloride. S3-5 not only grew well in the YPD (peptone, yeast extract and dextrose) medium containing high concentrations of sodium chloride with various pH values, but also exhibited improvement of growth ability in soy-sauce medium. The main aroma compounds in soy sauce were distinctly improved. Notably, S3-5 produced about 2.78 times as much ethanol as the control strain. Another important aroma compound, 4-hydroxy-2 (or 5)-ethyl-5 (or 2)-methyl-3 (2H)-furanone (HEMF) was enhanced by up to 80%. Meanwhile, S3-5 accelerated flavour formation of soy sauce thus decreasing the total time required for the aroma development.     

Determination of the key aroma compounds in Sachima and using solid phase micro extraction (SPME) and solvent-assisted flavour evaporation (SAFE)-gas chromatography-olfactometry-mass spectrometry (GC-O-MS)

The aroma-active compounds present in Sachima samples purchased at retail from the same batch code and stored for different durations of the shelf life were analysed by two methods: solid phase micro extraction (SPME) and solvent-assisted flavour evaporation (SAFE)-gas chromatography-olfactometry-mass spectrometry (GC-O-MS). A total of 41 volatile key compounds were identified. Among them, the predominant compounds in Sachima were tentatively identified by dilution analysis as being 3-(methylthio)propionaldehyde, 2-pentylfuran, 2-methyl-3-(methylthio)pyrazine, dimethyl disulfide, and dipropyl trisulfide. These compounds produced the highest due to their highest calculated flavour dilution (FD) factors. Sensory evaluations of the extracted compounds by a panel of trained individuals revealed that the ‘egg’ aroma was the main characteristic aroma due to its high sensory assessment score. With increasing length of storage of the product from 0 to 10 months, the overall acceptability of the Sachima aroma declined gradually. The observed changes in concentration of the different volatile compounds during storage indicated that the Maillard reaction and lipid oxidation continued during storage, so that aroma compounds and off-flavour compounds were being generated simultaneously. In addition, the undesirable smell of Sachima that increased during storage was not just generated from one volatile compound with a distinct off-flavour, but rather it was the result of an increase in both pleasant and unpleasant aromas. Furthermore, the pleasant aroma components appeared to still play a dominant role in the overall aroma profile of Sachima even after 10 Months of storage, which is within the stated shelf life on the product label.     

Investigation of important odorants of palm wine (Elaeis guineensis)

Palm wine (Elaeis guineensis) was sensorially evaluated and the key odorants were investigated by means of high resolution gas chromatography–olfactometry and mass spectrometry of solvent extracts as well as headspace samples. A total of 41 compounds were identified, 32 of them previously unknown in palm wine. From these, a total of 13 compounds were quantified by means of stable isotope dilution assays. Quantitation and calculation of the odour-activity values (OAVs) of the 13 key odorants revealed that the earthy-smelling 3-isobutyl-2-methoxypyrazine, the buttery-smelling acetoin, the fruity compounds ethyl hexanoate, 3-methylbutyl acetate and the popcorn-like-smelling 2-acetyl-1-pyrroline are likely to be important odorants of palm wine, with 3-isobutyl-2-methoxypyrazine, acetoin, and 2-acetyl-1-pyrroline being reported here for the first time as aroma constituents of palm wine.     

蛇龙珠葡萄成熟过程中6种甲氧基吡嗪分析

建立了顶空固相微萃取和气相色谱-氮磷检测器法(HS-SPME-GC-NPD)测定葡萄中6种3-烷基-2-甲氧基吡嗪(MPs)的方法。经优化采用CAR/DVB/PDMS三相SPME萃取头浓缩提取葡萄中MPs,在30℃恒温条件下吸附3h。该方法具有良好的线性,6种MPs标准曲线的线性相关性系数均大于0.99;线性范围在0.78～100ng/L之间;检测限在0.20～1.40ng/L范围内;除2-甲氧基吡嗪(73.12%)外,其他5种MPs的回收率在83.20%～113.09%之间。应用本方法检测蛇龙珠葡萄成熟过程中MPs,发现在果实成熟过程中MPs含量呈递减趋势,其中2-异丁基-3-甲氧基吡嗪最为突出;3-异丁基-和3-异丙基-2-甲氧基吡嗪的含量大于其阈值,对蛇龙珠葡萄的"青椒"气味具有重要贡献。     

Quantitative analysis of flavour volatiles detects differences among closely related traditional cultivars of tomato

Volatile compounds with a major contribution to aroma have been quantitatively determined in four traditional tomato cultivars and one commercial F1 hybrid. One of the traditional cultivars was the most appreciated for flavour and overall acceptability in tests performed using a panel of 30 untrained tasters. The same cultivar showed significantly higher contents of hexanal and cis‐3‐hexenal volatile compounds, which have been previously reported to be two of the most important contributors to tomato flavour. On the basis of a small number of fruits per cultivar, significant differences among very closely related tomato cultivars can be detected for volatile aromas, thus allowing the use of the determination of volatiles as a possible tool in tomato breeding programs, making even the selection of single plants possible. Copyright © 2004 Society of Chemical Industry     

Flavour evaluation of three black mulberry (Morus nigra) cultivars using GC/MS,chemical and sensory data

The flavour characteristics of three black mulberry (Morus nigra) cultivars from the Aegean region of Turkey were investigated using GC/MS and sensory analysis techniques. A total of 18 flavour compounds were identified by GC/MS in the three cultivars. Total sugar content varied between 11.3 and 16.2%, pH between 3.60 and 3.80 and total acidity between 1.51 and 1.79%. The sensory assessment indicated that black mulberry has fruity, sweet, sour, musky and woody flavour notes and fruity, acid, musky, leafy and woody‐fresh aroma characteristics. The evaluation of GC/MS and sensory data revealed that ethyl linolenate was the most effective compound contributing to the unique flavour of black mulberry. © 2002 Society of Chemical Industry     

Characterisation of Malaysian durian (Durio zibethinus Murr.) cultivars: Relationship of physicochemical and flavour properties with sensory properties

The physicochemical (pH, soluble solids, titratable acidity, sugars and organic acids), flavour and sensory properties of five Malaysian durian cultivars (D2, D24, MDUR78, D101 and Chuk) were studied. There were significant differences (P < 0.05) among the five cultivars in terms of all physicochemical characteristics tested with the exception for D2 and MDUR 78, which had similar physicochemical characteristics. Twenty two esters, 14 sulphur compounds, 7 alcohols, 3 aldehydes and 1 ketone were detected in the durian pulp of the five different cultivars using solid-phase microextraction coupled to gas chromatography-time of flight mass spectrometry. Diethyl disulphide, ethyl-n-propyl disulphide, diethyl trisulphide and ethanethiol were the predominant sulphur-containing compounds in all the cultivars. The major esters present in durian were either ethyl propanoate, ethyl-2-methyl butanoate, or propyl-2-methylbutanoate and their levels varied within cultivars. Principal component analysis applied to the data differentiated all cultivars based on 29 volatile flavour compounds exhibiting significant differences (P < 0.05) between cultivars. Principal components 1 and 2 explained 89% of the total variance. A strong correlation was observed between sensory properties with flavour compound and physicochemical characteristics of the fruit.     

基于GC-MS结合化学计量学方法探究特征清香味辣椒粉的香气特点

以探究特征清香味辣椒粉的香气特点及特征挥发性物质为目的,采用固相微萃取及气相色谱-质谱联用技术,对8 种不同品种的辣椒粉进行分析。运用气相色谱-质谱法可检测到112 种不同品种辣椒粉中普遍存在的挥发性化合物,从中筛选出63 种与特征清香味相关的特定的化合物并进行偏最小二乘回归分析。结果表明：特征清香味辣椒粉主要与感官属性煮熟蔬菜味、青草味和新鲜味有关。煮熟蔬菜味与β-月桂烯、(E)-2-戊烯醇、(E)-2-己烯醛、辛醛、4-辛烯-3-酮和2-戊基呋喃呈显著正相关,与大部分挥发性化合物呈非显著正相关,与己醛、(E,E)-2,4-癸二烯醛和2,3-丁二酮呈显著负相关;青草味与雪松烯、(Z)-3-己烯醇、己醛、(E)-2-庚烯醛和2-甲基丙酸呈显著正相关,与4-甲基-1-戊醇、己醇、(E)-2-辛烯醛和2-甲基丁酸己酯呈显著负相关;新鲜味与3-蒈烯、柠檬烯、(E,E)-2,4-癸二烯醛、(E)-2-壬烯醛、2-甲基丙酸和2-甲氧基-3-异丁基吡嗪呈显著正相关,与己醇、壬醛和2-甲基丁酸己酯呈显著负相关。由此确定特征清香味辣椒粉的香气特点及其特征挥发成分,为清香味辣椒粉的品质控制和系列风味产品的开发提供科学依据。     

Eating quality of raw carrots––correlations between flavour compounds,sensory profiling analysis and consumer liking test

Sensory profiling, analysis of aroma, sugar and dry matter, as well as consumer liking test were used to characterise the quality of six carrot cultivars, grown at two locations in Denmark. The carrot samples were examined at harvest, and after three months of cold storage. Carrot cultivar had an effect on most sensory and flavour compound variables, due particularly to the influence of one cultivar; and also location influenced carrot quality. Storage of carrots was characterised by an increase of a range of aroma components, but the changes in flavour compounds were not correspondingly observed by the sensory analysis. By Partial Least Squares Regression (PLSR) two thirds of the flavour compound variables was found to correlate significantly with one or more of the nine sensory attributes; and all of the sensory attributes were significantly correlated with one or more of the consumer liking test variables bitterness, sweetness and liking.     

Feasibility and application of solvent assisted flavour evaporation and standard addition method to quantify the aroma compounds in flavoured baked matrices

In order to determine the feasibility of the solvent assisted flavour evaporation extraction (SAFE) technique and the standard addition method to quantify the aroma compounds retained in baked matrices after processing, three doughs that mainly vary in one ingredient, M1 (with eggs and palm oil), M2 (without eggs but with palm oil) and M3 (without eggs and without palm oil) were flavoured with an aromatic formulation of 19 different aroma compounds in propylene glycol that is responsible for a viennoiserie aromatic note. From the 19 aroma compounds added, 12 of them were quantified, so was also the propylene glycol. After the application of standard addition method 36 linear regression models were obtained and 28 of them showed good r² values and allowed quantification. The results from the comparison of the slopes (95%) showed significant differences of the aroma compounds depending on matrix composition, which influences the degree of interaction of the aroma compounds in the matrix and the losses of the aroma during processing. The percentage of retention of the aroma compounds after processing was lower in M3 than in matrices M1 and M2.     

基于HS-SPME-GC-MS非靶向分析不同发酵小米辣的风味差异

采用顶空固相微萃取结合气相色谱-质谱联用的非靶向分析技术,对比9个品种小米辣发酵前后的挥发性香气轮廓,并通过多元数据分析,进一步探究不同品种发酵小米辣的特征性香气物质.结果表明:酯类和萜烯类物质是小米辣的主要特征性香气成分,且经过发酵后其种类和含量均显著增加(P<0.05).对于新鲜小米辣,罗勒烯、己醛、(E)-2-己...     

Keeping qualities of potato chips flavoured with kebab and salt

The volatile components from kebab flavour used in dusting potato chips were isolated by continuous steam distillation extraction (SDE) method. Sixteen volatile components were identified by gas chromatography-mass spectrometry (GC-MS) technique. The main constituents were aldehydes, hydrocarbons, thiophenes and fatty acids. Two potato chips samples, one flavoured with salt and the other with the kebab flavour, were stored for six months at room temperature. The aroma of each sample was isolated before and after storage. The results showed that the most contributor components to potato chips aroma were decreased by storage while the components which are responsible for rancid flavour were increased in the two samples, but with better results for the sample flavoured with salt.     

SPME-GC-MS detection of volatile compounds in apricot varieties

Aroma compounds of the eight Malatya apricot cultivars, six cultivars grown in the same breeding conditions from different locations and one hybrid cultivar were determined using SPME-GC-MS technique. In general, total concentration (sum of identified and unidentified peaks) of aroma compounds in Malatya apricot cultivars were lower than those others. Total concentration of aroma compounds were found to be in the range of 514 and 6232 μg/kg fresh weight. The main volatiles of apricot cultivars were aldehydes, alcohols, acetates, esters, terpenes and acids. Among these compounds; ethanol, hexanal, hexyl acetate, (Z)-3-hexenyl acetate, (E)-2-hexenyl acetate, 1-hexanol, (Z)-3-hexenol and (E)-2-hexen-1-ol, were present in all cultivars studied at certain levels.