Werner Grosch

German Research Centre for Food Chemistry | DFA · Food Chemistry

Vor allem die stürmische Entwicklung physikalischer, physikalisch-chemischer und biochemischer Methoden zur Trennung und Identifizierung von Komponenten in so außerordentlich heterogen zusammengesetzten Materialien wie es Lebensmittel ihrer Natur nach sind, ermöglichte in den vergangenen 50 Jahren immer umfassendere Erkenntnisse dieser Zusammenhäng...

Some plants with intensive and distinctive flavors and aromas are used dried or in fresh form as seasonings or spices. Table 22.1 lists the most important spice plants together with the part of the plant used for seasoning.

Minerals are the constituents which remain as ash after the incineration of plant and animal tissues. They may be divided into two categories; main elements (Ca, P, K, Cl, Na, Mg) and trace elements (Fe, Zn, Cu, Mn, I, Mo, etc.). According to their biological roles, they may also be divided into essential elements, for which the biological roles ar...

Special attention must be paid to the possibility of contamination of food with toxic compounds. They may be present incidentally and may be derived in various ways. Examples of such contaminants are: Pollutants derived from burning of fossil fuels, radionuclides from fallout, or emissions from industrial processing (toxic trace elements, radionucl...

Water (moisture) is the predominant constituent in many foods (Table 0.1). As a medium water supports chemical reactions, and it is a direct reactant in hydrolytic processes. Therefore, removal of water from food or binding it by increasing the concentration of common salt or sugar retards many reactions and inhibits the growth of microorganisms, t...

Much evidence from many civilizations has verified that the meat of wild and domesticated animals has played a significant role in human nutrition since ancient times. In addition to the skeletal muscle of warm-blooded animals, which in a strict sense is “meat”, other parts are also used: fat tissue, some internal organs and blood. Definitions of t...

Milk is the secreted fluid of the mammary glands of female mammals. It contains nearly all the nutrients necessary to sustain life. Since the earliest times, mankind has used the milk of goats, sheep and cows as food. Today the term “milk” is synonymous with cow’s milk. The milk of other animals is spelled out, e. g., sheep milk or goat milk, when...

Amino acids, peptides and proteins are important constituents of food. They supply the required building blocks for protein biosynthesis. In addition, they directly contribute to the flavor of food and are precursors for aroma compounds and colors formed during thermal or enzymatic reactions in production, processing and storage of food. Other food...

Eggs have been a human food since ancient times. They are one of nature’s nearly perfect protein foods and have other high quality nutrients. Eggs are readily digested and can provide a significant portion of the nutrients required daily for growth and maintenance of body tissues. They are utilized in many ways both in the food industry and the hom...

Most fats and oils consist of triacylglycerides (recently also denoted as triacylglycerols; cf. 3.3.1) which differ in their fatty acid compositions to a certain extent. Other constituents which make up less than 3% of fats and oils are the unsaponifiable fraction (cf. 3.8) and a number of acyl lipids; e. g., traces of free fatty acids, mono- and d...

Carbohydrates are the most widely distributed and abundant organic compounds on earth. They have a central role in the metabolism of animals and plants. Carbohydrate biosynthesis in plants starting from carbon dioxide and water with the help of light energy, i. e., photosynthesis, is the basis for the existence of all other organisms which depend o...

Vegetables are defined as the fresh parts of plants which, either raw, cooked, canned or processed in some other way, provide suitable human nutrition. Fruits of perennial trees are not considered to be vegetables. Ripe seeds are also excluded (peas, beans, cereal grains, etc.). From a botanical point of view, vegetables can be divided into algae (...

Alcoholic beverages are produced from sugarcontaining liquids by alcoholic fermentation. Sugars, fermentable by yeasts, are either present as such or are generated from the raw material by processing, i. e. by hydrolytic cleavage of starches and dextrins, yielding simple sugars. The most important alcoholic beverages are beer, wine and brandy. Beer...

When food is consumed, the interaction of taste, odor and textural feeling provides an overall sensation which is best defined by the English word “flavor”. German and some other languages do not have an adequate expression for such a broad and comprehensive term. Flavor results from compounds that are divided into two broad classes: Those responsi...

IntroductionMethodologyRaw CoffeeRoasted CoffeeCoffee BrewFormation of OdorantsConclusions References

ABSTRACTA systematic study was performed to determine the odorants contributing to the warmed-over flavor (WOF) of cooked beef patties. The most potent odorants of the freshly cooked patties and of the cooked, refrigerated and reheated patties showing WOF were screened by dilution experiments. Eleven odorants were selected for quantification by sta...

The volatile components of cucumbers and muskmelons were analyzed by a technique which reveals the odorants having the highest odor units (ratio of the concentration to the odor threshold). (E/Z)-2,6-Nonadienal, followed by (Z)-2-nonenal and (E)-2-nonenal were the most significant odorants of cucumbers. The flavor of muskmelons was more complex. Me...

The volatile components of dill seed and herb were analyzed by gas chromatography-olfactometry which revealed the odorants having highest odor-activity value (ratio of concentration to odor threshold). (+)-(4S)-Carvone was the predominent odorant of dill seed. (+)-(3R,4S,8S)-3,9-Epoxy-1-p-menthene, methyl 2-methylbutanoate, (+)-(4S)-α-phellandrene...

The effect of the nonstarchy polysaccharide (NSP)-hydrolases on the properties of rye bread was established by enzymatic modification of the enriched soluble and insoluble NSP fractions, followed by flour recombination and bread baking (20g flour per minibread). Two microbial enzyme preparations were used for the modification (incubation 2 hr at 28...

The following steps are suitable for the analysis of the odorants causing aromas of foods: Isolation of the volatile fraction using distillation and/or extraction procedures. Detection of important odorants in the volatile fraction by aroma extract dilution analysis; identification of these compounds. Development of stable isotope dilution assays.

Procedures for the isolation, enrichment, identification and quantification of aroma compounds are reported in detail.

Vitamins are minor but essential constituents of food. They are required for the normal growth, maintenance and functioning of the human body. Hence, their preservation during storage and processing of food is of far-reaching importance. Data are provided in Tables 6.1 and 6.2 to illustrate vitamin losses in some preservation methods for fruits and...

Coffee (coffee beans) includes the seeds of crimson fruits from which the outer pericarp is completely removed and the silverskin (spermoderm) is occasionally removed. The seeds may be raw or roasted, whole or ground, and should be from the botanical genus Coffea. The drink prepared from such seeds is also called coffee.

Cereal products are amongst the most important staple foods of mankind. Nutrients provided by bread consumption in industrial countries meet close to 50% of the daily requirement of carbohydrates, one third of the proteins and 50–60% of vitamin B. Moreover, cereal products are also a source of minerals and trace elements.

The role of 2-methylisoborneol (MIB) in coffee aroma is controversically discussed in the literature. MIB is known as an off-flavor compound in drinking water and food, but it has also been suggested as a key flavor component of Robusta coffee, discriminating Robusta from Arabica coffee. To check this hypothesis the rolr of MIB in coffee brews was...

Extracts obtained from Elstar and Cox-Orange apples (Malus var. domestica Borkh.) were screened for potent odorants by aroma extract dilution analysis (AEDA). (E)-beta-Damascenone (I), (E)-beta-damascone (II), hexanal (III), (Z)-3-hexenal (IV), (Z)-2-nonenal (V), linalool (VI), butyl acetate (VII), 2-methylbutyl acetate (VIII) and hexyl acetate (IX...

The state of the art in aroma analysis is reviewed with emphasis on aroma-recombination studies using synthetic blends of odorants (aroma models) which have been prepared on the basis of analytical data. The model that matches the original aroma is the starting material for omission experiments which are performed to establish the odorants that act...

The concentrations of 22 potent odorants, including acetaldehyde, methylpropanal, 2- and 3-methylbutanal, 2,3-butanedione, 2,3-pentanedione, 2-furfurylthiol, 2-ethyl-3,5-dimethylpyrazine and 2,3-diethyl-5-methylpyrazine, were quantified in the headspace of roasted coffee powder. A model mixture containing these odorants was prepared on the basis of...

The potent odorants of boiled beef, Camembert cheese and black pepper were screened by AEDA and AECA. The latter procedure starts with gas chromatography/olfactometry (GCO) of the original extract which then is concentrated stepwise. After each step an aliquot is analyzed by GCO. This differs from AEDA in which the extract is concentrated to a smal...

Based on the principles of static and dynamic headspace sampling, an apparatus was developed for the determination of the release of potent odorants from two types of baguette (industrial process or "intensifée" and traditional or "artisanal") differing in their odor profiles. We applied this apparatus to get an insight into the aroma changes of fr...

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-...

12-Methyltridecanal (MT) smelling tallowy, beef-like was formed from plasmalogens when beef was boiled. To clarify the origin of MT, its concentration was determined by a stable isotope dilution assay in bacteria and protozoa isolated from the rumen of bovine animals as well as in the plasma, erythrocytes, and other physiological samples. The highe...

Aroma extract dilution analysis of raw Arabica coffee revealed 3-isobutyl-2-methoxypyrazine (I), 2-methoxy-3,5-dimethylpyrazine (II), ethyl 2-methylbutyrate (III), ethyl 3-methylbutyrate (IV), and 3-isopropyl-2-methoxypyrazine (V) as potent odorants. The highest odor activity value was found for I followed by II, IV, and V. It was concluded that I...

Sensory experiments reviewed in the paper indicated that the following odorants are essential for the flavor of roasted coffee. 2-furfurylthiol, acetaldehyde, propanal, 2- and 3-methylbutanal, 2-ethyl-3,5-dimethylpyrazine, 2-ethenyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine and 4-vinylguaiacol. Model experiments revealed that 2-furfurylthi...

The potent odorants of boiled potatoes were screened by aroma extract dilution analysis, aroma extract concentration analysis, and gas chromatography-olfactometry of static headspace samples. Altogether 45 odorants were found of which 42 were identified. trans-4,5-Epoxy-(E)-2-decenal, methional, 2-acetyl-1-pyrroline, dimethyltrisulfide, 2,3-diethyl...

 Twenty-eight potent odorants were quantified by stable isotope dilution assays of medium-roasted Arabica coffee blends from Colombia (Col), Brazil (Bra), El Salvador (El) and Kenya (Ken) as well as the varieties Tipica (Tip) from Colombia and Caturra from the regions Pinas (Cat-P) and Quevedo (Cat-Q) in Ecuador. The blends from Col and Bra were si...

A stable isotope dilution assay was developed for the quantitation of the hazelnut odorant 5-methyl-(E)-2-hepten-4-one by mass chromatography using synthesized [(2)H](2)-5-methyl-(E)-2-hepten-4-one as the internal standard. Application of the method on two batches of commercial hazelnut oils, processed from either roasted or unroasted nuts, reveale...

To answer the question of which fatty acid residue is the most effective, diacetyltartaric esters of monoglycerides (DATEMs) with fatty acids of chain lengths 6:0-20:0 were synthesized. The activity of synthesized DATEMs and commercial DATEM products was studied by means of rheological methods and a microscale baking test with 10 g of flour. Variat...

 The odour thresholds (i.e. the lowest concentration at which an odour can be detected) of 80 alkylpyrazines, most of them synthesized, were determined by gas chromatography-olfactometry. Trimethylpyrazine (1) had the lowest threshold (50 ng/l air) amongst mono-, di-, tri- and tetramethylpyrazine. Substitution of the methyl group in position 2 of 1...

 Quantification of 19 odorants and calculation of their odour activity values were together the basis for an aroma model which reflected the odour profile of a white pepper sample having a faecal off-flavour. Omission tests indicated limonene, linalool, α-pinene, 1,8-cineole, piperonal, butyric acid, 3-methylbutyric acid, methylpropanal, and 2- and...

 Quantification of 14 odorants and calculation of their odour activity values were the basis of an aroma model reflecting most of the odour notes of black pepper. Omission tests indicated α- and β-pinene, myrcene, α-phellandrene, limonene, linalool, methylpropanal, 2- and 3-methylbutanal, butyric acid and 3-methylbutyric acid as key odorants. A sto...

The potent odorants were quantified in a sample of roasted Arabica coffee. On the basis of the results, 27 odorants were dissolved in an oil/water mixture. The flavor profile of the model obtained was very close to that of the real sample. In duo and triangle tests, the model was compared with models missing one or more odorants. These experiments...

 Dilution and concentration experiments as well as enantioselective analysis of optically active monoterpenes indicated (±)-linalool, (+)-α-phellandrene, (–)-limonene, myrcene, (–)-α-pinene, 3-methylbutanal and methylpropanal as the most potent odorants of black pepper. Additionally, 2-isopropyl-3-methoxypyrazine and 2,3-diethyl-5-methylpyrazine we...

The concept of flavour analysis developed in our laboratory during the last decade to evaluate the key odorants of foods and beverages, is demonstrated in a review on coffee flavour. The results obtained by aroma extract dilution analysis (AEDA), gas chromatography/olfactometry of headspace samples and quantitation of potent odorants using correspo...

The sensitivity of a stable isotope dilution assay for 4-methoxy-2-methyl-2-butanethiol (MMB) causing the blackcurrant-like odour in olive oils was improved. After spiking the oil sample with labelled MMB, the thiols were separated from the volatile fraction with an immobilized reagent for thiols. MMB and its standard were purified by multi-dimensi...

Dilution techniques, like aroma extract dilution analysis (AEDA) and static headspace analysis and olfactometry (SHA-O), were applied to analyse food flavors. AEDA of soybean oil led to the identification of butane-2,3-dione and 3-methylnonane-2,4-dione as the most important odorants, which mainly caused the "butter-like" and "beany" off-flavors wh...

For more than two decades, this work has remained the leading advanced textbook and easy-to-use reference on food chemistry and technology. Its fourth edition has been extensively re-written and enlarged, now also covering topics such as BSE detection or acrylamide. Food allergies, alcoholic drinks, or phystosterols are now treated more extensively...

Lipids are formed from structural units with a pronounced hydrophobicity. This solubility characteristic, rather than a common structural feature, is unique for this class of compounds. Lipids are soluble in organic solvents but not in water. Water insolubility is the analytical property used as the basis for their facile separation from proteins a...

A food additive is a substance (or a mixture of substances) which is added to food and is involved in its production, processing, packaging and/or storage without being a major ingredient. Additives or their degradation products generally remain in food, but in some cases they may be removed during processing. The following examples illustrate and...

Only a few of the sugars occurring in nature are used extensively as sweeteners. Besides sucrose (saccharose), other important sugars are: glucose (starch sugar or starch syrup); invert sugar (equimolar mixture of glucose and fructose); maltose; lactose; and fructose. In addition, some other sugars and sugar alcohols (polyhydric alcohols) are used...

 On the basis of chemical analysis, taste activity values (ratio of concentration to taste threshold) and omission tests, the following substances and ions were identified as taste components of the juice formed during stewing of beef: 5′-inosine monophosphate, 5′-adenosine monophosphate, glutamic acid, aspartic acid, lactic acid, succinic acid, ca...

Twenty-one compounds, which had been screened in preceding experiments as potent odorants of french fries prepared in palm oil (PO), were quantified by stable isotope dilution assays. Nineteen odorants were dissolved in sun-flower oil in concentrations equal to those in PO. The flavor profile of the model obtained was close to that of a real sample...

Ascorbic acid (AA) is used as bread improver,as its addition in dough causes an increase in loaf volume and improvement in crumb structure. To explain these effects we review the stereospecifity of the improver action and the properties of ascorbate oxidase and glutathione dehydrogenase and the occurrence of low molecular thiols and their concentra...

the crusts of two white breads (French type), differing in the flavour profiles owing to differences in both the amount of yeast and the dough-making process, were analysed busing instrumental and sensory methods. 2-Acetyl-1-pyrroline, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,3-butandione, methional, (E)-2-nonenal, methylpropanal, andd 2- and 3-met...

Seven odorants causing the roasty, malty notes in the odour profile of baguettes were quantified in the crust to clarify the effect of modifications of the baking proess on the crust flavour. An increase in the yeast level enhanced the concentration of the rosty smelling 2-acetyl-1-pyrroline. Fermentation of the dough at lower temperatures for a lo...

The potent odorants of virgin olive oils from Italy (I), Spain (S), and Morocco (M) were screened by aroma extract dilution analyses and gas chromatography olfactometry of headspace samples. After Quantification, odor activity values (OAVs) were calculated by dividing the concentrations of the odorants in the oil samples by their nasally and retron...

A stable isotope dilution assay was developed for quantification of the potent odorants 2-methyl-3-furanthiol (MFT), 2-furfurylthiol (FFT), 2-mercapto-3-pentanone (2M3P), and 3-mercapto-2-pentanone (3M2P) in heated meat. The volatiles of meat were extracted with dichloromethane, which was spiked with definite amounts of stable isotopomers of MFT, F...

Wheat kernels were stored for 21 months at 20 C. Flours were milled before (I) and after storage (II). Doughs from II were firmer than those from I, possiblly due to the decrease of reduced glutathione (GSH) from 124 to 30 nmol/g the two flours, as wll as doughs that were prepared by the addition of GSH, oxidised glutathione (GSSG) and ascorbic aci...

On the basis of dilution experiments, 17 odorants of two parsley cultivars were selected for quantification and their odour activity values (OAVs, ratio of concenration to odour threshold) were calculated. The odurants showing higher OAVs with regard to the different odour profile of parsley were mixed As the aroma of this mixture was close to that...

 Gas chromatography-olfactometry of headspace samples revealed that (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine are potent odorants of raw spinach. Boiling the spinach led to a change, such that dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and...

 The flavour of parsley was found to change during drying and storage. Quantification of 27 potent odorants, selected by dilution experiments and calculation of odour activity values, indicated that 3-methyl-2,4-nonanedione was mainly responsible for the hay-like off-flavour. Two furanoid fatty acids, known to be precursors of 3-methyl-2,4-nonanedi...

Potent odorants in commercially processed peanut, hazelnut, and pumpkin seed oils were evaluated by the application of aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry of headspace samples (GCOH). AEDA revealed 38, 28 and 27 odour active compounds in peanut, hazelnut. and pumpkin seed oils, respectively. Fifteen odorants w...

The following substances were evaluated by the combined application of chemical and sensory analytical methods as the characteristic taste compounds of Camembert cheese: succinic acid, monosodium glutamate, ammonia and sodium chloride. It was also found that cadaverine, ornithine and citrulline, when present in the cheese, may cause a bitter note....

Sixteen neutral compounds, which had been screened in preceding dilution experiments as potent odorants of Camembert cheese, were quantified by stable isotope dilution assays in two samples of this cheese. In addition, seven volatile acids were determined by using conventional methods. The odour activity values (OAVs) of the compounds were calculat...

 An apparatus, based on the principle of dynamic headspace analysis, has been developed for the analysis of potent odorants released from two types of baguette (“intensifiée”, INT and “artisanal”, ART) which differ in their odour profiles. The odour profiles of model mixtures containing the odorants at concentrations found in bread were evaluated b...

Altogether 15 odorants and 18 taste substances, including volatile acids and minerals, were quantified in four loaves of Emmental manufactured with and without addition ofL. caseisubsp.casei. 2-Methylbutanal, three esters, 2-heptanone, 5-ethyl-4-hydroxy-2-methyl-3 (2H) -furanone, acetic acid, propionic acid, glutamic acid and succinic acid increase...

The present work describes the ripening of eight quarters of raw milk Swiss Emmental cheese loaves which were packaged at 3 months in a plastic sheet. The loaves were manufactured with and without addition ofL. caseisubsp.caseito the usual starter cultures. Samples were taken at 3, 6, 9 and 12 months of ripening. The following parameters were measu...

The most potent odorants of freshly boiled chicken and boiled, refrigerated and reheated chicken showing warmed-over flavour (WOF) were screened by dilution experiments. In total, 20 odorants were selected for quantification by stable isotope dilution assays. Calculation of odour activity values (ratio of concentration to odour threshold) indicated...

Aroma extract dilution analysis (AEDA) and headspace gas chromatography–olfactometry of freshly prepared French fries resulted in 48 odour compounds being identified. Among these, methional (I), 2-ethyl-3, 5-dimethylpyrazine (II), 2,3-diethyl-5-methylpyrazine (III), (E,E)-2,4-decadienal (IV), 4-hydroxy-2, 5-dimethyl-3(2H)-furanone (V), methanethiol...

Analysis of the positional distribution of the furanoid fatty acids, 10,13-epoxy-11,12-dimethyloctadeca-10, 12-dienoic acid (F20) and 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid (F22), in soybean oil (SBO) indicated that they were preferentially esterified with the primary-OH groups of glycerol molecules. Hydrogenation of SBO reduced the co...

The review is focused on studies presenting quantitative data and odor activity values (ratio of concentration to odor threshold) of key odorants in bread (wheat and rye), toasted bread, puff pastries made with different fats, fragrant and nonfragant rices, sweet corn, popcorn, and tortillas. The influence of raw materials, processing parameters, a...

Methyl linoleate (ML) was autoxidized at room temperature in the dark. In comparison to hexanal, (E)- and (Z)-2-octenal, only very small amounts of (E)-2-nonenal were formed, indicating that linoleic acid was not an important precursor of the latter aldehyde. Palmitic acid in form of its methyl ester (MP) was studied as an alternative. Aroma extrac...

Aroma extract dilution analysis (AEDA), aroma extract concentration analysis (AECA) and headspace gas chromatography-olfactometry (HGCO) of Camembert cheese resulted in the detection of42 odorants. Both AEDA and AECA indicated that 2,3-butanedione, 3-methylbutanal, 1-octen-3-ol, 1-octen-3-one, phenyl acetate, 2-undecanone, delta-decalactone, butyri...

After boiling, beef was extracted with dichloromethane, and the volatile fraction including the solvent was distilled from the non-volatile material. The distillate was divided into two portions; one-half was subjected to aroma extract dilution analysis (AEDA), and the other to aroma extract concentration analysis (AECA). In the latter case, the AE...

Slices of wheat bread were toasted until a distinct intensity of brown colour. Potent odorants formed were evaluated by aroma extract dilution analysis and gas chromatography/olfactometry of headspace samples. Compouns showing high dilution factors were quantified, and their aroma activity values (OAV, ratio of concentration to odour threshold) wer...

In roasted Robusta coffee, two potent earthy smelling compounds were identified as 2-ethenyl-3,5-dimethylpyrazine and 2-ethenyl-3-ethyl-5-methylpyrazine by comparison of gas chromatography and mass spectrometry data with those of the corresponding reference substances. The odor threshold values (0.014 ng/L, air) of the new pyrazines were as low as...

Homogenates of salmon /A,B) and of cod (C,D) re stored at minus 60°C (AC) and minus 13°C (BD) . After boiling, A and C exhibited the mild flavor of fresh fish, whereas B smelled fatty and train-oily and D showed a malty osor defect. The potent odorants of the four samples were screened by dilution experiments and then quantified by stable isotope d...

twentytwo compounds, which had been revealed by dilution experiments as potent odorants, were quantified by stable isotope dilution assays in brews prepared fro roasted Arabica and Robusta coffees. Calculation of odor activity values (OAVs); ratio of concentration to odor threshold) indicated 2-furfurylthiol, 3-mecapto-3-methylbutyl formate, methan...

Dilute ethereal solutions of mercaptoacetone (MA), 2-mercapto-3-butanone (MB), 3-mercapto-2-pentanone (MP), 2-methyl-3-furanthiol (MFT), and 2-furfurylthiol (FFT), either alone or in pairs, were stored at 6 °C. During a period of 10 days the oxidation of the thiols to the corresponding disulfides or mixed disulfides was followed by high-resolution...

The following substances were evaluated as potent taste compounds: acetic acid, propionic acid, lactic acid, succinic acid and glutamic acid, each in free form and/or as ammonium, sodium, potassium, magnesium and calcium salts, as well as the corresponding chlorides and phosphates. Magnesium and calcium propionate mainly caused the sweetish note in...

Flavour models were developed for two samples (A and B) of Swiss cheese which differed in their ripening stage and flavour profile. The models were based on an unripened, freeze-dried cheese of the Mozzarella type. Compounds which, in previous studies had been screened as contributors to the odour and taste of Swiss cheese, were added to the base i...

The highly volatile, potent odorants of coffee samples were evaluated by gas chromatography-olfactometry of decreasing headspace samples (GCO-H). 2,3-Butanedione, 2,3-pentanedione, 3-methyl-2-butenthiol (I), methional, 2-furfurylthiol (II) and 3-mercapto-3-methylbutylformate (III) were the key odorants of both, the powders of Arabica and Robusta co...

The content of 12-methyltridecanal (12-MT), which contributes greatly to the characteristic aroma of stewed beef, was determined by a stable isotope dilution assay in meat samples from nine bovine animals of different ages. The results, which were related to the amount of phospholipids (PL), indicate that 12-MT content increases with the age of bee...

Bis(2-methyl-3-furyl) disulfide (MFT-MFT) and bis(2-furfuryl) disulfide (FFT-FFT) dissolved either in benzene or in water were heated at 100 degrees C for 2 h. In benzene, 2-methyl-3-furanthiol and 2-furfurylthiol were formed when the hydrogen donor 1,4-cyclohexadiene or 1,4-hexadiene or the antioxidant BHT was present. In water, MFT-MFT, FFT-FFT,...

Hexanal (I), 1-octen-3-one (II), (E,E)-2,4-nonadienal (III), (E,E)-2,4-decadienal (IV) andtrans-4,5-epoxy-(E)-2-decenal (V) were quantified in cooked meat (beef, pork, chicken) in which the warmed-over flavour (WOF) was observed after storage for 2 days at 4C. Odour activity values of the compounds on the basis of odour threshold values in water re...

The concentrations of 10, 13-epoxy-11, 12-dimethyloctadeca-10, 12-dienoic acid (F20) and 12,15-epoxy-13, 14-dimethyleicosa-12, 14-dienoic acid (F22) were determined by a stable isotope dilution assay in oils extracted from the soybean cultivar Century and from five soybean genotypes that lacked one or two of the three lipoxygenase isoenzymes. The c...

The most potent high volatile odorants occurring in the air above boiled cod and troutwere evaluated by gCO of decreasing headspace volumes . Acetaldehyde, dimethyl sulfide, dimethyl trisulfide, propanal, methional, 1-octen-3-one, and (Z)-1,5-octadien-3-one in that of boiled trout (Salmo fario)). Storage of the raw material at minus 13°C led to odo...

HDMF is one of the key compounds which determine the flavour of Swiss cheese (Emmentaler). As this odorant has been detected in whey permeate supplemented with amino acids and in oculated with Lactobacillus helveticus, three strains of bacteria involved in the ripening of Swiss cheese have been compared with respect to their production of HDMF.