Corn Gluten Meal Odorants and Volatiles After Treatment to Improve Flavor

Production of corn gluten meal (CGM), a high‐protein coproduct from wet milling of corn, is increasing as production of fuel ethanol from corn increases. Unpleasant taste and odor have limited the use of CGM in human food. Adjustment of pH and extraction with water have been reported to reduce the off‐flavor of CGM but the improvement is not enough for substantial addition of CGM to the human diet. More study of CGM is needed. In this study, volatile compounds released under different conditions of pH, water extraction, and temperature were identified and compared using solid‐phase microextraction‐gas chromatography‐mass spectrometry (SPME‐GC‐MS). The water‐extractable portion, which improves the taste of CGM by its absence, was dried and analyzed by SPME‐GC‐MS. In addition, materials extractable from CGM with methylene chloride were identified by gas chromatography‐mass spectrometry (GC‐MS). Further, the spontaneous generation of a CGM‐like odor accompanied by a change in physical appearance of the CGM sample was described. Flavors and odors known to be associated with the identified CGM compounds were listed. Some possible origins of the volatiles, from degradation of corn constituents or as fermentation products of the corn steeping process, were noted.     

Changes in volatile compounds of carrots (Daucus carota L.) during refrigerated and frozen storage

Carrots (Daucus carota L.) of cv. Bolero and cv. Carlo were processed into shreds and stored for up to 4 months at -24 degrees C (frozen storage), or the roots were stored for up to 4 months at 1 degrees C (refrigerated storage) followed by processing into shreds. Volatiles from the carrot shreds were collected by dynamic headspace technique and analyzed by GC-FID, GC-MS, GC-MS/MS, and GC-O to determine the volatile composition and aroma active components of carrots stored under different temperature conditions. A total of 52 compounds were quantified, of which mono- and sesquiterpenes accounted for approximately 99% of the total volatile mass. Major volatile compounds were (-)-alpha-pinene, beta-myrcene, (-)-limonene, (+)-limonene, (+)-sabinene, gamma-terpinene, p-cymene, terpinolene, beta-caryophyllene, alpha-humulene, and (E)- and (Z)-gamma-bisabolene. A considerable increase in the concentration of mono- and sesquiterpenes was observed during refrigerated storage, whereas the concentration of terpenoids was around the same level during frozen storage. GC-O revealed that the major volatiles together with (+)-alpha-pinene, (-)-beta-pinene, (+)-beta-pinene, 6-methyl-5-hepten-2-one, (-)-beta-bisabolene, beta-ionone, and myristicin had an odor sensation, which included notes of "carrot top", "terpene-like", "green", "earthy", "fruity", "citrus-like", "spicy", "woody", and "sweet".     

GC-olfactometric characterization of aroma volatiles from the thermal degradation of thiamin in model orange juice

Model orange juice solutions containing 0.024 mM thiamin hydrochloride were stored for up to 8 weeks at 35 degrees C in amber glass containers. Volatiles were evaluated, primarily, using gas chromatography (GC) with olfactometry but also with flame ionization detector, pulsed-flame photometer detector (PFPD) (sulfur specific), and MS detection. Both 2-methyl-3-furanthiol (MFT) and its dimer, bis(2-methyl-3-furyl) disulfide (MFT-MFT) were identified thus confirming that thiamin could serve as the precursor to these potent off-flavors in thermally degraded citrus juices. Thirteen aroma active components were observed. MFT and MFT-MFT were observed after only a few days storage, and produced 33% of the total aroma activity after 7 d storage. Both compounds were observed olfactometrically earlier than they could be detected using PFPD. Other aroma-active compounds included 4,5-dimethylthiazole (skunky, earthy), 3-thiophenethiol (meaty, cooked), 2-methyl-4,5-dihydro-3(2H)-thiophenone (sour-fruity, musty, green), 2-acethylthiophene (burnt), 2-formyl-5-methylthiophene (meaty), and 2-methyl-3-(methyldithio) furan (meaty).     

Identification of potent odorants in Japanese green tea (Sen-cha)

Application of aroma extract dilution analysis using the volatile fraction of a Japanese green tea (Sen-cha) sample resulted in the detection of 36 odor-active peaks with flavor dilution (FD) factors between 10 and 5000. Thirty-six potent odorants were identified from 36 odor-active peaks by gas chromatography/mass spectrometry (GC/MS) and/or the multidimensional GC/MS (MDGC/MS) system. Among these components, 4-methoxy-2-methyl-2-butanethiol (meaty), (Z)-1, 5-octadien-3-one (metallic), 4-mercapto-4-methyl-2-pentanone (meaty), (E,E)-2,4-decadienal (fatty), beta-damascone (honey-like), beta-damascenone (honey-like), (Z)-methyl jasmonate (floral), and indole (animal-like) showed the highest FD factors. Therefore, these odorants were the most important components of the Japanese green tea odor. In addition, 4-methoxy-2-methyl-2-butanethiol, 4-mercapto-4-methyl-2-pentanone, methional, 2-ethyl-3, 5-dimethylpyrazine, (Z)-4-decenal, beta-damascone, maltol, 5-octanolide, 2-methoxy-4-vinylphenol, and 2-aminoacetophenone were newly identified compounds in the green tea.     

Purification of fusaproliferin from cultures of Fusarium subglutinans by preparative high-performance liquid chromatography

Thirty-six Fusarium strains were grown on cracked yellow corn and evaluated for optimum fusaproliferin production, with Fusarium subglutinans E-1583 producing the highest levels (1600 microg/g). Three solvent systems were tested for extracting fusaproliferin from the cultures of F. subglutinans E-1583. Methanol gave the highest fusaproliferin recovery, followed by methanol/1% aqueous NaCl (55:45, v/v) and acetonitrile/methanol/H(2)O (16:3:1, v/v/v). Hexane partitioning was effective in removing many impurities from the crude fusaproliferin extracts prior to the liquid chromatography step. Fusaproliferin samples were further purified by high-performance liquid chromatography (HPLC) with a C18 preparatory column using a mobile phase of acetonitrile/H(2)O (80:20, v/v). The purity of the fusaproliferin was verified by analytical HPLC, GC/MS, (1)H NMR spectroscopy, and electrospray ionization (ESI) MS. The isolated fusaproliferin was shown to be free of impurities and can be used as a standard for routine analysis. Fusaproliferin was shown to be temperature-sensitive when samples were stored at room temperature (20-24 degrees C) for more than several days. After 30 days at 4 degrees C, approximately 8% of the fusaproliferin had been transformed to deacetyl-fusaproliferin; however, samples stored at -20 degrees C for 1 year contained only trace amounts of the deacetylated form.     

Analysis of volatile compounds released during the grinding of roasted coffee beans using solid-phase microextraction

A dynamic solid-phase microextraction (SPME) method to sample fresh headspace volatile compounds released during the grinding of roasted coffee beans was described and the analytical results using gas chromatography/mass spectrometry (GC/MS) and GC/olfactometry (GC/O) were compared to those of the conventional static SPME sampling methods using ground coffee. Volatile compounds released during the grinding of roasted coffee beans (150 g) were obtained by exposing the SPME fiber (poly(dimethylsiloxane)/divinylbenzene, PDMS/ DVB) for 8 min to nitrogen gas (600 mL/min) discharged from a glass vessel in which the electronic coffee grinder was enclosed. Identification and characterization of volatile compounds thus obtained were achieved by GC/MS and GC/O. Peak areas of 47 typical coffee volatile compounds, separated on total ion chromatogram (TIC), obtained by the dynamic SPME method, showed coefficients of variation less than 5% (n = 3) and the gas chromatographic profile of volatile compounds thus obtained was similar to that of the solvent extract of ground coffee, except for highly volatile compounds such as 4-hydroxy-2,5-dimethyl-3(2H)-furanone and 4-ethenyl-2-methoxyphenol. Also, SPME dilution analysis of volatile compounds released during the grinding of roasted coffee beans showed linear plots of peak area versus exposed fiber length (R (2) > 0.89). Compared with those of the headspace volatile compounds of ground coffee using GC/MS and GC/O, the volatile compounds generated during the grinding of roasted coffee beans were rich in nutty- and smoke-roast aromas.     

Chemical and sensory properties of liquid beet sugar.

Sensory analysis and headspace gas chromatography-flame ionization detection (GC-FID) analysis of liquid sugars (sucrose) designated for food-industrial use were performed in order to elucidate which compounds are responsible for perceived off-odors and off-flavors in liquid sugar. The liquid sugar samples investigated had various kinds of off-odors and off-flavors that might influence the quality of any food product in which they might be used, such as a jam or a soft drink. The sensory scores for the different attributes and the levels of different volatile compounds as measured by GC were analyzed for correlation using partial least-squares (PLS) analysis. A link between sensory analysis and GC analysis was thereby established, and compounds critical for the odor and flavor were identified using MS (mass spectrometry). Approximately 10 compounds were found to be correlated with the defined sensory attributes. Among these compounds associated with the sensory attributes were dimethyl disulfide, 2,6-dimethylpyrazine, 4-methoxyphenol, and 2, 5-dimethylfuran.     

Relationships between antioxidant activity, color, and flavor compounds of crystal malt extracts.

Aqueous extracts were prepared from five barley crystal malts (color range 15-440 degrees EBC, European Brewing Convention units). Antioxidant activity was determined by using the 2,2'-azinobis(3-ethylbenothiazoline-6-sulfonic acid) (ABTS(*)(+)) radical cation scavenging method. Antioxidant activity increased with increasing color value although the rate of increase decreased with increasing color value. Color was measured in CIELAB space. Extracts of the 15, 23, and 72 degrees EBC malts followed the same dilution pathway as did the 148 degrees EBC sample at higher dilution levels, indicating that they could each be used to give the same color by appropriate dilution. The 440 degrees EBC sample followed a different dilution pathway, indicating that different compounds were responsible for color in this extract. Fifteen selected volatile compounds were monitored using gas chromatography/mass spectrometry (GC/MS). Levels of methylpropanal, 2-methylbutanal, and 3-methylbutanal were highest for the 72 degrees EBC sample. When odor threshold values of the selected compounds were taken into account, 3-methylbutanal was the most important contributor to flavor. Relationships between levels of the lipid oxidation products, hexanal and (E)-2-nonenal, and antioxidant activity were complex, and increasing antioxidant activity for samples in the range of 15-148 degrees EBC did not result in reduced levels of these lipid-derived compounds. When different colored malt extracts were diluted to give the same a* and b* values, calculated antioxidant activity and amounts of 3-methylbutanal, hexanal, and (E)-2-nonenal decreased with increasing degrees EBC value.     

微波烫漂和速冻加工黑毛豆仁挥发性风味成分分析

采用固相微萃取（SPME）与气相色谱-质谱（GC-MS）联用技术,分析微波烫漂和速冻后新大粒1号黑毛豆仁挥发性风味成分的变化。结果表明：黑毛豆仁鲜样、微波烫漂和速冻处理后分别检测到31、34和32种挥发性风味成分,主要为醇类、醛类、酮类化合物。1-辛烯-3-酮、己醛、（E,Z）-2,6-壬二烯醛、1-戊烯-3-酮、（E...     

Comparison of proanthocyanidins in commercial antioxidants: grape seed and pine bark extracts

The major constituents in grape seed and pine bark extracts are proanthocyanidins. To evaluate material available to consumers, select lots were analyzed using high-performance liquid chromatography, gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), gel permeation chromatography (GPC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Atmospheric pressure chemical ionization (APCI) LC/MS was used to identify monomers, dimers, and trimers present. GC/MS analyses led to the identification of ethyl esters of hexadecanoic acid, linoleic acid, and oleic acid, as well as smaller phenolic and terpene components. The GPC molecular weight (MW) distribution indicated components ranging from approximately 162 to approximately 5500 MW (pine bark less than 1180 MW and grape seed approximately 1180 to approximately 5000 MW). MALDI-TOF MS analyses showed that pine bark did not contain oligomers with odd numbers of gallate units and grape seed contained oligomers with both odd and even numbers of gallate. Reflectron MALDI-TOF MS identified oligomers up to a pentamer and heptamer, and linear MALDI-TOF MS showed a mass range nearly double that of reflectron analyses.     

Enhancing quality and oxidative stability of aged fried food with gamma-tocopherol

To determine the effects of gamma-tocopherol on the stability of fried food, potato chips were fried in triolein with 0, 100, or 400 ppm gamma-tocopherol. Potato chips, sampled at 1, 3, and 6 h of frying time, were aged for 0, 2, and 4 days at 60 degrees C and then evaluated for odor attributes by sensory analysis and for volatile compounds by purge-and-trap gas chromatography-mass spectrometry. Oil sampled after 1, 3, and 6 h of frying time from the fryer was evaluated for total polar compounds and retention of gamma-tocopherol. Oil extracted from the potato chips was also analyzed for residual gamma-tocopherol. gamma-Tocopherol disappeared rapidly, with only slight amounts of the original 100 ppm level detectable after the triolein was used for frying. gamma-Tocopherol significantly inhibited polar compound production in the triolein. Results showed that gamma-tocopherol inhibited the oxidation of the fried food even when only very low levels of retained gamma-tocopherol were present in the frying oil or potato chips. Nonanal formation was inhibited by gamma-tocopherol in aged potato chips. Odor analysis of the aged potato chips showed that samples with 0 ppm gamma-tocopherol had a rancid odor after being aged for 4 days. Potato chips with 400 ppm gamma-tocopherol had no rancid odors; however, as the level of gamma-tocopherol decreased in the triolein and in the potato chips, a weak plastic odor characteristic of oxidized triolein was detected.     

Changes in the volatile compounds and chemical and physical properties of Kuerle fragrant pear (Pyrus serotina Reld) during storage

Volatiles from stored Kuerle fragrant pears (Pyrus serotina Reld) were studied using high-resolution gas chromatography and the solid-phase microextraction (SPME) method of gas chromatography/mass spectrometry (GC/MS). The dominant components were hexanal, ethyl hexanoate, ethyl butanoate, ethyl acetate, hexyl acetate, ethanol, alpha-farnesene, butyl acetate, and ethyl (E,Z)-2,4-decadienoate. By using GC-olfactometry, it demonstrated that the volatile compounds from SPME were responsible for the aroma of the Kuerle fragrant pear. The levels of sugars, organic acids, and phenolic acids in Kuerle fragrant pears were investigated using high-performance liquid chromatography (HPLC). Fructose was the dominant sugar, followed by glucose and sucrose. With increasing storage time, sucrose levels decreased; however, changes in fructose and glucose levels were not remarkable. There was a slight decrease in flesh firmness during storage. The general soluble solids concentration (SSC) declined slightly after 5 months storage. Some aroma-related volatile components increased during storage, while others decreased, especially the esters. The organic acids and phenolic acids also changed. The flavor of the Kuerle fragrant pears was affected by the change of volatile compounds and changes in chemical and physical properties.     

Metabolites of lesser grain borer in grains

Many volatile alcohol and ester metabolites of the lesser grain borer (LGB, Rhyzopertha dominica) cultured on wheat grain were identified. Volatiles from infested samples at 80 degrees C were collected on Tenax absorbent, thermally desorbed, and analyzed by gas chromatography (GC) using infrared (IR) and mass (MS) detectors for component identification. A solid-phase microextraction (SPME) technique was used to analyze selected samples with a GC-MS system set up for obtaining chemical ionization mass spectra. SPME was also used in a synthesis process required to identify ester metabolites. Predominant compounds in LGB-infested grains were 2-pentanol and its esters of 2-methyl-2-pentenoic (A) and 2,4-dimethyl-2-pentenoic (B) acids, which are known aggregation pheromones, dominicalures 1 and 2. 2-Pentanol esters of saturated A, beta-keto- and beta-hydroxy derivatives of A and B, homologues of A and B, and acid moieties lacking the 2-methyl substitution were found. Other straight- and branched-chain secondary alcohols and their esters were also observed. Reexamination of GC-MS-IR data acquired in previous investigations of LGB cultured on sorghum grain and commercial samples in a grain odor study showed the presence of many LGB metabolites in addition to the known dominicalures.     

不同栽培基质对6种侧耳属食用菌风味成分的影响

为探究不同栽培基质对侧耳属食用菌风味成分的影响以及不同品种食用菌间的风味成分差异,本研究采用顶空固相微萃取结合气相色谱-质谱联用(HS-SPME-GC-MS)技术对桑枝、杂木屑和棉籽壳基质上栽培的6种侧耳属食用菌风味成分进行了分析。结果表明,18个样品中共检出47种挥发性化合物,包括13种醛类化合物、9种醇类化合物、9种酮类化合物、2种呋喃类化合物、2种酯类化合物等。18个样品中的共有成分有17种,包括正己醛、壬醛、1-辛烯-3-醇、3-辛酮、1-辛烯-3-酮、2-正戊基呋喃等。18个样品中挥发性化合物的种类和相对含量差异较大,但棉籽壳基质上栽培的6个菌株子实体中均出现了较高含量的酯类化合物。所有样品中的关键风味成分(ROAV≥1)均包括1-辛烯-3-酮和1-辛烯-3-醇,桑枝基质和杂木屑基质栽培的部分菌株中关键风味成分还包括正己醛、壬醛和2-壬烯醛等。18个样品中总5'-核苷酸含量和总游离氨基酸含量分别为7.86~43.86 mg·g^-1 DW和8.54~25.34 mg·g^-1 DW, 且杂木屑基质栽培的所有菌株中总游离氨基酸含量均高于桑枝基质和棉籽壳基质。综上所述,棉籽壳基质有利于侧耳属食用菌中酯类化合物的生成,而杂木屑基质有利于游离氨基酸的生成。本研究结果为侧耳属食用菌栽培及风味成分的开发利用提供了科学依据。     

京甜紫花糯2号玉米软罐头加工过程中风味成分变化

采用顶空固相微萃取(HS-SPME)技术与气-质联用技术结合,分析京甜紫花糯2号玉米软罐头加工过程中风味成分变化。结果表明,在鲜样、烫漂及高温高压杀菌后的京甜紫花糯2号玉米中分别检测到30、29和39种风味化合物,这些成分可归类为:含硫类、酯类、醛类、醇类、酮类、烃类、芳香族类、酸类、呋喃类和含氮类化合物。在糯玉米软罐头成品的风味成分中,含硫类、醇类、醛类和酸类化合物分别占化合物总数的65.55%、9.62%、4.81%和4.36%。京甜紫花糯2号玉米加工过程中风味物质的总峰面积增加,尤其是含硫类、酯类、芳香族类、酸类等化合物最为显著,这些物质对形成京甜紫花糯2号玉米软罐头特有的风味起到重要的作用。     

Freshness assessments of Moroccan sardine (Sardina pilchardus): comparison of overall sensory changes to instrumentally determined volatiles

Freshness of ice-stored sardine was assessed by two sensory methods, the quality index method (QIM) and the European Union freshness grading system, and by instrumental means using the method of aroma extract dilution analysis. Screening of sardine potent volatiles was carried out at three freshness stages. In the very fresh state, the plant-like fresh volatiles dominated the odor pattern, with the exception of methional. Overall odor changes in sardine throughout storage correlated with changes in the concentration of some potent volatiles: after 2 days of ice storage, (Z)-4-heptenal, (Z)-1,5-octadien-3-one, and methional imparted an overall "fishy" odor character to sardine, whereas at a lower sensory grade (B), the compounds (E)-2-nonenal and (E,Z)-2,6-nonadienal could be, in part, associated with the slightly rancid aroma top notes. Trimethylamine was detected as a highly volatile odorant using solid-phase microextraction (SPME) headspace analysis of refrigerator-stored sardine. Intensity and sensory characteristics of some SPME determined volatiles, for example, 3-methylnonane-2,4-dione, were closely related to overall odor changes. SPME headspace analysis may be useful in the characterization of off-flavors in fish.     

Characteristic odor components of kumquat (Fortunella japonica Swingle) peel oil

This study was conducted to determine the composition of kumquat (Fortunella japonica Swingle) cold-pressed peel oil and to determine which volatile components are primarily responsible for the aroma of this oil. Eighty-two compounds were identified in the oil by GC and GC-MS. The major compounds were limonene (93.73%), myrcene (1.84%), and ethyl acetate (1.13%). Flavor dilution (FD) factors and relative flavor activities (RFA) of volatile constituents were evaluated by aroma extract dilution analysis with gas chromatography-olfactometry (GC-O). Camphene, terpinen-4-ol, citronellyl formate, and citronellyl acetate showed high FD factors (>/=5) and RFA (>20). Citronellyl formate and citronellyl acetate were regarded as the characteristic odor components of the kumquat peel oil from the results of FD factor, RFA, and GC-sniffing. Citronellyl acetate is considered to be the odor component most similar to kumquat by organoleptic evaluation with GC-O.     

Similarities in the aroma chemistry of Gewürztraminer variety wines and lychee (Litchi chinesis sonn.) fruit

GC/O analysis of canned lychees indicated that cis-rose oxide, linalool, ethyl isohexanoate, geraniol, furaneol, vanillin, (E)-2-nonenal, beta-damascenone, isovaleric acid, and (E)-furan linalool oxide were the most odor potent compounds detected in the fruit extracts. However, on the basis of calculated odor activity values (OAVs), cis-rose oxide, beta-damascenone, linalool, furaneol, ethyl isobutyrate, (E)-2-nonenal, ethyl isohexanoate, geraniol, and delta-decalactone were determined to be the main contributors of canned lychee aroma. When these results were compared with GC/O results of fresh lychees and Gewürztraminer wine, 12 common odor-active volatile compounds were found in all three products. These included cis-rose oxide, ethyl hexanoate/ethyl isohexanoate, beta-damascenone, linalool, ethyl isobutyrate, geraniol, ethyl 2-methylbutyrate, 2-phenylethanol, furaneol, vanillin, citronellol, and phenethyl acetate. On the basis of OAVs, cis-rose oxide had the highest values among the common odorants in the three products, indicating its importance to the aroma of both lychee fruit and Gewürztraminer wines. Other compounds that had significant OAVs included beta-damascenone, linalool, furaneol, ethyl hexanoate, and geraniol. This indicated that while differences exist in the aroma profile of lychee and Gewürztraminer, the common odorants detected in both fruit and wine, particularly cis-rose oxide, were responsible for the lychee aroma in Gewürztraminer wine. When headspace SPME was used as a rapid analytical tool to detect the levels of selected aroma compounds deemed important to lychee aroma in Gewürztraminer-type wines, cis-rose oxide, linalool, and geraniol were found to be at relatively higher levels in Gewürztraminers. No cis-rose oxide was detected in the control wines (Chardonnay and Riesling), while lower levels were detected in the Gewürztraminer-hybrid wine Traminette. Gewürztraminers produced in the Alsace region showed differences in the levels of the 3 monoterpenes when compared to those from New York State, which could be attributed to differences in viticultural and enological practices between regions.     

Study of light-induced volatile compounds in goat's milk cheese

Light-induced volatile compounds in goat cheese were studied by a combination of solid phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS), headspace oxygen depletion, and sensory evaluation. Samples stored under fluorescent light for 2 days at 30 degrees C had 90% more volatile compounds and 4 times more headspace oxygen depletion than samples stored in the dark at 30 degrees C. The volatiles 1-heptanol, heptanal, nonanal, and 2-decenal were formed and increased only in the light-stored samples, which may be formed from singlet oxygen oxidation of unsaturated fatty acids. Sensory evaluation showed that samples stored under light had significantly more off-flavor than samples stored in the dark at 30 degrees C (P < 0.05), and 1-heptanol, heptanal, nonanal, and 2-decenal increased the goat cheese off-flavor significantly (P < 0.05).     

Determination of key aroma compounds in the crumb of a three-stage sourdough rye bread by stable isotope dilution assays and sensory studies

An investigation of the volatile fraction of a freshly prepared sourdough rye bread crumb by means of the aroma extract dilution analysis (AEDA), followed by identification experiments, revealed 22 flavor compounds in the flavor dilution (FD) factor range of 128 to 2048. Quantitations performed by stable isotope dilution assays (SIDA) and a calculation of odor activity values (OAV; ratio of concentration to odor threshold) revealed the following as contributors to the overall crumb flavor: 3-methylbutanal (malty), (E)-2-nonenal (green, fatty), (E,E)-2,4-decadienal (fatty, waxy), hexanal (green), acetic acid (sour, pungent), phenylacetaldehyde (honey-like), methional (boiled potato-like), vanillin (vanilla-like), 2,3-butandione (buttery), 3-hydroxy-4,5-dimethyl-2(5H)-furanone (spicy), and 2- and 3-methylbutanoic acid (sweaty). Using either citrate buffer, starch, or deodorized crumb as model matrixes, the typical malty and sour rye bread crumb flavor was reproduced by adding a mixture of 20 reference odorants in the "natural" concentrations as quantitatively determined in the fresh crumb.