Grassy Odor Research Articles

Metabolomics reveals a differential attitude in phytochemical profile of black tea (Camellia Sinensis Var. assamica) during processing

Black tea's quality and flavor are largely influenced by its processing stages, which affect its volatile and non-volatile phytochemicals. This study aimed to optimized black tea manufacturing by investigating withering time, fermentation time, and temperature's impact on sensory quality. Using a U*15 (157) uniform design, optimal conditions were determined: 14 h of withering, 5.6 h of fermentation, and a 34 °C temperature. A verification experiment analyzed the volatile and non-volatile profiles. HPLC, GC–MS, and LC-MS revealed dynamic changes in phytochemicals. Among 157 VOCs and 2642 metabolites, 19 VOCs (VIP > 1.5) were crucial for aroma, while 50 (VIP > 1.5, p < 0.01) characteristic metabolites were identified. During processing, fragrant volatile compounds like linalool oxides, geraniol, benzeneacetaldehyde, benzaldehyde, methyl salicylate, and linalyl acetate increased, contributing to rose and honey like aromas. These changes were crucial in developing the characteristic flavor and color of black tea. Twenty-four new compounds formed, while 80 grassy odor volatiles decreased. Non-volatile metabolites changed notably, with decreased catechins and increased gallic acid. Theaflavin compounds rose initially but declined later. This study outlines metabolite changes in Yunkang 10 black tea, crucial for flavor enhancement and quality control.

Investigation of the Effect of Fragrance-Enhancing Temperature on the Taste and Aroma of Black Tea from the Cultivar Camellia sinensis (L.) O. Kuntze cv. Huangjinya Using Metabolomics and Sensory Histology Techniques

Huangjinya has recently seen widespread adoption in key tea-producing areas of China, celebrated for its unique varietal traits. Its leaves are also used to produce black tea with distinctive sensory characteristics. The fragrance-enhancing (EF) process is essential in crafting Huangjinya black tea (HJYBT) and is significant in flavor development. However, the impact of EF on non-volatile metabolites (NVMs), volatile metabolites (VMs), and their interactions remains poorly understood. This study aims to investigate how EF temperatures (60 °C, 70 °C, 80 °C, 90 °C, and 110 °C) influence HJYBT flavor transformation. Quantitative descriptive analysis revealed that EF improved the color, aroma, and appearance of tea leaves. Moreover, after an EF temperature of 80 °C, the HJYBT exhibited lower bitterness and astringency, whereas floral, sweet, and fruity aromas became stronger. However, when EF temperatures exceeded 90 °C, a pronounced burnt aroma developed, with HJYBT at 100 °C exhibiting caramel and roasted notes. Partial least squares discriminant analysis indicated that geraniol and linalool contribute to floral and fruity aromas, while 2-ethyl-6-methyl-pyrazine, furfural, and myrcene are key volatiles for caramel and roast aromas. Heptanal, methyl salicylate, α-citral, 1-hexanol, and (E)-3-hexen-1-ol were found to modify the green and grassy odor. Overall, HJYBT treated at 80 °C EF exhibited the highest umami, sweetness, floral and fruity aromas, and overall taste, exhibiting the least astringency, bitterness, and green and grassy notes. These results provide a significant theoretical basis for enhancing HJYBT quality and selecting the optimal EF method.

Characterizing and decoding the key odor compounds of Spirulina platensis at different processing stages by sensomics

Processing is an indispensable technology in the preparation of Spirulina platensis (S. platensis). The key odorants in liquids, muds, and powders from S. platensis (NM and GZ) were characterized. A total of 90 odorants were identified and 41 odorants were sniffed with the flavor dilution (FD) factors ranging from 1 to 729. Among them, nonanal, decanal, d-limonene, β-cyclocitral, and β-ionone with FD factors ≥1 were detected in S. platensis during the whole processing stages. In addition, heptanal, (E, E)-2,4-nonadienal, trans-4,5-epoxy-(E)-2-decenal, 1-hepten-3-one, isophorone, 3-ethyl-2,5-dimethylpyrazine, and α-ionone exhibited higher odor activity values in powders; β-myrcene, methional, and S-methyl methanethiosulphonate were key odorants in muds; while trans-3-penten-2-ol was key odorant in liquids. Besides, the GZ-mud presented stronger earthy and fishy odor than NM-mud. S. platensis powders have the stronger grassy odor, roasted odor, and marine odor than S. platensis muds. Overall, drying process promotes the formation of aldehydes, heterocyclic compounds, and terpenoids.

Sensory quality of emulsions prepared with the seaweed Ulva spp. or a derived protein ingredient

The sensory quality of seaweed, whether as a whole biomass or as a protein ingredient, plays a crucial role in its successful commercialization. This study explored the effect of different Ulva species, biomass washing, and pH-shift-based protein extraction on the sensory quality of emulsions with 0, 5, and 10 % oil. A trained panel assessed the sensory profile, complemented by analyses of volatile compounds, total ash, and amino acids. Saltiness emerged as the primary distinction between emulsions with unwashed U. linza and U. fenestrata, due to higher ash in the former. Washing U. fenestrata retained sensory qualities despite reduced ash and increased content of the lipid oxidation-marker pentanal. Protein extraction up-concentrated total amino acids 2.9-fold, and yielded emulsions with reduced particle sensation and grassy flavor, while bitterness, sourness, dark color, pentanal, hexanal, and 2-ethylfuran increased. Increased oil content of emulsions lowered their grassy odor which correlated with reduced hexanal content. Overall, these findings can contribute to the development of food products containing seaweed or protein ingredients thereof that match consumer preferences.

The effect of drying, cell disruption and storage on the sensory properties of Nannochloropsis sp.

Adding microalgae into food could strongly influence the flavor of the final product which is the key factor for consumer acceptation. To assist food processors in the development of tasteful food products containing microalgae, it is necessary to understand the impact of processing and storage on the flavor of freshly harvested microalgae biomass. In this study, the effect of commonly used drying techniques (freeze-drying, spray drying and thin-layer oven drying) and cell disruption (high pressure homogenization) on the sensory quality of fresh Nannochloropsis sp. biomass was investigated. Furthermore, the impact of storage on the flavor properties of intact (non-disrupted) and disrupted Nannochloropsis paste was examined. Sensory evaluation by a trained panel indicated that the flavor of Nannochloropsis was not affected by freeze-drying. Whereas thin-layer oven drying at 60 °C resulted in a strong bitter taste and a musty odor. This odor is positively correlated with volatile organic compounds (VOCs) including Strecker aldehydes that arise from the Strecker degradation in the course of the Maillard reaction. Spray drying reduced the odor intensity and grassy odor of Nannochloropsis which could be attributed to the loss of several VOCs including esters, saturated alcohols and dimethyl sulfide. Furthermore, cell disruption of Nannochloropsis using high pressure homogenization resulted in intense grassy and fish oil odors features due to high amounts of fatty acid-derived unsaturated aldehydes, ketones and alcohols. Finally, dark storage of fresh intact and disrupted Nannochloropsis paste at ambient temperature strongly impacts the volatile profile due to the rapid formation of several VOCs, which negatively impact the palatability of the Nannochloropsis biomass. Our results provide the basis to be applied in downstream food processing of harvested Nannochloropsis biomass in order to maintain or optimize the flavor properties for specific food products.

Potential of microalgae as flavoring agents for plant-based seafood alternatives

The aroma and taste of eight different phototrophic microalgae species were investigated and compared with five seaweeds to evaluate their potential as flavor ingredients in plant-based seafood alternatives. To assess their performance, commercial seafood flavoring products were used as a reference during the sensory evaluation and their chemical odor-active and taste-active profiles were compared with those of the algae. Stronger seafood odor and taste were observed in microalgae Rhodomonas salina, Tetraselmis chui and Phaeodactylum tricornutum compared to seaweeds which could be explained by the presence of important seafood aroma compounds (dimethylsulfide, fatty acids-derived compounds and trimethylamine) and taste compounds (glutamic acid, alanine, arginine and 5′-ribonucleotides). R. salina has potential as a plant-based seafood flavoring because of its crab aroma. P. tricornutum possess a high umami taste and shellfish flavor, however, its bitterness could be undesirable. T. chui is less bitter and characterized by high umami and seafood (crab, fishy) flavor, however, it possesses a slightly higher grassy odor.

Metabolite-Flavor Profile, Phenolic Content, and Antioxidant Activity Changes in Sacha Inchi (Plukenetia volubilis L.) Seeds during Germination.

Sacha inchi seeds are abundant in nutrients such as linolenic acids and amino acids. Germination can further enhance their nutritional and medicinal value; however, germination time is positively correlated with off-flavor in germinated seeds. This study investigated the changes in the metabolite and flavor profiles and evaluated the nutritional quality of sacha inchi seeds 8 days after germination (DAG). We also determined their phenolic content and antioxidant activity. We used gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography–mass spectrometry (GC-MS) and identified 63 metabolites, including 18 fatty acid methyl esters (FAMEs). FAMEs had the highest concentration in ungerminated seeds, especially palmitic, stearic, linoleic, linolenic, and oleic acids. Amino acids, total phenolic compounds (TPCs), and antioxidant activity associated with health benefits increased with germination time. At the final germination stage, oxidation products were observed, which are associated with green, beany, and grassy odors and rancid and off-flavors. Germination is a valuable processing step to enhance the nutritional quality of sacha inchi seeds. These 6DAG or 8DAG seeds may be an alternative source of high-value-added compounds used in plant-protein-based products and isolated protein.

Characteristic fingerprints and volatile flavor compound variations in Liuyang Douchi during fermentation via HS-GC-IMS and HS-SPME-GC-MS

The present study investigates volatile organic compound (VOC) compositional changes in Liuyang Douchi during fermentation via a HS-GC-IMS and HS-SPME-GC-MS combination approach. A total of 115 VOCs were identified from Douchi, most of which were accumulated during pile fermentation. Notably, most alcohols and acids decreased with fermentation, while esters, ketones, pyrazines, and phenols accumulated during pile fermentation. Depending on the VOCs identified by GC-IMS/MS, the different fermentation stages of Douchi could be facilely distinguished. Of these, 49 VOCs were regarded as the marker VOCs of Douchi in different fermentation stage: hexanol, hexanal, and propanoic acid was the marker VOCs of the black beans before fermentation and contributing beany and grassy odors; 1-octen-3-ol and 3-octanone supplying a mushroom aroma to the Douchi fermented for 3–9 days; and esters and pyrazine, especially ethyl acetate and 2,6-dimethylpyrazine, contributing the cocoa, fruity, and nutty aromas of matured Douchi.

Variation and mitigation of musty, septic, chemical, grassy, fishy odors and corresponding odorants in a full-scale drinking water treatment plant with advanced treatments

Ozone and biological activated carbon (BAC) are known to be effective at removing odors in drinking water. However, the specific variations in complex odors and odorants along the course of advanced treatments in full-scale drinking water treatment plants (DWTP) have remained unclear. In this paper, the migration of odors and odorants through pre-ozonation, sedimentation, post-ozonation, and BAC treatment processes were studied from January to December 2019 in a DWTP. The results indicated that septic, musty, and chemical odors with intensities of 6–6.7, 6–7.5, 4–5 could be removed by both ozonation and BAC, while grassy, fishy odors with intensities of 3.3–4.8, 2.3–5.8 could not be removed until the BAC step. Twenty-four odorants identified in raw water were classified as musty (2-methylisoborneol, geosmin), chemical (e.g. indane, eucalyptol), septic (e.g. dimethyl disulfide, pentanethiol), fishy (2,4-decadienal) and grassy (nonanal, decanal) odor compounds. It is noteworthy that eleven additional odorants were produced after ozonation; in addition, the concentrations of fishy and grassy odorants were increased after ozonation, and the concentrations of musty, septic, fishy, and grassy odorants were increased after sedimentation, suggesting that sedimentation and ozonation should be carefully managed. BAC was the most effective at removing the above odorants simultaneously. This study would be helpful for providing more insights into the migration of odorants along treatment processes and understanding the mitigation of odors in DWTPs using raw waters with complex odors.

Removal of Trans-2-nonenal Using Hen Egg White Lysosomal-Related Enzymes.

2-Nonenal is a long-chain aliphatic aldehyde containing nine carbons and an unsaturated bond. 2-Nonenal is the primary cause of odor associated with aging, with an unpleasant greasy and grassy odor. Lysosome, mitochondria, and peroxisome are significant organelles in eukaryotic cells that contain various hydrolases that degrade biomolecules. Proteins in mitochondria and peroxisome also contain aldehyde dehydrogenase. We performed trans-2-nonenal treatment using lysosomal-related enzymes extracted from hen egg white (HEW). As trans-2-nonenal is more structurally stable than cis-2-nonenal, it was selected as the target aldehyde. HEW contains various biologically active proteins and materials such as albumin, ovotransferrin, lysosome, peroxisome, and mitochondria. Here, complementary experiments were conducted to evaluate the role of lysosomal-related enzymes in the treatment of trans-2-nonenal. The activity of lysosomal-related enzymes was confirmed via antimicrobial test against E. coli. HPLC analysis was used to determine the reduction of trans-2-nonenal. The trans-2-nonenal treatment depended on the reaction time and enzyme concentration. Materials considered as an intermediate from trans-2-nonenal treatment were detected by GC/MS spectrometer. Under acidic conditions (pH 6), lysosomal-related enzymes were the most efficient in the treatment of trans-2-nonenal. Furthermore, based on differential pH testing, we found the conditions under which all the 50ppm trans-2-nonenal was removed. Therefore, our results suggest that the lysosomal-related enzymes reduced trans-2-nonenal, suggesting clinical application as anti-aging deodorants.

A systematic study on the odorants characterization and evaluation in a plain reservoir with wetlands ecosystem

The odor problems in plain reservoirs are more complex compared to valley reservoirs and ground water reservoirs. Just as YL Reservoir with wetlands ecosystem in Lixiahe Plain, Jiangsu Province has been suffering from complex odors, however, the odorants were unclear. In this study, a systematic study on odorants characterization and evaluation of plain YL reservoir was accomplished. Totally musty, septic, fishy, chemical and grassy odors were first identified simultaneously, twenty-four odorants were identified correspondingly. According to odor activity value ranking, 2-methylisoborneol and geosmin, with odor activity values of 14–18 and 2.5–3.8, were major musty odorants, while bis(2-chloroisopropyl) ether, dimethyl disulfide, dimethyl trisulfide, pentanethiol and indole, with odor activity values of 15.3–18.8, 1–1.3, 1.5–2.3, 2–3 and 0.7-0.9, were major septic compounds. Fishy and grassy odors were associated with 2,4-decadienal, hexanal, nonanal, decanal, benzaldehyde and β-cyclocitral, while chemical odor was related to indane, eucalyptol, 2-nitrophenol, 2-methylphenol, tetramethylpyrazine, 1,4-dichlorobenzene, p-xylene and ethylbenzene. By reconstituting tests, 98, 95, 88, 85 and 81 % of musty, septic, fishy, chemical and grassy characteristics in source water could be explained. It was notable that wetlands ecosystem has almost no effect on odor removal. This study would offer more understandings and supports for odors's control in such source waters.

Investigation of effect of antioxidant and antimicrobial agents on the quality of frozen crab gonads by E‐nose, GC‐MS, and sensory evaluation

The aim of present study was to estimate the synergistic effect of antioxidant and antimicrobial agents on the quality of frozen crab gonads in terms of parameters including lipid oxidation analysis, total volatile basic nitrogen (TVBN) content, total viable counts (TVC), volatile odor (by E-nose and SPME-GC-MS), and sensory evaluation. Aqueous ginger extract (GE), nisin (N), and tea polyphenols (TP) were applied alone and in combination (GE+N) to cooled crab gonad, and stored at −19°C under vacuum packaging for 60 days. Results showed that, lipid oxidation and formation of total volatile based nitrogen and total microbial viable counts were effectively suppressed by the application of combination of N and GE compared to controls (air and vacuum packed without additives). The E-nose was used to analyze the effectiveness of the treatments and compared with HS-SPME-GC-MS volatile profile and microbial analysis. The odor activity value (OAV) (summations of aroma active compounds) in the combined treatment decreased significantly, especially trimethylamine and ethylamine with ammonia odor, hexanal, (Z)-4-heptenal, 1-octen-3-ol, and (E, E)-2, 4-heptadienal with fishy odor, octanal, and (E, Z)-2, 6-nonadienal with grassy odor, (E)-2-decenal with earth odor. A 73 volatile components and 20 aroma-active compounds (AACs) were identified by HS-SPME-GC-MS in the sample aroma profiles. The results of GC-MS presented a good accordance with those of sensory assessment using e-nose in differentiating odor profiles. Practical applications GE showed best antioxidant activity against lipid oxidation compared with N and TP during frozen storage of crab gonad, while N inhibited the formation of TVBN and TVC most effectively. On the contrary, the combined use of GE and N in frozen storage could show a synergistic effect in promoting quality parameters and odor profiles of crab gonad. The information obtained from this work can be as the basis for further mass production of frozen crab gonads with excellent quality.

Grassy Odour in Beef

The quality of beef is given by a number of factors whereas the most important are considered the texture properties and the odour [1].

Evaluation of Late-Maturing Peach and Nectarine Fruit Quality by Chemical, Physical, and Sensory Determinations

In this work, both analytical and sensory determinations were carried out to evaluate the quality of yellow (‘Summerset‘, ‘Tardiva 2000‘, ‘Fairtime’, ‘Guglielmina’) and white flesh (‘Daniela’) late-ripening peach and nectarine (‘California’ and ‘Fairlane’) cultivars. Analytical measurements included weight, diameter, soluble solid content, titratable acidity, pH, and peel color. To describe and quantify the peach and nectarine sensory profile, a panel of 10 judges generated 15 descriptors. According to univariate analysis of fruit quality attributes, ‘Fairtime’, ‘Summerset, ‘Daniela’, and ‘California’ produced large and attractive fruits with an extensive red peel color. On the other hand, ‘Guglielmina’, ‘Daniela’, ‘Tardiva 2000’, and ‘Fairlane’ produced superior quality fruit in terms of soluble solids, titratable acidity, sweetness, and flavor. The white flesh peach ‘Daniela’ produced fruits with the best balance between external and internal quality. Cluster analysis on standardized component coordinates from biplot analysis allowed for the identification of two main groups. One group included ‘Daniela’, ‘Guglielmin’, ‘Tardiva 2000’, and ‘Fairlane’, along with attributes that are more indicative of ripe fruit such as soluble solids, sweetness, sugar/acid, juiciness, ground color index, peel color uniformity, flesh color intensity, mealiness, peach odor and flavor, and flower odor and flavor. The other group included ‘Summerset’, ‘Fairtime’, and ‘California’ along with weight, diameter, consistency, flesh firmness, percentage of cover color, bitterness, titratable acidity, sour odor and flavor, and grassy odor and flavor. The dual approach adopted in this study indicates that cultivars with large and attractive fruits are often lacking real eating quality. This poses serious doubts on the real value of exterior appearance for recognizing high-quality peaches and nectarines.

GC–MS-based metabolomic study reveals dynamic changes of chemical compositions during black tea processing

The chemical composition of black tea during tea processing is in a state of flux. However, the dynamic changes of this sophisticated metabolic process are far from clear. GC–MS-based metabolomic analyses were performed to examine changes in volatile and non-volatile compounds throughout the five stages of tea processing. The results showed that the most striking differences were observed at the withering and rolling stages, during which 62 non-volatile and 47 volatile compounds were significantly changed. The levels of most monosaccharides decreased at the withering stage and increased in subsequent stages while di-saccharides decreased as the process progressed. Free amino acids increased sharply at the withering stage, and most kept increasing or remained stable afterwards. However, levels of catechin, epicatechin, epigallocatechin, and epigallocatechin gallate decreased after withering and remained at low levels afterwards. Among the 47 volatile compounds with altered levels, phenylpropanoids/benzenoids and carotenoid-derived volatiles, which contribute to the honey-like and rose-like fragrances and quality of Danxia2 tea, kept increasing during the processing, among them eight were newly produced. Furthermore, 19 volatiles with a grassy odor decreased during processing. This study provides a comprehensive profile of metabolic changes during black tea processing, which is potentially important for both quality control and improvement of the flavor of black teas.

Characterization of odor-active compounds in three varieties of ciruela (Spondias purpurea L.) fruit

ABSTRACTThe aroma-active compounds present in tree ripened fruits of ciruela (Spondias purpurea L.) cultivars Chi abal, Campech abal, and Ek abal were isolated by means of simultaneous distillation solvent extraction and solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Application of odor activity values (OAV) afforded 22 compounds in higher amounts than their threshold concentrations (OAVs >1). Results of the identification experiments in combination with the OAVs suggested that methyl 3-methylbutanoate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl hexanoate, hexyl acetate, with fruity odor notes; (E)-2-hexenal, (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, 1-hexanol, and (Z)-3-hexenyl acetate, with grassy odor notes, and limonene (citrus-like) were the potentially important common odorants in all ciruela cultivars. Clear differences in the OAVs of some odorants between each of the cultivars suggested that they contributed to the unique sensory profiles of the individual cultivars.

Lipidomics analysis unravels the effect of nitrogen fertilization on lipid metabolism in tea plant (Camellia sinensis L.)

BackgroundNitrogen (N) plays an important role in the formation of tea quality-related compounds, like amino acids and flavor/aroma origin compounds. Lipids, which have been reported to be affected by N deficiency, are precursors to the generation of flavor/aroma origin compounds in tea plant. However, there is no literature about the lipid profiles of tea plant affected by N fertilization. Hence, we hypothesize that the biosynthesis of flavor-related compounds in tea was affected by N through its regulation of lipid metabolism.ResultsIn this study, mature leaves and new shoots of tea plant grown under three N levels at the rates of 0, 285 and 474 kg/ha were applied for ultra-performance liquid chromatography-mass spectrometry (UPLC/MS) based lipidomic analysis. Totally, 178 lipid species were identified. The results showed that the composition of lipid compounds in mature leaves and new shoots varied dramatically, which was also affected by N levels. The higher content of the storage lipid TAG and higher carbon (C)/N ratio in mature leaves than that of new shoots in tea plants grown under low N level (0 kg/ha) suggested that tea plants could remobilize the C stored in TAG to maintain their C/N balance and help to improve the quality of tea. N fertilization resulted in a higher content of the compounds 36:6 MGDG and 36:6 DGDG. Since these compounds contain linolenic acid (18:3), a precursor to the formation of aroma origin compounds, we suggested their increase could contribute to the quality of tea.ConclusionsTaken together, the present work indicated that appropriate application of N fertilizer could balance the lipid metabolism and the formation of flavor/aroma origin compounds, which help to improve the quality of tea. Moreover, excess N fertilization might deteriorate the aroma quality of made tea due to increases of precursors leading to grassy odor.

Characterization of important odorants in steamed male Chinese mitten crab (Eriocheir sinensis) using gas chromatography-mass spectrometry-olfactometry.

Chinese mitten crab (Eriocheir sinensis) from Yangcheng Lake in Jiangsu Province is a popular species due to its unique pleasant aroma and intensive umami taste. In this study, odorants in steamed male E. sinensis were investigated using the headspace-monolithic material sorptive extraction technique coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A total of 74 volatile compounds were found, and the results of the GC-MS-O analysis, combined with odor activity values, showed that trimethylamine (fishy, ammonia-like odor), (Z)-4-heptenal (mushroom-like odor), and benzaldehyde (paint-like odor) were the important odorants (IOs) in all 4 of the edible parts of steamed male E. sinensis. Furthermore, heptanal (mushroom-like odor) was common to the abdomen, claw, and leg meat but was not found as the IO in the gonad. The abdomen meat also contained 3-methylbutanal (vegetable-like, grassy odor), while 2 additional IOs were found in claw meat (2-methylbutanal, which has a mushroom odor and 3-ethyl-2,5-dimethylpyrazine, which has a chocolate-like, musty odor). Another IO (2-nonanone, chocolate-like odor) was also found in leg meat, while (E)-2-nonenal (green, fruity odor) was the IO found exclusively in the gonad.

Effects of binary organic solvents and heating on lipid removal and the reduction of beany odour in Bambara groundnut (Vigna subterranean) flour

Effects of various binary organic solvents at different temperatures on the removal of lipids and beany or grassy odour of Bambara groundnut flour were studied. The highest lipid removal was achieved at 60°C (P<0.05), regardless of binary organic solvents used. Under the optimal temperature, chloroform/methanol showed the highest lipid removal (87%), followed by hexane/isopropanol (78%). All binary solvents containing methanol had higher efficiency in removal of phospholipids, and inactivation of lipoxygenase and trypsin inhibitors, as compared to isopropanol containing solvents (P<0.05). Based on FTIR spectra, lipids removed by methanol containing solvents had high content of phospholipids. The flours defatted by methanol containing solvents exhibited the lowest peroxide value, thiobarbituric acid-reactive substances and beany odour intensity than the non-defatted flour and those defatted by isopropanol containing solvents throughout the storage (P<0.05) of 30days at refrigerated and room temperatures. In general, chloroform/methanol was the most effective in inactivating lipoxygenase and trypsin inhibitors, retarding lipid oxidation as well as beany odour development in flour. Therefore, chloroform/methanol could be used to lower beany or grassy odour in Bambara groundnut flour.

Evaluation of Volatiles from Ampelopsis brevipedunculata var. heterophylla Using GC-Olfactometry, GC-MS and GC-pulsed Flame Photometric Detector

Ampelopsis brevipedunculata var. heterophylla is extensively cultivated in Asia, and the dried leaves and branches have a characteristic odor and have been used as a tea. To investigate the odorants contributing to the characteristic odor of A. brevipedunculata var. heterophylla, the aroma extraction dilution analysis method was performed through gas chromatography olfactometry. In addition, volatile sulfur compounds were evaluated using pulsed flame photometric detector. As a result, 86 compounds were identified in the oils of leaves and 78 in branches, accounting for 80.0% and 68.3%, respectively, of the compounds identified. The main compounds in the essential oil of leaves were palmitic acid (12.5%), phenylacetaldehyde (4.1%) and hexahydrofarnesyl acetone (3.9%). On the other hand, the essential oil of branches contained palmitic acid (12.7%), terpinen-4-ol (4.4%) and α-cadinol (3.7%). The total number of odor-active compounds identified in the leaf and branch oils was 39. The most odorous compounds of leaves and branches of A. brevipedunculata var. heterophylla were (E, Z)-2,6-nonadienal (melon, green odor), (E)-2-nonenal (grassy odor), phenylacetaldehyde (honey-like) and (E)-linalool oxide (woody odor).