Insights into the flavor endowment of aroma-active compounds in cloves (Syzygium aromaticum) to stewed beef.

Clove (Syzygium aromaticum) is one of the most commonly used spices in stewed beef to enrich and improve its aroma during the stewing process. Gas chromatography ion mobility spectroscopy (GC-IMS), Q Exactive GC-Orbitrap-MS-O (QE-GC-MS/O), combined with sensory evaluation were employed to analyze the flavor endowment of aroma-active compounds in cloves to stewed beef. A total of 173 volatiles were identified in the clove powder (CP), stewed beef with clove (SBC), and stewed beef with salt (SBS), of which 21 volatiles were considered as aroma-active compounds. The concept of flavor endowment of aroma-active compounds in cloves was defined innovatively, and the endowment rate values (ERVs) of stewed beef were calculated. Nine aroma-active compounds in cloves were found to have a flavor endowment effect on stewed beef, while the terpenoids exhibited high ERVs. Despite the low ERV of eugenol, it still significantly impacted the aroma profile of SBC due to its high odor activity value (OAV) and flavor dilution (FD) factor. These volatiles offered mainly the clove, herbal, anise, and floral odor to stewed beef, which was also confirmed by sensory evaluation. These findings indicated that the terpenoids, phenolics and ethers in cloves had a significant influence on the overall aroma of stewed beef through the flavor endowment, which contributed to the precise use of cloves and improved the aroma of stewed beef.

Interaction between a Lactococcus lactis autochthonous starter and a raw goat milk microbial community during long-term backslopping.

Traditional cheesemaking processes often involve backslopping practice. However, over successive inoculations, acidification deficiencies may arise. In such cases, adding a starter is recommended to restore the ecosystem stability. This study examines the impact of an autochthonous starter composed of three Lactococcus lactis strains on a raw goat milk microbial community during their evolution. Bacterial composition and technological features (acidification and aroma) were analyzed during communities' evolution over 800 generations. 16S rRNA gene metabarcoding showed that Lactococcus lactis strains predominated. The raw goat milk community acidification capacities varied early in the evolution and then remained stable. Adding the L. lactis starter to this community stabilized the ecosystem from the beginning of the evolution. The acetoin production was associated with the starter presence, consistent with the establishment of the diacetylatis biovar strain from the starter in the raw goat milk community throughout the evolution. Increased or decreased production of some volatile organic compounds when the starter was added revealed a specific aroma footprint due to interactions between the two communities. This study showed that adding a starter could help to achieve the maximum acidification rate from the early inoculation cycles and could significantly modify the aroma profile during long-term backslopping.

Effect of hot-air drying processing on the volatile organic compounds and maillard precursors of Dictyophora Rubrovalvata based on GC-IMS, HPLC and LC-MS.

The dynamic changes in volatile organic compounds (VOCs), reducing sugars, and amino acids of Dictyophora rubrovalvata (DR) at various drying temperatures were analyzed using GC-IMS, HPLC, and LC-MS. Orthogonal partial least squares discriminant analysis (OPLS-DA) combined with VOCs indicated that drying temperature of 80 °C was optimal. Variable importance in the projection (VIP) and relative odor activity value (ROAV) were employed to identify 22 key VOCs. The findings suggested that esters played a predominant role among the VOCs. Pearson correlation analysis revealed that serine (Ser), glutamine (Gln), lysine (Lys), alanine (Ala), threonine (Thr), glutamic acid (Glu), asparagine (Asn), ribose, and glucose were closely associated with the formation of esters, aldehydes, ketones, pyrimidines, and pyrazines. In conclusion, this study laid a foundational theory for elucidating the characteristics aroma substances and their production pathways, providing a valuable reference for analysing the flavor characteristics of DR.

Decoding of the enhancement of saltiness perception by aroma-active compounds during Hunan Larou (smoke-cured bacon) oral processing.

The enhancement of saltiness induced by odrants perceived from the retronasal cavity during Larou oral processing was analyzed. During the oral processing of Xiangtan Larou, the smoky attribute was the dominant when chewing 0-15 times, followed by the savory (15-24 times) and meaty (24-42 times). Partial least squares analysis predicted 33 aroma compounds from the retronasal cavity significantly (p < 0.05) contributing to the aroma perception. A total of 12 aroma compounds with saltiness-enhancement ability were confirmed by odorant-NaCl mixture model experiments. Results revealed that 2-methoxy-4-vinylphenol (1.00-1000.00 µg/L) had the strongest enhancing effect on saltiness at NaCl (2969.85 mg/L), followed by diallyl sulfide (0.156-2.50 µg/L), 2,5-dimethylthiophene (0.156-50.00 µg/L), 2,6-dimethylphenol (1.00-100.00 µg/L), 2,5-dimethylpyrazine (0.391-50.00 µg/L), and 2,3-butanedione (0.50-100.0 µg/L). The sulfur-containing, nitrogen-containing, and phenolic odorants with savory, roasty, sulfide, meaty or smoky, attributes showed the better ability in saltiness enhancement.

Changes in volatile flavors during the fermentation of tomato (Solanum lycopersicum L.) juice and its storage stabilization.

Flavor is a crucial indicators of the quality of fermented tomato juice; however, there has been limited research in this area. Herein, headspace solid-phase microextraction gas chromatography-mass spectrometry was used to analyze the volatile metabolites at different stages during FTJ fermentation. 131 volatile organic compounds (VOCs) were identified, with alcohols, acids, and esters as the main compounds. The content of superoxide dismutase (SOD) and lycopene (LYC) had a positive correlation with methyl salicylate, ethyl acetate, and linalyl acetate. Subsequently, the storage stability of FTJ was evaluated at temperatures of 4 °C, 25 °C, and 37 °C over a period of 45 d, revealing that the quality of FTJ decreased with increasing storage temperature. The shelf life of FTJ under different storage conditions was determined using SOD activity and LYC content as quality indicators. The final shelf life was 47 d at 37 °C, 69 d at 25 °C, and 123 d at 4 °C.

Enhancing variety aromatic characteristics of Muscat wine through cold maceration with indigenous cryotolerant Metschnikowia pulcherrima Mp0520.

Cold maceration (CM) is widely applied in winemaking to improve wine aroma and overall quality. However, more efficient CM techniques for industrial-scale winemaking are still needed. This study examined the impact of CM with indigenous cryotolerant Metschnikowia pulcherrima Mp0520 (Mp-CM) on the Muscat wine aromatic characteristics. The results demonstrated a significant divergence in the types and concentrations of aroma compounds between Mp-CM wine and the control. The Mp-CM wine exhibited a significantly higher terpenes content, resulting in a Muscat wine characterized by terpenes, compared to the control predominated by esters. Additionally, the Mp-CM wine demonstrated elevated levels of α-terpineol and terpinolene, potentially enhancing the varietal aroma stability of Muscat wine. Furthermore, Mp-CM gave Muscat wine a heightened fruity aroma and a more complex aroma. These findings suggested that the Mp-CM utilized in this study offered promising avenues for enhancing the variety aroma characteristics of Muscat wine on large scale winemaking.

Investigation of the aroma profile and blending strategy of Lu'an Guapian teas during grain rain period by sensory evaluation combined with SBSE-GC-MS, GC-O and OAV.

Grain Rain Period (GRP), one of the 24 solar terms in China, signifies a crucial phase for the transformation of tea quality, especially for Lu'an Guapian (LAGP) tea. During GRP, LAGP teas showed 3 distinct aroma profiles, each spanning 3-4 days. Specifically, the sensory evaluation result revealed that LAGP tea exhibited stronger flowery and fresh aromas in the early phase, with the soybean-like aroma significantly intensifying as the harvest period progressed during GRP. Furthermore, the key contributors to the aroma profile and its variation during GRP were identified as indole, δ-decalactone, geraniol, linalool, decanal, jasmone, (E)-ß-ionone, benzeneacetaldehyde, dihydroactinolide, nonanal, octanal, (E)-isoeugenol, (E,E)-2,4-nonadienal, 4-ketoisophorone, (E,Z)-2,6-nonadienal, and 1-octen-3-one. Additionally, we proposed a binary blending strategy using sensory evaluation with the methods of triangle test and normal distribution fitting to predict the blending threshold accurately. This study elucidated the dynamics of LAGP tea aroma during GRP and offered insights for tea blending optimization.

Exploring the effect of greenhouse covering cultivation on the changes of sensory quality and flavor substances of green tea.

To protect tea plant (Camellia sinensis (L.) O. Kuntze) from freezing injury, plastic greenhouse covering is widely used in northern tea areas of China. Currently, there was few researches about the effect of greenhouse covering on tea quality. Our results showed greenhouse covering increased tea yield, changed leaf phenotype and decreased green tea quality. Further analysis revealed greenhouse increased the content of soluble sugars and decreased the content of EGCG and 14 amino acids. Besides, there were 223 differential volatile components were identified in green tea produced by fresh leaves with plastic greenhouse covering (GT) and green tea produced by fresh leaves without plastic greenhouse covering (TT). 81 key aroma components were contributors to the bean-like aroma of TT. 98 key aroma components contributed to the clean aroma of GT. Based on these results, the flavor wheels were constructed, providing a visual presentation of flavor between TT and GT.

Characterization of Important Odorants in Dried Lobster Mushrooms.

Lobster mushrooms, a type of wild edible mushroom that primarily grows in North America, have a distinctive aroma resembling seafood and are highly desired by fine dining establishments and food enthusiasts. Lobster mushrooms have a short collection season; therefore, they are usually dried for a year-round sale. Owing to their rising popularity, lobster mushrooms have become one of the most expensive mushroom species in the dried mushroom market. Herein, 35 odorants were identified from dried lobster mushrooms using solvent assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA). Fourteen odorants were quantitated using stable isotope dilution assays (SIDA), and their odor activity values (OAVs) were calculated. Eleven of the quantitated odorants exhibited OAVs of ≥1. Some notable odorants with relatively high OAVs included 2-acetyl-1-pyrroline (OAV 730), γ-nonalactone (OAV 410), 1-octen-3-one (OAV 180), and sotolon (OAV 170). The organohalogen molecule 2,6-dichlorophenol was determined to be key to the seafood aroma character of the mushrooms. An aroma simulation model formulated based on the quantitation data closely matched the aroma profile of the dried mushrooms. This study lays the groundwork for future studies aimed at understanding the effect of processing on lobster mushroom aroma chemistry and the biotechnological production of natural seafood flavors.

Discriminating three lab scale dark chocolate bars from fine Cameroon cocoa hybrids using sensorial evaluation and organic acid content.

Previous studies have shown a correlation between chocolate sensory profile and certain (bio)chemical components. The aim of this study was to examine the sensorial profile and organic acid content of three lab scale chocolate brands produced from different cocoa genotypes. The sensorial evaluation was examined by a team of 12 panelists and evaluation of aroma volatiles was done by means of HS-SPME-GC-MS. On the other hand, organic acids were assessed using a high-performance ion chromatography coupled with an electrochemical detector (HPIC-ED). Results showed a variability in sensorial profile: SCA12×ICS40 chocolate (vanilla/sweet, spicy, and floral), ICS40 × SCA12 chocolate (fruity, bitter, and dry) and SNK16 × T60/887 chocolate (chocolate, honey-like, woody, sweet). Moreover, some aroma volatiles like (2-methyl, 3-methyl, iso) butanal (ICS), terpenes (SCA), and ketones (acetophenone and 2-nonanone) (SNK) allowed to discriminate dark chocolate sample according to their raw cocoa genetic group. Besides, the organic acid content differed from one chocolate brand to another, and it was obtained a high content of oxalic acid and a low lactic acid content which are good indicators of chocolate quality. Results of the current study highly recommend knowing the variety of cocoa beans with high content of some volatiles and high oxalic and low acetic acid and lactic contents to produce high aromatic (special flavor) chocolates.

Comparative study of volatile compounds of cold-pressed oils extracted from three different oilseeds after gamma irradiation.

To investigate the effect of gamma irradiation on the volatile compounds of edible oils. Three types of oilseeds, including peanut, sesame, and flaxseed, were subjected to 8 kGy gamma irradiation, followed by cold pressing to extract their oils. The volatile compounds of the oils were isolated by simultaneous distillation extraction and analyzed by gas chromatography-mass spectrometry. A total of 91 volatile compounds were identified, which can be grouped into eight categories: hydrocarbons, aldehydes, ketones, alcohols, acids, esters, furans, and benzene derivatives. Irradiation treatment resulted in a significant increase in the levels of hydrocarbons, aldehydes, and ketones in all oil samples (p < 0.05), with the greatest increase observed in hydrocarbons (4-14 times). In contrast, changes in alcohols, acids, esters, furans, and benzene derivatives were related to oilseed type. The increased hydrocarbons mainly originated from the degradation of palmitic, stearic, oleic, and linoleic acids. The irradiation resistance of the three oilseeds varied considerably, in the order: flaxseed > sesame > peanut. Based on the odor activity value, 11 key aroma compounds were selected, and (E)-2-decenal (tallow, oily, and orange), 1-octanol (soapy and oily), and 1-nonanol (floral and soapy) were only detected in the irradiated samples. Principal component analysis revealed that the oil samples of the three oilseeds could be well classified based on their key aroma compounds, and that the irradiation treatment had no remarkable effect on their intrinsic aroma.

Characterization of Potent Odorants Causing an Oily Odor in Rice-Made Baijiu by Comparative Aroma Extract Dilution Analysis, Quantitative Measurements, and Aroma Addition and Omission Studies.

The presence of an oily odor in rice-made Baijiu is a unique characteristic that has not been thoroughly studied. This study qualitatively and quantitatively identified important aroma-active compounds in samples with typical and atypical oily odors using aroma extract dilution analysis (AEDA). By comparing the differences between flavor dilution (FD) and odor activity values (OAVs), nine compounds showing significant differences were selected. By combining normal-phase silica gel column and sensory analysis, these nine potential oily odor compounds were isolated from the typical oily odor sample. Addition and omission experiments confirmed that hexanal, trans-2-heptenal, trans,trans-2,4-nonadienal, (2E)-2-decenal, trans,trans-2,4-decadienal, and γ-nonanolide are key contributors to the oily odor.

Unlocking the potential of Kluyveromyces marxianus in the definition of aroma composition of cheeses.

Introduction: The cheese microbiota is very complex and is made up of technologically-relevant, spoilage, opportunistic and pathogenic microorganisms. Among them lactic acid bacteria and yeasts are the main ones. One of the most interesting dairy yeasts is Kluyveromyces marxianus because of its technological properties including the ability to produce aroma compounds. Methods: This study investigated the contribution of Kluyveromyces marxianus to the gross composition and aroma profile of cow cheeses. Experimental cheeses were prepared by inoculating a co-culture of K. marxianus FM09 and a commercial strain of Lacticaseibacillus casei and compared with cheeses obtained with only L. casei. The gross composition was determined by a FoodScan™ 2 Dairy Analyser, and free amino acids were evaluated at 507 nm after reaction with Cd-ninhydrin. The volatile organic compounds were extracted by head-space solid phase micro-extraction and analyzed by gas chromatography-mass spectrometry coupled with odor activity values. qRT-PCR was applied to determine the expression of genes involved in esters synthesis and degradation. Results: The inoculation of K. marxianus induced an increase of pH and a reduction of protein content of cheeses, in agreement with the stronger proteolysis detected in these cheeses. K. marxianus influenced the content of aroma compounds both quantitatively and qualitatively. In particular, an increase of higher alcohols, esters and organic acids was observed. Moreover, 12 compounds were detected only in cheeses obtained with the co-culture. These differences were in agreement with the odor activity values (OAV). In fact, only 11 compounds showed OAV > 1 in cheeses obtained with the commercial strain, and 24 in those obtained with the co-culture. The qPCR analysis revealed an over expression of ATF1, EAT1, and IAH1 genes. Conclusion: Kluyveromyces marxianus could act as an important auxiliary starter for cheese production through the development and diversification of compounds related to flavor in short-aged cow cheeses.

Olfactory perception complexity induced by key odorants perceptual interactions of alcoholic beverages: Wine as a focus case example.

The odorants in alcoholic beverages are frequently experienced as complex mixtures, and there is a complex array of influence factors and interactions involved during consumption that deeply increase its olfactory perception complexity, especially the complexity induced by perceptual interactions between different odorants. In this review, the effect of olfactory perceptual interactions and other factors related to the complexity of olfactory perception of alcoholic beverages are discussed. The classification, influencing factors, and mechanisms of olfactory perceptual interactions are outlined. Recent research progress as well as the methodologies applied in these studies on perceptual interactions between odorants observed in representative alcoholic beverages, especially wine, are briefly summarized. In the future, unified theory or systematic research methodology need to be established, since up to now, the rules of perceptual interaction between multiple odorants, which is critical to the alcoholic beverage industry to improve the flavor of their products, are still not revealed.

The tea cultivar 'Chungui' with jasmine-like aroma: From genome and epigenome to quality.

'Chungui' is a newly promoted tea cultivar in China, renowned for producing oolong tea with a distinctive jasmine-like aroma. However, the genetic basis of this unique aroma remains unclear. In this study, the 'Chungui' genome, one of the most complete and well-annotated tea genomes, was assembled using PacBio HiFi reads and Hi-C sequencing. Through comparative analysis with typical jasmine flower volatiles, eight core compounds responsible for this aroma were identified. Further research revealed that the jasmine-like aroma in 'Chungui' is regulated by a coordinated mechanism involving a significant increase in chromatin accessibility and the demethylation of CHH and CHG in the promoter regions of key aroma-related genes during oolong tea processing. The study proposes that the formation of this unique aroma is driven by the synergistic effect of enhanced chromatin accessibility and reduced methylation, which together lead to the robust upregulation of genes involved in the biosynthesis of these core aroma components. These results provide a molecular foundation for understanding the unique jasmine-like aroma of 'Chungui' tea and sets the stage for future studies to explore the roles of these regulatory mechanisms in aroma formation.

Development of analytical "aroma wheels" for Oolong tea infusions (Shuixian and Rougui) and prediction of dynamic aroma release and colour changes during "Chinese tea ceremony" with machine learning.

The flavour of tea as a worldwide popular beverage has been studied extensively. This study aimed to apply established flavour analysis techniques (GC-MS, GC-O-MS and APCI-MS/MS) in innovative ways to characterise the flavour profile of oolong tea infusions for two types of oolong tea (type A- Shuixian, type B- Rougui). GC-MS identified 48 aroma compounds, with type B having a higher abundance of most compounds. GC-O-MS analysis determined the noticeable aroma difference based on 20 key aroma compounds, facilitating the creation of an analytical "Aroma Wheel" with 8 key odour descriptors. APCI-MS/MS assessed real-time aroma release during successive brews linked with the "Chinese tea ceremony" (Gongfu Cha). Multivariate Polynomial Regression (MPR) and Long Short-Term Memory (LSTM) network approaches were applied to aroma and colour data from seven successive brews. The results revealed a progressive decline in both colour and aroma with seven repeated brews, particularly notable after the fourth brew.

Exploring the possible mechanisms of X-rays treatment for retention aroma volatiles in shiitake mushrooms during low temperature storage.

X-rays irradiation has been demonstrated to effectively preserve the freshness of edible fungi and delay the loss of aroma during storage. In this study, shiitake mushrooms were irradiated with X-rays dose of 0.5 kGy and stored at 2 °C for 35 days. Non-irradiated mushrooms were recorded as control group. Results indicated that 0.5 kGy X-rays treatment preserved the flavor quality by exhibiting higher volatile substance content in shiitake mushrooms. X-rays treatment promoted the activities of lipoxygenase (LOX) and alcohol dehydrogenase (ADH) and oxidation of linoleic acid. In addition, the degradation of methionine and cysteine was facilitated by X-rays. Higher enzymes activities for γ-glutamyl transpeptidase (GGT) and cystine sulfoxide lyase (CS lyase) were found in 0.5 kGy X-rays irradiated mushrooms. These findings suggest that the retention of mushroom flavor by X-rays treatment is closely related to fatty acid metabolism, sulfur-containing amino acid metabolism, and lentinic acid metabolism.

Effects of the extrusion conditions, the addition of oil and the food matrix on the physical and sensory characteristics of pre-extrusion flavored products.

Thermoplastic extrusion is important in processing a wide variety of food products. In this paper, the effects of different extrusion conditions, addition of vegetable oil and the food matrix itself on the physical and sensory characteristics of corn snacks and meat analogs were evaluated. Cysteine and butyric acid (cheese aroma precursors) and thiamine (a meat aroma precursor) were added to corn grits and soy protein concentrate, respectively, before extrusion. For each matrix, three combinations of moistures of the raw material and extrusion temperatures were used and, after extrusion, vegetable oil was added to one portion of each product and not to another one. The extrusion conditions and the addition of oil affected the physical properties and sensory characteristics of corn snacks more while they had less influence on the properties of the meat analogs. There were similar correlations between the physical and sensory variables, independent of the food matrix used. The sensory acceptance stood out for samples from intermediate and less severe extrusion conditions and with added oil, showing that these factors have an impact on the physical properties and sensory characteristics, with little effect from the food matrix. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05985-3.

Unraveling Shengmuxiang in Jiang-flavor base baijiu using a combination of metabolomics and sensomics strategy.

Shengmuxiang (SMX), an important aroma in Jiang-flavor base baijiu, significantly influences the quality of the product. This study employed untargeted metabolomics combined with sensomics to explore the key compounds responsible for SMX. Results indicated that SMX samples had higher intensities of green and woody-like odors compare to control samples. A total of 87 aroma compounds were identified by headspace solid phase microextraction combined with gas chromatography-mass spectrometry technology. Based on the variable projection importance, PCA and OPLS-DA were employed to identify 22 potential marker compounds. Quantitative results combined with hierarchical cluster and OAV analysis revealed that 9 aroma compounds (OAV > 1) had high concentrations in SMX samples. Aroma recombination and omission experiments further indicated that acetaldehyde and acetal were the key compounds responsible for the characteristic aroma of SMX in Jiang-flavor base baijiu. These findings provide valuable insights into the distinct aroma profile of SMX and offer a basis for quality control of Jiang-flavor base baijiu.

Unravelling the formation of characteristic aroma of traditional braised pork through untargeted and targeted flavoromics.

Untargeted flavoromics and targeted quantitative analysis of key aroma compounds, and analysis of dynamic change of aroma precursors concentration were used to investigate the aroma evolution of traditional braised pork and the underlying mechanism. The results indicated that lipid oxidation dominated at early cooking stage (0th-45th min), resulting in an increased concentration of most aldehydes, alcohols, ketones, such as hexanal, heptanal, octanal, nonanal, (E)-2-octenal, benzaldehyde, 1-octen-3-ol, and 2,3-octanedione, accompanied with an enhanced unpleasant fatty odor. From 45th to 73rd min, the seasonings alleviated excessive oxidation of unsaturated fatty acids accompanied with decreased aldehydes. Moreover, the diffusion of glucose and amino acids from seasonings to lean meat promoted the consumption of endogenous ribose and amino acids in meat through Maillard reaction, and facilitated the formation of dimethyl trisulfide, dimethyl disulfide, methanethiol, and 2-furfural, which contributed to the meaty, sauce-like, and sweety aroma, thus formed the characteristic aroma of traditional braised pork.