Volatile Flavor Compounds Research Articles

Assessment of Greenness for Solid Phase Microextraction Techniques of Sample Preparation for Flavors by AGREE Prep & SPMS Tools

Assessing the greenness of sample preparation techniques is essential due to the use of various solvents, chemicals, reagents, sorbents, pH adjustments, and energetic inputs. Solid-Phase Microextraction (SPME) is preferred over traditional flavor extraction methods such as Simultaneous Distillation Extraction (SDE) and Solvent-Assisted Flavor Evaporation (SAFE) because of its sensitivity, efficiency, speed, versatility, and economy. SPME fibers coated with stationary phases can extract volatile and semi-volatile flavor compounds from food samples, which are then desorbed and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). This article provides an assessment of the greenness of 50 SPME techniques for flavor analysis using the AGREE Prep and Sample Preparation Metric of Sustainability (SPMS) tools. This evaluation offers valuable insights into the environmental impact and sustainability of SPME as sample preparation techniques for flavour analysis. As per AGREE Prep, method 34 was found to be environmental friendly with score of 0.66, attributed to safe solvents, minimized waste, high sample throughput, and low energy consumption where as method 7 with SPMS scores of 7.05 is more sustainable due to miniaturization, fewer steps, and low energy use.

Characterization and Evaluation of Taihe Black-Boned Silky Fowl Eggs Based on Physical Properties, Nutritive Values, and Flavor Profiles.

Taihe black-boned silky fowl (TS) is a native chicken breed in China with more than 2000 years of history. The present study aimed to characterize and evaluate the physical, nutritional, and flavor properties of TS eggs with a comparison to two other commercial breeds. Eggs from TS (n = 60) crossbred black-boned silky fowl (CB, n = 60) and Hy-line Brown (HL, n = 60) were used for physicochemical analysis. The evaluation system was divided into four parts based on nutrient and flavor profiles: protein and amino acids, lipids and fatty acids, mineral elements, and flavor-related amino acids and volatile compounds. Results showed that TS eggs were typically associated with the lowest egg weight and the highest yolk color, as compared with CB and HL eggs. No differences were found in crude protein, crude fat, triglycerides, and cholesterol content between eggs from the different breeds, but these eggs were distinct in terms of the amino acid, fatty acid, and volatile flavor compound profiles. Moreover, the differences in amino acid and fatty acid profiles might contribute to the specific flavor of TS eggs. Evaluation results indicated that TS egg whites may be suitable as a protein source for premature infants and young children under three years old and TS egg yolks could be considered a beneficial dietary lipid source due to their potential anti-cardiovascular properties. Additionally, TS whole eggs could serve as a valuable source of selenium (Se), molybdenum (Mo), zinc (Zn), and phosphorus (P) for adults aged 18 to 65. However, TS and CB eggs showed inferior Haugh units, eggshell quality, and essential amino acid compositions for older children, adolescents, and adults. These findings provide a better insight into the health benefits of TS eggs and contribute to the breeding and nutrition regulation of TS breeds.

Evaluation of differences in volatile flavor compounds between liquid-state and solid-state fermented Tartary buckwheat by Monascus purpureus

The differences in volatile flavor compounds (VFCs) between Monascus-solid-state fermented Tartary buckwheat (MSFTB) and Monascus-liquid-state fermented Tartary buckwheat (MLFTB) were investigated using electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) analysis. The study revealed several significant differences in the composition and abundance of VFCs between the two states. Compared to MSFTB, MLFTB exhibited notable increases in various elements including protein, crude fat, total flavonoids, total polyphenols, Monacolin K, Monascus pigments. Principal component analysis demonstrated significant increases in the production of specific VFCs in MLFTB compared to MSFTB. A total of 25 VFCs were identified through GC-IMS, including 9 esters, 7 alcohols, 5 ketones, and 4 aldehydes. The content of pleasant VFCs in MLFTB was significantly higher than in MSFTB. These compounds served as both VFCs and key aroma components during fermentation. In conclusion, the Monascus fermentation state played a crucial role in enhancing the flavor quality of Tartary buckwheat.

Research Progress on the Mechanism of the Impact of Myofibrillar Protein Oxidation on the Flavor of Meat Products.

Myofibrillar proteins primarily consist of myosin, actin, myogenin, and actomyosin. These proteins form complex networks within muscle fibers and are crucial to the physical and chemical properties of meat. Additionally, myofibrillar proteins serve as significant substrates for the adsorption of volatile flavor compounds, including aldehydes, alcohols, ketones, and sulfur and nitrogen compounds, which contribute to the overall flavor profile of meat products. A series of chemical reactions occur during the processing, storage, and transportation of meat products. Oxidation is one of the most significant reactions. Oxidative modification can alter the physical and chemical properties of proteins, ultimately impacting the sensory quality of meat products, including flavor, taste, and color. In recent years, considerable attention has been focused on the effects of protein oxidation on meat quality and its regulation. This study investigates the impact of myofibrillar protein oxidation on the sensory attributes of meat products by analyzing the oxidation processes and the factors that initiate myofibrillar protein oxidation. Additionally, it explores the control of myofibrillar protein oxidation and its implications on the sensory properties of meat products, providing theoretical insights relevant to meat processing methods and quality control procedures.

Dynamic Changes and Potential Correlations between Microbial Diversity and Volatile Flavor Compounds in Chinese Medium-Temperature Daqu during Manufacturing.

To investigate the dynamic changes and potential correlations between microbial diversity and volatile organic compounds (VOCs) during Chinese medium-temperature Daqu (MTD) manufacturing at different key stages, in this study, high-throughput sequencing (HTS) and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to analyze the microbial diversity and VOCs of MTD, respectively. The results showed that Weissella, Staphylococcus, Thermoactinomyces, Kroppenstedtia, and Lactobacillus were the dominant bacterial genera, while Aspergillus, Alternaria, Thermoascus, Thermomyces, Wickerhamomyces, and Saccharomyces were the dominant fungal genera. A total of 61 VOCs were detected by GC-IMS, among which, 13 differential VOCs (VIP > 1) were identified, that could be used as potential biomarkers to judge the fermentation stage of MTD. Kroppenstedtia and Saccharopolyspora were positively correlated with 3-methyl-2-butenal and 2,2,4,6,6-pentamethylheptane-D, respectively, and both of these were positively correlated with butanal-D. Acetobacter, Streptomyces, and lactic acid bacteria (LAB) including Leuconostoc, Pediococcus, Weissella, and Lactobacillus were negatively correlated with their associated VOCs, while fungi were generally positively correlated with VOCs. Wickerhamomyces, Saccharomyces, and Candida were positively correlated with butan-2-one-M. This study provides a theoretical basis for explaining the mechanisms of MTD flavor formation and screening functional microorganisms to improve the quality of MTD.

Enhancement of flavor quality in oyster hydrolysate through fermentation with oyster-derived lactic acid bacteria

This study investigates the effect of autochthonous oyster-derived bacteria on mitigating the off-flavors in oyster hydrolysate (OPH) using flavoromics, microbiomics, and non-targeted metabolomics technologies. Results showed that the taste and odor sensory scores of oyster-derived lactic acid bacteria (LAB) fermentation were significantly better than those of commercial fermentation (p < 0.05), scoring 4.14 ± 0.47 and 4.23 ± 0.26, respectively (out of 5). Significant alterations were observed in volatile flavor compounds (VOCs) such as 5-nonanone, 2-undecanone, 3-octanol, 3,6-nonadien-1-ol, phenylethanol, and γ-decalactone. Non-volatile flavor metabolites were mainly represented by a rise in unsaturated fatty acids and a decrease in saturated fatty acids and bitter amino acids (Tyr and Arg). A total of 569 differential metabolites were identified, mainly involved in linoleic acid metabolism, glycerophospholipids, phenylalanine (Phe), tyrosine (Tyr), arginine (Arg), and proline (Pro). Lecithin, Tyr, Phe, histidine (His), Arg, and glutamine (Gln) were identified as flavor precursor compounds for oyster-derived LAB fermentation. High-throughput sequencing clarified the dominant role of oyster-derived LAB in influencing metabolites and precursors during fermentation. This study offers new insights into the mechanisms of flavor development in autochthonous bacteria-inoculated fermented shellfish.

Dynamic changes and correlation of quality, flavor and microorganisms of Mei (Prunus mume) vinegar during fermentation and clarification

Mei (Prunus mume) is a highly nutritious fruit whose value is often underutilized due to its perishable nature and challenges in post-maturation storage. This study evaluated the changes and correlations among quality, volatile flavor compounds (VFCs), and microorganisms in Mei vinegar (MV) during acetic acid fermentation (AAF) and low temperature clarification (LTC) using various clarifiers. The results indicated that AAF enhanced the bioactive components and antioxidant capacity of MV. A total of 73 VFCs were identified, comprising 9 alcohols, 28 esters, 5 aldehydes, 18 acids, 4 phenols, 1 ketone, 5 alkanes, and 3 others. Among these, the number and relative content of esters and acids exhibited dominance both in AAF and LTC. Firmicutes and Pediococcus were predominant at the phylum and genus levels, respectively. After 1 d of AAF, the relative abundances of Firmicutes and Pediococcus increased significantly, while LTC reduced their abundance. Among the 20 stable VFCs in MV, most esters and alcohols showed positive correlations with the top 10 bacteria at the phylum and genus levels, while certain acids were negatively correlated with these bacteria. Therefore, these findings offer valuable insights for the development of MV, the selection of clarifiers, and offer a theoretical basis for improving MV quality and flavor.

Effects of different enzymatic hydrolysis techniques on volatile flavor compounds and nutritional metabolites of soybean meal yogurt

AbstractBACKGROUNDThis study explores enzymatic hydrolysis as a method of modifying soybean meal (SM). It can reduce the particle size, improve flavor, and convert macromolecules into absorbable nutrients. The purpose is to provide technical information regarding the use of SM. Papain alone, and a combination of papain and acid protease, and a mixture of papain, acid protease, and Lactiplantibacillus plantarum were employed for the enzymatic hydrolysis of SM.RESULTSSensory evaluation and nutritional and flavor analyses were performed with yogurt produced after SM enzymatic hydrolysis. The enzymatic hydrolysis improved yogurt quality significantly in comparison with non‐enzymatically hydrolyzed soybean meal yogurt (SMY) by accelerating the decrease in pH and shortening the duration of fermentation. Enzymatic hydrolysis also reduced beany flavors and bitterness and enhanced the aromatic compound, flavor‐related amino acid, and organic acid content, rendering the yogurt more appealing to consumers. Microstructural analysis revealed favorable characteristics that textural and rheological properties of the yogurt produced after enzymatically hydrolyzed SM were improved.CONCLUSIONIn this study, the biotechnological approach was used to demonstrate the efficacy of enzymatic hydrolysis in improving the quality and value of SM, promoting the efficient application of SM in the food industry. © 2024 Society of Chemical Industry.

Effects of surimi by-product hydrolysates on processing quality and difference analysis of volatile compounds of silver carp surimi gel

The aim of this study was to investigate the effects of surimi by-product hydrolysates (SBPHs) on the processing quality, gel characteristics, microstructure, and volatile compounds of surimi. The results showed that the addition of SBPHs improved the water holding capacity (95.18% and 94.32%), texture property, and gel characteristic (546.04 g cm) of the surimi gel, reduced the cooking loss (7.15%) and aperture area (34.10%) of the surimi gel (P < 0.05), causing no difference in their whiteness (P > 0.05). The SBPHs reduced the free water and increased the immobilized water of the gel. At the same time, SBPHs made tighter cross-linking of the surimi gel proteins. The results of gas chromatography-ion mobility spectrometry showed that 62 volatile flavor compounds were detected in each group of surimi, and the relative contents of aldehydes, alcohols, and ketones were relatively high. A total of 19 volatile flavor compounds were selected as the potential markers in samples by orthogonal partial least square siscriminant analysis. The additions of SBPHs (0.6% and 1.2%) in this study were much lower than those of commercial cryoprotectant (6%). In conclusion, SBPHs emerges as a potential cryoprotectant for the surimi industry and have promising advantages in enhancing the quality of surimi.

Effect of rosemary extract on volatile flavor profile and flavor source of skipjack tuna

A fishy odor can significantly hinder the development of products made from nutritious skipjack tuna. To address this issue, rosemary extract (RE) was used as a deodorizing agent for skipjack tuna. Multi-omics techniques, including e-nose, e-tongue, gas chromatography-ion mobility mass spectrometry (GC-IMS), and gas chromatography-mass spectrometry (GC-MS), were employed to analyze the volatile flavor compounds in the skipjack tuna meat before and after deodorization. The main fishy odors found in the skipjack tuna were identified as nonanal, heptanal, hexanal, and 1-octen-3-ol, primarily resulting from lipid oxidation. Treatment with RE solutions at concentrations of 0.8% and 1.0% completely removed nonanal, hexanal, and heptanal from the skipjack tuna meat, while the level of 1-octen-3-ol was significantly reduced by 67.21% (p < 0.05). The GC-MS analysis of the impregnated solution indicated a 31% increase in 1-octen-3-ol content at a concentration of 0.2% (p < 0.05). Additionally, skipjack tuna meat treated with 0.8% and 1.0% RE showed lower peroxide values and thiobarbituric acid reactive substances values (p < 0.05). The reduction of fishy odor by RE was directly linked to decreased lipid oxidation. Quantitative analysis of phenolics revealed that the relative content of phenolics in RE was 52.54%, with the main phenolics being chlorogenic acid, caffeic acid, and luteolin. Thus, RE shows promise in eliminating fishy odors and minimizing lipid oxidation in skipjack tuna.

Impact of thermal processing methods on physicochemical properties and flavor-related compounds of Pearl gentian grouper with waterless preservation

This study investigated the impact of various treatments (boiling, steaming, microwave heating, and baking) on the physicochemical properties and flavor profile of pearl gentian grouper after undergoing waterless preservation. The grouper meat treated with Csteaming (non-preservation steaming treatment) and WLsteaming (waterless preservation steaming treatment) exhibited the highest levels of springiness (P < 0.05). Additionally, Csteaming and WLsteaming significantly reduced the hardness and cooking loss (P < 0.05) and demonstrated the highest umami values. The TBARS value of the baking groups exhibited a significantly lower level compared to that of the other heat treatment groups (P < 0.05). The primary volatile compounds in the heated grouper samples were nitrogen oxide, sulfides, and long-chain alkanes. The volatile flavor compounds of heated grouper samples were determined by headspace solid-phase microextraction gas chromatography-mass spectrometry, and a total of 35 volatile compounds were identified, including 8 aldehydes, 8 alcohols, 1 acid, 5 nitrogen-containing compounds, 6 hydrocarbons, and 7 ketones. The boiling treatments exhibited the highest levels of 5′-IMP and lactic acid. Meanwhile, steaming treatment emerged as a preferred method for maintaining the umami taste. Additionally, the waterless preservation technique effectively enhanced the content of succinic acid in pearl gentian grouper.

Real-time monitoring of 2,5-dimethylpyrazine in solid, liquid, and gas phases during processing of fried skipjack tuna steaks using intestinal villus-like Ag nanoparticles@Au nanowires surface-enhanced Raman substrate chips

The production and distribution of 2,5-dimethylpyrazine (2,5-DMP), a key volatile flavor compound, are associated with the frying of skipjack tuna steaks. In this study, an intestinal villus-like chip was fabricated to quantitatively detect 2,5-DMP in multiphase systems based on surface-enhanced Raman spectroscopy (SERS). The chip exhibited excellent SERS performance with an enhancement factor of 1.16 × 108, excellent uniformity and reproducibility, and low detection limits of 6.49 pg/mL, 0.182, and 0.920 ng/mL for 2,5-DMP solid, liquid, and gas models, respectively. The results indicated the 2,5-DMP content with growth rates in the order of frying steam > frying steaks > frying oil, and the 2,5-DMP content in frying steam was linearly correlated (R2 = 0.992) with the trend of the acid value and total polar compounds in frying oil. Therefore, this strategy for achieving the reliable detection of 2,5-DMP can assist in monitoring the frying process and food safety.

Effect of atmospheric cold plasma treatment on the flavor of high-fat aquatic products: A case study of golden pomfret (Trachinotus ovatus, family Bramidae) oil using GC-MS, GC-IMS, and an E-nose

This study examines the effects of atmospheric cold plasma (AP) treatment on golden pomfret oil, particularly its physicochemical properties and flavor compounds. Volatile flavor compounds in the golden pomfret fish oil were investigated following AP treatment and cold storage for 30 d using gas chromatography-mass spectrometry, gas chromatography-ion mobility mass spectrometry, and an electronic nose. The relative odor activity values revealed that certain molecules, including pentane, tridecane, styrene, methyl palmitate, benzyl benzoate, 1-methyl-2-pyrrolidinone, and oleic acid, were potential markers for distinguishing between the aromas at fresh group, 30 d of storage, and 30 d of AP storage. The content of volatile compounds changed during low-temperature refrigeration. AP treatment was a protective measure against flavor changes during storage. This information can aid in exploring the formation mechanism of the characteristic odor of AP-treated golden pomfret oil and its related metabolic pathways.

Metagenomic and Metabolomic Profiling Reveals the Differences of Flavor Quality between Hongqu Rice Wines Fermented with Gutian Qu and Wuyi Qu.

Jiuqu (starter) makes an important contribution to the formation of the flavor characteristics of Hongqu rice wine (HQW). Gutian Qu (GTQ) and Wuyi Qu (WYQ) are two kinds of Jiuqu commonly used in HQW brewing, but the comparison of the two kinds of HQW is still insufficient at present. The objective of this study was to compare the dynamic changes of amino acids (AAs), higher alcohols (HAs), bioamines (BAs), volatile flavor compounds (VFCs), and microbial communities in HQW fermentation, with GTQ and WYQ as starter. This study used an automatic amino acid analyzer, GC, HPLC, and GC-MS to detect AAs, HAs, Bas, and VFCs during fermentation; metagenomic sequencing technology was used to elucidate the microbial community and its functional characteristics. The results showed that the contents of AAs and HAs in HQW brewed with WYQ (WYW) were significantly higher than those in HQW brewed with GTQ (GTW). On the contrary, the majority of BAs in GTW were significantly higher than those in WYW. The composition of VFCs in WYW and GTW were obviously different, as most of the VFCs were notably enriched in WYW, while ethyl caproate, isoamyl acetate, ethyl heptanoate, ethyl nonanoate, 1-decanol, citronellol, phenethyl acetate, and hexanoic acid were more abundant in GTW. Burkholderia gladioli, Pantoea dispersa, Weissella cibaria, Monascus purpureus, and Saccharomyces cerevisiae were the predominant microbial populations in GTW brewing at the species level, while Sphingomonas sp., Kosakonia cowanii, Enterobacter asburiae, Leuconostoc lactis, Aspergillus niger, and Saccharomyces cerevisiae were the dominant microbial species in WYW brewing. The abundance of functional genes involved in BAs biosynthesis were much higher in GTW brewing, while the abundance of functional genes related to the metabolism of characteristic VFCs were much higher in WYW brewing. Collectively, these findings provided evidence for elucidating the effects of Jiuqu and microbial communities on HQW flavor quality, and laid a solid foundation for the improvement of HQW flavor quality.

Changes of physicochemical and volatile flavor compounds of dry-cured Diqing Tibetan pig hams during fermentation

This study aimed to explore the flavor formation mechanism of Diqing Tibetan pig hams by investigating changes of their physicochemical and volatile flavor compounds during fermentation (0, 30, 90, 180, 360, and 540d) using amino acid analyzer , texture profile analysis, and gas chromatography-ion mobility spectroscopy (GC-IMS). During fermentation, the hams significantly decreased in moisture and centrifugal loss, while increased in chewiness, hardness, and proteolysis index, with their free amino acids content reaching the maximum at 360d and significantly decreasing at 540d. GC-IMS identified 78 volatile organic compounds, with the highest total content of alcohols and aldehydes at 180d, ketones and heterocycles at 360d, and esters at 540d. PLS-DA screened 24 volatile flavor markers, with aldehyde (2-methyl-2-propenal), ketone (2-heptanone-D), alcohol (3-methylbutanol-D), ester (ethyl3-methylbutanoate-M), and heterocyclic substances (2,3-dimethylpyrazine-M) as the main VFMs at 360d. The unique flavor of 540d Diqing Tibetan pig hams was attributed to their higher content of 3-methyl-2-butenal, 3-(methylthio) propanal, ethyl caproate and 2-butanone. These findings provide a scientific basis for the flavor formation mechanism of hams which favoring the further development processing strategies for Diqing Tibetan pig.

Insights into flavor quality and metabolites profiles of fresh cheese with different probiotics by SPME-GC-MS and untargeted metabolomics

In this study, fresh cheeses produced with four novel probiotics (Lactobacillus casei PB-LC39, Lactobacillus rhamnosus PB-LR76, Lactobacillus helveticus HH-LH17, and Lactobacillus plantarum HH-LP56) were named as LC, LR, LH, and LP, respectively. SPME-GC-MS and untargeted metabolomics were used to compare and analyze the flavor quality, metabolites and metabolic pathways of LC, LR, LH and LP, and the potential function of differential metabolites was emphasized. The results demonstrated that the incorporation of probiotics resulted in a significant increase in the number of volatile flavor compounds and varying flavor profiles within the cheese. Especially LC, exhibited aromas reminiscent of wine, fruit and rose, and displayed the most favorable flavor qualities among all probiotic cheeses. The results of differential metabolite screening and metabolic pathway demonstrated that probiotic cheese could result in the production of 146–192 differential metabolites, mainly carbohydrates, proteins and acids. Arginine biosynthesis was a key differential metabolite pathway made by probiotics. The LC, LR, LH, and LP groups contained 22, 27, 23, and 24 functional metabolites, including L-carnitine, naringenin, and turanose et al., which might confer anti-inflammatory and improve lipid metabolism functions. These findings provide a theoretical basis for the further functional evaluation and development of probiotic cheese.

Effect of temperature on the quality and microbial community during Daocai fermentation

Daocai is a traditional salted pickle in the southeastern region of Guizhou with a unique aroma, color, and taste. The quality of Daocai is greatly influenced by the fermentation temperature. In this study, high-throughput sequencing and headspace-gas chromatography-ion mobility spectrometry were used to investigate the changes in microbial community succession and volatile flavor compounds during Daocai fermentation under temperature-controlled (D group) and non-temperature-controlled (C group).We found that the predominant genera in the C group samples were Latilactobacillus(40.57 %), Leuconostoc(21.25 %), Cystofilobasidium(22.12 %), Vishniacozyma(23.89 %), and Leucosporidium(24.95 %), whereas Weissella(29.39 %), Lactiplantibacillus(45.61 %), Mucor(68.26 %), and Saccharomyces(23.94 %) were the predominant genera in the D group. A total of 92 VFCs were detected in Daocai samples, including 5 isothiocyanates, 16 esters, 14 alcohols, 24 aldehydes, 17 ketones, 3 acids, 2 pyrazines, 1 pyridines, 1 thiazoles, 3 furans, 4 alkenes, and 2 nitriles. Further analysis revealed Latilactobacillus, Leuconostoc, Lactococcus, Cystofilobasidium, Leucosporidium, Holtermanniella, and Dioszegia as key bacteria involved in flavor formation. They are closely related to the formation of flavors such as aldehydes, furans, pyridines, and alkenes. This study contributes to our understanding of the relationship between bacterial communities and the flavor formation during Daocai fermentation.

The regulation of volatile flavor compounds in fermented meat products mediated by microorganisms: A review

Fermented meat products are widely consumed and favored by consumers because of their unique flavor and texture. Flavor formation is a complicated biochemical process, and microorganisms (mainly lactic acid bacteria, staphylococci, yeasts, and molds) play an essential role in flavor regulation. Elucidating the role of microorganisms in regulating the flavor formation of fermented meat products is critical for rationally designing microorganisms to improve the flavor quality of fermented meat products. Therefore, microorganisms, volatile compounds, and flavor-generating mechanisms of microorganisms in fermented meat products are summarized. This review also highlight correlations between microorganisms and flavor development and the effects of microorganisms on flavor development, which may provide important progress for the selection and application of microorganisms to improve the flavor of fermented meat products.

Interaction and dynamic changes of microbial communities and volatile flavor compounds during the fermentation process of coffee flower rice wine.

To develop a unique flavor of rice wine, coffee flowers (by-products of the coffee industry) were added because of their biologically active compounds that are conducive to health, and the fermentation parameters were optimized. In addition, the dynamic changes of microbial communities and volatile flavor compounds (VFCs) during the different fermentation stages were investigated. After the optimization of the fermentation parameters, a novel product, i.e., the coffee flower rice wine (CFRW), was obtained with a bright yellow transparent, fragrant, and harmonious aroma and mellow and refreshing taste by sensory evaluation, when 4.62% of the coffee flowers and 1.93% koji were added and fermented at 24.10°C for 3.88 days. The results showed that Lactococcus was the dominant bacteria, accounting for 87.0-95.7%, while Rhizopus and Cladosporium were the main fungi, accounting for 68.2% and 11.3% on average, respectively, in the fermentation process of the CFRW. Meanwhile, twenty-three VFCs were detected in the CFRW, which included three alcohols, six terpenes, ten esters, three aromatics, and one furan. The correlation analysis revealed that there were 16 significant positive correlations and 23 significant negative correlations between the bacterium and VFCs (|ρ| > 0.6, p < 0.05), while there were 12 significant positive correlations and one significant negative correlation between the fungi and VFCs (|ρ| > 0.6, p < 0.05). Furthermore, five VFCs, including linalool, geraniol, ethyl acetate, 1-hexanol, and 3-methyl-1-butanol, contributed vital flavors to the CFRW, and they were all significantly negatively correlated with the changes of Massilia and Acinetobacter (|ρ| > 0.6, p < 0.05). Moreover a significant positive correlation was found between the relative abundance of Lactococcus and the contents of 3-methyl-1-butanol and ethyl acetate (|ρ| > 0.6, p < 0.05). Therefore, this study provides a valuable theoretical basis for further improving the quality and production technology of CFRW.

Variation of volatile flavor substances in salt-baked chicken during processing

Salt-baked chicken was a traditional delicacy of Guangdong, but the effects of volatile flavor compounds at different stages of its processing remained unclear. This study utilized sensory analysis, e-nose, and GC–MS to investigate the changes in volatile flavor compounds during the processing of salt-baked chicken. The results indicated significant alterations in volatile flavor compounds at different stages of processing, resulting in flavor transitioning from the original flavor to salty, scorched, and fatty flavor. 75 volatile compounds were identified by GC–MS, with 15 key flavor compounds highlighted based on OAV, including aldehydes, alcohols, terpenes, heterocycles and esters. The research revealed the dynamic changes in volatile flavor compounds throughout the cooking process of salt-baked chicken and emphasized the important role of salt-baked in shaping its distinctive taste profile. These findings provided a theoretical foundation and practical guidance for enhancing and optimizing the authentic taste of this traditional dish, while fostering innovative advancements in prepared cuisine.