Flavor Compounds Research Articles

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.

Dynamic changes in dissolved oxygen concentration, microbial communities, and volatile compounds during industrial oak-barrel fermentation of Sauvignon Blanc wine

Oak-barrel fermentation is used in white wine production to enhance aroma and flavor complexity. However, the dynamics of microbial communities and their impact on the formation of flavor compounds during barrel fermentation remain unclear. This study investigated the changes in dissolved oxygen concentrations, microbial communities, and volatile compounds during Sauvignon Blanc wine fermentation in various oak barrels (new and two-year-old Francois Freres and new Taransaud) and stainless-steel tanks. We found that oak barrels had higher dissolved oxygen levels than steel tanks, with new barrels exhibiting higher levels than the old ones during fermentation. The dominant bacterial genera across all the vessels during the fermentation included Ralstonia, Pantoea, Gluconobacter, and Mesorhizobium, whereas the dominant fungal genera were Saccharomyces, Aspergillus, Alternaria, and Aureobasidium. The fermentation environment altered the microbial composition as the fermentation progressed in various vessels. Compared with steel tanks, difference in microbial composition between oak barrels was less significant. The new oak barrels increased the levels of esters, alcohols, and acids in the wine, while only minor differences were observed between old barrels and steel tanks. Correlation analysis showed that Ralstonia, Gluconobacter, Mesorhizobium, and Saccharomyces were positively correlated with the production of wine volatiles. Structural equation modeling indicated the interactions between dissolved oxygen, microbial communities, and wine aromas. The impact of dissolved oxygen on fungal communities during fermentation differed significantly between new and old oak barrels, indirectly influencing aroma. Conversely, in stainless-steel tanks, dissolved oxygen weakly influenced the bacterial and fungal communities, with the influence on wine aroma primarily dependent on the fungal communities. These findings provide valuable insights for optimizing the Sauvignon Blanc wine fermentation in oak barrels

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 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.

Bacterial community succession and its correlation with the dynamics of flavor compound during processing of Enshi bacon

Enshi bacon, a famous specialty in Enshi Prefecture, Hu Bei, China, is renowned among customers for the nutritious content and distinct smoky flavor. This study explored the flavor and bacterial flora changes of Enshi bacon during processing and investigated the effect of bacteria on flavor formation. The results showed that the main genera in the pre-processing stage were Brochothrix, Lactococcus and Psychrobacter, which originated from raw meat. Salt-tolerant Staphylococcus and Cobetia were the dominant genera in the late stage of processing. Five free amino acids (aspartic acid, glutamic, alanine, valine, and lysine) were recognized as the flavor substances promoting taste, while aldehydes and phenols were the volatiles that contributed the most to odor. Particularly, compared to the smoking phase, phenolic content increased 2.25-fold at the end of fermentation through microbial action and tyrosine catabolism. The correlation study showed Staphylococcus and Lactococcus as fundamental functional genera that are essential for the formation of bacon flavor. This study provided reference data for the changes in flavor indicators and flora during the processing of Enshi Bacon, revealed the potential mechanism of core functional flora and characteristic flavor formation, and provided a theoretical basis for quality control of the manufacturing process.

Machine learning discrimination and prediction of different quality grades of sauce-flavor baijiu based on biomarker and key flavor compounds screening

The quality grade of base Baijiu directly determines the final quality of sauce-flavor Baijiu. However, traditional methods for assessing these grades often rely on subjective experience, lacking objectivity and accuracy. This study used GC-FID, combined with quantitative descriptive analysis (QDA) and odor activity value (OAV), to identify 27 key flavor compounds, including acetic acid, propionic acid, ethyl oleate, and isoamyl alcohol etc., as crucial contributors to quality grade differences. Sixteen bacterial biomarkers, including Komagataeibacter and Acetobacter etc., and 7 fungal biomarkers, including Aspergillus and Monascus etc., were identified as key microorganisms influencing these differences. Additionally, reducing sugar content in Jiupei significantly impacted base Baijiu quality. Finally, 11 machine learning classification models and 9 prediction models were evaluated, leading to the selection of the optimal model for accurate quality grade classification and prediction. This study provides a foundation for improving the evaluation system of sauce-flavor Baijiu and ensuring consistent quality.

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.

Study on Sensory Quality and Flavor Characteristics of Jiangxiang Baijiu Produced by Different Fermentation Techniques

As a representative of traditional Chinese distilled liquor, the unique flavor of Sauce Flavor Baijiu is closely related to its brewing techniques. This study systematically explored the sensory quality and flavor characteristics of Sauce Flavor Baijiu produced by different fermentation techniques through sensory evaluation, gas chromatography analysis, and multivariate statistical methods. The results indicated that the techniques of Chuansha, Suisha, Kunsha, and their blends significantly influenced the concentration and proportion of flavor compounds in Baijiu, subsequently altering its aroma and taste. Specifically, Chuansha Baijiu exhibited weaker aroma and thinner taste; Suisha Baijiu presented certain complexity and a softer taste; while Kunsha Baijiu boasted a strong aroma and full-bodied taste. This study established a scientific quality evaluation system for Sauce Flavor Baijiu, providing theoretical foundations and technical support for the optimization of brewing techniques and improvement of Baijiu quality.

Effects of Variable-Temperature Roasting on the Flavor Compounds of Xinjiang Tannur-Roasted Mutton.

This study investigates the effect of variable-temperature roasting on the flavor compounds of Xinjiang tannur-roasted mutton. Gas chromatography coupled with ion mobility spectroscopy (GC-IMS) was used to compare and analyze the volatile components and flavor fingerprints of Xinjiang tannur-roasted mutton using variable-temperature electrically heated air roasting (VTR), constant-temperature electrically heated air roasting (EHAR), and constant-burning charcoal roasting (BCR) techniques. The changes in fatty acids and free amino acids in Xinjiang tannur-roasted mutton under different roasting conditions were compared. By using GC-IMS analysis, 11 flavor compounds, including 4-methyl-3-penten-2-one, isoamyl propionate, trans-2-heptenal, trans-2-heptenal, 2-hexanone, n-hexanol, 2-hexenal, 2-ethylfuran, and ethyl 2-methylbutanoate, were identified as characteristic volatile compounds in the temperature-controlled electrothermal roasting of Xinjiang tannur-roasted mutton using the following conditions: 0-4 min, 300 °C; 5-10 min, 220 °C; and 11-17 min, 130 °C (VTR3). Through principal component analysis, it was found that the substances with the highest positive correlation with PC1 and PC2 were n-hexanol and 3-methylbutanol. The sensory evaluation showed that VTR3 had high acceptability (p < 0.05) and a fat flavor (p < 0.05). There was no significant difference in the total fatty acid (TFA) content between the VTR3 and burning charcoal roast for 1-17 min at 300 °C (BCR3) (p > 0.05), but it was lower than that in the other experimental groups (p < 0.05). The lowest proportion of glutamic acid content in VTR3 was 22.44%, and the total free amino acid content in the electric thermostatic roasting for the 1-17 min, 300 °C (EHAR3) group (347.05 mg/100 g) was significantly higher than that in the other experimental groups (p < 0.05). By using Spearman correlation analysis, the roasting loss rate showed a highly significant negative correlation with essential amino acids (EAAs), non-essential amino acids (NEAAs), and total free amino acids (TAAs) (the correlation coefficients (r) were 0.82, 0.87, and 0.87, respectively) with p < 0.01. There was no correlation between changes in the free amino acid content and fatty acid content (p > 0.05). By using Differential scanning calorimetry (DSC) analysis, we also found that there was no significant difference in peak temperature (Tp) between the VTR3 and EHAR experimental groups (p > 0.05). Variable temperature electric heating can affect the flavor of lamb, and there are significant differences in the content of flavor precursors such as fatty acids and amino acids in Xinjiang tannur-roasted mutton.

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.

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.

Metagenomics-based insights into the microbial community dynamics and flavor development potentiality of artificial and natural pit mud

Strong-flavor Baijiu (SFB) production has relied on pit mud (PM) as a starter culture. The maturation time of natural PM (NPM) is about 30 years, so artificial PM (APM) with a shorter maturation time has attracted widespread attention. This study reveals the microbial and functional dissimilarities of APM and NPM, and helps to elucidate the different metabolic roles of microbes during substrate degradation and flavor formation. Significant differences in the microbial community were observed between APM and NPM, manifesting as variations in the abundance of core microorganisms. Total of 187 high-quality metagenome-assembled genomes (MAGs) were obtained based on the metagenomic binning technology, mainly including Firmicutes (n = 106), Bacteroidota (n = 15) and Chloroflexota (n = 14). Furthermore, the relative concentration of flavor compounds in 4-year APM was similar to those in 30-year NPM, but different from those in 100-year NPMs. Methanosarcina, Methanobacterium, Methanoculleus, Anaerolineae bacterium and Aminobacterium were the key bacteria responsible for the flavor differences. From a functional perspective, amino acid and carbohydrate metabolism were key functions of PM microbial, and showed differences between APM and NPM. Finally, substrate degradation and flavor generation pathways were found to exist in multiple microorganisms. Combine the relative abundance of microorganisms with the absolute abundance of enzymes, Clostridium, Lactobacillus, Petrimonas, Methanoculleus, Prevotella, Methanobacterium, Methanosarcina, Methanothrix, Proteiniphilum, Bellilinea, Anaerolinea, Anaeromassilibacillus, Syntrophomonas and Brevefilum were identified as the key microorganisms in APM and NPM.

Effect of the addition of cocoa sweatings and time of fermentation on flavor compounds and sensory perception of 100% roasted cocoa liquor.

Fermentation is critical for producing high-quality cocoa, yet its kinetics and resulting chemical and sensory outcomes are poorly understood and thus difficult to manage. Cocoa sweatings (CS), the liquid runoff produced early during fermentation and typically drained off, may beneficially affect fermentation outcome when added back into the fermenting mass. Here, we report how back-addition of CS affects composition and sensory perception of roasted cocoa liquor after 5, 6, and 7 days of fermentation. Cocoa liquor (=100% chocolate) made from beans fermented for 5 days with the addition of CS were similar in sensory perception to those fermented for 7 days without added CS. Twenty-one flavor compounds showed similar patterns to the sensory results: In the beans fermented with CS, these compounds remained at similar levels after 5, 6, and 7 days of fermentation, while the same compounds significantly changed in the samples fermented conventionally, without CS addition. These results suggest a link between changes in flavor composition and sensory differences in roasted cocoa. Future work is needed to reveal the mechanism of flavor stabilization throughout fermentation resulting from the back-addition of CS. PRACTICAL APPLICATION: Roasted cocoa liquor fermented with cocoa sweating (CS) is sensorily similar when fermented for 5 or 7 days and produces cocoa that is sensorily similar to traditionally fermented cocoa in shorter time (5 days vs. 7 days). The addition of CS seems to stabilize 21 flavor compounds throughout fermentation mimicking changes in sensory perception. The back-addition of CS could help standardize cocoa fermentation as indicated by more consistent temperature evolution.

Study on Characteristic Aroma in Special Beers Brewed with Coriander (Coriandrum sativum L.) Seeds: Profiling of Flavor Compounds Derived from Coriander Seeds in Different Growing Areas

Study on Characteristic Aroma in Special Beers Brewed with Coriander (<i>Coriandrum sativum</i> L.) Seeds: Profiling of Flavor Compounds Derived from Coriander Seeds in Different Growing Areas

The interaction of Lactiplantibacillus plantarum and Latilatilactobacillus sakei regulated the formation of characteristic quality attributes of low-salt fermented tilapia

The regulation of quality characteristics of fermented aquatic food based on microbial metabolic interaction is a hot spot in the innovative processing of aquatic products around the world. In this study, electronic sensory system, gas phase method and liquid phase method based on mass spectrometry were used to study the effects of the interaction between Lactiplantibacillus plantarum and Latilactobacillus sakei on the quality and flavor of dry-cured tilapia. The targeted supplementation of Latilactobacillus sakei S199 can improve the texture and flavor characteristics of tilapia meat fermented by Lactiplantibacillus plantarum 550. Latilactobacillus sakei S199 can cross metabolize with Lactiplantibacillus plantarum 550 to produce more 1-Octen-3-ol, 3-methyl-1-Butanol, 1-Hexanol, 2-ethyl-1-Hexanol, (E)-2-Octen-1-ol, 2-Heptanone, 3-Octanone, 2-Pentyl-Furan, and 2,5-diethyltetrahydro-Furan, and reduce the content of Heptanal, Nonanal, and Benzaldehyde to enhance the aroma of fermented tilapia fish. The aroma intensity increased by three times, from 129.46 μg/kg to 373.02 μg/kg, white the bitterness of tilapia meat fermented by the two bacteria was reduced by half, from 231.26 μg/g to 153.65 μg/g. The interaction of Lactiplantibacillus plantarum 550 and Latilactobacillus sakei S199 promoted proteolysis and utilized the FAAs and other small molecular compounds to generate other flavor compounds. The results were helpful to understand the effect of the interaction between Lactiplantibacillus plantarum 550 and Latilactobacillus sakei S199 on the flavor formation of dry cured tilapia.

The regulatory mechanism of mannan from millet Huangjiu on flavor release

Huangjiu, the national wine of China, has the characteristics of low grain consumption, low alcohol content and high nutrition, which aligns with the world's beverage wine consumption trend. The research on glutinous rice huangjiu from southern China is more extensive, while millet huangjiu from northern China has received less attention, hindering the diversified development of huangjiu. Polysaccharides play an important role in huangjiu's health activity and flavor characteristics. In this study, the polysaccharide components in millet huangjiu were separated and identified for the first time, and the influence of polysaccharides on the flavor release was explored through sensory evaluation, SPME-GC–MS, threshold determination and isothermal titration calorimetry. The millet huangjiu polysaccharide HJ-1 was composed of →3)-α-Manp(1→, α-Manp-(1→, →2,6)-α-Manp-(1→, →3)-α-Xylp-(1→ and →3)-β-Arap-(1→. HJ-1 (0.1–1 mg/mL) could regulate the release performance of key flavor compounds in millet huangjiu, inhibit the herbal, fruity and alcoholic aromas, and promote the sweet and rice aromas. Further studies showed that HJ-1 formed complexes with ethyl acetate, acetic acid, 2,3-butanediol and γ-butyrolactone through van der Waals forces and hydrogen bonds, and the process was a spontaneous exothermic entropy reduction reaction. This study provides a new idea for optimizing the overall aroma of huangjiu and improving its sensory quality.

Modelling and nondestructive quality prediction of Guanxi Honey Red Pomelo (&lt;i&gt;Citrus grandis&lt;/i&gt; (L.) Osbeck) based on shape characteristics and bitterness

Currently, it is difficult to distinguish the inner quality of pachycarpous fruits using nondestructive instruments, and trace nutrients and flavor compounds are rarely considered in fruit sorting. In this study, the external features and internal quality indices of an extensively farmed citrus fruit, the Guanxi honey red pomelo, were measured. The correlation between the inner and external quality was analyzed using Pearson correlation, canonical correlation, and grey correlation analyses. This research innovatively introduced bitter substances and revealed that the height-diameter ratio could serve as a predictor for ultra-size fruits, which partially reflects inner quality indices. Several grey formulas were developed to express these correlations and were fitted to a matrix, which demonstrated accuracies at all level 1 (C &lt; 0.35, P &gt; 0.95). Based on the matrix, fruit quality analysis of white and red pomelo showed high prediction accuracy in TSS and bitter substance indices (R2 = 0.6 – 0.8) and indicated that mature and symmetrical pomelo (height-diameter ratio of 0.9 – 1.1) exhibit a similar quality pattern. This study achieved rapid quality assessment using easy measurable shape characteristics and explored the application of characteristic bitter substances in the quality evaluation model, providing theoretical references and potential application guidance for pachycarpous fruit sorting, as well as introducing a new idea to incorporating characteristic quality into modeling index.

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.