Flavor Analysis Research Articles

Impact of Water Ionic Chemistry on Kombucha Fermentation

Kombucha is made by using a symbiotic culture of bacteria and yeast (SCOBY) to ferment sweetened tea. This fermentation produces a beverage with a unique aroma and acidic flavor. Kombucha has recently gained popularity in the United States and has been reported to have numerous health benefits. While there is a wide variation in kombucha composition, little is known about the impact water’s chemistry has on the fermentation and the resulting kombucha. Brewing water for kombucha was altered using the following ions: bicarbonate, chloride, calcium, magnesium, and sulfate at different concentrations. Pre-(tea) and post-(kombucha) fermentation (kombucha) products were analyzed for total acidity, pH, free amino nitrogen (FAN), total phenols, antioxidants, and biological components. A one-way ANOVA was run to determine statistical (p < 0.05) differences between the characteristics analyzed. Statistical differences were observed between the different water chemistry ions for all of the characteristics analyzed. Further investigation into the impact water chemistry has on flavor analysis is required. The information obtained from this research can be used to help producers to make kombuchas with an optimized chemical profile and improved antioxidant potentials.

Ultrasound-assisted microwave vacuum drying enhances flavor release during stewing of dried shiitake mushrooms

The introduction of ultrasonic energy into microwave vacuum drying (MVD) enhances drying efficiency and product quality. To investigate the effect of ultrasonically coupled microwave vacuum (USMVD) drying on the flavor release of shiitake mushrooms, differences in the pore structure of dried mushrooms were analyzed in relation to the flavor of mushroom soup. The results showed that ultrasound mainly changed the pore structure of shiitake mushrooms in the range of 5000–50,000 nm, and the total pore volume of shiitake mushrooms was the largest when the ultrasound amplitude was 70 %. In flavor analysis, 9 volatiles and 7 non-volatiles significantly contributed to flavor differences in shiitake mushroom soup, characterized by increased aroma, umami, and saltiness, along with decreased sourness and astringency. This study offers valuable insights for future research on high-quality drying and processing of edible mushrooms.

Investigating flavor and quality characteristics in Chinese bacon from different regions using integrated GC-IMS, electronic sensory assessment, and sensory analysis

To investigate the variance in the quality and flavor profiles of bacon from different regions, gas chromatography-ion mobility spectrometry and electronic sensory techniques (including electronic nose and tongue [e-nose and e-tongue, respectively]) were employed for the flavor analysis of the sourced bacon samples. Both the e-nose and e-tongue successfully distinguished the aromas and flavors of different bacon varieties. Additionally, organic sulfides, aromatic benzenes, and short-chain alkanes, were more abundant in different bacon types. Employing GC-IMS technology, identified 52 volatile flavor compounds within diverse bacon samples, culminating in the establishment of a distinct fingerprint for each individual sample. The relative odor activity value identified 1-propene-3-methylthio, 2-heptanone, phenylacetaldehyde, furfuryl methyl sulfide, and 1-octene as the primary contributors to bacon flavor. These flavor substances were the main cause of the differences in bacon flavor in different regions. The interaction of volatile flavor compounds resulted in notable disparities between the odor profiles detected using the e-nose and e-tongue, even among bacon with similar volatile flavor constituents. In addition, the color and texture of the bacon varied significantly. Bacon from HB (Hubei), YN (Yunnan), and CQ (Chongqing) showed darkness in color. Meanwhile, the hardness of bacon from HN (Hunan), HB (Hubei), and SC (Sichuan) was relatively low. These results not only provide theoretical and technical insights for bacon flavor identification and control but also offer a foundation for consumers to make informed choices when purchasing bacon.

Dynamic changes in quality and flavor compounds of pork tendons during puffing process

To improve the portability of dried pork tendons for consumption, this study investigated the effects of different puffing temperatures (190 °C - 250 °C) and times (1-7 min) on the quality and flavor of pork tendons. As the temperature and time increased, the expansion ratio of pork tendons exhibited a gradual increase. The microstructure of the puffed pork tendons exhibited a uniform porous structure at 230 °C and 250 °C for 6 min. However, further puffing treatment destroyed the spatial structure. GC-IMS identified 68 volatile organic compounds (VOCs), and a total of 16 key VOCs including 2-trans-4-trans-decadienal were screened by GC-MS. Nonanal, 1-octen-3-ol, 2-amylfuran and 2-ethylfuran proved to have a significant effect on the flavor of the puffed pork tendon. The combined puffing performance and flavor analysis revealed that puffing at 230 °C for 6 min was the preferred parameter for puffed pork tendons.

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.

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.

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.

Volatile Flavor Analysis in Yak Meat: Effects of Different Breeds, Feeding Methods, and Parts Using GC-IMS and Multivariate Analyses.

This study investigates the effects of breeds, feeding methods, and parts on the volatile flavor of yak meat. Gas chromatography-ion mobility spectrometry (GC-IMS) and multivariate analysis were used to analyze the volatile organic components (VOCs) in yak meat from various sources. A total of 71 volatile compounds were identified, 53 of which were annotated based on the GC-IMS database. These include 20 alcohols, 16 ketones, 10 aldehydes, four alkenes, one ester, one acid, and one furan. Using VOC fingerprinting and multivariate analysis, yak meats from different sources were distinctly categorized. Breed had the most significant impact on yak meat VOCs, followed by feeding method and then part. Six volatiles with a variable importance in projection value greater than one were identified as potential markers for distinguishing yak meat. This study offers insights into the flavor profile of yak meat from different sources and demonstrates the efficacy of GC-IMS and multivariate analysis in characterizing and discriminating meats.

An effective means to improve the flavor quality of traditional fermented sour meat: The salt reduction strategy

The flavor formation of fermented meat products is significantly influenced by salt. In this study, the flavor analysis methods of electronic tongue and nose, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry were utilized to explore the effect of salt content on the formation of sour meat flavor. The results demonstrated a significant decrease in pH value with the reduction of salt content (P < 0.05), while there was a significant rise in thiobarbituric acid reactive substances (TBARS) value associated with the decline in salt content (P < 0.05). Alcohols, aldehydes, and esters such as 1-octen-3-ol, 3-methyl-1-butanol, hexanal, heptanal, ethyl octanoate, ethyl heptanoate, etc. were considered to have significant contributions to the overall flavor of sour meat. The rapid accumulation of these aroma compounds under low-salt conditions was regarded as one of the key factors in the overall flavor enhancement of sour meat products. Additionally, the low-salt fermentation also promoted the accumulation of free amino acids and free fatty acids in sour meat products, thereby facilitating the formation of more complex aroma compounds. This study offers new technological ways to improve the conventional method of fermenting sour meat and offers theoretical justification for studies on salt reduction in conventionally fermented meat products.

The possible inhibition mechanism of low salt dry-curing on volatile flavor deterioration in refrigerated grass carp (Ctenopharyngodon idella) blocks: Metabolomics and microorganisms

Complex microbial communities have an important impact on the flavor of low salt dry-curing (LSD)-pretreated grass carp blocks. Here, the flavors, metabolites, and bacterial diversity of LSD-pretreated fish during cold storage were analyzed using flavor analysis, metabolomics, and high-throughput sequencing to investigate their correlations in detail. LSD promoted the volatile flavor deterioration of grass carp blocks under 6 days of refrigeration but inhibited it under 15 days of refrigeration. Furthermore, 924 metabolites were identified in the refrigerated grass carp blocks, and LSD inhibited the growth of Psychrophilic dominant spoilage microorganisms (Proteobacteria) and promoted microbial abundance (Actinobacteriota, Firmicutes, Bacteroidota, and Cyanobacteria). Correlation analysis revealed that the degradation of phosphatidylcholine connected with the monomonas genus in LSD-pretreated fish blocks played a vital role in inhibiting the key volatile flavor (esters, aldehydes, and alcohols) deterioration. This information is useful for elucidating the inhibition mechanism of LSD on flavor deterioration in refrigerated fish blocks.

Tuning and modeling cheese flavor.

Flavor is a major sensory attribute affecting consumers' preference for cheese products. Differences in cheesemaking change the cheese microenvironment, thereby affecting cheese flavor profiles. A framework for tuning cheese flavor is proposed in this study, which depicts the full picture of flavor development and modulation, from manufacturing and ripening factors through the main biochemical pathways to flavor compounds and flavor notes. Taking semi-hard and hard cheeses as examples, this review describes how cheese flavor profiles are affected by milk type and applied treatment, fat and salt content, microbiota composition and microbial interactions, ripening time, temperature, and environmental humidity, together with packaging method and material. Moreover, these factors are linked to flavor profiles through their effects on proteolysis, the further catabolism of amino acids, and lipolysis. Acids, alcohols, ketones, esters, aldehydes, lactones, and sulfur compounds are key volatiles, which elicit fruity, sweet, rancid, green, creamy, pungent, alcoholic, nutty, fatty, and sweaty flavor notes, contributing to the overall flavor profiles. Additionally, this review demonstrates how data-driven modeling techniques can link these influencing factors to resulting flavor profiles. This is done by providing a comprehensive review on the (i) identification of key factors and flavor compounds, (ii) discrimination of cheeses, and (iii) prediction of flavor notes. Overall, this review provides knowledge tools for cheese flavor modulation and sheds light on using data-driven modeling techniques to aid cheese flavor analysis and flavor prediction.

Flavor identification based on olfactory-taste synesthesia model and hybrid convolutional neural network-random forest

Abstract The bionic-based electronic nose (e-nose) and electronic tongue (e-tongue) show satisfactory performance in flavor analysis. Traditional flavor analysis of the e-nose and e-tongue systems focuses on data fusion, and the effects of the bionic characteristics on the flavor analysis performance are rarely studied. Motivated by this, a method, including an olfactory-taste synesthesia model (OTSM) and a convolutional neural network-random forest (CNN-RF), is proposed for the effective identification of flavor substances. The OTSM is developed for human nerve conduction mechanisms to enhance the bionic characteristics of the e-nose and e-tongue systems and is combined with a CNN-RF model for flavor identification. The results show that, first, when stimulated by e-nose and e-tongue data, physiological 1/f characteristics and synchronization are shown using the OTSM. The enhancement effects on the bionic characteristics of the fusion system are validated using the 1/f characteristics and synchronization. Second, the fully connected layer for the CNN is replaced by RF to improve the identification performance of flavor substances. Finally, CNN-RF is evaluated in comparison with other flavor recognition models and ablation studies to confirm its effectiveness. By comparison, the best recognition performance, including the accuracies of 96.67%, 96.67%, and 95.00%, the F1-scores of 96.65%, 96.66%, and 94.95%, and the kappa coefficients of 96.03%, 96.10%, and 93.44%, for five beers, five apples, and four mixed solutions, respectively, is obtained by CNN-RF. In conclusion, excellent flavor identification for the fusion system is achieved using the OTSM and CNN-RF models.

Comparative analyses of physicochemical and volatile flavor characteristics in hooked, trawl-net, and radar-net hairtail (Trichiurus haumela) muscles during long-term cryopreservation at -18°C.

Chemical analysis showed that pH, b* values, myosin turbidity, carbonyl content, and surface hydrophobicity elevated in hooked, trawl-net, and radar-net hairtail (Trichiurus haumela, HH, TH, and RH) muscles with the prolonged cryopreservation time (-18℃, 120 d). In contrast, L*, a* values, textural properties, and myosin solubility existed decreasing trends. Microstructural results showed that freezing resulted in disordered myofibrils, decreased collagen fibers, widened myofibrillar space, and increased fragmentation in hairtail muscles. Furthermore, volatile flavor analysis suggested that aldehydes, ketones, alcohols, and amines were the key factors for the overall flavor formation in hairtails during cold storage. Pearson correlation coefficient analysis revealed that the color, texture, and protein oxidation had close correlations with VOCs. Among the three different kinds of hairtail, fresh RH fillets exhibited an attractive aroma with high economic value, long-term frozen TH muscle tissues were prone to deterioration in texture, microstructure, and flavor, and the HH samples presented stable quality characteristics and storage performance.

Extraction of egg yolk lipids via salt-induced synergistic heat treatment: Fabrication, characterization and flavor analysis

In this study, the oxidation of egg yolk lipids (EYL) by salt-induced heat and non-heat treatments was investigated for quality and flavor. The correlation between physicochemical properties, lipid oxidation and antioxidant activity was modeled using partial least squares discriminant analysis (PLS-DA). The results indicated that the prolonged salt-induced synergistic heat treatment produced the highest level of lipid oxidation, antioxidant activity and oil exudation, along with the lowest level of polyunsaturated fatty acid content. In addition, higher contents of pyrazines and fewer acid species were detected, which was not the case with the salt-free heat treatment. In total, 14 identical volatile organic compounds (VOCs) were produced, yet their overall flavor profiles determined by the electronic nose would remain dramatically distinguished. Therefore, heat treatment was particularly critical for lipid oxidation and the generation of aromatic compounds, implying that heat-treated EYL induced by salt is a flavor component with good antioxidant potential.

Recent progress in food quality control through flavor analysis using gas chromatography–ion mobility spectrometry

Recent progress in food quality control through flavor analysis using gas chromatography–ion mobility spectrometry

Application of ion chromatographic fingerprint analysis for quality evaluation of tobacco flavors

Tobacco flavor, an important tobacco additive, is an essential raw material in cigarette production that can effectively improve the quality of tobacco products, add aroma and taste, and increase the suction flavor. The quality consistency of tobacco flavors affects the quality stability of branded cigarettes. Therefore, the quality control of tobacco flavors is a major concern for cigarette and flavor manufacturers. Physical and chemical indices, odor similarity, and sensory efficacy are employed to evaluate the quality of tobacco flavors, and the analysis of chemical components in tobacco flavors is usually conducted using gas chromatography (GC) and high performance liquid chromatography (HPLC). However, because the composition of tobacco flavors is complex, their quality cannot be fully reflected using a single component or combination of components. Therefore, establishing an objective analytical method for the quality control of tobacco flavors is of extreme importance. Chromatographic fingerprint analysis is routinely used for the discriminative analysis of tobacco flavors. Chromatographic fingerprints refer to the general characteristics of the concentration profiles of different chemical compounds. In the daily procurement process, fingerprints established by GC and HPLC are effective for the evaluation and identification of tobacco flavors. However, given continuous improvements in aroma-imitation technology, some flavors with high similarity cannot be directly distinguished using existing methods. In this study, a method for the determination of organic acids and inorganic anions in tobacco flavors based on ion chromatography (IC) was developed to ensure the quality consistency of tobacco flavors. A 1.0 g sample of tobacco flavors and 10 mL of deionized water were mixed and vibrated for 30 min. The aqueous sample solution was passed through a 0.45 μm membrane filter and RP pretreatment column in succession to eliminate interferences and then subjected to IC. Standard solutions containing nine organic acids and seven inorganic anions were used to identify the anions in the tobacco flavors, and satisfactory reproducibility was obtained. The relative standard deviations (RSDs) for retention times and peak areas were <0.71% and <6.02%, respectively. The chromatographic fingerprints of four types of tobacco flavors (samples A-D) from five different batches were obtained. Nine tobacco flavor samples from different manufacturers (samples AY1-AY3, BY1-BY2, CY1-CY2, DY1-DY2) were also analyzed to obtain their chromatographic fingerprints. Hierarchical cluster and similarity analyses were used to evaluate the quality of tobacco flavors from different manufacturers. Hierarchical clustering refers to the process of subdividing a group of samples into clusters that exhibit a high degree of intracluster similarity and intercluster dissimilarity. The dendrograms obtained using SPSS 12.0 indicated good quality consistency among the samples in different batches. Samples AY3, BY2, CY2, and DY1 clustered with the batches of standard tobacco flavors. Therefore, hierarchical cluster analysis can effectively distinguish the quality of products from different manufacturers. The Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine (version 2.0) was used to evaluate the similarity between the standard tobacco flavors and products from different manufacturers. Among the samples analyzed, samples AY3, BY2, CY2, and DY1 showed the highest similarity values (>97.7%), which was consistent with the results of the hierarchical cluster analysis. This finding indicates that IC combined with chromatographic fingerprint analysis could accurately determine the quality of tobacco flavors. GC combined with ultrasonic-assisted liquid-liquid extraction was also used to analyze the tobacco flavors and verify the accuracy of the proposed method. Compared with GC coupled with ultrasonic-assisted liquid-liquid extraction, IC demonstrated more significant quality differences among certain tobacco flavors.

Impact of Bacillus subtilis on Chinese yellow rice wine (Huangjiu) fermentation: Method variations and flavor analysis

This investigation explores the impact of various fermentation techniques and the inoculation of Bacillus subtilis spores on the physicochemical properties and principal flavor profiles of Huangjiu. Employing sensory analysis, headspace solid-phase microextraction, gas chromatography-tandem mass spectrometry (HS-SPME-GC–MS), and orthogonal partial least squares discriminant analysis (OPLS-DA), we observed that these variables significantly alter the physicochemical attributes of Huangjiu. Our analysis, integrating volatile organic compounds (VOCs) with odor activity values (OAV), revealed that while B. subtilis inoculation modifies the concentrations of key flavor compounds, it does not affect their types. Notably, the inoculation enhances the concentrations of 13 primary flavor compounds, thereby enriching floral and fruity notes while reducing higher alcohol levels. These findings contribute valuable insights into the flavor formation mechanisms of Huangjiu and guide the optimization of fermentation processes.

Mechanism of key volatiles in osmanthus scented green tea on the improvement of its aroma and taste quality

The intensity of green tea's floral and sweet flavors was enhanced after being scented by osmanthus (OSGT). However, the mechanism of flavor enhancement by key volatiles remains unknown. Here, the role of key volatiles in OSGT on aroma and taste was explored by sensory experiment-guided flavor analysis. Binary mixed models of (E)-β-ionone, dihydro-β-ionone, and α-ionone showed additive interactions on floral aroma enhancement, the interactions were increased with increasing concentrations. At the concentration in OSGT, binary mixed models of (E)-β-ionone, geraniol, linalool, and γ-decalactone showed additive interactions on sweet aroma enhancement. (E)-β-ionone, geraniol, linalool, and γ-decalactone all significantly increased the perceived intensity of sweetness of sucrose solutions. Additionally, molecular docking revealed the perception mechanism of olfactory and taste receptors to the above characterized volatiles, with hydrogen bonding and hydrophobic interactions being the main interactions. This study highlights the importance of characteristic volatiles in enhancing the flavor of OSGT.

Dynamic water migration and flavor analysis of sea cucumber in the process of Sichuan pepper seasoning soak

Soaking in seasoning solution is the main process of sea cucumber seasoning. This study analyzed the dynamic changes in water migration and flavor substances in sea cucumbers during soaking in a Sichuan pepper solution. It was found that the sea cucumber experienced a process of water absorption followed by water loss during the 0–48 h soaking process. During this period, the flavor compounds in sea cucumbers showed different dynamic trends. A total of 46 volatiles were identified, of which 29 were key flavor compounds. Its flavor profiles tended to stabilize as soaking time increased. m-Xylene, d-Limonene, Eucalyptol, p-Xylene, Sabinene, Beta-Myrcene, and Beta-Phellandrene were the main characteristic substances contributing to the differences in sea cucumber flavor. Correlation analysis predicted the relationship between water migration and the dynamic shifts in flavor compounds. This study provides a crucial reference for future studies on the processing and flavor modulation of sea cucumber products.

Ultrasound-induced modifications of beef flavor characteristics during postmortem aging

To investigate the effect of ultrasound treatment on the flavor profile of beef during postmortem aging, a comprehensive analysis of beef flavor was conducted at 0, 7, and 12 d of aging using sensory evaluation and electronic nose. Furthermore, the key volatile flavor compounds were identified using gas chromatography-mass spectrometry (GC–MS), and the odor activity value (OAV) was further evaluated. In addition, the primary pathway involved in flavor formation during beef aging after ultrasound treatment was explored. The results indicated that ultrasound enhanced the flavor profile of beef during postmortem aging by modifying the OAV of hexanal, heptanal, octanal, nonanal, decanal, (Z)-2-nonenal, dodecanal, pentanal, 1-octen-3-ol, octanoic acid, and 2-pentylfuran. Lipid oxidation was a crucial pathway through which ultrasound promoted the generation of volatile flavor compounds in beef, confirmed by the improved oxidation level of fatty acids, particularly monounsaturated ones. The study indicates that ultrasound technology can be regarded as an effective method for enhancing the beef flavor profile during postmortem aging.