Evaluation of aroma characteristics in grass carp mince as affected by different washing processes using an E-nose, HS-SPME-GC-MS, HS-GC-IMS, and sensory analysis

Identification of key physicochemical properties and volatile flavor compounds for the sensory formation of roasted tilapia

Tilapia is suitable for industrial roasting production because of its good flavor and processing adaptability. In this study, the key physicochemical properties and volatile compounds for sensory formation of roasted tilapia were identified after roasting condition optimization. The highest sensory score was obtained at 215 °C, 45 min, and 4% oil. During roasting, the a*, b*, hardness, chewiness, and oxidation of proteins and lipids significantly increased, the moisture content decreased, and the myofibrillar protein aggregation was observed by scanning electron microscope. After identification and quantification by headspace-gas chromatography-ion mobility spectrometry, 10 compounds with odor active value ≥1 were selected as characteristic flavor compounds. The correlation network indicated that the sensory formation mainly resulted from Maillard reaction, myofibrillar protein aggregation, and improvement of pleasant volatile flavor compounds induced by oxidation of proteins and lipids and water loss. This study provides an important theoretical basis and technical support for roasted tilapia production.

Different stages of flavor variations among canned Antarctic krill (Euphausia superba): Based on GC-IMS and PLS-DA

The aim of the present study was to explore changes in the profile of volatile compounds (VCs) in canned Antarctic krill (Euphausia superba) at different processing stages using partial least squares discriminant analysis (PLS-DA) and gas chromatography-mass spectrometry (GC-IMS). A total of 43 VCs were detected using GC-IMS in all krill meat samples, which included mainly alcohols, aldehydes, ketones, esters, and furans. Considering the different processing stages, the highest variation in VCs and the highest VC content were observed in krill meat which underwent both blanching and salt addition. PLS-DA further revealed flavor differences in canned Antarctic krill meat at different processing stages, with octanal, 2-hexanol, 2-octane, 2,3,5-trimethyl pyrazine, and cis-3-hexanol as the main contributors to observed differences in VC profiles. These findings contribute to the production of high-quality canned krill meat, enhancing its flavor quality and providing a feasible theoretical basis for future krill meat pretreatment and industry development.

Insight into the role of lipids in odor changes of frozen grass carp (Ctenopharyngodon idella) based on lipidomics and GC-MS analysis: Impact of freeze-thaw cycles and heat treatment

The role of lipids in changes of volatile organic compounds (VOCs) in grass carp during 1 month of frozen storage with different freeze-thaw cycles and subsequent heat treatment was investigated. Sixty VOCs were identified in all groups by SPME-GC-MS. Odor contents fluctuated along with the freeze-thaw cycles and heat treatment, and the highest odor content was observed in frozen sample without freeze-thaw cycles. Freeze-thaw and heat treatment significantly promoted the lipid oxidation and hydrolysis for all the groups(p<0.05). Lipid metabolites were analyzed using non-targeted lipidomics and could be well distinguished among different freeze-thaw groups and heat-treatment groups. A total of 10 key differential lipid molecules were annotated, involving 4 metabolic pathways related to lipid degradation and odor formation. Spearman correlation analysis showed that these key differential lipids were significantly related to the formation of key VOCs (p<0.05).

Analysis of volatile compound metabolic profiles during the fermentation of filler tobacco leaves through integrated E-nose, GC-MS, GC-IMS, and sensory evaluation

Tobacco is an agricultural commodity with great economic significance. Producers recognize that the flavor characteristics of filler tobacco clear-out (FTLs) affect the quality of cigar tobacco items. To identify the major volatile organic compounds (VOCs) responsible for differences in FTLs, E-nose, HS-SPME-GC-MS, and HS-GC-IMS were employed for multi-dimensional analysis of nine groups of FTLs at various fermentation stages. The E-nose results indicated a progressive increase in nitrogen-oxygen compounds during fermentation. Coupled with these findings, HS-SPME-GC-MS identified 56 VOCs, and HS-GC-IMS revealed 55 VOCs in the FTLs. Principal component analysis (PCA) suggested that FTLs from various fermentation stages of the Yunxue No 39 tobacco plant exhibit significant differences. Partial least squares discriminant analysis (PLS-DA), along with the variable importance in projection (VIP) method for feature selection, pinpointed 12 VOCs as the essential unmistakable metabolites embroiled within the agrarian fermenting prepare of matured FTLs. During the fermentation process, these crucial metabolites are predominantly enriched in pathways including pyruvate metabolism, phenylalanine metabolism, as well as nicotinate and nicotinamide metabolism. The study provides insights into the differences and diversity of FTLs at agricultural fermentation stages. It offers valuable information for optimizing the quality of agricultural fermentation and guiding the directional fermentation of tobacco leaves.

Identification of Key Volatile Compounds in Tilapia during Air Frying Process by Quantitative Gas Chromatography-Ion Mobility Spectrometry

Air frying as a new roasting technology has potential for roasted fish production. In this study, the changes in volatile compounds (VCs) during air frying of tilapia were studied by quantitative gas chromatography-ion mobility spectrometry, followed by the identification of key VCs based on their odor activity value (OAV). There were 34 verified VCs, of which 16 VCs were identified as the key VCs with OAV ≥ 1. Most of the VCs were improved by air frying and peaked at 20 min. During the air frying, the total sulfhydryl content markedly decreased, while the protein carbonyl and MDA content significantly increased, suggesting the enhancement in the oxidation of lipids and proteins. The correlation network among the chemical properties and key VCs was constructed. The change in total sulfhydryl, protein carbonyl, and MDA showed significant correlation with most of the key VCs, especially 2-methyl butanal, ethyl acetate, and propanal. The results indicated that the oxidation of lipids and proteins contributed the most to the flavor improvement in air-fried tilapia. This study provides a crucial reference for the volatile flavor improvement and pre-cooked product development of roasted tilapia.

Characterization of the flavor profile of four major Chinese carps using HS-SPME-GC-MS combined with ultra-fasted gas chromatography-electronic nose

The four major Chinese carps are highly popular for their distinctive nutritional benefits. However, the differences in flavor among these carps remain unclear. This study investigated the flavor profiles of these carps using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with ultra-fasted gas chromatography electronic nose (GC E-nose). The four major Chinese carps had high protein content (16.68-18.61 %) and low fat levels (0.42-1.29 %). A total of 45 volatile compounds were identified in these carps. Both the GC E-nose and HS-SPME-GC-MS results consistently showed significant flavor profiles differences among these carps, with Ctenopharyngodon Idella (CI) exhibiting the most pronounced distinctions compared to the other three species. Based on VIP >1 and p < 0.05, 10 key compounds including 2-Nonanone, Cyclodecanol, Eugenol, 1,3-Cyclooctadiene, etc., largely contributed to the distinctive overall flavor profile of four major Chinese carps derived mainly from amino acid and fatty acid metabolism.

Cryoprotective effect of epigallocatechin gallate replacing sucrose on Hypophythalmichthys molitrix surimi during frozen storage

BACKGROUND

The present study aimed to investigate the cryoprotective effect of epigallocatechin gallate (EGCG) replacing sucrose on surimi during frozen storage. Substitution or partial substitution of 0.1% EGCG for sucrose (1.5%) was added to surimi, and the surimi samples without and with commercial cryoprotectants (4% sucrose and 4% sorbitol) were used as the control group.

RESULTS

The results obtained suggest that, with the increase in frozen storage time, the structural performance of surimi protein gradually weakened (e.g. the decrease in the surface hydrophobicity, the increase in the total sulfhydryl and solubility, and the protein myosin heavy chain bands became shallow) and surimi gel quality gradually deteriorated (e.g. the decrease in water-holding capacity, gel strength and all texture profile attributes). However, compared with the other three group surimi samples during the frozen period, the surimi proteins with partial replacement of sucrose by EGCG had a higher total sulfhydryl group content and solubility of proteins, as well as lower surface hydrophobicity of protein, suggesting that the addition of EGCG as a partial substitute for sucrose can enhance the antifreeze ability of surimi. Meanwhile, the surimi gel with the partial replacement of sucrose by EGCG had a higher water retention capacity, gel strength and texture attributes (e.g. hardness, springiness, cohesiveness, chewiness, and resilience), indicating that the addition of EGCG as a partial substitute for sucrose can inhibit the deterioration of surimi gel quality.

CONCLUSION

Overall, EGCG partially replacing sucrose can play an alternative cryoprotectant with a lower sweetness to prevent the quality of surimi from deteriorating. © 2024 Society of Chemical Industry.

Comparison of Different Deodorizing Treatments on the Flavor of Paddy Field Carp, Analyzed by the E-Nose, E-Tongue and Gas Chromatography-Ion Mobility Spectrometry

Changes in the flavor and taste profiles of Paddy Field Carp after deodorization with perilla juice (PJ), cooking wine (CW) and a mixture of the two (PJ-CW) were analyzed using the E-nose, E-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), free amino acid analysis and taste nucleotide analysis. The E-nose and E-tongue revealed that deodorization reduced the content of sulfur-containing compounds, enhanced umami, bitterness, sourness and astringency, and decreased saltiness. PCA and OPLS-DA analysis successfully distinguished between the effects of the treatments. Free amino acids increased from 8777.67 to 11,125.98 mg/100 g and umami amino acids increased from 128.24 to 150.37 mg/100 g after PJ-CW deodorization (p < 0.05). Equivalent umami concentration (EUC) comparisons showed that PJ-CW treatment produced the greatest synergistic umami enhancement (to 3.15 g MSG equiv./100 g). GC-IMS detected 52 aroma compounds; PJ treatment produced the greatest diversity of aldehydes, including heptanal, nonanal, hexanal, 3-methylbutanal, (E)-2-heptenal and (E,E)-2,4-heptadienal. The total content of volatile flavor compounds was the highest after PJ-CW treatment, and the content of many characteristic flavor substances (3-hydroxy-2-butanone, benzaldehyde, 5-methyl-2(3H)-furanone) increased. These findings provided a theoretical basis for the further development of deodorization methods for Paddy Field Carp.

Characterization and Differentiation of Flavor Profile of 12 Air-Dried Yak Meat Products Using GC-IMS and Multivariate Analysis

Volatile organic compounds (VOCs) in food are key factors constituting their unique flavor, while the characteristics of VOCs in air-dried yak meat (AYM) from various regions of the Tibetan Plateau and their inter-regional differences remain unclear. Therefore, this study conducted a comprehensive analysis of VOCs in the five-spice (FS), spicy and numbing (SN), and aromatic and spicy (AS) versions of AYM from four regions of the Tibetan Plateau (Gansu, Qinghai, Sichuan, and Tibet) using gas chromatography-ion mobility spectrometry (GC-IMS) A total of 58 VOCs were identified, with alcohols accounting for 28.40%, ketones 22.89%, aldehydes 18.85%, and terpenes 17.61%. Topographic plots, fingerprint profiles, and multivariate analysis not only distinguished AYM of the same flavor from different regions but also discriminated those of different flavors within the same region. Furthermore, 17 key VOCs were selected as the primary aroma characteristics of the 12 types of AYM, including linalool, 3-methylbutanal, acetone, and limonene. Meanwhile, the differential VOCs for each flavor were determined, with linalyl acetate being unique to the FS, (E)-ocimene and ethyl propanoate being specific to the SN, and 2-methyl-3-(methylthio)furan-D and Hexanal-D being characteristic of the AS flavor. Based on the above results, the flavor of AYM can be improved to suit the taste of most people and increase its consumption.

Effect of Potentilla anserina L. powder on gel properties and volatile flavor characteristics of silver carp surimi

BACKGROUND

Potentilla anserina L. is rich in various nutrients, active ingredients and unique flavor, comprising a natural nutrition and health food. However, its application in aquatic food has been rarely reported. Therefore, the effects of Potentilla anserina L. powder (PAP) on gel properties and volatile flavor profile of silver carp surimi were investigated.

RESULTS

The gel strength and water-holding capacity of the surimi gels were significantly improved (P < 0.05), and the whiteness and cooking loss of all the samples decreased slightly with the increase in PAP content. The addition of PAP shortened the relaxation time (T2) of the surimi gels and converted some of the free water into immobile or bound water, which resulted in a better immobilization of water in the surimi. Scanning electron microscopy images demonstrated that the network of surimi gels with PAP added was denser and had a smoother surface compared to the control. Volatile components (VCs) analysis showed that 33 VCs were identified in the surimi gel samples with different additions of PAP, among which aldehydes, alcohols and esters were the major VCs, accounting for more than 50% of the VCs in the surimi gels. PAP addition reduced the fishy and rancid flavor compounds in surimi gels, such as 1-propanol, 1-octen-3-ol, etc., and promoted the production of aldehydes, alcohols, esters and other flavor substances.

CONCLUSION

These results of the present study provide theoretical support for the investigation and development of new nutrient-health-flavored surimi products. © 2024 Society of Chemical Industry.

Evaluation of aroma characteristics of Penaeus vannamei with different drying methods using HS-SPME-GC-MS, MMSE-GC-MS, and sensory evaluation

The effects of microwave drying (MD), hot air drying (HAD), vacuum hot air drying (VD), and vacuum freeze drying (VFD) on the volatile profiles of Penaeus vannamei were investigated. A total of 89 and 94 volatile compounds were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and monolithic material sorptive extraction gas chromatography-mass spectrometry (MMSE-GC-MS), respectively. Orthogonal partial least squares-discriminant analysis (OPLS-DA) and variable influence on projection (VIP) models were utilized to select characteristic volatiles and key marker compounds (e.g., octanal, 1-octen-3-ol, 2-methyl-butanal, 2-ethyl-furan, and trimethyl-pyrazine) to discriminate among four drying methods. Based on synthesis of odor descriptions and sensory evaluation, it was found that P. vannamei via MD, HAD, and VD greatly reduced the fishy and generated roasted, fatty, and smoked odors. This study systematically analyzed the aroma characteristics of four traditional dried P. vannamei products, which may provide theoretical guidance for industrial production.

Effect of Lactobacillus plantarum and flavourzyme on protein degradation and flavor development in grass carp during fermentation

This study examined the effect of Flavourzyme and Lactobacillus plantarum (L. plantarum) on protein degradation and flavor development during grass carp fermentation. The control groups comprised natural fermentation and fermentation with L. plantarum. Compared with the two control samples, those exposed to combined Flavourzyme and L. plantarum fermentation exhibited lower moisture content and enhanced protein hydrolysis, which accelerated the production of water-soluble taste substances (trichloroacetic acid-soluble peptides and free amino acids). The electronic tongue and electronic nose results indicated that the grass carp subjected to combined fermentation way displayed a more intense umami taste and aroma. Moreover, the sensory evaluation results confirmed that the combined fermentation method significantly improved the taste and odor attributes of fermented grass carp. In conclusion, combined fermentation with Flavourzyme and L. plantarum may effectively reduce fermentation time and enhance the flavor of fermented grass carp products.

Characterization of the key flavor compounds in cream cheese by GC-MS, GC-IMS, sensory analysis and multivariable statistics

The aroma types of cream cheese affect its commercial value and consumer acceptability. However, the types of volatile substances and sensory characteristics of cream cheese at different fermentation stages are still unclear. Therefore, in this study, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) were used to analyze the volatile substances in cream cheese fermentation. Orthogonal partial least squares discriminant analysis (OPLS-DA), odor activity value (OAV), relative odor activity value (ROAV) and variable projection importance (VIP) were used to identify the characteristic flavor substances in cream cheese fermentation. Finally, the relationship between key flavor substances and sensory characteristics was determined by partial least squares (PLS) analysis. A total of 34 and 36 volatile organic compounds were identified by HS-SPME-GC-MS and HS-GC-MS, respectively, and 14 characteristic flavor substances were found, based on VIP, ROAV and OAV models. Combined with sensory analysis and flavor substance changes, it was found that the cream cheese fermented for 15 d had the best flavor and taste. This study reveals the characteristics and contribution of volatile substances in cream cheese at different fermentation stages, which provides new insights into improving flavor and quality control.

Explorative study for the rapid detection of adulterated surimi using gas chromatography-ion mobility spectrometry

Driven by economic interests, surimi adulteration has become a high-frequency issue. This study aims to assess the feasibility of gas chromatography-ion mobility spectrometry (GC-IMS) in detecting surimi adulteration. In this work, three common adulterated surimi models were established by mixing with different fish species and ratios. The fingerprints enabled a clear discrimination among different tuna surimi, and other two surimi models with different mixing ratios also showed VOCs (volatile organic compounds) differences. Results of unsupervised principal component analysis (PCA) and supervised partial least-squares discrimination analysis (PLS-DA) revealed that different types of adulterated surimi models can be well separated from each other. A total of 12, 16, and 9 VOCs were selected as the potential markers in three simulated models by PLS-DA method, respectively. Therefore, GC-IMS coupled with certain chemometrics is expected to serve as an alternative analytical tool to directly and visually detect adulterated surimi.

Comparative analysis of soluble and insoluble dietary fiber on improving the gelation performance and fishy odors of silver carp surimi

This work investigated the effects and mechanisms of soluble and insoluble dietary fiber (SDF and IDF) on the gelation performance and fishy odors of silver carp surimi. The results showed that the gel properties of surimi increased and then decreased with increasing SDF content, and the best gel properties were achieved at 1 wt% SDF. The gel strength, elasticity and deformation resistance of surimi increased in a dose-dependent manner as affected by IDF, but its effect on viscosity and recovery ratio was similar to SDF. Moreover, 2 wt% SDF and 1 wt% IDF reduced the content and odor activity value (OAV) of most fishy compounds in surimi, and the latter was superior to the former. The rheological characteristics indicated that SDF affected the thermal gelation properties of surimi mainly through filling, concentration and volume exclusion, and IDF mainly through filling, concentration and intermolecular interactions between IDF and myofibrillar protein. Additionally, SDF and IDF inhibited the release of fishy odors by improving the gel network structure and their adsorption, but more SDF (2 wt%) promoted the formation of escape channels for odors release. In summary, 1 wt% IDF could simultaneously improve the gelation performance and fishy odors of silver carp surimi.

Research progress of fishy odor in aquatic products: From substance identification, formation mechanism, to elimination pathway

Fishy odor in aquatic products has a significant impact on the purchasing decisions of consumers. The production of aquatic products is a complex process involving culture, processing, transportation, and storage, which contribute to decreases in flavor and quality. This review systematically summarizes the fishy odor composition, identification methods, generation mechanism, and elimination methods of fishy odor compounds from their origin and formation to their elimination. Fishy odor compounds include aldehydes (hexanal, heptanal, and nonanal), alcohols (1-octen-3-ol), sulfur-containing compounds (dimethyl sulfide), and amines (trimethylamine). The mechanism of action of various factors affecting fishy odor is revealed, including environmental factors, enzymatic reactions, lipid oxidation, protein degradation, and microbial metabolism. Furthermore, the control and removal of fishy odor are briefly summarized and discussed, including masking, elimination, and conversion. This study provides a theoretical basis from source to elimination for achieving targeted regulation of the flavor of aquatic products, promoting industrial innovation and upgrading.

Discrimination and characterization of different ultrafine grinding times on the flavor characteristic of fish gelatin using E-nose, HS-SPME-GC-MS and HS-GC-IMS

Three different methods were used to identify and analyze the flavor of fish gelatin with different ultrafine grinding time (0, 2, 4 and 8 h). The results of electronic nose showed that overall flavor of the samples changed. HS-SPME-GC-MS identified 65 volatile compounds, including 18 aldehydes, 7 ketones, 7 alkanes, 11 alcohols, 8 esters, 7 phenols, and 7 acids. HS-GC-IMS identified 46 volatile compounds, including 21 aldehydes, 5 ketones, 5 alcohols, 6 esters, 7 acids, 1 ether, and 1 amine. The particle size analysis results indicate that the size distribution decreases from 918.97-1167.16 and 1388.81-1780.40 nm to 157.63-177.37 and 285.90-344.55 nm with the increased of grinding time. The SEM analysis results indicate that the change in flavor characteristics of FG is due to the different storage and release abilities of volatile compounds in FG with different particle sizes.

Adsorption characteristics of V-type starch for off-odors of sea cucumber intestinal peptides in solid-phase environment

With the concern of the strong fishy odor of sea cucumber intestinal peptides, the deodorization potential of V-type starch with a flexible cavity was investigated. By gas chromatography-mass spectrometry and electronic nose, it was confirmed that V-type starch effectively deodorized key off-odor compounds (isobutyric acid, butanoic acid, 1-octen-3-ol, nonanal, and trimethylamine), and the optimum deodorization performance (adsorption ratio of 92.45%) was achieved after 8 h adsorption at the sea cucumber intestinal peptide to starch ratio of 1:15 (w/w). In the Fourier transform infrared spectrum of the V-type starch inclusion complexes, a new characteristic peak was observed at 1563 cm-1 when the sea cucumber intestinal peptide to starch ratio was 1:1 (w/w). The presence of this peak was attributed to the complexation between V-type starch and trimethylamine. For the first time, we demonstrated that the V-type starch could deodorize aquatic products, and this study contributes to the application of starch materials.

Identification and biotransformation analysis of volatile markers during the early stage of Salmonella contamination in chicken

Salmonella is one of the most prevalent foodborne pathogens in poultry and its products. Its rapid detection based on volatile organic compounds (VOC) has been widely accepted. However, the variation in the VOCs of Salmonella-contaminated chicken during the early stage (48 h) remains uncertain. Headspace-SPME-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace-gas chromatography-ion migration spectroscopy (HS-GC-IMS) were used to identify VOCs and their variations after the chicken meat was contaminated with Salmonella. Chemometric and KEGG enrichment analyses were performed to identify VOC markers and their potential metabolic pathways. A total of 64 volatile compounds were detected using HS-GC-IMS, which showed a better differentiation than HS-SPME-GC-MS (45 volatile compounds) based on principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). Fatty acid degradation was the main cause of VOC variation. 2-Propanol, hexadecane, 3-methylbutanol, acetic acid, propyl acetate, acetic acid methyl ester, and 3-butenenitrile were identified as VOC markers in the middle stage of decomposition, and 1-octen-3-ol was recognized as a VOC marker of Salmonella-contaminated chicken during the first 48 h of contamination. This provides a theoretical basis for the study of Salmonella contamination VOC markers in poultry meat.

Flavor and sensory profile of Chinese traditional fish noodles produced by different silver carp (hypophthalmichthys molitrix) mince ingredients

This study employs sensory evaluation, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) techniques to investigate the effect of different pretreatment of fresh silver carp mince (running water rinsing 0, 1, or 2 times) and commercially frozen surimi on the odor characteristics of fish noodles. The free choice profiling (FCP) and check all that apply (CATA) sensory analysis methods were utilized to identify 10 characteristic descriptors, which include "grass, fish fragrance, unpleasant fishy, fatty, roast, ammonia, caramel, warmed-over, earthy, and mushroomy". HS-GC-IMS and HS-SPME-GC-MS detected 80 and 37 volatile compounds (VCs) in fish noodles. The 1-Penten-3-ol, (E)-2-pentenal-D, hexanal-D, pentanal-D, (E,E)-2, 4-heptadienal-D contents were significantly correlated with "fish fragrance" and "unpleasant fishy", and octanal, nonanal, heptanal, 2-methylpyrazine contents were significantly correlated with "warmed-over" flavor. The results of this study can be helpful for fish noodle quality improvement and industrial production.

Insights into the volatile flavor and quality profiles of loquat (Eriobotrya japonica Lindl.) during shelf-life via HS-GC-IMS, E-nose, and E-tongue

Loquat fruits are among the most popular Chinese fruits because of their unique taste and aroma. The quality profiles of these fruits during 18 days of shelf-life at 20 °C were elucidated by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), E-nose, and E-tongue. During shelf-life period, the properties and variations of 43 (20 aldehydes, 7 esters, 6 ketones, 1 alcohol, and 1 furan) volatile flavored compounds were determined by GC-IMS, which showed that the contents of methyl 3-methyl butanoate, ethyl acetate, and dimethyl ketone gradually decrease with prolonged shelf-life time, while (E)-2-heptenal, heptanal, (E)-2-pentenal, 1-penten-3-one 3-pentanone and 2-pentylfuran increase. The PCA based on the signal intensity of GC-IMS and E-nose, revealed that loquat fruits are well distinguished at different shelf-life times. The taste profile alternates as the storage time increases, along with higher pH, and lower amounts of total soluble solids, vitamin C, and total phenolics. The visual plots of GC-IMS, E-nose, and E-tongue had good consistency, and they characterized the aroma characteristics of loquat fruits well during different shelf-life periods. The findings of this research provide a useful understanding of the flavors of loquat fruits during their prolonged shelf-life, and a potential research basis for advancements in the loquat industry.

Comprehensive evaluation of aroma and taste properties of different parts from the wampee fruit

Wampee is a tropical fruit having high medicinal value. To fully realize the fruit's potential, it is essential to reveal the flavor characteristics. In this study, a comprehensive analysis of the aroma and taste profiles of different parts from the wampee fruit was conducted. The aroma profile was analyzed by E-nose, and 67 volatile components were identified through HS-SPME-GC-MS. Among them, 11 were considered as crucial compounds. Additionally, 42 volatile components were identified by HS-GC-IMS, with 22 compounds showing a variable importance in projection scores greater than 1.0. Moreover, the taste profile and representative compounds were analyzed by E-tongue and HPLC, and 12 compounds were considered as important taste contributors based on taste activity value. These findings shed light on the various compounds responsible for the unique aroma and taste of the wampee fruit, providing theoretical foundation for exploring ways for its comprehensive utilization and development.

Potential biomarkers analysis and protein internal mechanisms by cold plasma treatment: Is proteomics effective to elucidate protein-protein interaction network and biochemical pathway?

New market trends of meat flavor, tenderness, and color quality indicators have prompted the research on meat preservation as a crucial topic to received attention. Present research about the effects of irradiation, cold plasma technology on meat is incomplete. There are strongly recommended that proteomics techniques be jointly to enhance the coverage of internal meat molecules for meat research. By identifying meat proteins, detecting biological functions, and quantifying the protein segments of specific meat biomarkers, which can be provided for the information of diagnostic components in preservative technologies. The current review provides scientific findings on various control strategies: (i) combine the data-independent acquisition to provide a reference for the meat molecular mechanism and rapid identification; (ii) design molecular networks biological functions assessment model; (iii) molecular investigations of cold plasma techniques and underlying mechanisms; (iv) explore the X-rays and γ-rays treatment in meat preservation and myoglobin change mechanism more comprehensively.

Identifying Early-Stage Changes in Volatile Organic Compounds of Ceratocystis fimbriata Ellis & Halsted-Infected Sweet Potatoes (Ipomoea batatas L. Lam) Using Headspace Gas Chromatography-Ion Mobility Spectrometry

Ceratocystis fimbriata Ellis & Halsted is the pathogen causing black rot in sweet potatoes that can lead to flavor change and toxin release. This study detected the volatile organic compounds (VOCs) of C. fimbriata-infected sweet potatoes in the early stages using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). A total of 55 VOCs were identified, including aldehydes, alcohols, esters, ketones, and others. The content of aldehydes and ketones showed a decreasing trend, while alcohols and esters showed an increasing trend. An increase in infection time elevated the content of malondialdehyde (MDA) and pyruvate, while the starch content decreased, the content of soluble protein initially increased, then decreased, and the activities of lipoxygenase (LOX), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and phenylalanine ammonia-lyase (PAL) increased. The changes in VOCs were closely related to the content of MDA, starch, pyruvate, and the activities of LOX, PDC, ADH, and PAL. Sweet potatoes showed a good discrimination effect by principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) from 0 to 72 h. Twenty-five differential VOCs could be used as early-stage characteristic compounds of C. fimbriata-infected sweet potatoes for early disease monitoring.

Hot Air Convective Drying of Ginger Slices: Drying Behaviour, Quality Characteristics, Optimisation of Parameters, and Volatile Fingerprints Analysis

Ginger is one of the most popular spices and medical herbs with its unique pungent flavour and taste. Although there has been much research into the drying methods of ginger, the effect of drying parameters in hot air convective drying on ginger quality needs to be explored in depth. This study investigated the differences in drying behaviour and quality characteristics of ginger with the variables of temperature, thickness, and loading density. The moisture states and diffusion pattern in the different stages during the drying process were analysed using low-field NMR techniques. The results of quality evaluation showed that the temperature greatly influenced the colour and gingerol content of dried ginger, and the thickness of a ginger slice greatly influenced the rehydration rate. Optimal drying conditions were determined by considering a combination of specific energy consumptions with quality retention based on the response surface methodology: a temperature of 66.41 °C, thickness of 2 mm, and loading density of 5 kg/m2. HS-GC-IMS combined with multivariate chemometrics was used to achieve the characterisation of flavour profiles and fingerprinting of dried ginger. The principal component analysis and correlation analysis revealed that the alterations in ginger quality were intimately related to moisture diffusion during drying.

Characterization of the key aroma compounds in soy sauce by gas chromatography-mass spectrometry-olfactometry, headspace-gas chromatography-ion mobility spectrometry, odor activity value, and aroma recombination and omission analysis

Most previous studies on volatile compounds in soy sauce were performed by gas chromatography-mass spectrometry (GC-MS). In this study, the volatile compounds of high-salt liquid-state fermentation soy sauce (HLFSS) were analyzed qualitatively and quantitatively by GC-MS and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). One hundred and seventy-four substances were detected using the two instruments, 87 by HS-GC-IMS and 127 by GC-MS. Aldehydes (26), ketones (28), esters (29), and alcohols (26) were the main compounds in HLFSS. In addition, ethyl pyruvate, (E)-2-pentenal and diethyl propanedioate were detected by HS-GC-IMS, which were previously not detected in HLFSS. Forty-eight aromatics including 34 key ones were identified by gas chromatography-olfactometry. Phenylacetaldehyde, methional, 2-methylbutanal, 1-octen-3-ol, ethyl acetate, 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone and 4-ethyl guaiacol were identified as the main aroma compounds in HLFSS by aroma recombination and omission test. This study laid foundation for developing flavor assessment standards for soy sauce.

Unraveling the microbial succession during the natural fermentation of grass carp and their correlation with volatile flavor formation

Complex microbial communities contribute significantly to the flavor formation of traditional fermented fish products. However, the relationship between microorganisms and flavor formation in traditional fermented grass carp products is still unclear. In this study, the diversity and succession of microbial communities and the variation of volatile compounds during natural fermentation of grass carp were analyzed using high-throughput sequencing of 16S rRNA and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), respectively. The core functional microorganism and key volatile compounds were identified, and their potential relationship was revealed using a correlation network model analysis. The microbial community analysis result showed that the microbial diversity during natural fermentation of grass carp decreased markedly with increasing fermentation time, and Lactiplantibacillus, Staphylococcus, and Enterobacter were the dominant genera in naturally fermented grass carp. HS-SPME-GC-MS analysis result showed that 45 volatile compounds were identified from fermented samples, among which 13 compounds (e.g., hexanal, heptanal, nonanal, decanal, 3-octanone, 3-methyl-1-butanol, 1-hexanol, 1-heptanol, 1-octen-3-ol, 1-octanol, ethyl acetate, 3-methyl-1-butanol acetate, and 2-methoxy-4-vinylphenol) were identified as the key volatile compounds. Additionally, the correlation network model analysis result revealed that Lactiplantibacillus showed significantly positive correlations with most of the key volatile compounds, making an important contribution to the formation of volatile flavor in naturally fermented grass carp. This study may lead to an understanding of the role of core functional microorganisms in the formation of volatile flavor during the natural fermentation of grass carp and provide some theoretical guidance for the industrial production of high-quality fermented grass carp products.

Identification of the key off-flavor odorants for undesirable spoiled odor in thermally sterilized fermented soymilk

Spoiled odors are a problem in thermally sterilized fermented soymilk. This study aims to clarify production conditions and key odorants of spoiled odors. The sensory evaluation showed that thermal sterilization caused a decrease in the sensory intensity of yogurt and fruity odors while significantly increasing undesirable aromas including beany, acidic, cooked-beans and spoiled odors. The spoiled odors increased with increasing acidity and heating temperatures. The strongest spoiled odor was observed in fermented soymilk at titratable acidity of 5.4 g/kg, sterilized at 90 °C. Apart from common volatiles that were inherent in soymilk and generated from lactic fermentation, 2-methyltetrahydrothiophen-3-one was found for the first time in soybean foods and was found to cause the spoiled odor. 44 volatiles found in thermally sterilized fermented soymilk were jointly formed its flavor wheel. This study provides important theoretical support for solving the problem of spoiled odor restricting the popularization of plant-based fermented soymilk.

Assessment of flavor characteristics in snakehead (Ophiocephalus argus Cantor) surimi gels affected by atmospheric cold plasma treatment using GC-IMS

The gel formation ability of freshwater surimi is weak, resulting in its poor flavor and quality. Atmospheric cold plasma (ACP), a widely developed non-thermal processing technology in the food industry, is considered to have potential applications in maintaining and improving the flavor characteristics of surimi gels. In this study, the effect of ACP on snakehead surimi gels flavor at different treatment times was investigated by sensory evaluation and gas chromatography-ion mobility spectrometry (GC-IMS) analysis. The results showed that ACP could better maintain and improve the original appearance and tissue state characteristics of surimi gels, scoring about 1-2 points higher than the ACP-untreated group. GC-IMS analysis demonstrated the obvious difference in the volatile organic compounds (VOCs) among the treatment groups. Specifically, the samples treated for 120 s with ACP exhibited the most unique aroma characteristics, which probably related to the highest thiobarbituric acid reactive substances values (73.28 μmol MDA/kg sample). Meanwhile, the reduced TCA-soluble peptides content indicated that ACP could inhibit protein degradation to maintaining the tissue state and flavor characteristics of the surimi gels. In conclusion, the advantages of ACP treatment, such as little damage to nutrients, and maximum retention of original sensory properties, provide new ideas for its application in the flavor characteristics of the snakehead surimi gels.

Investigation on the quality regulating mechanism of antifreeze peptides on frozen surimi: From macro to micro

Freeze denaturation of protein caused by ice crystals is the main motivation for the quality deterioration of surimi during circulation and storage. This investigation aimed to cryoprotect surimi by adding antifreeze peptides from Takifugu obscurus skin (TsAFP) which can inhibit ice recrystallization, and to elucidate regulating mechanism. The comprehensive results showed that 4% TsAFP, half dosage of commercial cryoprotectant, had good cryoprotection on surimi by reducing the moisture variation and maintaining protein solubility of surimi at macro level, as well as inhibiting the degeneration and structure changes of myofibrillar proteins at micro level. Meanwhile, TsAFP could directly bind to the structural cavity of myosin, inhibit protein freezing-induced oxidation, maintain the spatial structure of myosin and water retention ability to preserve the surimi quality. This study helped better comprehend the protective mechanisms of antifreeze peptides in frozen surimi and was expected to provide a promising cryoprotectant for low-sweetness and low-calorie surimi.

Ready-to-Eat Fish Cake Processing Methods and the Impacts on Quality and Flavor

This study aimed to compare tilapia fish cake drying and sterilization conditions (105, 115, and 121 °C) on the quality of the cakes. The impacts of volatile flavor substances, the chroma value, quality and structure characteristics, microscopic structure, and the types and content of volatile flavor substances were also analyzed. The results showed that after drying and sterilization, the L* value, W value and delta-E value of fish cakes decreased significantly from 77.12 to 64.77, 66.21 to 52.57, 10.46 to 24.50, respectively. However, a* value and b* value increased significantly from 0.30 to 6.97 and 24.85 to 30.89, respectively. The elasticity, hardness, and chewiness increased significantly with the drying process but decreased significantly with the increased sterilization temperature. Scanning electron microscopy results showed that the internal pores of the fish cakes became smaller, and the tissue structure was closer after drying. Gas chromatography-ion mobile spectrometry analysis identified a total of 36 volatile flavor compounds. Among these, ketones comprised the largest content, aldehydes represented the largest variety, and all volatile compounds contributed significantly to the flavor of fish cake. PCA results and nearest-neighbor fingerprint analysis showed that there were obvious differences in volatile flavor compounds between different treatments. In summary, this study conducted a detailed comparative analysis of the quality and flavor of fish cakes subjected to different processing methods. These findings contribute suggestions for sterilization temperatures in industrial production processes.

Characterization of the Key Aroma Volatile Compounds in Nine Different Grape Varieties Wine by Headspace Gas Chromatography-Ion Mobility Spectrometry (HS-GC-IMS), Odor Activity Values (OAV) and Sensory Analysis

During this study, the physicochemical properties, color, and volatile aroma compounds of the original wines produced from the grape varieties ‘Hassan’, ‘Zuoshaner’, ‘Beibinghong’, ‘Zuoyouhong’, ‘Beta’, ‘Shuanghong’, ‘Zijingganlu’, ‘Cabernet Sauvignon’, and ‘Syrah’ were determined and sensory evaluation was performed. Results indicated that ‘Hassan’ contained the most solids, ‘Zuoshaner’ produced the most total acid, residual sugar, total anthocyanin, and total phenol, and ‘Shuanghong’ produced the most tannin. Calculation of the chroma and hue of the wines according to the CIEL*a*b* parameters revealed that the ‘Cabernet Sauvignon’ wines were the brightest of the nine varieties and that the ‘Zuoshaner’ wines had the greatest red hue and yellow hue and the greatest saturation’. A total of 52 volatile compounds were identified and quantified in nine wine samples by HS-GC-IMS analysis, with the most significant number of species detected being 20 esters, followed by 16 alcohols, 8 aldehydes, four ketones, one terpene, and one furan, with the highest total volatile compound content being ‘Beta’. A total of 14 volatile components with OAV (odor activity value) >1 were calculated using the odor activity value (OAV) of the threshold of the aromatic compound, and the OPLS-DA analysis was performed by orthogonal partial least squares discriminant analysis (OPLS-DA) using the OAV values of the compounds with OAV values >1 as the Y variable. The VIP (Variable Importance in Projection) values of six compounds, ethyl isobutyrate, ethyl hexanoate-D, 2-methylpropanal, ethyl octanoate, ethyl butanoate-D, and Isoamyl acetate-D, were calculated to be higher than one between groups, indicating that these six compounds may influence aroma differences. It is essential to recognize that the results of this study have implications for understanding the quality differences between different varieties of wines and for developing wines that have the characteristics of those varieties.

Flavor Differences of Edible Parts of Grass Carp between Jingpo Lake and Commercial Market

This study investigated the flavor differences among three individual parts (abdomen, back, and tail) of Jingpo Lake grass carp (JPGC) and commercial grass carp (CGC). The growing environment and fish parts influenced the volatile compounds of the fish. The highest total contents of alcohols and ethers were found in the back of JPGC (p < 0.05). The combination of an electronic tongue and electronic nose (E-nose) could effectively distinguish the flavor differences between the different parts of JPGC and CGC by principal component analysis. Both the content of total free amino acids (FAAs) and content of amino acids contributing to the sweet and fresh flavors were higher in JPGC than CGC (p < 0.05). Among the ATP-associated products, the inosine 5’-monophosphate (IMP) contents of the back and tail of JPGC were higher (p < 0.05), but the abdomen content was lower (p > 0.05) than the respective contents in the corresponding parts of CGC. Sensory evaluation shows that JPGC had a better texture, odor, and taste, compared to CGC. Correlation analysis showed that the E-nose data and FAAs were highly correlated with the content of alcohols, aldehydes, and ethers. This study showed that the flavors of the different parts of JPGC differed significantly from those of CGC.