Identification of changes in volatile compounds in sea cucumber Apostichopus japonicus during seasonings soaking using HS-GC-IMS

GC-IMS combined with multivariate statistical analysis: An efficient strategy for characterizing flavor components and assessing storage stability of egg yolk powder

The lack of understanding of the characteristic aroma components and the absence of effective monitoring methods for flavor changes during storage are significant bottlenecks that hinder the development of egg yolk powder (EYP) products. This study validated the effectiveness of gas chromatography-ion mobility spectrometry (GC-IMS) technology in monitoring the short-term storge flavor changes of EYP. Using this technology, the 34 volatile signals were detected in EYP, primarily consisting of aldehydes, ketones, and esters. 2,3-butanedione, 2-methylbutanal (D), 2-propanone, and 2-pentanone are typical characteristic flavor compounds of EYP. During storage, the flavor profile of EYP products underwent significant changes. Additionally, the study confirmed that combining GC-IMS with multivariate statistical analysis can effectively assess the flavor stability of EYP during storage. This provides a rapid, accurate, and comprehensive evaluation strategy for assessing the flavor quality of EYP products during storage and offers valuable reference for consumers when making purchasing decisions.

Impact of Steam Processing on the Physicochemical Properties and Flavor Profile of Takifugu flavidus: A Comprehensive Quality Evaluation

As a culturally iconic Chinese delicacy, pufferfish lacks systematic research on thermal processing optimization and pre-cooked meal development, limiting its industrial standardization and quality preservation. This study aimed to bridge this gap by evaluating steaming effects on Takifugu flavidus quality. This study systematically evaluated its physicochemical properties and flavor profiles under different steaming durations by determining the water loss rate, mass loss rate, water distribution status, textural properties, color, and free amino acid content using an electronic nose, electronic tongue, and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results indicated that the core temperature of the fish meat reached 70 °C after 9 min of steaming. With higher steaming time, its mass loss rate and water loss rate generally increased, though the water loss rate temporarily decreased at 10 min. The mass loss rate stabilized after 12.5 min. The hardness and chewiness of the fish meat increased significantly when steamed for 12.5 min or longer. After 5 min of steaming, the brightness value and yellow-blue value of the fish meat significantly increased, whereas the red-green value significantly decreased. The total free amino acid content showed a fluctuating upward trend and electronic tongue analysis revealed an increase in umami and richness after steaming. Electronic nose and HS-GC-IMS analyses demonstrated that the variety and content of volatile flavor compounds significantly increased with prolonged steaming. Sensory evaluation showed that the 10 min steaming group exhibited better texture and color, while the 15 min steaming group had the best odor. Therefore, the optimal steaming time for T. flavidus was determined to be 10-15 min. For home cooking, a 15 min steaming process achieves the peak abundance of flavor compounds and the highest sensory evaluation score. For the industrial production of pre-cooked meals, a 10 min steaming process can meet the doneness requirements while maintaining suitable textural properties and color stability. The findings of this study not only advance the scientific understanding of thermal processing effects on pufferfish quality attributes, but also establish a critical technological foundation for developing standardized industrial processing protocols and high-quality pre-prepared pufferfish products.

Chemical and Volatile Compounds in Sweet Potato Brandy: Impact of Processing Methods

This study investigated the impact of various thermal processing methods-steaming, boiling, frying, and baking-on the volatile organic compounds (VOCs) in sweet potato (Ipomoea batatas L.) brandy using gas chromatography-ion mobility spectrometry (GC-IMS). Yanshu No. 25 sweet potatoes, recognized for their high levels of mucin protein and soluble sugars, were employed for the fermentation of the brandy. GC-IMS analysis generated three-dimensional spectrograms, which revealed distinct VOC profiles depending on the processing method used. Notably, steaming, frying, boiling, and baking significantly altered the VOC composition, imparting unique flavor characteristics. A total of 37 VOCs were identified, with esters being the predominant class, contributing to fruity and floral notes in the brandy. Principal component analysis (PCA) and Euclidean distance-based fingerprint similarity analysis further differentiated the VOC profiles, highlighting the essential role of processing techniques in flavor development. These findings provide a foundation for future research aimed at optimizing processing methods to create specific aromatic profiles in sweet potato brandy.

Enhancement of Apostichopus japonicus peptide flavor through bacterial and enzyme co-fermentation (BECF) and the identification of novel antioxidant peptides in the fermented product

In this study, we optimized the BECF process parameters by single-factor experiments and response surface methodology (RSM). Additionally, various analytical techniques were employed to determine the volatile flavor compounds, amino acid composition, and peptide sequences of the fermented product. The antioxidant activities of 10 peptides were evaluated via free radical scavenging assays. The results indicated that the optimal BECF conditions for Apostichopus japonicus body wall (AJBW) were as follows: 2.3 % bacterial inoculum, fermentation for 31 h at 30 °C, 463 U/g enzyme dosage, and enzymatic hydrolysis at 50 °C for 4 h. Gas chromatography-ion mobility spectrometry analysis revealed a significant reduction in aldehydes, which impart a pungent odor, in the co-fermented product (AJM) as compared to the control. While the content of alcohols, ketones, and esters, which contribute to aromatic flavors, was significantly increased. The content of essential amino acids in AJM, as analyzed through an automatic amino acid analyzer, was slightly higher compared to that in AJBW. Liquid chromatography-tandem mass spectrometry identified a total of 808 sea cucumber peptide fragments with high confidence. DPPH, ABTS, and hydroxyl radical scavenging assays revealed that peptides LFW and LFPW exhibited the strongest antioxidant activities. Molecular docking studies showed significant hydrogen-bonding interactions. In conclusion, BECF is an effective strategy for enhancing the flavor of A. japonicus peptide.

Effects of sterilization intensity on the flavor profile of canned Antarctic krill (Euphausia superba): Moderate vs. excessive

Selecting the appropriate sterilization intensity is crucial for the canning of Antarctic krill (Euphausia superba). This study investigated the effects of different sterilization intensities on volatile organic compounds (VOCs) of canned krill. Using gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS), which identified 45 and 36 VOCs, respectively. As the sterilization intensity was increased, the flavor profile became more stabilized; however, excessive sterilization led to the generation of off-flavor compounds. Eight key flavor markers were identified at different sterilization intensities. Cluster analysis could distinguish between samples obtained from low (F = 6, 9) and high (F = 12, 15) sterilization intensities. Odor Activity Value (OAV) analysis revealed that higher sterilization intensities led to the generation of fishy, fatty, and earthy notes. The findings suggest that sterilization at F = 9 can best maintain the desired flavor characteristics. Overall, this work provides valuable insights into the optimization of the canning process of Antarctic krill.

Effect of sous-vide processing duration on flavor and taste variations of oyster (Crassostrea gigas)

Sous-vide (SV), as a mild processing technique, exhibits some potential for keeping the original flavor of oyster. The dynamic changes mechanism of flavor and taste in oyster during SV processing (0-30 min/75 °C) were investigated. SV processing for 10-15 min improved the umami of oysters, likely due to the increase in adenosine monophosphate and glutamate, while processing for 20-30 min resulted in a significant loss of "grassy" flavor. GC-MS and GC-IMS analysis showed that the loss of short-chain aldehydes, such as (E)-2-pentenal, (E)-2-hexenal and (E, E)-2,4-hexadienal may be related to the weakening of the "grassy" flavor, and the formation of 2,3-diethylpyrazine and octanal produced a "cooked" and "fatty" flavor. The analysis of lipidomics indicated that phosphatidylethanolamine, lysophosphatidylcholine and sphingomyelin, synthesized mainly through glycerophospholipid and sphingolipid metabolism, were key precursors for aldehyde formation. This study provides a theoretical basis for controlling the flavor quality of oyster during mild processing.

Dynamic evolution of volatile compounds during cold storage of sturgeon fillets analyzed by gas chromatography-ion mobility spectrometry and chemometric methods

This study investigated the changes in quality and volatile flavoring compounds in sturgeon fillets during refrigeration. Potential flavor compounds were identified using orthogonal partial least squares discriminant analysis (OPLS-DA) and gas chromatography- ion mobility spectrometry (GC-IMS). The results showed that TVB-N content, TBARS values, total colony counts, and K-value increased with prolonged refrigeration, reaching spoilage thresholds after approximately eight days. A total of 33 volatile compounds (including monomers and dimers) were detected in sturgeon fillets during different refrigeration periods, including aldehydes, alcohols, ketones, acids, esters, ethers, and other compounds. OPLS-DA further revealed flavor differences in sturgeon fillets across different refrigeration stages, identifying 18 distinct volatile compounds. Correlation analysis showed that trans-2-Pentenal, 2-methylpropanal, and glutaraldehyde were associated with pleasant odor to the frozen sturgeon fillets in the early stage, while hexane nitrile and thiazole were the main substances that caused unpleasant odors.

The revelation of characteristic volatile compounds in egg powder and analysis of their adsorption rules based on HS-GC-IMS technology

The study constructed fingerprints and analyzed adsorption rules of volatile compounds (VOCs) in egg powder (EP) under different production processes, including egg white powder (EWP), egg yolk powder (EYP) and whole egg powder (WEP) by HS-GC-IMS. The 29 VOCs identified were primarily ketones and aldehydes. Characteristic VOCs responsible for flavor differences were clarified by difference comparison, clustering and PCA analysis. Additionally, variations in lipid and protein were the primary causes of the VOCs differences in EP through microscopy imaging, infrared and fluorescence spectroscopy. EWP's stretched structure favored fishy-smelling VOCs adsorption but limited total aldehyde binding due to strong hydrophobic interaction. EYP's higher β-sheet ratio and fewer hydrogen bond sites weakened its alcohol VOCs binding capacity. The abundance of ketone VOCs in EP was linked to their low steric hindrance. Therefore, this study elucidated the flavor differences reasons among EWP, EYP and WEP, laying foundation for EP applications in food industry.

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.

Characteristic Polyphenols in 15 Varieties of Chinese Jujubes Based on Metabolomics

BACKGROUND

Jujube is a homologous herb of medicine and food, and polyphenols are key in determining the functional effects of jujubes.

METHODS

In this study, characteristic polyphenols in 15 varieties of Chinese jujubes were investigated based on untargeted metabolomics.

RESULTS

The results showed that a total of 79 characteristic polyphenols were identified in the 15 varieties of Chinese jujube, and 55 characteristic polyphenols such as syringetin, spinosin and kaempferol were reported for the first time. Scopoletin (63.94% in LZYZ), pectolinarin (22.63% in HZ) and taxifolin (19.69% in HZ) contributed greatly and presented significant (p < 0.05) differences in the 15 varieties of Chinese jujubes. HZ was characterized by pectolinarin, erianin and wogonoside, while XSHZ, NYDZ and RQHZ, with similar polyphenol profiles, were characterized by (+)-catechin, combretastatin A4 and tectorigenin. JSBZ, HMDZ, TZ, JCJZ and HPZ had similar polyphenol profiles of galangin, isoferulic acid and hydroxysafflor yellow A.

CONCLUSIONS

Metabolomics is critical in grasping the full polyphenol contents of jujubes, and the differences in the polyphenol profiles and characteristic individual polyphenols of the 15 varieties of Chinese jujubes were well analyzed by principal component analysis (PCA).

Study on the adsorption and migration rule of Sichuan pepper characteristic volatile compounds during the cooking process in the sea cucumber body wall

The natural flavor of sea cucumber is generally not easily accepted by consumers. In this study, the effect of different cooking conditions on the adsorption of the characteristic flavor of Sichuan pepper by sea cucumber was investigated by response surface methodology, and the optimal cooking conditions were identified. A total of 45 volatiles were identified based on gas chromatography-mass spectrometry, of which 27 were key flavor actives. Low-field nuclear magnetic resonance and textural analysis showed that the addition of Sichuan pepper during the cooking process affected the water migration and the textural properties of sea cucumbers. It was shown that the addition of Sichuan pepper could significantly improve the flavor and other quality characteristics of sea cucumber. This study has important practical guiding significance for the flavor improvement and product innovation of sea cucumber food.

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.

Determination of key volatile fishy substances of sea cucumber powder during the processing and their removal by supercritical fluid extraction

More than 40 volatile compounds were detected in sea cucumber powder during the processing (through freeze-dried, desalination, supercritical fluid extraction and ultra-micro grinding) by multiple methods including e-nose, GC-IMS and GC-MS. It has been determined that aldehydes are the predominant volatile substances in the original freeze-dried sample, accounting for about 30 % of the total volatile substances. In addition, we established a supercritical fluid extraction strategy that could efficiently remove the aldehydes from the sea cucumber powder. GC-IMS and GC-MS showed that the relative content of aldehydes significantly decreased by 14 % and 28 %, respectively. Quantification of aldehydes using GC-MS showed a significant decrease in octanal from 927 µg/kg to 159 µg/kg. Further investigation combined with OAV analysis showed that 17 volatile substances in the freeze-dried sea cucumber powder were considered to be the predominant volatile compounds (OAV > 1).The primary fishy compounds found in sea cucumber powder were identified as hexanal, octanal, and an unidentified compound using GC-O, which can be effectively removed (OAV can't been estimated) by the supercritical fluid extraction strategy we established.

The selective adsorption mechanism of V-type starches for key off-odors of sea cucumber intestinal peptides

The off-odors of sea cucumber intestinal peptide (SCIP) severely limit its application. In this study, the V-type starches were derived from high amylose maize starch to adsorb odors of SCIP and the adsorption mechanism was explored. The inclusion complexes formed by V-type starches and volatile compounds of SCIP were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The electronic nose results revealed a decreasing trend in response values of SCIP, with significant differences before and after deodorization (p < 0.05). Furthermore, 82 volatiles were identified from SCIP, and six were determined as key volatiles using gas chromatography-mass spectrometry. The V6- and V7-type starches with smaller cavity sizes selectively adsorb butyric acid, isobutyric acid and nonaldehyde, and V8-type starches with a larger cavity size selectively adsorb trimethylamine. This study proved that using V-type starches for deodorization could effectively improve SCIP flavor.

The characteristic terpenes in sea cucumber soaked in star anise solution were characterized by HS-SPME-GC-MS and PCA analysis

The quality of sea cucumber is closely associated with its processing technology. In this study, the response surface methodology (RSM) was employed to optimize the thermal process conditions for seasoned sea cucumber, while gas chromatography-mass spectrometry (GC-MS) technique identified 25 characteristic compounds. Terpenes and their oxygen derivatives constituted approximately 70% of all compounds detected. Among these, trans-anethole emerged as the predominant volatile aroma compound in seasoned sea cucumber at a concentration of 39.99 ± 4.52 mg/g, followed by p-anisaldehyde, cis-anethole, linalool, estragole, and d-limonene. Principal component analysis (PCA) revealed that trans-anethole, cis-anethole, estragole, and d-limonene collectively contributed over 45.0% to the flavor profile of sea cucumber. This investigation provides an initial exploration into the alterations in volatile compounds within star anise-seasoned seasoned sea cucumber, thereby establishing a foundation for instant sea cucumbers' flavor processing.

Characterization of volatile flavor compounds from fish maw soaked in five different seasonings

In this study, sensory evaluation, electronic nose, and HS-GC-IMS were used to investigate the effects of different seasonings (deionized water, onion, ginger, Sichuan pepper, and mixed seasonings) on the flavor of fish maw. The results showed that the volatile compounds of fish maw soaked in different seasonings were mainly organic sulfides and aromatic compounds. A total of 95 volatile compounds were identified, including 25 aldehydes, 23 olefins, 19 alcohols, 11 esters, 9 ketones, 3 acids, 2 sulfides, 1 furan, 1 ether and 1 ketoxime. Sichuan pepper group and mixed seasoning group had the most significant changes in volatile components, and had the most effective improvement on the flavor of fish maw compared with other groups. These findings will provide reference for producing high quality fish maw and improving its flavor quality. These findings will provide feasible theoretical support for the pretreatment and exploration of fish maw products in the future.

Flavor characteristics of semi-dried yellow croaker (Pseudosciaena crocea) with KCl and ultrasound under sodium-reduced conditions before and after low temperature vacuum heating

This study investigated the flavor characteristics of semi-dried yellow croaker made by KCl instead of partial NaCl combined with ultrasound treatment before and after low temperature vacuum heating. The electronic tongue, electronic nose, free amino acids, 5'-nucleotides, and gas chromatography-ion mobility spectrometry were employed. Electronic nose and electronic tongue results showed that different treatment groups had different sensitive signals to smell and taste. The odor and taste of each group were mainly affected by Na⁺ and K⁺. The difference between the groups becomes larger after thermal treatment. Ultrasound and thermal treatment both changed the content of taste components. In addition, each group contained 54 volatile flavor compounds. Among them, the combined treatment method gave semi-dried large yellow croaker pleasant flavor characteristics. Besides, it also improved the content of flavor substances. In conclusion, the semi-dried yellow croaker under sodium-reduced conditions showed better performance in flavor characteristics.

Characterization of Flavor Profile of "Nanx Wudl" Sour Meat Fermented from Goose and Pork Using Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) Combined with Electronic Nose and Tongue

Sour meat is a highly appreciated traditional fermented product, mainly from the Guizhou, Yunnan, and Hunan provinces. The flavor profiles of sour meat from goose and pork were evaluated using gas chromatography-ion mobility spectrometry (GC-IMS) combined with an electronic nose (E-nose) and tongue (E-tongue). A total of 94 volatile compounds were characterized in fermented sour meat from both pork and goose using GC-IMS. A data-mining protocol based on univariate and multivariate analyses revealed that the source of the raw meat plays a crucial role in the formation of flavor compounds during the fermentation process. In detail, sour meat from pork contained higher levels of hexyl acetate, sotolon, heptyl acetate, butyl propanoate, hexanal, and 2-acetylpyrrole than sour goose meat. In parallel, sour meat from goose showed higher levels of 4-methyl-3-penten-2-one, n-butyl lactate, 2-butanol, (E)-2-nonenal, and decalin than sour pork. In terms of the odor and taste response values obtained by the E-nose and E-tongue, a robust principal component model (RPCA) could effectively differentiate sour meat from the two sources. The present work could provide references to investigate the flavor profiles of traditional sour meat products fermented from different raw meats and offer opportunities for a rapid identification method based on flavor profiles.

Metabolomics investigation on the volatile and non-volatile composition in enzymatic hydrolysates of Pacific oyster (Crassostrea gigas)

To investigate the differences of volatile and non-volatile metabolites between oyster enzymatic hydrolysates and boiling concentrates, molecular sensory analysis and untargeted metabolomics were employed. "Grassy," "fruity," "oily/fatty," "fishy," and "metallic" were identified as sensory attributes used to evaluate different processed oyster homogenates. Sixty-nine and 42 volatiles were identified by gas chromatography-ion mobility spectrometry and gas chromatography-mass spectrometry, respectively. Pentanal, 1-penten-3-ol, hexanal, (E)-2-pentenal, heptanal, (E)-2-hexenal, 4-octanone, (E)-4-heptenal, 3-octanone, octanal, nonanal, 1-octen-3-ol, benzaldehyde, (E)-2-nonenal, and (E, Z)-2,6-nonadienal were detected as the key odorants (OAV > 1) after enzymatic hydrolysis. Hexanal, (E)-4-heptenal, and (E)-2-pentenal were significantly associated with off-odor, and 177 differential metabolites were classified. Aspartate, glutamine, alanine, and arginine were the key precursors affecting the flavor profile. Linking sensory descriptors to volatile and nonvolatile components of different processed oyster homogenates will provide information for the process and quality improvement of oyster products.

Comparison of aroma active compounds in cold- and hot-pressed walnut oil by comprehensive two-dimensional gas chromatography-olfactory-mass spectrometry and headspace-gas chromatography-ion mobility spectrometry

Aroma composition of cold-pressed walnut oil (CWO) and hot-pressed walnut oil (HWO) was analyzed by comprehensive two-dimensional gas chromatography-olfactory-mass spectrometry (GC × GC-O-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). A total of 83 and 197 compounds were identified in the CWO and HWO, respectively; among these, 76 and 123 compounds were sniffed exclusively by GC × GC-O-MS, respectively. A total of 36 volatile compounds were detected by HS-GC-IMS, of which 10 in CWO and 32 in HWO. Based on of flavor dilution (FD) factors, odor-activity values (OAVs), and recombination and omission experiments, 1-octen-3-ol, cyclohexanol, and benzaldehyde were found to be the key aroma-active compounds in CWO, while 3-methylbutanal, (E,E)-2,4-nonadienal, nonanal, 1-octen-3-ol, 3-pentanol, 1-octanol, and furfural were the key aroma-active compounds in HWO. Moreover, Maillard reaction and lipid oxidation were found to play an important role in flavor formation in HWO. This study provides a guide to improve the quality of walnut oil based on aroma characteristics.

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.

Comparative Studies on the Physicochemical and Volatile Flavour Properties of Traditional Deep Fried and Circulating-Air Fried Hairtail (Trichiurus lepturus)

The aim of this study is to investigate the effects of deep frying (DF) and air frying (AF) on the quality and flavour profile of hairtail (Trichiurus lepturus) fillets. The changes of some physicochemical indices such as moisture content, oil content, colour, thiobarbituric acid reactive substances (TBARS) and peroxide values (POV) in hairtail fillets were detected with increasing frying time. According to these physicochemical indices and sensory evaluation, deep frying for 7 min under 190 °C (DF7) and air frying for 24 min under 190 °C (AF24) were selected as samples for their great quality. The flavour fingerprint of hairtail (Raw, DF7, AF24) was developed and volatile compounds were investigated by HS-GC-IMS. A total of 28 volatile substances including aldehydes, alcohols, ketones and others were identified both in the DF7 and AF24 samples. There are differences in the aroma fingerprint between the DF7 and AF24 samples. DF was characterised by 2-Heptanone, (E)-2-Heptenal, 2-Pentyfuran and 1-Pentanol, AF was characterised by 2-methylbutanol, Ethyl methyl ketone-M and 3-hydroxy-2-butanone. These findings suggest that the aroma of hairtail fillets after DF7 and AF24 was significantly different and supply flavour information and practical applications of the fried hairtail fillets.