Characterization of donkey-meat flavor profiles by GC–IMS and multivariate analysis

Application of Omics in Donkey Meat Research: A Review

This review comprehensively examines the molecular basis of donkey meat characteristics and growth-associated genes, integrating findings from multiple omics approaches. This study examines the nutritional profile of donkey meat, which is rich in protein, essential amino acids, and unsaturated fatty acids. Through a systematic literature search across Web of Science, Google Scholar, PubMed, and Scopus databases (2000-2024), we collected and analyzed data from 400 research articles using predefined inclusion criteria focused on nutritional composition, omics approaches, and meat quality parameters in donkey populations. The study also evaluates various factors affecting meat quality, including breed differences, age, feeding management, and storage conditions. Advanced genomic and transcriptomic analyses have revealed numerous candidate genes, such as ACTN3, BMP7, NR6A1, Wnt7a, HOXC8, LCORL, TPM2, and TPM3, associated with growth traits and meat quality characteristics, providing valuable insights for genetic improvement programs. Furthermore, the review discusses various authentication methods for ensuring donkey meat quality and preventing adulteration, highlighting the integration of traditional and modern analytical approaches.

The Effect of Different Freezing and Thawing Methods on Physicochemical, Sensory, and Flavor Characteristics of Korean Native Chicken Breast

This study compared the physicochemical, sensory, and flavor-related properties of breast from two Korean native chicken (KNC) breeds, Woorimatdag No. 1 (WRMD1) and Woorimatdag No. 2 (WRMD2), to those of broilers, under fresh and various freeze-thaw treatments. WRMD1 generally exhibited the highest shear force value among the breeds, indicating tougher meat. The total aerobic bacteria count was significantly lower (p<0.05) in broiler meat compared to WRMD1 and WRMD2. The appearance perception on the sensory evaluation of fresh WRMD1 meat was significantly lower than that of broiler meat (p<0.05). The chicken breed influenced the fatty acid profile. The KNC breeds exhibited higher levels of essential and taste-related fatty acids compared to the broilers. Notably, WRMD1 exhibited the highest inosine monophosphate concentration, a key nucleotide responsible for umami taste. The freeze-thaw treatment did not significantly influence the fatty acid profile. Several volatile organic compounds such as (S)-(+)-3-methyl-1-pentanol, propanal, 2-methyl-, sec-butylamine, 3,3-dimethyl-1,2-epoxybutane, hexanal, 5-methyl-, 1-octen-3-ol, and 5-ethylcyclopent-1-enecarboxaldehyde were identified as potential markers for differentiating broiler and KNC meat. Overall, the breed had a more significant impact on the physicochemical and flavor characteristics of the meat, while quick freezing effectively preserved its fresh quality.

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.

Characterization changes of volatile organic compounds in Aconitum sinomontanum Nakai (Gao Wu Tou) with different proportions of yellow wine steamed by GC-IMS, E-nose

Gas chromatography-ion mobility spectrometry (GC-IMS) combined with multiple analytical methods and E-nose were used to study the differences in volatile organic compounds (VOCs) in 0 %, 10 %, 15 %, 20 %, 25 % yellow wine steamed A. sinomontanum and its raw products. The results indicated that the VOCs in different proportions of yellow wine steamed A. sinomontanum and its raw products were mainly composed of aldehydes, ketones, alcohols, ethers, esters, acids, and heterocycles. Among them, the contents of the aldehydes, ketones, heterocycles, alcohols and esters are remarkably higher than those of other compounds. The results based on multiple analysis methods such as PCA and fingerprint analysis showed that there were certain differences between steaming A. sinomontanum with different proportions of yellow wine and the raw products. Among them, yellow wine has a 15 % proportion and the highest content of VOCs, and perhaps the best proportion of yellow wine for steaming A. sinomontanum. Simultaneously, it is speculated that the unique odor of steamed A. sinomontanum may be related to the aldehydes and esters it contains, such as benzalde-hyde, 2-Methylbutanol acetate. In addition, the E-nose results of this study could be helpful for flavor identification and distinction of raw and processed products from A. sinomontanum.

Insights into the potential quality markers of Rubus chingii Hu fruit at different growth stages

Rubus chingii Hu fruit (RHF) is a medicinal and edible resource with excellent biological activities. Currently, the existing identification markers can't meet the needs of RHF quality control. This study collected RHF from cultivation fields of three origins [Qiandaohu (QDH), Lishui (LS), and Fuyang (YF)] at green, green to yellow, yellow to orange, and mature stages (G, G to Y, Y to O, M). The physicochemical information of RHF was examined. Water migration and characteristic volatile compounds of RHF at growth stages from different origins were investigated by low field-nuclear magnetic resonance (LF-NMR) technology and gas chromatography-ion mobility spectrometry (GC-IMS) technology. It showed that samples from QDH possessed the highest antioxidant activity at the first three growth stages (e.g.

, DPPH

0.062 ± 0.000, 0.059 ± 0.004 and 0.037 ± 0.002 mmol Trolox/100 g), while FY had the highest at the mature stage (e.g.

, DPPH

0.026 ± 0.001 mmol Trolox/100 g). The total carbohydrates content ranged from 15 % to 43 %. Besides, in the first two stages, the total acidity value was lower (e.g.

, QDH

2.69 ± 0.04 and 2.45 ± 0.04 in g citric acid/L). Furthermore, three origins had the same water migration rule, and finally, 10 compounds, including 5 from the G growth stage, 4 from the G to Y growth stage, and 1 from the Y to O growth stage, were highly correlated with antioxidant activity and can significantly indicate RHF quality from different origins, so they can potentially serve as Q-markers for RHF. Identifying Q-markers provides a research direction for the quality control of RHF, promoting the development of the RHF industry.

Factors affecting the quality and nutritional value of donkey meat: a comprehensive review

Donkey meat is characterized by a high content of proteins, essential amino acids, and unsaturated fatty acids and is low in fat, cholesterol, and calories. Thus, it is considered a high-quality source of meat. Based on the data from PubMed and Web of science within past 10 years, this review summarizes the factors affecting the quality of donkey meat and its nutritional value, including breed, genetics, gender, age, muscle type, feeding regimen, storage and processing conditions. Breed, gender, age, and feeding regimen mainly affect the quality of donkey meat by influencing its intramuscular fat content and carcass quality. Meanwhile, the tenderness and flavor of donkey meat depend on the muscle type, storage and processing conditions. Genetics, on the other hand, fundamentally affect donkey meat quality by influencing the polymorphism of genes. These findings provide valuable insights and guidance for producers, consumers, and decision-makers in the donkey meat industry, promoting the development of more effective marketing strategies and the improvement of meat quality, thereby enabling the expansion and progress of the entire industry.

Transcriptomic analysis of different intramuscular fat contents on the flavor of the longissimus dorsi tissues from Guangling donkey

BACKGROUND

In this study, researchers aimed to explore the impact of intramuscular fat (IMF) concentration on the flavor of donkey meat, specifically in the longissimus dorsi muscle of Guangling donkeys. The internal volatile organic compounds that cause the flavor differences between donkey muscles are not clear at present. Transcriptomic technologies were utilized to analyze gene expression and its relationship to donkey meat flavor.

METHOD

Thirty Guangling donkeys had their IMF content evaluated in the longissimus dorsi muscle. Based on IMF content, 16 donkeys of similar ages were divided into two groups: low-fat (L) and high-fat (H). Headspace solid-phase microextraction Gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace solid phase microextraction mass spectrometry were used to identify potential flavor components that differed between the two groups.

RESULTS

Five key volatile substances were identified, and WGCNA and KEGG analysis was conducted to analyze the genes associated with these substances. The results showed that pathways like PPAR signaling, nucleotide excision repair, glucagon signaling, arachidonic acid metabolism, and glycolysis/glycogenesis were involved in lipid deposition. Additionally, a gene-gene interaction network map was constructed, highlighting the importance of hub genes such as EEF2, DDX49, GAP43, SNAP25, NDUFS8, MRPS11, RNASEH2A, POLR2E, POLR2C and ALB in regulating key flavor substances.

CONCLUSION

This study provided valuable insights into the regulation of genes and protein expression related to flavor substances in donkey meat. It also deepened understanding of the influence of IMF on flavor and laid a foundation for future molecular breeding improvements in Guangling donkeys.

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.

GC-IMS and multivariate analyses of volatile organic components in different Chinese breeds of chickens

This study examined the difference in volatile flavor characteristics among four different local breeds of chicken by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with multivariate analysis. In total, 65 volatile organic compounds (VOCs) were identified (17 aldehydes, 12 alcohols, 7 ketones, 5 esters, 2 acids, and 22 unidentified, i.e., 26.15% aldehydes, 18.46% alcohols, 10.77% ketones, 7.69% esters, 3.08% acids, and 33.84% unidentified), of which 43 were annotated. The chicken meats from the four breeds exhibited good separation in topographic plots, VOC fingerprinting, and multivariate analysis. Meanwhile, 20 different volatile components, with variable importance in projection value > 1, were selected as potential markers to distinguish different breeds of chicken by partial least squares discriminant analysis (PLS-DA). These findings provide insights into the flavor traits of chicken meat. Also, HS-GC-IMS combined with multivariate analysis can be a convenient and powerful method for characterizing different meats.

Physicochemical Features and Volatile Organic Compounds of Horse Loin Subjected to Sous-Vide Cooking

The purpose of this study was to evaluate the effect of temperature and time of sous-vide cooking method on the characteristics of Thoroughbred horse loin. Sliced portions (200 ± 50 g) were cooked by boiling (control) and sous-vide (65 and 70 °C for 12, 18, and 24 h). The samples were analyzed for proximate composition, pH, color, texture, microstructure, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), microbiology, volatile organic compounds (VOCs), nucleotide content, and fatty acids composition. The color analysis showed decreased redness at elevated temperatures. Improved tenderness, demonstrated by reduced shear force values (36.36 N at 65 °C for 24 h and 35.70 N at 70 °C for 24 h). The micrographs indicated dense fiber arrangements at 70 °C. The SDS-PAGE revealed muscle protein degradation with extended sous-vide cooking. The VOC analysis identified specific compounds, potentially distinctive markers for sous-vide cooking of horse meat including 1-octen-3-ol, decanal, n-caproic acid vinyl ester, cyclotetrasiloxane, octamethyl, and 3,3-dimethyl-1,2-epoxybutane. This study highlights the cooking time's primary role in sous vide-cooked horse meat tenderness and proposes specific VOCs as potential markers. Further research should explore the exclusivity of these VOCs to sous-vide cooking.

Characterization of Volatile Compounds in Donkey Meat by Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) Combined with Chemometrics

Volatile compounds (VOCs) are an important factor affecting meat quality. However, the characteristic VOCs in different parts of donkey meat remain unknown. Accordingly, this study represents a preliminary investigation of VOCs to differentiate between different cuts of donkey meat by using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with chemometrics analysis. The results showed that the 31 VOCs identified in donkey meat, ketones, alcohols, aldehydes, and esters were the predominant categories. A total of 10 VOCs with relative odor activity values ≥1 were found to be characteristic of donkey meat, including pentanone, hexanal, nonanal, octanal, and 3-methylbutanal. The VOC profiles in different parts of donkey meat were well differentiated using three- and two-dimensional fingerprint maps. Nine differential VOCs that represent potential markers to discriminate different parts of donkey meat were identified by chemometrics analysis. These include 2-butanone, 2-pentanone, and 2-heptanone. Thus, the VOC profiles in donkey meat and specific VOCs in different parts of donkey meat were revealed by HS-GC-IMS combined with chemometrics, whcih provided a basis and method of investigating the characteristic VOCs and quality control of donkey meat.

Monitoring of Volatile Compounds of Ready-to-Eat Kiwifruit Using GC-IMS

Ready-to-eat kiwifruit has gained significant market value in recent years due to its convenience and the increasing consumer demand for healthy ready-to-eat snacks. The volatile compound content (VOC) in ready-to-eat kiwifruit is a crucial factor determining its flavor and aroma. VOC is an important characteristic that positively affects the overall evaluation of ready-to-eat kiwifruit. In this study, we utilized gas chromatography-ion mobility spectrometry (GC-IMS) to investigate changes in the composition of VOCs in ready-to-eat kiwifruit during different storage periods (every 12 h). Our results revealed the presence of 55 VOCs in ready-to-eat kiwifruit, with alcohols, esters, and ketones being the dominant compounds responsible for the aromatic flavor. Among these compounds, methyl caproate, ethyl butyrate, and ethyl propionate provided specific fruit flavors to ready-to-eat kiwifruit, whereas esters played a secondary role. Furthermore, varying trends were observed for different compound types as the storage period increased: alcohols exhibited a decreasing trend, whereas ester products and some sulfur-containing compounds showed an increase. Additionally, fingerprint profiles of volatile compounds were established for each storage period, enabling the identification of characteristic substances. This comprehensive analysis of volatile flavor substances during the ripening of ready-to-eat kiwifruit will greatly contribute to enhancing its sensory quality, consumer appeal, and overall marketability.

Comparison of Lipids and Volatile Compounds in Dezhou Donkey Meat with High and Low Intramuscular Fat Content

The intramuscular fat (IMF) content is considered an important factor for assessing meat quality, and is highly related to meat flavor. However, in donkey meat, the influences of IMF content on lipid and volatile profiles remain unclear. Thus, we conducted lipidomic and volatilomic investigations on high- and low-IMF samples from donkey longissimus dorsi muscle. When the IMF level increased, the monounsaturated fatty acid (especially oleic acid) content significantly increased but the saturated fatty acid content decreased (p < 0.05). Twenty-nine of 876 lipids showed significant differences between the two groups. Volatile profiles from differential IMF content samples were also distinct. Five differential volatile odorants were identified in the two groups: 2-acetyl-2-thiazoline, octanal, 2-pentylfuran, pentanal, and 1-(2-pyridinyl) ethanone. Additionally, strong correlations were found between differential fatty acids and lipids with differential odorants. Thus, the difference in volatile odorants may result from the change in the fatty acid composition and lipid profiles induced by different IMF contents, highlighting the urgent need to increase IMF levels in donkey meat.

A Genome-Wide Association Study of the Chest Circumference Trait in Xinjiang Donkeys Based on Whole-Genome Sequencing Technology

Animal genotyping by means of genome-wide association studies is important for connecting phenotypes of interest with their underlying genetics in livestock. However, the use of whole genome sequencing to investigate chest circumference (CC) in donkeys has rarely been reported. We aimed to use the genome-wide association study approach to detect significant single nucleotide polymorphisms (SNPs) and key genes associated with chest circumference traits in Xinjiang donkeys. We assessed 112 Xinjiang donkeys in this study. The chest circumference of each was measured 2 h before milking. We re-sequenced blood samples from the Xinjiang donkeys, and genome-wide association study analyses were performed using a mixed model with the PLINK, GEMMA, and REGENIE programs. We tested 38 donkeys for candidate SNPs for genome-wide association study using three software programs. Additionally, 18 SNP markers reached genome-wide significance (p < 1.61 × 10^-9). On the basis of these, 41 genes were identified. Previously proposed candidate genes for CC traits were supported by this study, including NFATC2 (Nuclear Factor of Activated T Cells 2), PROP1 (PROP Paired-Like Homeobox 1), UBB (Ubiquitin B), and HAND2 (Heart and Neural Crest Derivatives Expressed 2). These promising candidates provide a valuable resource for validating potential meat production genes and will facilitate the development of high-yielding Xinjiang donkey breeds through marker-assisted selection or gene editing.