Lipidomics of sheep and goat Milk-based infant formulae during in vitro dynamic digestion.

Lipid hydrolysis process during IF digestion, particularly the characterization of the lipidome and the resulting lipid breakdown products, has not been thoroughly investigated. This study aimed to compare the lipid hydrolysis profiles during the in vitro dynamic digestion of IFs made from whole sheep and goat milk. Using a lipidomics platform and multivariate statistical analysis, we observed changes in complex lipid levels during digestion. In the gastric compartment, we noted a progressive hydrolysis of triacylglycerols, phosphatidylcholines, and sphingomyelins. Conversely, lipolysis breakdown products like monoacylglycerols (e.g., MG(16:0), MG(18:0)), diacylglycerols, lysophosphatidylcholines (LPC 16:0, LPC 18:1, LPC 18:2), and free fatty acids increased in the intestinal compartment. The lipolysis trends were similar for both types of infant formulas, with long-chain fatty acid triglycerides (C > 46) exhibiting lower digestibility compared to medium-chain fatty acid triglycerides. Overall, these results indicate that sheep milk can be used as an ingredient in the manufacturing of IF.

Advances in LDI-MS Analysis: The Role of Chemical Vapor Deposition-Synthesized Silver Nanoparticles in Enhancing Detection of Low-Molecular-Weight Biomolecules.

In this investigation, we detail the synthesis of silver nanoparticles (AgNPs) via a precise chemical vacuum deposition (CVD) methodology, aimed at augmenting the analytical performance of laser desorption/ionization mass spectrometry (LDI-MS) for the detection of low-molecular-weight analytes. Employing a precursor supply rate of 0.0014 mg/s facilitated the formation of uniformly dispersed AgNPs, characterized by SEM and AFM to have an average diameter of 33.5 ± 1.5 nm and a surface roughness (Ra) of 11.8 nm, indicative of their homogeneous coverage and spherical morphology. XPS and SEM-EDX analyses confirmed the metallic silver composition of the nanoparticles with Ag peak splitting, reflecting the successful synthesis of metallic Ag. Comparative analytical evaluation with traditional MALDI matrices revealed that AgNPs significantly reduce signal suppression, thereby enhancing the sensitivity and specificity of LDI-MS for low-molecular-weight compounds such as triglycerides, saccharides, amino acids, and carboxylic acids. Notably, the application of AgNPs demonstrated a superior linear response for triglyceride signals with regression coefficients surpassing 0.99, markedly outperforming conventional matrices. The study further extends into quantitative analysis through nanoparticle-based laser desorption/ionization (NALDI), where AgNPs exhibited enhanced ionization efficiency, characterized by substantially lower limits of detection (LOD) and quantification (LOQ) for tested standards. Particular attention was paid to lipids with a detailed examination of their fragmentation pathways. These results highlight the significant potential of AgNPs synthesized via CVD to transform the analytical detection and quantification of low-molecular-weight compounds using NALDI. This approach offers a promising avenue for expanding the scope of analytical applications in mass spectrometry and introducing innovative methodologies for enhanced precision and sensitivity.

Unraveling the formation mechanism of aroma compounds in pork during air frying using UHPLC-HRMS and Orbitrap Exploris GC-MS.

Lipids are the key matrix for the presence of odorants in meat products. The formation mechanism of odorants of air-fried (AF) pork at 230 °C was elucidated from the perspectives of lipids and heat transfer using physicochemical analyses and multidimensional statistics. Twenty-nine key aroma compounds were identified, with pyrazines predominantly contributing to the roasty aroma of air-fried roasted pork. Untargeted lipidomics revealed 1184 lipids in pork during roasting, with phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triglyceride (TG) being the major lipids accounting for about 60 % of the total lipids. TG with C18 acyl groups, such as TG 16:1_18:1_18:2 and TG 18:0_18:0_20:3, were particularly significant in forming the aroma of AF pork. The OPLS-DA model identified seven potential biomarkers that differentiate five roasting times, including PC 16:0_18:3 and 2-ethyl-3,5-dimethylpyrazine. Notably, a lower specific heat capacity and water activity accelerated heat transfer, promoting the formation and retention of odorants in AF pork.

Comprehensive evaluation and screening of phytochemical compounds and their hypolipidemic activities of lotus leaf based on HPLC-Q-TOF-MS and spectral-effect analysis.

This study aimed to identify and quantify the primary components in lotus leaf and to explore the hypolipidemic components through spectral-effect relationships and chemometric methods. Utilizing a data-dependent acquisition-diagnostic fragment ion/characteristic neutral loss screening strategy (DFI-NLS), a reliable HPLC-Q-TOF-MS analysis was conducted, identifying 77 compounds, including 36 flavonoids, 21 alkaloids, 3 terpenoids, 11 organic acids, 4 phenols, 1 lignin and 1 unsaturated hydrocarbon. A straightforward HPLC-DAD method was developed for the simultaneous determination of seven major components in lotus leaf, and quercetin-3-O-glucuronide (Q3GA) was identified as the most abundant component. The HPLC fingerprints of 36 lotus leaf sample batches were assessed using chemometric approaches such as principal component analysis and hierarchical cluster analysis. The hypolipidemic effect of these samples was analyzed by measuring total cholesterol (TC) and total triglycerides (TG) levels in palmitic acid (PA) and oleic acid (OA)-induced lipid modeling in HepG-2 cells, employing partial least squares regression and grey relation analysis to investigate the spectral-effect relationship of the lotus leaf. The in vivo hypolipidemic effect of these compounds was assessed using an egg yolk powder-induced high-fat zebrafish model. The findings indicated that peak No.11 (Q3GA) in the chemical fingerprint was significantly associated with hypolipidemic activity, suggesting it as a potential hypolipidemic compound in lotus leaf. In summary, this study facilitates the exploration of the phytochemical compounds and their bioactive properties in the lotus leaf.

Lipidomics and metabolomics reveal the molecular mechanisms underlying the effect of thermal treatment on composition and oxidative stability of walnut oil.

Roasting walnut kernel significantly improves the oxidative stability and sensory properties of its oil. However, the effect of roasting temperatures on the molecular change of main components and micronutrients in walnut oil is still unclear. Herein, lipidomics and metabolomics were integrated to comprehensively profile the walnut oil obtained at different roasting temperatures (30 °C, 120 °C, 140 °C, 160 °C, and 180 °C). Lipidomics showed that the content of glycerolipids, sphingolipids, and glycerophospholipids decreased with roasting temperatures, while the oxidized fatty acids and triglycerides increased. Ratios of linoleic acid and linolenic acid varied with roasting temperatures and were most close to 4-6:1 at 140 °C, 160 °C, and 180 °C. Major classes of micronutrients showed a tendency to increase at the roasting temperature of 120 °C and 140 °C, then decrease at 160 °C and 180 °C. Liposoluble amino acids identified for the first time in walnut oil varied with roasting temperatures. Correlation analysis demonstrated that the higher contents of liposoluble amino acids and phenolics are positively associated with enhanced oxidative stability of walnut oil obtained at 140 °C. Furthermore, glutamine and 5-oxo-D-proline were expected to be potential biomarkers to differentiate the fresh and roasted walnut oil. The study is expected to provide new insight into the change mechanism of both major lipids and micronutrients in walnut oil during the roasting process.

A comparative lipid profile of four fish species: From muscle to industrial by-products based on RPLC-Q-TOF-MS/MS.

Fish are crucial for the fishing industry and essential nutrient provision, including lipids. This study employed a high-throughput lipidomic approach to evaluate and contrast the lipid profiles of three marine fish species (P. crocea, S. fuscens, and C. saira) and one freshwater species (H. molitrix) across head, muscle, and viscera. Over 1000 molecular lipid species across 17 subclasses were identified. Notably, acylated monogalactosyldiacylglycerol (acMGDG) was detected for the first time in these species, with a high prevalence of saturated fatty acids (44.7 %-87.7 %). Glycerolipids (67.7 - 86.3 %) and PLs (10.7 - 31.8 %) were identified as the dominant lipid classes. Marine fish muscles displayed higher PL content than freshwater species, and P. crocea viscera contained over 30 % PLs of total lipids. In particular, ether phosphatidyl ethanolamine incorporated more DHA than ether phosphatidylcholine. The viscera of four fish species also exhibited a significant abundance of diacylglycerol (DG), indicating their potential as functional lipid sources. Multivariate analysis identified triglyceride (TG) (59:13), DG (16:1/22:5), and MGDG (16:0/18:2) as potential biomarkers for differentiating among fish anatomical parts. This study deepens the understanding of the nutritional values of these fish, providing guidance for consumer dietary choices and paving the way for transforming previously underutilized by-products into resources with high-value potential.

Chemical Composition of Fat Bloom on Chocolate Products Determined by Combining NMR and HPLC-MS.

To reduce unwanted fat bloom in the manufacturing and storage of chocolates, detailed knowledge of the chemical composition and molecular mobility of the oils and fats contained is required. Although the formation of fat bloom on chocolate products has been studied for many decades with regard to its prevention and reduction, questions on the molecular level still remain to be answered. Chocolate products with nut-based fillings are especially prone to undesirable fat bloom. The chemical composition of fat bloom is thought to be dominated by the triacylglycerides of the chocolate matrix, which migrate to the chocolate's surface and recrystallize there. Migration of oils from the fillings into the chocolate as driving force for fat bloom formation is an additional factor in the discussion. In this work, the migration was studied and confirmed by MRI, while the chemical composition of the fat bloom was measured by NMR spectroscopy and HPLC-MS, revealing the most important triacylglycerides in the fat bloom. The combination of HPLC-MS with NMR spectroscopy at 800 MHz allows for detailed chemical structure determination. A rapid routine was developed combining the two modalities, which was then applied to investigate the aging, the impact of chocolate composition, and the influence of hazelnut fillings processing parameters, such as the degree of roasting and grinding of the nuts or the mixing time, on fat bloom formation.

Cultivation and nutritional characteristics of Chlorella vulgaris cultivated using Martian regolith and synthetic urine.

Long-term spatial missions will require sustainable methods for biomass production using locally available resources. This study investigates the feasibility of cultivating Chlorella vulgaris, a high value microalgal specie, using a leachate of Martian regolith and synthetic human urine as nutrient sources. The microalga was grown in a standard medium (BBM) mixed with 0, 20, 40, 60, or 100 % Martian medium (MM). MM did not significantly affect final biomass concentrations. Total carbohydrate and protein contents decreased with increasing MM fractions between 0 % and 60 %, but biomass in the 100% MM showed the highest levels of carbohydrates and proteins (25.2 ± 0.9 % and 37.1 ± 1.4 % of the dry weight, respectively, against 19.0 ± 1.7 % and 32.0 ± 2.7 % in the absence of MM). In all MM-containing media, the fraction of the biomass represented by total lipids was lower (by 3.2 to 4.5%) when compared to BBM. Conversely, total carotenoids increased, with the highest value (97.3 ± 1.5 mg/100 g) measured with 20% MM. In a three-dimensional principal component analysis of triacylglycerols, samples clustered according to growth media; a strong impact of growth media on triacylglycerol profiles was observed. Overall, our findings suggest that microalgal biomass produced using regolith and urine can be used as a valuable component of astronauts' diet during missions to Mars.

Novel theoretical database-assisted UHPLC-Q-TOF/MS strategy for profiling and identifying oxidized triglycerides in pharmaceutical excipient soybean oil.

Pharmaceutical excipient soybean oil is widely used in injections. Its main components, triglycerides, are easily oxidized due to their unsaturated fatty acyls, raising safety concerns. However, it is hard to analyze those oxidized triglycerides due to their diverse compositions and low abundance. In this study, all theoretical oxidized triglycerides were predicted and a database consisting of 329 oxidized triglycerides was constructed. Then, a novel theoretical database-assisted ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) strategy was developed to finely profile and identify oxidized triglycerides in soybean oil. A total of 106 and 116 oxidized triglycerides were identified and relatively quantified in oxidized soybean oil and long-term stored soybean oil and preparations. It was found that oxidized triglycerides containing carbonyl groups were significantly more prevalent than other forms and oxidized triglycerides with two oxidized fatty acyl chains had the highest relative abundance. Fifteen markers indicating the oxidation of soybean oil were discovered. This strategy could rapidly and directly analyze the oxidized triglycerides and assign their fatty acyl compositions for the first time. This study will improve the quality control of soybean oil and its preparations.

Lipophilic and Hydrophilic Metabolites as Descriptors of Different Coffee Beverages.

Coffee is a widely consumed beverage rich in bioactive phytochemicals. This study investigated the effect of brewing method on the profile of potential bioactive compounds in different coffee beverages using metabolomics and lipidomics based on UHPLC-MS/QTOF. The oil contents of the espresso coffee (EC), pot coffee (PC), instant coffee (IC), and filter coffee (FC) beverages studied were 0.13% ± 0.002, 0.12% ± 0.001, 0.04% ± 0.002, and 0.03% ± 0.003, respectively. Univariate analysis indicated significant differences (P < 0.001) in oil content when EC and PC beverages were compared with IC and FC beverages. Principal component analysis revealed similarities in the lipid profiles of FC and EC beverages and the hydrophilic profiles of PC and FC beverages. The EC beverage had the highest intensity of hydrophilic compounds such as adenine, theobromine, chlorogenic acid, and caffeine. The PC beverage was the most abundant in triglycerides, phosphatidylcholine, and diterpenes. Cafestol and kahweol esters, but not their free forms, were the most abundant diterpenes in the PC beverage. This work provides information on the differences in the profile of potentially bioactive compounds in four commonly consumed coffee beverage types and, thus, on the possible differences in the health effects of these coffee beverage types.

Quantitative Analysis of Blended Oils Based on Intensity Ratios of Marker Ions in MALDI-MS Spectra.

Determination of quantitative compositions of blended oils is an essential but challenging step for the quality control and safety assurance of blended oils. We herein report a method for the quantitative analysis of blended oils based on the intensity ratio of triacylglycerol marker ions, which could be obtained from the highly reproducible spectra acquired by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to directly analyze blended oils in their oily states. We demonstrated that this method could provide good quantitative results to binary, ternary, and quaternary blended oils, with simultaneous quantitation of multiple compositions, and was applicable for quantitative analysis of commercial blended oil products. Moreover, the intensity ratio-based method could be used to rapidly measure the proportions of oil compositions in blended oils, only based on the spectra of the blended oils and related pure oils, making the method as a high-throughput approach to meet the sharply growing analytical demands of blended oils.

Two protocols for the detection of oleaginous bacteria using Oil Red O.

The selection of oleaginous bacteria, potentially applicable to biotechnological approaches, is usually carried out by different expensive and time-consuming techniques. In this study, we used Oil Red O (ORO) as an useful dye for staining of neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates. ORO could detect minimal quantities of both compounds (detection limit, 0.0025 mg of tripalmitin or 0.005 mg of cetylpalmitate). In addition, we developed a specific, rapid, and inexpensive screening methodology to detect triacylglycerol-accumulating microorganisms grown on the agar plate. This staining methodology detected 9/13 strains with a triacylglycerol content higher than 20% by cellular dry weight. ORO did not stain polyhydroxyalkanoates-producing bacteria. The four oleaginous strains not detected by this screening methodology exhibited a mucoid morphology of their colonies. Apparently, an extracellular polymeric substance produced by these strains hampered the entry of the lipophilic dye into cells. The utilization of the developed screening methodology would allow selecting of oleaginous bacteria in a simpler and faster way than techniques usually used nowadays, based on unspecific staining protocols and spectrophotometric or chromatographic methods. Furthermore, the use of ORO as a staining reagent would easily characterize the neutral lipids accumulated by microorganisms as reserve compounds. KEY POINTS: • Oil Red O staining is specific for triacylglycerols • Oil Red O staining is useful to detect oleaginous bacteria • Fast and inexpensive staining to isolate oleaginous bacteria from the environment.

Exploring Iberian ham triacylglycerols: Unraveling the influence of growing area, season, breed, and feeding patterns through innovative compositional data analysis.

This research examined the triacylglycerol composition of Iberian pig hams from Sevilla province, focusing on the influence of growing area, season, breed, age, montanera duration, and feeding types. Compositional data analysis (CoDA) tools and standard multivariate statistics were employed to analyse the original and CoDa-transformed data. ANOVA (ilr) and ANCOVA (log ratios) revealed significant effects of season, feeding type, and towns on triacylglycerol profiles, while montanera showed limited or no effect. Breeds and age were deemed irrelevant. Various discriminant analysis (DA) methods consistently distinguished samples from the 2004/2005 season and the cebo feeding type but struggled with other distinctions. PLS-R analysis indicated that bellota feeding was associated with triacylglycerols rich in oleic acid, while cebo was predominantly linked to those containing palmitic and stearic acids. The study challenges traditional assumptions about the effects of montanera, breeds, and age on Iberian pig hams and highlights the need for further investigation.

Infant Formula with 50% or More of Palmitic Acid Bound to the sn-2 Position of Triacylglycerols Eliminate the Association between Formula-Feeding and the Increase of Fecal Palmitic Acid Levels in Newborns: An Exploratory Study.

The binding ratio of palmitic acid (PA) at the sn-2 position of triacylglycerols in infant formulas is lower than that in breast milk, resulting in higher levels of fecal PA. Even if the ratio is increased to 40-50%, fecal PA levels in formula-fed infants remain higher than those in breast-fed infants. In Japan, infant formulas with 50% or more of PA bound to sn-2 (high sn-2 PA milk) are commercially available; however, their effects on PA excretion have not been investigated. Therefore, this observational study aimed to preliminarily evaluate whether the feeding volume of high sn-2 PA milk is significantly associated with fecal total/soaped PA levels in newborns. Infant formulas were classified as high (≥50% of PA bound to sn-2) or low sn-2 (<50%) PA milk. Associations between feeding volume of high or low sn-2 PA milk and fecal PA levels were evaluated using multiple regression analysis models. The results showed that the feeding volume of low sn-2 PA milk was positively associated with fecal total/soaped PA levels, while there was no significant association between those of high sn-2 PA milk and fecal total/soaped PA levels. Our preliminary study suggests that high sn-2 PA milk may reduce increased fecal PA levels in formula-fed newborns.

Lipidomics profile and volatile compounds of squids (Illex argentinus, Ommastrephes Bartram and Dosidicus gigas) in the Argentine, North Pacific Ocean, Equator and Peru by UPLC-triple TOF-MS and HS-SPME-GC-O-MS.

Comprehensive lipid and volatile compound analyses were performed with squids collected from four varied geographical locations to discriminate the regional characteristics. A total of 1442 lipid molecules and 110 volatiles were detected in the squid muscle samples. There were significant differences in the lipid profiles between Argentine squid (Illex argentinus, AGT), North Pacific Ocean squid (Ommastrephes Bartram, NPO), Equatorial squid (Dosidicus gigas, EQ), and Peruvian squid (Dosidicus gigas, PR) muscle. Phosphatidylcholines (14.64%), triacylglycerols (12.42%), and ceramides (10.97%) were the main lipid components. The contents of polyunsaturated fatty acid in phospholipids and in glycerolipids were 30.35-52.05% and 18.11-25.15%, respectively. The volatiles in squids exhibited significant regional variation; 1-pentanol and 1-octanol, 2-ethyl-1-hexanol and terpinen-4-ol, 2,7-ethyl-1-hexanol, 3-methy-1-butanol and 2-propyl-1-pentanol were identified as characteristic flavor compounds in AGT, NPO, EQ, and PR, respectively. Sphingomyelin, phosphatidylserine, phosphatidylethanolamine, and ceramide were strongly correlated with volatiles in squid muscle. Our study is a reference for the lipid nutritional value and flavor compounds of squids.

Distinctive Lipid Characteristics of Colorectal Cancer Revealed through Non-targeted Lipidomics Analysis of Tongue Coating.

The metabolites and microbiota in tongue coating display distinct characteristics in certain digestive disorders, yet their relationship with colorectal cancer (CRC) remains unexplored. Here, we employed liquid chromatography coupled with tandem mass spectrometry to analyze the lipid composition of tongue coating using a nontargeted approach in 30 individuals with colorectal adenomas (CRA), 32 with CRC, and 30 healthy controls (HC). We identified 21 tongue coating lipids that effectively distinguished CRC from HC (AUC = 0.89), and 9 lipids that differentiated CRC from CRA (AUC = 0.9). Furthermore, we observed significant alterations in the tongue coating lipid composition in the CRC group compared to HC/CRA groups. As the adenoma-cancer sequence progressed, there was an increase in long-chain unsaturated triglycerides (TG) levels and a decrease in phosphatidylethanolamine plasmalogen (PE-P) levels. Furthermore, we noted a positive correlation between N-acyl ornithine (NAOrn), sphingomyelin (SM), and ceramide phosphoethanolamine (PE-Cer), potentially produced by members of the Bacteroidetes phylum. The levels of inflammatory lipid metabolite 12-HETE showed a decreasing trend with colorectal tumor progression, indicating the potential involvement of tongue coating microbiota and tumor immune regulation in early CRC development. Our findings highlight the potential utility of tongue coating lipid analysis as a noninvasive tool for CRC diagnosis.

Formation of Epoxy Fatty Acids in Triacylglycerol Standards during Heating.

Epoxy fatty acid formation during heating was estimated using triolein (OOO) and trilinolein (LLL). Epoxy octadecanoic acids were found in heated OOO, while epoxy octadecenoic acids were found in heated LLL. The content of epoxy fatty acids increased with heating time, and trans-epoxy fatty acids were formed significantly more than cis-epoxy fatty acids. A comparison between OOO and LLL indicated that epoxy fatty acid formation was higher in the OOO than that in the LLL. Heating tests in the presence of α- tocopherol suggested that the formation of epoxy fatty acids could be suppressed by antioxidants.

Exploration of the Lipid Profile of Edible Oleaginous Microgreens by Mass Spectrometry-Based Lipidomics.

The spreading awareness of the health benefits associated with the consumption of plant-based foods is fueling the market of innovative vegetable products, including microgreens, recognized as a promising source of bioactive compounds. To evaluate the potential of oleaginous plant microgreens as a source of bioactive fatty acids, gas chromatography-mass spectrometry was exploited to characterize the total fatty acid content of five microgreens, namely, chia, flax, soy, sunflower, and rapeseed (canola). Chia and flax microgreens appeared as interesting sources of α-linolenic acid (ALA), with total concentrations of 2.6 and 2.9 g/100 g of dried weight (DW), respectively. Based on these amounts, approximately 15% of the ALA daily intake recommended by the European Food Safety Authority can be provided by 100 g of the corresponding fresh products. Flow injection analysis with high-resolution Fourier transform single and tandem mass spectrometry enabled a semi-quantitative profiling of triacylglycerols (TGs) and sterol esters (SEs) in the examined microgreen crops, confirming their role as additional sources of fatty acids like ALA and linoleic acid (LA), along with glycerophospholipids. The highest amounts of TGs and SEs were observed in rapeseed and sunflower microgreens (ca. 50 and 4-5 µmol/g of DW, respectively), followed by flax (ca. 20 and 3 µmol/g DW). TG 54:9, 54:8, and 54:7 prevailed in the case of flax and chia, whereas TG 54:3, 54:4, and 54:5 were the most abundant TGs in the case of rapeseed. ß-Sitosteryl linoleate and linolenate were generally prevailing in the SE profiles, although campesteryl oleate, linoleate, and linolenate exhibited a comparable amount in the case of rapeseed microgreens.

Characterization of lipids and volatile compounds in boiled donkey meat by lipidomics and volatilomics.

Lipids are crucial substances for the formation and retention of volatile compounds (VOCs). The lipid and VOC profiles of boiled donkey meat were investigated by lipidomics and volatilomics. In total, 4277 lipids belonging to 39 subclasses were identified, comprising 26.93% triglycerides (TGs), 15.74% phosphatidylcholins (PCs), and 9.40% phosphatidylethanolamines. The relative percentage of TG in the meat significantly decreases (p < 0.001) from 0 to 40 min, after which there is no significant change, whereas PCs, sphingomyelins, and methyl phosphatidylcholines (MePCs) show the opposite trend. TG(16:1_18:1_18:2) and TG(16:0_16:1_18:2) appear to be key lipids for retaining VOCs in boiled donkey meat. Furthermore, PC(18:3e_16:0) and MePC(31:0e) were found to be potential markers for discriminating donkey meat. A total of 83 VOCs were detected, including 25.30% aldehydes, 18.07% hydrocarbons, 14.46% ketones, and 13.25% alcohols. Eleven characteristic VOCs with relative odor activity values >1 were identified as the predominant flavor compounds in boiled donkey meat, mainly hexanal and 1-octen-3-ol. Of the 258 differential lipids, 72 of them, especially polyunsaturated-fatty acid-rich lipids, are the main contributors to the formation of VOCs. Together, the key lipids for retention and formation of VOCs in donkey meat were revealed, providing a theoretical basis for VOC regulation.