The present study focuses on the differentiation of Deqingyuan (n = 90), Taihe (n = 90) and crossbred (n = 90) black-boned silky fowl eggs based on chemometrics analysis of multi-element and lipidomics data. A total of 53 chemical elements were simultaneously quantified in the eggs using inductively coupled plasma mass spectrometry. Multivariate statistical analysis of element data screened 30, 13 and 12 candidate discriminants for whole egg, egg yolk and egg white samples, respectively. Moreover, we utilized an LC-MS/MS-based lipidomics approach to profile lipids in the three types of egg yolks. In total, 1633 lipid species (including 43.78% glycerophospholipids, 25.66% glycerolipids, 16.66% fatty acyls, 6.86% sphingolipids, 4.10% sterol lipids, 1.53% polyketides, 1.10% prenol lipids and 0.31% saccharolipids) were consistently detected in all samples. A partial least squares discriminant analysis model was established based on the lipidomics data, which enables a 100% correct classification of the egg yolks. Using a cutoff of variable importance in projection value >1 and p value <.05, a panel of 22 potential lipid markers was discovered for the discrimination of Deqingyuan, Taihe and crossbred egg yolks. These results could facilitate a better understanding of the nutritional qualities of the evaluated eggs. Our method of combining chemical analysis with chemometrics offers a convenient and powerful tool to distinguish commercially-available eggs.

The present study sought to analyze the lipid profiles of oyster Crassostrea gigas from Yellow Sea (YS), East China Sea, and South China Sea (SCS) through the untargeted lipidomics strategy based on UPLC-Q-Exactive Orbitrap mass spectrometry and multivariate statistics. The results elucidated that geographical differences had profound effects on the lipid content, composition, and lipid molecular profiles. Notably, oysters from the YS group contained the highest lipid content, including triacylglycerol, diacylglycerols, and the majority of phospholipid molecule species, while oysters from the ECS group contained most of the phosphatidylcholine species and the SCS group contained most of the sphingolipid species. Totally, 1155 lipid molecular species belonging to 21 subclasses were identified; of them, 45 lipid molecular species could serve as differential marker for lipid of oysters from different sea areas. Overall, lipidomics could be a potential approach for discrimination of lipid characters between marine shellfishes for geographical origin traceability.

The lipids in goat milk from Guangdong Province (GGM), Shaanxi Province (SGM), and Inner Mongolia Province (NGM) were analyzed and compared using untargeted lipidomics. A total of 16 lipid sub-classes and 638 lipid molecules were identified in the three groups. The main lipids were diacylglycerol (DG), triacylglycerol (TG), and glycerophosphatidylethanolamine (PE). The contents of glycerophosphatidylcholine (PC), PE, glycerophosphatidylinositol (PI), sphingomyelin (SM), glucosylceramide (GlcCer), lactosylceramide (LacCer), DG, and TG were significantly different (P < 0.05) in three groups. Moreover, 173 significantly different lipids were screened out, and 13 lipid molecules could be applied as potential lipid markers for identifying the geographic region of goat milk. In addition, the related metabolic pathways were also analyzed. A hypothetical scheme was drawn by linking the most relevant metabolic pathways. This work will provide basics for the establishment of the Saanen goat milk traceability system and provide comprehensive lipid information for the goat milk of different regions.

The geographical traceability of food products is seen as a distinctive feature of the future of food which is increasingly becoming a concern for consumers. In this research, differences in the lipid composition of Coix seed samples from four major Chinese origins were investigated using non-targeted lipidomics. By multivariate statistical analysis, unsupervised PCA and OPLS-DA based differentiation between the four origins of Coix seed samples could be achieved. The OPLS-DA VIP > 1 screened 72 lipids out of 1211 lipids as potential markers to distinguish Coix seeds from different origins. In addition, the potential markers (SPH(d16:0), Cer(d18:2/20:0 + O) and PC(8:0e/8:0) were combined with statistical analysis algorithms to construct a discriminant function for rapid differentiation of Coix seed samples from different origins and a specific function for different origins with 100% discrimination accuracy. In general, a rapid and accurate method combining multivariate chemometrics and algorithms was developed based on untargeted lipidomics to determine the geographical origin of Coix seed samples, which can also be applied to other agricultural products.

Vegetable oil is one of the most important components of human nutrition. Soybean () is an important oil crop worldwide and contains rich unsaturated fatty acids. Diacylglycerol acyltransferase (DGAT) is a key rate-limiting enzyme in the Kennedy pathway from diacylglycerol (DAG) to triacylglycerol (TAG). In this study, we conducted further research using T transgenic soybean. A high-performance gas chromatography flame ionization detector showed that oleic acid (18:1) content and total fatty acid content of transgenic soybean were significantly higher than those of the wild type (WT). However, linoleic acid (18:2) was much lower than that in the WT. For further mechanistic studies, 20 differentially expressed proteins (DEPs) and 119 differentially expressed metabolites (DEMs) were identified between WT (JACK) and transgenic soybean mature seeds using proteomic and lipidomics analyses. Combined proteomic and lipidomics analyses showed that the upregulation of the key DEP (lipase GDSL domain-containing protein) in lipid transport and metabolic process induced an increase in the total fatty acid and 18:1 composition, but a decrease in the 18:2 composition of fatty acids. Our study provides new insights into the deep study of molecular mechanism underlying the enhancement of fatty acids in transgenic soybeans, especially oleic acid and total fatty acid, which are enhanced by over-expression of .

Mislabeling and adulteration of tuna are common due to the diminishing of morphological characteristics during processing. The tuna authenticity is now being focused in the seafood supply chain. In this study, the lipid profiles of 3 commercial tuna species (skipjack tuna, bigeye tuna and yellowfin tuna) were investigated via ultra-high performance liquid chromatography coupled with Q-Exactive Orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap MS). A total of 439 lipid species were identified and semi-quantitated by MS-DIAL. Further biomarkers discovery was carried out by chemometrics, leading to 27 lipids being identified as potential lipid biomarkers. Comparisons to reference standards revealed that lipid biomarkers were effective for discrimination of different tuna species. Interestingly, the proposed lipid biomarkers were all glycerophospholipids, implying that they might be the focus of future study.

Liquid chromatography-mass spectrometry was used to study the changes of lipids in salmon muscle stored at 4 °C for different storage times to explore the relationship between lipid composition and salmon freshness. Ninety-two kinds of lipid changes were observed at three different storage times (5, 10, and 15 days) compared with the fresh control group (0 day). Bioinformatics analysis revealed that the contents of four lipids were significantly increased from the tenth day, namely, lysophosphatidylcholine (LPC) (17:0), LPC (18:0), LPC (22:2), and phosphatidylcholine (PC) (18:4/16:1). LPC (17:0) and LPC (18:0) are produced by PC (18:4/16:1) hydrolysis. The traditional freshness index also showed that the salmon slices were in the initial state of spoilage on the tenth day. Therefore, they may be indicators of raw salmon freshness.

Goat milk samples of three lactation stages (colostrum, mature and late milk) were collected from three farms and analyzed with an untargeted method based on UPLC-Q-Exactive Orbitrap Mass Spectrometry and multivariate statistics. A total of 14 lipid subclasses and 756 lipid molecules were identified in samples. Five lipid subclasses and 51 lipid molecules in milk were significantly different among different geographical origins. Two lipid subclasses and 26 lipid molecules were significantly different among different lactation stages. Combined with the partial least squares discriminant analysis results of lipid molecules with a VIP value (Variable Importance in the projection) higher than 1, totally 38 and 19 lipid molecules could be used as potential indicators to identify geographical origins and lactation stages, respectively. Based on six and five selected molecules, the correct rates of discrimination models for geographical origin and lactation stage respectively reached 100% and 96%.

The integration of lipidomics and metabolomics approaches, based on UPLC-QTOF-MS technology coupled with chemometrics, was established to authenticate camellia oil adulterated with rapeseed oil, peanut oil, and soybean oil. Lipidomics revealed that the glyceride profile provides a prospective authentication of camellia oil, but no characteristic markers were available. Sixteen characteristic markers were identified by metabolomics. For camellia oil, all six markers were sapogenins of oleanane-type triterpene saponins. Lariciresinol, sinapic acid, doxercalciferol, and an unknown compound were identified as markers for rapeseed oil. Characteristic markers in peanut oil were formononetin, sativanone, and medicarpin. In the case of soybean oil, the characteristic markers were dimethoxyflavone, daidzein, and genistein. The established OPLS-DA and OPLS prediction models were highly accurate in the qualitative and quantitative analyses of camellia oil adulterated with 5% other oils. These results indicate that the integration of lipidomics and metabolomics approaches has great potential for the authentication of edible oils.

Heat treatment is an important processing technique related to milk quality and nutritional value in the dairy industry. In this study, changes in milk lipids in response to different heat treatments were comprehensively characterized using a lipidomic approach. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) were used to identify and quantify 29 classes and 788 different lipids. In general, heat treatment promoted milk lipid hydrolysis and oxidation; in particular, ultra-high temperature (UHT) treatment resulted in more phospholipid hydrolysis than did pasteurization and extended shelf-life (ESL) treatment. Heat treatment resulted in further lipid oxidation reactions and a reduction in the amount of mild oxidation products. Moreover, the levels of lysophospholipids and free fatty acids (including oxidized free fatty acids) can be used to distinguish UHT-treated milk. In turn, oxidized phosphatidylcholine, oxidized phosphatidylethanolamine, ether-linked phosphatidylethanolamine, diacylglycerol, triacylglycerol, and oxidized triacylglycerol can be used to differentiate raw, pasteurized, and ESL milk. These biomarkers can potentially be used in the dairy industry to monitor the degree and method of heat treatment of milk.

Hazelnut oil is a high-grade edible oil with high nutritional value and unique taste. However, it is prone to oxidative degradation during storage. Herein, we used liquid chromatography coupled to tandem mass spectrometry to carry out a lipidomics analysis of the storage process of hazelnut oil. A total of 41 triacylglycerols and 12 oxylipids were determined. The contents of all oxylipids increased significantly after storage ( < 0.05). The oxylipid accumulation of hazelnut oil during storage was clarified for the first time. Nine significantly different oxylipids were further screened out. It was considered that the 15th day of storage is the dividing point. In addition, the lipoxygenase-catalyzed oxidation may be the major contributor to lipid oxidation of hazelnut oil. This study provides a new insight and theoretical basis to explore the storage oxidation mechanism of hazelnut oil and take quality control measures.

Roasting before oil extraction improves the oxidative stability and odor of flaxseed oil; however, the effect of roasting on lipid profile is still unclear. Herein, the changes in lipid profile in flaxseed oil during roasting were investigated based on lipidomic approach. 238 lipids including fatty acid (45 species), phospholipid (37 species), triacylglycerol (125 species), and oxidized fatty acid (21 species) were determined in unroasted and roasted flaxseed oils. After roasting, unsaturated fatty acids including oleic, linoleic, and lenolenic acid decreased. Triacylglycerols such as TAG(18:3/18:3/18:3) and TAG(18:2/18:3/18:3) had the same change trends with unsaturated fatty acids. However, phosphatidylcholines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, lysophosphatidylcholines, lysophosphatidylethanolamines, and oxidized fatty acids firstly increased and then decreased during roasting. Cyclic phosphadic acids identified for the first time in flaxseed oils increased rapidly at high-temperature roasting. 23 lipids were determined as potential biomarkers to differentiate the light and dark roasted flaxseed oils. Our finding could provide useful information for flaxseed oil processing and lipidomics.

Intramuscular fat (IMF) content is conducive to multiple meat quality properties, while abdominal fat (AF) is treated as waste product in chicken industry. However, the heterogeneity and distinct regulatory mechanisms of lipid composition between the IMF and AF are still unclear. In this study, we carried out non-targeted lipidomics analyses of pectoralis IMF and AF, and detected a total of 423 differential lipid molecules (DLMs) between chicken IMF and AF, including 307 up-regulated and 116 down-regulated DLMs in pectoral IMF. These DLMs exhibited the definite alteration of lipid composition. The up-reglated DLMs in IMF were mainly glycerophospholipids (GPs), including the bulk of phosphatidylcholines (PC, PC (P) and PC (O)), phosphatidylethanolamines (PE, PE (P) and PE (O)), phosphatidylglycerols (PG) and phosphatidylinositol (PI), while the up-reglated DLMs in AF were mainly glycerolipids (GLs), including most of triacylglycerols (TG) and diacylglycerols (DG). We further identified 28 main DLMs contributing to the heterogeneous deposition of IMF and AF, including 11 TGs common to IMF and AF, 12 PCs/PC (P)s specific to IMF and 5 DGs specific to AF. Further integration of transcriptome with the main DLMs by weighted gene co-expression network analysis (WGCNA), we found five key gene sets that included 386 unique genes promoting IMF deposition in pectoralis, 213 unique genes promoting AF deposition, 6 unique genes detrimental to AF deposition, 7 common genes that promote IMF deposition in pectoralis while adversely affect AF deposition, and 28 genes that only promoted IMF deposition in pectoralis but had no effect on AF deposition. In addition, we also observed the expression characteristics of key genes in vivo and in vitro, and found that transmembrane protein family gene TMEM164 might be mainly involved in the positive regulation of intramuscular fat deposition in pectoralis and zinc finger protein family gene ZNF488 had a potential unique positive regulatory function on abdominal fat deposition. These findings provide new perspectives for understanding IMF and AF heterodeposition and will serve as a valuable information resource for improving meat quality via breeding selection in chicken.

BACKGROUND:Soybean is a major oil crop; the nutritional components of soybean oil are mainly controlled by unsaturated fatty acids (FA). Unsaturated FAs mainly include oleic acid (OA, 18:1), linoleic acid (LLA, 18:2), and linolenic acid (LNA, 18:3). The genetic architecture of unsaturated FAs in soybean seeds has not been fully elucidated, although many independent studies have been conducted. A 3 V multi-locus random single nucleotide polymorphism (SNP)-effect mixed linear model (3VmrMLM) was established to identify quantitative trait loci (QTLs) and QTL-by-environment interactions (QEIs) for complex traits. RESULTS:In this study, 194 soybean accessions with 36,981 SNPs were calculated using the 3VmrMLM model. As a result, 94 quantitative trait nucleotides (QTNs) and 19 QEIs were detected using single-environment (QTN) and multi-environment (QEI) methods. Three significant QEIs, namely rs4633292, rs39216169, and rs14264702, overlapped with a significant single-environment QTN. CONCLUSIONS:For QTNs and QEIs, further haplotype analysis of candidate genes revealed that the Glyma.03G040400 and Glyma.17G236700 genes were beneficial haplotypes that may be associated with unsaturated FAs. This result provides ideas for the identification of soybean lipid-related genes and provides insights for breeding high oil soybean varieties in the future.