Comprehensive foodomics analysis reveals key lipids affect aroma generation in beef.

Lipids are vital precursors to beef aroma compounds, but the exact lipid molecules influencing aroma generation remain unconfirmed. This study employs gas chromatography-olfactometry-mass spectrometry and absolute quantitative lipidomics to identify beef's aroma and lipid profiles and to examine lipid alterations post-thermal processing. The aim is to understand the role of lipids in aroma generation during beef's raw-to-cooked transition. Eighteen key aroma compounds were identified as significant contributors to the aroma of beef. 265 lipid molecules were quantified accurately, and we found that triglycerides containing C18:1 or C18:2 chains, such as TG(16:0_18:1_18:1), TG(16:0_18:1_18:2), TG(16:0_16:1_18:1), as well as phosphatidylcholine and phosphatidylethanolamine containing PC(16:1e_20:4), PC(16:0e_20:4), PC(18:2e_18:2), and PE(16:1e_20:4), played important roles in the generation of key aroma compounds in beef. C18:1, C18:2, C18:3, and C20:4 were key substrates for the formation of aroma compounds. In addition, lysophosphatidylcholine and lysophosphatidylethanolamine containing unsaturated fatty acid chains may serve as important aroma retainers.

Identification of Active Molecules against Thrombocytopenia through Machine Learning.

Thrombocytopenia, which is associated with thrombopoietin (TPO) deficiency, presents very limited treatment options and can lead to life-threatening complications. Discovering new therapeutic agents against thrombocytopenia has proven to be a challenging task using traditional screening approaches. Fortunately, machine learning (ML) techniques offer a rapid avenue for exploring chemical space, thereby increasing the likelihood of uncovering new drug candidates. In this study, we focused on computational modeling for drug-induced megakaryocyte differentiation and platelet production using ML methods, aiming to gain insights into the structural characteristics of hematopoietic activity. We developed 112 different classifiers by combining eight ML algorithms with 14 molecule features. The top-performing model achieved good results on both 5-fold cross-validation (with an accuracy of 81.6% and MCC value of 0.589) and external validation (with an accuracy of 83.1% and MCC value of 0.642). Additionally, by leveraging the Shapley additive explanations method, the best model provided quantitative assessments of molecular properties and structures that significantly contributed to the predictions. Furthermore, we employed an ensemble strategy to integrate predictions from multiple models and performed in silico predictions for new molecules with potential activity against thrombocytopenia, sourced from traditional Chinese medicine and the Drug Repurposing Hub. The findings of this study could offer valuable insights into the structural characteristics and computational prediction of thrombopoiesis inducers.

Enrichment efficiency of lutein in eggs and its function in improving fatty liver hemorrhagic syndrome in aged laying hens.

In this study, we evaluated the enrichment efficiency of lutein in eggs and its function in preventing fatty liver hemorrhagic syndrome (FLHS) in aged laying hens. Five groups of laying hens (65 wk old) were fed basal diets supplemented with 0, 30, 60, 90, or 120 mg/kg of lutein. The supplementation period lasted 12 wk followed by 2 wk of lutein depletion in feed. The results revealed that lutein efficiently enriched the egg yolks and improved their color with a significant increase in relative redness (P < 0.001). Lutein accumulation increased in the egg yolk until day 10, then depletion reached a minimum level after 14 d. Overall, zeaxanthin content in all the groups was similar throughout the experimental period. However, triglycerides and total cholesterol were significantly decreased in the liver (P < 0.05) but not significantly different in the serum (P > 0.05). In the serum, the lipid metabolism enzyme acetyl-CoA synthetase was significantly reduced (P < 0.05), whereas dipeptidyl-peptidase 4 was not significantly different (P > 0.05), and there was no statistical difference of either enzyme in the liver (P > 0.05). Regarding oxidation and inflammation-related indexes, malondialdehyde, tumor necrosis factors alpha, interleukin-6, and interleukin-1 beta were decreased, whereas superoxide dismutase and total antioxidant capacity increased in the liver (P < 0.001). The function of lutein for the same indexes in serum was limited. It was concluded that lutein efficiently enriched the egg yolk of old laying hens to improve their color and reached the highest level on day 10 without being subject to a significant conversion into zeaxanthin. At the same time, lutein prevented liver steatosis in aged laying hens by exerting strong antioxidant and anti-inflammatory functions, but also through the modulation of lipid metabolism, which may contribute to reducing the incidence of FLHS in poultry.

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.

Comparative characterization of flavor precursors and volatiles of Taihe black-boned silky fowl and Hy-line Brown yolks using multiomics and GC-O-MS-based volatilomics.

Eggs are nutritious and highly valued by consumers. However, egg flavor varies greatly among different hen breeds. The present study used gas chromatography-olfactometry-mass spectrometry-based volatilomics to identify and compare volatile compounds in Taihe black-boned silky fowl (TS) and Hy-line Brown (HL) egg yolks. In addition, the relationships between the levels of different metabolites and lipids and flavor-associated differences were investigated using multiomics. Twenty-eight odorants in total were identified; among them, the levels of 3-methyl-butanal, 1-octen-3-ol, 2-pentylfuran, and (E, E)-2,4-decadienal differed significantly (P < 0.05) between TS and HL egg yolks. The difference in flavor compounds results in TS egg yolks having a stronger overall odor and flavor and a higher acceptance level than HL egg yolks. Metabolomic analysis revealed that 112 metabolites in the egg yolks were significantly different between the two breeds. Furthermore, these different metabolites in the egg yolks of both breeds were significantly enriched in phenylalanine, tyrosine, and tryptophan biosynthesis pathways and phenylalanine metabolism, alanine, aspartate, and glutamate metabolism pathways (P < 0.05), as identified by both metabolite set enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Lipidomic analysis revealed significant differences in the lipid subclasses, lipid molecules, and fatty acid profiles between the egg yolks from the two breeds. As a result, 48 lipid molecules had variable influence in projection values > 1 based on the partial least squares regression model, which may play a role in the differences in aroma characteristics between the two breeds through oxidative degradation of fatty acids. Our study revealed the metabolite, lipid, and volatility profiles of TS and HL egg yolks and may provide an important basis for improving egg flavor to satisfy various consumer preferences.

Deposition and bioconversion law of ß-carotene in laying hens after long-term supplementation under adequate vitamin A status in the diet.

ß-Carotene, because it is the precursor of vitamin A and has versatile biological roles, has been applied as a feed additive in the poultry industry for a long time. In this study, we investigated the deposition and bioconversion of ß-carotene in laying hens. A total of 600 Hy-line brown laying hens at 40 wk of age were randomly divided into 5 dietary treatments, each group's dietary supplemental levels of ß-carotene were 0, 15, 30, 60, 120 mg/kg feed, and the vitamin A levels were all 8,000 IU/kg. After 14-wk trial, samples were collected, then carotenoids and different forms of vitamin A were detected using the novel method developed by our laboratory. We found that dietary ß-carotene treatment had no significant effects on laying hens' production performance and egg quality (P > 0.05), except the yolk color. The deposition of ß-carotene in the body gradually increased (P < 0.01) with the supplemental dose, whereas the contents of lutein and zeaxanthin decreased (P < 0.05). When the ß-carotene supplemental level was above 30 mg/kg in the diet, the different forms of vitamin A in in serum, liver, ovary, and yolks were increased compared to the control group (P < 0.05). However, these indicators decreased when the additional dose was 120 mg/kg. Moreover, the mRNA levels of the genes involved in ß-carotene absorption, bioconversion, and negative feedback regulation in duodenal mucosa and liver were upregulated after long-term feeding (P < 0.05). Histological staining of the ovaries indicated that the deposition of ß-carotene led to a lower rate of follicle atresia (P < 0.05), and this positive effects may be related to the antioxidant function of ß-carotene, which caused a reduction of oxidation products in the ovary (P < 0.05). Altogether, ß-carotene could accumulate in laying hens intactly and exert its biological functions in tissue. Meanwhile, a part of ß-carotene could also be converted into vitamin A but this bioconversion has an upper limit and negative feedback regulation.

Metabolome-Based Genome-Wide Association Study of Duck Meat Leads to Novel Genetic and Biochemical Insights.

Meat is among the most consumed foods worldwide and has a unique flavor and high nutrient density in the human diet. However, the genetic and biochemical bases of meat nutrition and flavor are poorly understood. Here, 3431 metabolites and 702 volatiles in 423 skeletal muscle samples are profiled from a gradient consanguinity segregating population generated by Pekin duck × Liancheng duck crosses using metabolomic approaches. The authors identified 2862 metabolome-based genome-wide association studies (mGWAS) signals and 48 candidate genes potentially modulating metabolite and volatile levels, 79.2% of which are regulated by cis-regulatory elements. The level of plasmalogen is significantly associated with TMEM189 encoding plasmanylethanolamine desaturase 1. The levels of 2-pyrrolidone and glycerophospholipids are regulated by the gene expression of AOX1 and ACBD5, which further affects the levels of volatiles, 2-pyrrolidone and decanal, respectively. Genetic variations in GADL1 and CARNMT2 determine the levels of 49 metabolites including L-carnosine and anserine. This study provides novel insights into the genetic and biochemical basis of skeletal muscle metabolism and constitutes a valuable resource for the precise improvement of meat nutrition and flavor.

Characterization of meat quality traits, fatty acids and volatile compounds in Hu and Tan sheep.

Sheep breed has a major influence on characteristics of meat quality and intramuscular fat (IMF), however, studies into the relationship between sheep breed and meat quality traits rarely consider the large variation in IMF within breed. In this study, groups of 176 Hu and 76 Tan male sheep were established, weaned at 56 days old, with similar weights, and representative samples were selected based on the distribution of IMF in each population, to investigate variations in meat quality, IMF and volatile compound profiles between breeds. Significant differences were observed in drip loss, shear force, cooking loss, and color coordinates between Hu and Tan sheep (p < 0.01). The IMF content and the predominate unsaturated fatty acids, oleic and cis, cis-linoleic acids, were similar. Eighteen out of 53 volatile compounds were identified as important odor contributors. Of these 18 odor-active volatile compounds, no significant concentration differences were detected between breeds. In another 35 volatile compounds, γ-nonalactone was lower in Tan sheep relative to Hu sheep (p < 0.05). In summary, Tan sheep exhibited lower drip loss, higher shear force values, and redder color, had less saturated fatty acids, and contained less γ-nonalactone against Hu sheep. These findings improve understanding of aroma differences between Hu and Tan sheep meat. Graphical Abstract.

Development and application of a SFC-DAD-MS/MS method to determine carotenoids and vitamin A in egg yolks from laying hens supplemented with ß-carotene.

ß-Carotene, a provitamin A carotenoid, can be converted into vitamin A in animals' bodies, and can also be accumulated intactly in many animal products. In this study, supercritical fluid chromatography-tandem mass spectrometry was utilized to determine ß-carotene and different forms of vitamin A in eggs simultaneously. According to the results, ß-carotene contained in yolk reached a plateau after about 2 weeks of supplementation. With an increase in dietary supplement level, the amount of ß-carotene gradually increased, as well as slightly changing the yolk color. Moreover, the contents of retinoids including retinol, retinyl propionate, retinyl palmitate and retinyl stearate were also elevated in yolks with the ß-carotene additive levels; meanwhile, the lutein and zeaxanthin decreased. On the whole, ß-carotene in the diet of laying hens could be partially deposited in egg yolk, and the contents of vitamin A in yolk could be increased due to ß-carotene bioconversion.

Untargeted Profiling and Differentiation of Volatiles in Varieties of Meat Using GC Orbitrap MS.

Volatile compounds play vital roles in food sensory attributes and food quality. An analysis of volatile compounds could illustrate the sensory attributes at the microscale level. Here, untargeted profiling approaches for volatiles in five most-consumed meat species were established using headspace SPME-GC/high resolution Orbitrap MS. An extended high-resolution database of meat volatile compounds was established to enhance the qualification accuracy. Using sulfur-containing compounds, aldehydes, and ketones as the research model, the parameters including fiber coating types, extraction temperature, extraction time, and desorbing time were optimized. Principle component analysis, volcano analysis and partial least squares discriminant analysis were applied to run the classification and the selection of discriminant markers between meat varieties, respectively. Different varieties could be largely distinguished according to the volatiles' profiles. 1-Octen-3-ol, 1-octen-3-one, 2-pentyl furan and some other furans degraded from n-6 fatty acids would contribute to distinguishing duck meat from other categories, while methyl esters mainly from oleic acid as well as dimethyl sulfoxide and carbon disulfide possibly produced from the sulfur-containing amino acids contributed to the discrimination of beef. Therefore, volatiles' profiling not only could interpret the aroma style in meat but also could be another promising method for meat differentiation and authentication.

Isotope-Coded Chemical Derivatization Method for Highly Accurately and Sensitively Quantifying Short-Chain Fatty Acids.

Short-chain fatty acids (SCFAs) are major gut microbiota-derived metabolites, which can reshape the intestine and regulate gut immunity. The application of conventional GC methods has been hampered for quantifying low-concentrated SCFAs, such as in serum, saliva, and digesta of germ-free animals. Herein, we established a LC-MS method to quantify SCFAs after 5-(dimethylamino)-1-carbohydrazide-isoquinoline (DMAQ) derivatization. The DMAQ derivatization significantly enhanced the detection sensitivity and improved separation of SCFAs. 2-methylbutyric acid and 3-methylbutyric acid were separately quantitated. Moreover, the matrix effect was diminished using DMAQ-13C/15N-tagged SCFAs as internal standards. The established quantitation method was successfully applied in the analysis of plasma and cecum digesta collected from neonatal piglets, revealing that significant increases in biological SCFA contents in cecum digesta were closely related to the variation of gut microbial diversity. The established quantitation method is capable of sensitively and comprehensively quantifying SCFAs that may provide insights into underlying gut-microbiota functions.

Changes in lipids and aroma compounds in intramuscular fat from Hu sheep.

Intramuscular fat (IMF) content is associated with lamb flavor and largely varies between individuals of the same breed. However, studies investigating the effects of IMF variations on lipid profiles and aroma compounds are limited. Here, we performed lipidomic and volatilomic profiling of high-IMF and low-IMF Hu lambs. Triglycerides and diglycerides in the high-IMF group were significantly higher than those in the low-IMF group (p < 0.05). Seventy-nine of 842 lipids identified were significantly different between the groups under positive and negative ion modes (variable importance in projection > 1, p < 0.05). Volatilomic analyses revealed that the aroma profiles also differed between the groups. Fifteen aroma compounds, mainly originating from lipid oxidation, could be responsible for this difference. Thus, our findings provide a comprehensive understanding of the increases in IMF content that drive consumers' satisfaction and also provide a basis for underpinning breeding value for IMF.

Optimization of the nitrogen and oxygen element distribution in microalgae by ammonia torrefaction pretreatment and subsequent fast pyrolysis process for the production of N-containing chemicals.

In this work, ammonia (NH3) torrefaction pretreatment (ATP) was developed to optimize the nitrogen and oxygen element distribution of microalgae via the N-doping and oxygen removal reaction, which could obviously improve the potential use of microalgae as a feedstock for the production of N-heterocyclic chemicals through fast pyrolysis technology. The nitrogen content increased from 8.3% of raw microalgae to 11.51% at 300 °C of ATP, while the oxygen content decreased from 35.96% to 21.61%, because of the Maillard reactions. In addition, the nitrogen-doping ratio and oxygen removal ratio of ATP was much higher than the conventional nitrogen torrefaction pretreatment (NTP). With the increase of ATP torrefaction temperature or the pyrolysis temperature, the relative content of the N-containing compounds increased, while the O-containing compounds decreased. For the N-heterocyclic chemicals, higher pyrolysis temperature favored the formation of pyrroles, while inhibited the formation of pyridines and indoles.

Risk screening of mycotoxins and their derivatives in dairy products using a stable isotope dilution assay and LC-MS/MS.

An liquid chromatography-tandem mass spectrometry method coupled with a stable isotope dilution assay was established for the simultaneous detection of 17 mycotoxins and their derivatives (aflatoxins B1 , B2 , G1 , G2 , M1 , and M2 ; fumonisins B1 and B2 ; ochratoxin A; zearalenone; zearalanone; α-zearalanol; α-zearalenol; T-2 toxin; deoxynivalenol; deepoxy-deoxynivalenol; and sterigmatocystin) in milk and dairy products. The mycotoxins were extracted with acidified acetonitrile and the lipids were removed using a Captiva EMR-lipid column. The average recoveries of the target compounds from samples spiked at three different concentrations were 67-102%, and the relative standard deviations of the peak areas were less than 10%. Limits of quantification (S/N = 10) of 0.004-1.25 µg/kg were achieved, which are significantly lower than the maximum levels allowed in various countries and regions for each regulated mycotoxin. Milk and yogurt products from local markets and e-commercial platforms were analyzed using the optimized method. The screening showed that aflatoxin M1 , deoxynivalenol, fumonisins B1 and B2 , and zearalenone could be found in milk and yogurt products, especially those products also containing grains or jujube ingredients, indicating that there is a risk of mycotoxins in dairy products.

WITHDRAWN: Clinical and CT imaging features of 2019 novel coronavirus disease (COVID-19).

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Enhancement of the production of bio-aromatics from renewable lignin by combined approach of torrefaction deoxygenation pretreatment and shape selective catalytic fast pyrolysis using metal modified zeolites.

In this work, combined approach of torrefaction deoxygenation pretreatment (TDP) and shape selective catalytic fast pyrolysis (SS-CFP) using bifunctional catalyst (metal modified HZSM-5) were employed to improve the yield of bio-BTX derived from the renewable starting material of lignin. Results showed that after TDP, the oxygen element could be removed effectively. The oxygen removal efficiency reached its maximum value of 22.27% at 300 °C, resulting in markedly decrease of unnecessary oxygenates in bio-oil. Compared to parent HZSM-5, all metal modified HZSM-5 (Ga/HZSM-5, Zn/HZSM-5, and Ga-Zn/HZSM-5) promoted the formation of bio-BTX. Zn/HZSM-5 showed the highest selective yield of bio-BTX because of the enhancement deoxygenation reaction of oxygenates and the aromatization reaction of olefins. The combined approach of TDP and SS-CFP remarkably improved the selective yield of bio-BTX, reaching the maximum value of 65.19%, which was much higher than that from single approach of TDP (33.84%) and SS-CFP (47.36%).

N-doping of biomass by ammonia (NH3) torrefaction pretreatment for the production of renewable N-containing chemicals by fast pyrolysis.

In this work, ammonia (NH3) torrefaction pretreatment was developed for the production of nitrogen-enriched lignocellulosic biomass and the production of N-containing chemicals via subsequent fast pyroysis process. Results showed that the content of nitrogen in biomass was significantly increased from 0.03% to 7.59% as the torrefaction temperature increased. XPS analysis showed that nitrogen-doped biomass mainly contained three types of N-containing functional groups, such as quaternary-N, pyrrolic-N, and pyridinic-N. Higher torrefaction temperature promoted the formation of pyrrolic-N, and quaternary-N, but inhibited pyridinic-N. Py-GC/MS analysis showed that higher torrefaction temperature and higher pyrolysis temperature both promoted the formation of N-containing chemicals (pyridines, pyrroles, and amines), which reached a maximum abundance of 19.89%. Amines were the dominant components in N-containing chemical fraction, accounting for 85.27% of the total chemical fraction. Lower torrefaction temperature and lower pyrolysis temperature were preferred for the production of pyridines and pyrroles.

New sight on the lignin torrefaction pretreatment: Relevance between the evolution of chemical structure and the properties of torrefied gaseous, liquid, and solid products.

In order to reveal the deoxygenation mechanism of lignin torrefaction, the relevance between evolution of chemical structure of torrefied lignin and the properties of torrefied gaseous, liquid, and solid products was established in this study. Results showed that the contents of oxygen element, ßO4 linkages, oxygen-containing functional groups (aliphatic OH, aliphatic COOH, aromatic OCH3) in lignin decreased with the increase of the torrefaction temperature from 210 to 300 °C. The oxygen removal efficiency of lignin torrefaction reached the maximum value of 25.53% at 300 °C. The removed oxygen in the torrefied lignin was transferred into the torrefied gaseous product (e.g. CO2, H2O, and CO) and torrefied liquid product (e.g. G-type and P-type phenols, acids). Among the torrefied gaseous products, CO2 was the dominant oxygen carrier, followed by CO and H2O. Among the torrefied liquid products, G-type phenols were the dominant oxygen carrier, followed by P-type phenols and acids.

Algicidal properties of extracts from Cinnamomum camphora fresh leaves and their main compounds.

Plant allelochemicals are considered as the source of effective, economic and friendly-environmental algaecides. To uncover the anti-algal activities of Cinnamomum camphora fresh leaves and their main algicidal agents, we investigated the inhibitory effects of water and methanol extracts from C. camphora fresh leaves on Microcystis aeruginosa and Chlamydomonas reinhardtii cell growth, analyzed the composition of the water and methanol extracts, and determined the main compounds in extracts on the growth of the two algae and their anti-algal mechanism from photosynthetic abilities. Water and methanol extracts from C. camphora fresh leaves can inhibit M. aeruginosa and C. reinhardtii cell growth, and methanol extracts showed stronger inhibitory effects, due to their more compounds and higher molar concentration. There were 23 compounds in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to the water extracts, 9 new compounds were detected in the methanol extracts, and the molar concentration of total compounds in methanol extracts increased by 1.3 folds. Camphor, α-terpineol and linalool were 3 main compounds in the water and methanol extracts. Their mixture (1: 3: 6) and individual compound showed remarkable inhibition on M. aeruginosa and C. reinhardtii cell growth. The degradation of photosynthetic pigments and the reduction of maximum quantum yield of photosystem II (PSII) photochemistry, coefficient of photochemical quenching as well as apparent electron transport rate in C. reinhardtii cells aggravated gradually with increasing the concentration of the mixture and individual compound, while the non-photochemical dissipation of absorbed light energy increased gradually, which led to the decline of photosynthetic abilities. This indicated that camphor, α-terpineol and linalool were 3 main algicidal agents in C. camphora fresh leaf extracts, and they inhibited algal growth by inducing photosynthetic pigment degradation and declining PSII efficiency. Therefore, C. camphora fresh leaf extracts and their main components have potential utilization values as algaecides.