Search Results (80)

Lard imparts unique organoleptic properties that underpin its essential role in Chinese gastronomy; however, the specific lipid precursors contributing to its aroma remain unclear. This study explores the flavor formation mechanism of lard by comparing its texture and aroma at two preparation temperatures, 130 °C and 100 °C. We identified a total of 256 and 253 lipids at these temperatures, respectively, with triacylglycerols (TGs) and diacylglycerols (DGs) being the predominant lipid species. An HS-GC-IMS analysis detected 67 volatile compounds, predominantly aldehydes, acids, and alcohols. A subsequent Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) identified 49 discriminatory lipids and 20 differential volatiles. A correlation analysis showed a positive relationship between aldehydes and unsaturated triglycerides in lard, with TG (16:1-16:1-18:0), TG (17:2-18:1-18:1), TG (16:1-17:1-18:1), and TG (18:1-18:1-20:1) identified as characteristic markers at both temperatures. Furthermore, there was a positive correlation between ketones and alcohols and phospholipids and sphingolipids containing unsaturated fatty acid chains. TGs and glycerophospholipids (GPs), rich in polyunsaturated fatty acids, are likely key precursors driving the formation of distinct flavors during lard processing. This study elucidates the mechanistic interactions between lipids and volatile organic compounds, providing a framework for optimizing lard processing protocols and flavor modulation. Full article

A traditional dairy product from northern Colombia is suero costeño (SC), typically handmade through artisanal processes involving the natural fermentation of raw cow’s milk (RM); it is characterized by a creamy texture and a distinctive sensory profile, with a sour/salty taste and rancid odor. This study aimed to determine the chemical identity (using GC-FID/MSD) of SC and RM samples (from eight locations in the department of Córdoba-Colombia) by analyzing volatile components (trapped by HS-SPME and SDE) and fatty acid content. Consequently, the most notable results were as follows: (a) myristic (7–12%), stearic (12–17%), oleic (13–23%), and palmitic (21–29%) acids were the most abundant constituents [without significant differences among them (p > 0.05)] in both RM and SC fats; these were also expressed as polyunsaturated (2–5%), monounsaturated (26–36%), saturated (59–69%), omega-9 (19–30%), omega-6 (0.5–1.6%), and omega-3 (0.2–1.2%) fatty acids; (b) differences in the composition (p < 0.05) of the volatile fractions were distinguished between RM and SC samples; likewise, the SC samples differed (from each other) in their volatile composition due to the preparation processes applied (processes with raw milk and natural fermentation had less variability); nonetheless, it was possible to determine the volatilome for the artisanal product; and (c) the major components responsible for the chemical identity of SC were ethyl esters (of linear saturated and unsaturated acids, short/medium chains), aliphatic alcohols (linear/branched, short/long chains), aliphatic aldehydes (long chains, >C₁₄), alkyl methyl ketones (long chains, >C₁₁), sesquiterpenes (caryophyllane/humulane types), monoterpenes (mono/bi-cyclics), short-chain fatty acids, and aromatic alcohol/acid, among others. Full article

Squid is rich in polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which exert various human health benefits. Pan-fried squid is a popular processed product beloved by consumers. However, the PUFAs of squid can be severely oxidized during thermal processing, which will result in the reduction in nutritional value and generation of harmful compounds like aldehydes. In this study, flavonoids extracted from coconut exocarp (CEF) and the metal ion chelating agent disodium ethylenediaminetetraacetate (EDTA-2Na) were used to inhibit lipid oxidation during the frying of squid, with the lipid oxidation level, the changes in fatty acid composition, and aldehyde concentrations being examined by gas chromatography mass spectrometry and high-performance liquid chromatography mass spectrometry. Results indicated that during pan-frying, the peroxide value, thiobarbituric acid value, and total oxidation value increased significantly, while the contents of EPA and DHA decreased significantly, and the concentrations of most aldehydes increased in a time- and temperature-dependent pattern. Both CEF and EDTA-2Na treatments inhibited these changes; comparatively, the CEF treatment was significantly better than that of EDTA-2Na. For instance, the CEF treatment inhibited the generation of HHE by 31.90%, 33.24%, and 19.73%, respectively, after pan-frying of squid at 180 °C for 6, 8, and 10 min, while the corresponding values for HNE were 22.65%, 18.96%, and 17.28% respectively. These results suggested that CEF can improve the oxidative stability of squid lipids during pan-frying and reduce the generation and accumulation of aldehydes and improve the security of processed squid products. Full article

The covering oils of twenty-two commercially canned sardines were studied by Proton Nuclear Magnetic Resonance spectroscopy (¹H NMR) freshly purchased and also after storage at room temperature for fifteen years. The filling oils studied were olive oils (one extra-virgin olive oil), sunflower oils, soybean oils, and vegetable oils (unspecified origin). The aim was to obtain qualitative and quantitative information on lipid composition, oxidative and hydrolytic status, and on the changes occurring during storage. Just after purchase, in all the samples, the migration of fish omega-3 polyunsaturated eicosapentaenoic (EPA, C20:5ω3) and docosahexaenoic (DHA, C22:6ω3) acyl groups was reported; the occurrence of oxidative or hydrolytic reactions was not observed. After storage, the main change in the spectra was the presence of signals due to hydrolytic compounds (mainly 1,3-diglycerides, together with 1,2-diglycerides, 1-monoglycerides, and lower proportions of 2-monoglycerides). In eleven samples very low concentrations of saturated aldehydes (alkanals) were detected, which is considered a low oxidative status. It is suggested that the above-mentioned partial glycerides and alkanals migrated from sardine muscle to the oils. The content in omega-3 lipids in the oils after storage indicated the occurrence of lipid interchange between the sardine muscle and the packing oil in both directions. Full article

Microalgae are among the most promising feedstocks for a wide range of applications due to their ease of cultivation, rapid growth rate, and ability to accumulate significant amounts of lipids and other valuable compounds. In the current study, two microalgae species, Chlorella sp. and Spirulina platensis, were studied regarding chemical composition, lipid extraction by ultrasound-assisted solvent extraction, and volatile compounds analysis. The optimization of the lipid extraction process was investigated with respect to the influence of different process parameters. The highest lipid content was found in Chlorella sp., which was more than twice as high compared to Spirulina platensis. Both microalgae contain saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs). Spirulina platensis contains high palmitic acid (42.9%) and linolenic acid (22.5%), and is low in MUFA content (8.5%), whereas Chlorella sp. contains high oleic (21.9%), linoleic (25.3%), and α-Linolenic acid (10.2%). Based on the fatty acids profile, nutritional lipid indices were calculated. Regarding the volatile content, Spirulina platensis contains amines, aldehydes, alcohols, ketones, and hydrocarbons, whereas Chlorella sp. contains hydrocarbons, heterocycle, aldehydes, thiocyanates, and esters which give the odor profile. Full article

This study evaluated the impact of reduced crude protein (CP) diets supplemented with four essential amino acids (EAAs) on production efficiency and meat quality characteristics in Bamei pigs. Thirty-six castrated Bamei pigs (half male and half female, 100 days old, with an average body weight of 50.65 kg) were randomly assigned to three different dietary CP levels: control group (16.0% CP), group I (14.0% CP + EAA), and group II (12.0% CP + EAA). In both experiments, the group I and group II diets were supplemented with crystalline AA to achieve equal contents of standardized ileal digestible (SID) lysine, methionine, threonine, and tryptophan. After a 70-day feeding trial, the results showed that (1) low-protein diets of different levels supplemented with four EAAs had no significant effect on the growth performance of Bamei pigs (p > 0.05) but had a tendency to increase average daily feed intake (ADFI). (2) In terms of slaughter performance, compared with the control group, the low-protein amino-acid-balanced diet significantly reduced the pH of gastric contents (p = 0.045), and tended to increase the backfat thickness and dressing percentage (p > 0.05). (3) The effect of low-protein diets on muscle amino acids showed that group I was significantly improved, including increased Threonine, Serine, Glycine and Bitter amino acids. (4) Compared with the control group, the low-protein group increased the ratio of unsaturated fatty acid (UFA)/total fatty acids (TFAs), Monounsaturated Fatty Acid (MUFA)/TFA, and Polyunsaturated Fatty Acid (PUFA)/TFA, and the content of decanoic acid, myristic acid, and cis-11-eicosenoic acid in group II was significantly higher than that in the other two groups (p ≤ 0.012). (5) The total number of flavor compounds in the muscle of the low-protein group was higher than that of the control group, including Aldehyde, Alcohol, sulfide, Alkane, and Furan compounds. Among them, the relative contents of Hexanal, Heptaldehyde, Benzaldehyde, E-2-Octenal, 2,3-Octanedione, and 2-Pentylfuran in group II were significantly higher than in those groups (p < 0.05). Notably, the 14% dietary protein level group had the most significant effect on the meat quality and flavor of Bamei pigs. Therefore, under the condition of amino acid balance, reducing the use of protein feed raw materials and adding synthetic amino acids can not only improve the meat quality and flavor of finishing pigs, but also save the feed cost. Full article

This study evaluated the effects of different lipid sources—fish oil (FO), soybean oil, rapeseed oil, and palm oil—on the growth and muscle quality of golden pompano (Trachinotus ovatus) cultured in offshore cages for 10 weeks. Three diets (D1–D3) were formulated: D1 used only fish oil, D2 blended fish, rapeseed oil, and palm oil, and D3 combined fish and soybean oils. Fish in the D1 group showed the highest weight gain, specific growth rate, and muscle protein content, significantly outperforming D3. No significant differences in muscle lipid content or edible quality were found between groups. D1 had the highest levels of long-chain and n-3 polyunsaturated fatty acids (PUFA), while D3 had higher n-6 PUFA. Saturated and monounsaturated fatty acids were higher in D1 and D2 than in D3. Muscle volatiles like aldehydes and amines were elevated in D1, with more pleasant flavors compared to D2 and D3. Muscle texture was superior in D2. These results suggest that rapeseed and palm oils can enhance growth, flavor, and texture in fish on low FO diets, offering a sustainable alternative to reduce reliance on marine-based feed in aquaculture. Full article

The present study aims to perform a comparative analysis of the chemical composition and thermal behavior of two distinct milk types, namely animal and plant-based. The thermal analysis revealed the presence of the following classes of compounds: hydrocarbons, heterocycles, aldehydes, ketones, amines and alcohols. All types of milk contain saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), though the relative proportions of these vary depending on the specific milk type. Animal milk powders contain SFAs, including palmitic, stearic, and myristic acids, as well as moderate amounts of MUFAs, such as oleic and palmitoleic acids. They also contain lower PUFAs, including linoleic and alpha-linolenic acids. In contrast, plant-based milk powders, particularly soy milk powder, are rich in both linoleic and alpha-linolenic acids. Plant-based milk typically exhibits lower levels of SFAs and higher levels of MUFAs and PUFAs when compared to milk of animal origin. In conclusion, the fatty acid profiles of animal and plant-based milk powders reflect the different nutritional attributes and health implications associated with each. Thermal behavior analysis offers insights into the stability and potential flavor changes that may occur during processing and storage. The comparative analysis highlights significant differences in the chemical composition and thermal behavior of animal and plant-based milk powders. Full article

Sclerocarya birrea kernel volatile compounds and fatty acid methyl esters (FAMEs) from the Bubi district in Matabeleland North province of Zimbabwe were characterised by GC–MS. The volatile compounds of the oil include 65 different compounds from 24 distinct classes, dominated by 13 alcohols and 14 aldehydes (42%). Other classes include carboxylic acids, phenols, sesquiterpenes, lactones, pyridines, saturated fatty acids, ketones, and various hydrocarbons. The kernel oils revealed essential fatty acids such as polyunsaturated (α-linolenic and linoleic acids) and monounsaturated fatty acids (palmitic, palmitoleic, and oleic acids). Notably, oleic acid is the predominant fatty acid at 521.61 mg/g, constituting approximately 73% of the total fatty acids. Linoleic acid makes up 8%, and saturated fatty acids make up about 7%, including significant amounts of stearic (42.45 mg/g) and arachidic (3.46 mg/g) acids. These results validate the use of marula oils in food, pharmaceutical, and health industries, as well as in the multibillion USD cosmetics industry. Therefore, the potential applications of S. berria kernel oils are extensive, necessitating further research and exploration to fully unlock their capabilities. Full article

During photosynthesis, reactive oxygen species (ROS) are formed, including hydrogen peroxide (H₂O₂) and singlet oxygen (¹O₂), which have putative roles in signalling, but their involvement in photosynthetic acclimation is unclear. Due to extreme reactivity and a short lifetime, ¹O₂ signalling occurs via its reaction products, such as oxidised poly-unsaturated fatty acids in thylakoid membranes. The resulting lipid peroxides decay to various aldehydes and reactive electrophile species (RES). Here, we investigated the role of ROS in the signal transduction of high light (HL), focusing on GreenCut2 genes unique to photosynthetic organisms. Using RNA seq. data, the transcriptional responses of Chlamydomonas reinhardtii to 2 h HL were compared with responses under low light to exogenous RES (acrolein; 4-hydroxynonenal), β-cyclocitral, a β-carotene oxidation product, as well as Rose Bengal, a ¹O₂-producing photosensitiser, and H₂O₂. HL induced significant (p < 0.05) up- and down-regulation of 108 and 23 GreenCut2 genes, respectively. Of all HL up-regulated genes, over half were also up-regulated by RES, including RBCS1 (ribulose bisphosphate carboxylase small subunit), NPQ-related PSBS1 and LHCSR1. Furthermore, 96% of the genes down-regulated by HL were also down-regulated by ¹O₂ or RES, including CAO1 (chlorophyllide-a oxygnease), MDH2 (NADP-malate dehydrogenase) and PGM4 (phosphoglycerate mutase) for glycolysis. In comparison, only 0–4% of HL-affected GreenCut2 genes were similarly affected by H₂O₂ or β-cyclocitral. Overall, ¹O₂ plays a significant role in signalling during the initial acclimation of C. reinhardtii to HL by up-regulating photo-protection and carbon assimilation and down-regulating specific primary metabolic pathways. Our data support that this pathway involves RES. Full article

This study investigated the dietary effect of curcumin (CUR) on amino acid, 5′-nucleotides, fatty acid, and volatile compound profiles of chicken meat. A total of 400 healthy 1-day-old broiler male chicks were divided into 4 groups (n = 10) and fed either a basal diet or a diet with the addition of CUR with concentrations of 100 mg/kg, 150 mg/kg, and 200 mg/kg for 43 days. The results show that the addition of CUR in chicken diets is conducive to promoting the deposition of amino acids and increasing the content of 5′-nucleotides in chicken meat, reducing the contents of saturated fatty acid (SFA) and C20:4 n6 but increasing the ratio between polyunsaturated fatty acid (PUFA) and SFA. In addition, the volatile compound profile shows that the main volatile compounds in chicken meat are aldehydes (including hexanal, heptanal, octanal, and nonanal), with significant increases in their contents observed among chickens in the CUR-intake group. Moreover, it has been found that (E, E)-2,4-nonadienal, trans-2-decenal, benzaldehyde, and trans-2-octenal in chicken meat can significantly increase its overall aroma, and the addition of CUR with 150 mg/kg had the best effect on improving nutritional quality and flavor of chicken meat. This study provides a basis for the comprehensive utilization of CUR as a feed additive with the potential to substitute antibiotics. Full article

To investigate the modification of muscle quality of farmed tilapia through dietary fatty acid strategies, two diets were formulated. Diet SO, using soybean oil as the lipid source, and diet BO, using blended soybean and linseed oils, each including 0.58% and 1.35% α-linolenic acid (ALA), respectively, were formulated to feed juvenile tilapia for 10 weeks. The muscular nutrition composition, positional distribution of fatty acid in triglycerides (TAGs) and phospholipids (PLs), volatile flavor, lipid mobilization and oxidation were then analyzed. The results showed that there was no distinct difference between the SO and BO groups in terms of the nutrition composition, including crude protein, crude lipid, TAGs, PLs, and amino acid. Although the fatty acid distribution characteristics in ATGs and PLs showed a similar trend in the two groups, a higher level of n-3 PUFA (polyunsaturated fatty acid) and n-3 LC-PUFA (long-chain polyunsaturated fatty acid) bound to the glycerol backbone of TAGs and PLs was detected in the BO group than the SO group, whereas the opposite was true for n-6 PUFA. Additionally, the muscular volatile aldehyde and alcohol levels were higher in the BO group. Moreover, the expression of enzymatic genes and protein activities related to lipid mobilization (LPL, LPCAT, DGAT) and oxidation (LOX and GPX) was higher in the BO group. The results demonstrate that high-ALA diets may improve the fatty acid bioavailability and volatile flavor of tilapia by improving the lipid mobilization and oxidation, which provides new ideas for the improvement of muscle quality in farmed fish. Full article

The lipid and volatile profiles of goat primal cuts (shoulder, rib, loin, breast, and leg), as well as their potential impact on nutritional and flavor/taste attributes, were investigated. The breast cuts had the lowest protein but the highest fat content. Triacylglycerol was the predominant lipid in all cuts (82.22–88.01%), while the breast cuts had the lowest triacylglycerol and the highest diacylglycerol and free fatty acids. Also, the highest unsaturated fatty acid (UFA), both monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), was obtained in the breast cuts. These findings correlated well with the highest peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) value. The volatile profiles of the various grilled cuts indicated that the breast and leg cuts had similar volatiles, with higher amounts of alcohol, aldehyde, ketone, and ester than others, which could explain the flavor oxidation by lipid and off-flavors in spoiled meat. While the shoulder, rib, and loin cuts had higher amounts of nitrogen-containing compounds. The highest sulfur-containing and hydrocarbon compounds were also observed in the shoulder cuts, which are mainly formed during the Maillard reaction and responsible for the cooked meat flavor. This investigation revealed that each cut of goat meat has a varied composition, especially in lipids and volatile compounds. Thus, meat quality differs in terms of nutritional aspects and flavor/taste characteristics, enabling consumers to select nutritious or proper cuts for their cooking to achieve the most satisfaction from goat meat consumption. Full article

Egg products after thermal treatment possess a unique flavor and are favored by consumers. In this study, the key aroma-active compounds of egg yolk products and their formation mechanism during thermal treatment were investigated. The volatile aroma compounds in egg yolks were monitored using an electronic nose, gas chromatography-mass spectrometry (GC–MS) and gas chromatography–olfactometry–mass spectrometry (GC–O–MS), and the lipid molecular species were explored using ultra-high-performance liquid chromatography– mass spectrometry with a Q-Exactive HF-X Orbitrap (UPLC-Q-Exactive HF-X). A total of 68 volatile compounds were identified. Boiled eggs mainly derived their flavor from hexanal, 2-pentyl-furan, 2-butanone, 3-methyl-butanal and heptane. Meanwhile, fried eggs relied mainly on 14 compounds, the most important of which were 2-ethyl-3-methyl-pyrazine, 3-ethyl-2,5-dimethyl-pyrazine, 2-ethyl-3,5-dimethyl-pyrazine, nonanal and 2,3-diethyl-5-methyl-pyrazine, providing a baked and burnt sugar flavor. A total of 201 lipid molecules, belonging to 21 lipid subclasses, were identified in egg yolks, and 13 oxidized lipids were characterized using a molecular network. Phosphoethanolamines (PEs) containing polyunsaturated fatty acids were the primary flavor precursors contributing to the development of egg yolks’ flavor, participating in lipid oxidation reactions and the Maillard reaction and regulating the production of aldehydes and pyrazine compounds. This study provides reference and guidance for the development of egg yolk flavor products. Full article

Diatoms are responsible for the fixation of ca. 20% of the global CO2 and live associated with bacteria that utilize the organic substances produced by them. Current research trends in marine microbial ecology show which diatom and bacteria interact mediated through the production and exchange of infochemicals. Polyunsaturated aldehydes (PUA) are organic molecules released by diatoms that are considered to have infochemical properties. In this work, we investigated the possible role of PUA as a mediator in diatom–bacteria interactions. To this end, we compare the PUA profile of a newly isolated oceanic PUA producer diatom, Cyclotella cryptica, co-cultured with and without associated bacteria at two phosphate availability conditions. We found that the PUA profile of C. cryptica cultured axenically was different than its profile when it was co-cultured with autochthonous (naturally associated) and non-autochthonous bacteria (unnaturally inoculated). We also observed that bacterial presence significantly enhanced diatom growth and that C. cryptica modulated the percentage of released PUA in response to the presence of bacteria, also depending on the consortium type. Based on our results, we propose that this diatom could use released PUA as a specific organic matter sign to attract beneficial bacteria for constructing its own phycosphere, for more beneficial growth. Full article