1,721,001 research outputs found
Valorization of Olive By-Products: Innovative Strategies for Their Production, Treatment and Characterization
Full text link: Presently, olive oil production signifies a valuable economic income for Mediterranean countries, where approximately 98% of the world's production is established [...]
Editorial to the special issue “lipidomics and neurodegenerative diseases”
Full text linkThe contribution of dysregulation of lipid signaling and metabolism to neurodegenerative diseases including Alzheimer’s and Parkinson’s is the focus of this special issue. Here, the matter of three reviews and one research article is summarized
Aniline/a-cyano-4-hydroxycinnamic acid is a highly versatile ionic liquid for matrix-assisted laser desorption/ionization mass spectrometry
No full textThe performance of a matrix-assisted laser desorption/ionization (MALDI) ionic liquid matrix (ILM) consisting of alpha-cyano-4-hydroxycinnamic acid (CHCA) and aniline (ANI) was evaluated to assess whether it could offer possible advantages over conventional matrices. Ultraviolet (UV), Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) and laser desorption/ionization mass spectrometry (LDI-MS) experiments were carried out with the aim of confirming the structure of the ANI-CHCA ILM. Different model analytes such as amino acids, peptides, proteins, lipids, phospholipids, synthetic polymers, and sugars were tested. Mass spectra with similar or improved signal-to-noise (S/N) ratio (compared to CHCA) were invariably obtained demonstrating the potential of this ILM as a general purpose matrix. Furthermore, protein identification by peptide mass fingerprinting (PMF) and database search was facilitated compared to CHCA since higher scores and increased sequence coverage were observed. Finally, a complex lipid mixture (i.e. a raw extract of a milk sample) analysed by MALDI-MS showed improved S/N ratio, a reduced chemical noise and a limited formation of matrix-clusters
X-ray photoelectron spectroscopy characterization of poly(2,3-diaminophenazine) films electrosynthesised on platinum
No full textDetection of hazelnut oil in extra-virgin olive oil by analysis of polar components by micro-solid phase extraction based on hydrophilic liquid chromatography and MALDI-ToF mass spectrometry
No full textThe oil polar fraction may have a great potential for the characterization of vegetable oils and for the individuation of
adulterations. In particular, adulteration of extra-virgin olive oil (EVOO) with hazelnut oil (HO) is one of the most difficult
ones to detect due to the similar composition as regards triacylglycerol, total sterol and fatty acid profile. A new micro-solid
phase extraction (μ-SPE) procedure based on hydrophilic liquid chromatography (HILIC) micro-columns was developed for the
selective extraction and enrichment of polar compounds from EVOO and HO beforematrix-assisted laser desorption ionization
time-of-flight mass spectrometry (MALDI-ToF-MS) analysis. The method permits a simple and fast qualitative analysis of the
polar fraction of the oils under study; furthermore, somepeaks (such as them/z ions 496.39, 520.46 and 522.47) were found tobe
present only inHO, indicating that they could be diagnostic for the presence ofHOin EVOO. In order to verify the potential of the
method for the individuation of this adulteration,EVOOwas progressively adulteratedwith variable quantities ofHO, subjected
to the HILIC enrichment and finally to MALDI-ToF-MS analysis; the detection of adulteration was possible up to the level of
5%. Eventually, diagnostic polar compoundswere identified as lysophosphatidylcholine (LPC) (16 : 0/0 : 0), LPC (18 : 2/0 : 0), LPC
(18 : 1/0 : 0) by means of capillary liquid chromatography-electrospray ionization-quadrupole-ToF-MS (CapLC-ESI-Q-ToF-MS)
analysis
Regiochemical Assignment of N-Acylphosphatidylethanolamines (NAPE) by Liquid Chromatography/Electrospray Ionization with Multistage Mass Spectrometry and Its Application to Extracts of Lupin Seeds
No full text1,2-Diacyl-sn-glycero-3-phospho-N-acyl-ethanolamines (NAPE) are low abundance phospholipids but important constituents of intracellular membranes of plant tissues, responsible for generating bioactive N-acylethanolamine (NAE), which participates in several physiological processes such as regulation of seed germination and protection against pathogenic attacks. From an analytical point of view, the critical aspect of these bioactive lipids lies in the determination of fatty acyl chains located in sn-1/sn-2 position on the glycerol backbone (O-linked), along with the amide-bound (N-linked) fatty acyl chain. Here, the identity and occurrence of NAPE in lipid extracts of lupin seeds (Lupinus luteus L.) was assessed by electrospray ionization in negative ion mode upon reversed-phase liquid chromatography (RPLC-ESI) coupled to mass spectrometry (MS) either at high- (i.e., Orbitrap FTMS) or low- (linear ion trap, LIT) resolution/accuracy. Collisional induced dissociation (CID)-tandem MS and MS3 acquisitions of chemically prepared NAPE allowed to unequivocally recognize the N-linked fatty acyl chain and to establish the diagnostic product ions that were successfully applied to identify NAPE in lipid extracts of yellow lupin seeds. The most abundant NAPE species were those containing N-acyl groups C18:1, C18:2; a minor prevalence was found for C16:0, C18:0, and C18:3, and almost the same acyl chains O-linked on the glycerol backbone in several sn-1/sn-2 combinations were observed. The positional isomers of NAPE species were identified as deprotonated molecules ([M-H]-) at m/z 978.7541 (three isomers 52:3), m/z 980.7694 (two isomers 52:2), m/z 1002.7535 (four isomers 54:5), m/z 1004.7686 (two isomers 54:4), m/z 1006.7837 (two isomers 54:3), and m/z 1008.8026 (single isomer 54:2). The total amount of NAPE in lupin seeds ranged in the interval of 2.00 ± 0.13 mg/g dw, in agreement with other edible legumes. We anticipate our approach to be a robust assessment method potentially applicable to biological extracts containing NAPE species and can provide comprehensive profiles and contents
Exploring the isomeric precursors of olive oil major secoiridoids: An insight into olive leaves and drupes by liquid-chromatography and fourier-transform tandem mass spectrometry
No full textSecoiridoids play a key role in determining health benefits related to a regular consumption of extra-virgin olive oil (EVOO), in which they are generated from precursors of the same class naturally occurring in drupes and leaves of the olive (Olea europaea L.) plant. Here, reversed-phase liquid chromatography coupled to electrospray ionization and Fourier-transform single/tandem mass spectrometry (RPLC-ESI-FTMS and MS/MS) was employed for a structural elucidation of those precursors. The presence of three isoforms in both matrices was assessed for oleuropein ([M-H]− ion with m/z 539.1770) and was emphasized, for the first time, also for ligstroside (m/z 523.1821) and for the demethylated counterparts of the two compounds (m/z 525.1614 and 509.1665, respectively). However, only the prevailing isoform included an exocyclic double bond between carbon atoms C8 and C9, typical of oleuropein and ligstroside; the remaining, less abundant, isoforms included a C=C bond between C8 and C10. The same structural difference was also observed between secoiridoids named elenolic acid glucoside and secoxyloganin (m/z 403.1246). This study strengthens the hypothesis that secoiridoids including a C8=C10 bond, recently recognized as relevant species in EVOO extracts, arise mainly from specific enzymatic/chemical transformations occurring on major oleuropein/ligstroside-like precursors during EVOO production, rather than from precursors having that structural feature
Contamination of Wheat Flour and Processed Foodstuffs with Soybean and Mustard Allergenic Proteins
No full textIn recent years, sustainable agricultural practices in wheat cultivation have garnered significant attention, particularly those focused on minimizing pesticide and herbicide usage to safeguard the environment. One effective approach is green manuring, which entails rotating wheat with crops such as soybean and mustard to harness their natural pesticidal and herbicidal properties. While this method presents clear environmental advantages, it also poses a risk of cross-contamination, as these globally recognized allergens may unintentionally pass through wheat-based products. To protect consumers with allergies, there is an urgent need for a reliable analytical method to detect and quantify these allergenic proteins in wheat-derived foodstuffs. In this study, we assessed various protein extraction protocols to optimize the recovery of soybean and mustard allergens from wheat flour. The extracted proteins were analyzed using a bottom-up proteomics approach involving trypsin digestion, coupled with reversed-phase liquid chromatography and mass spectrometry in multiple reaction monitoring (MRM) mode. Two key allergenic proteins, Glycinin G1 and 11S Globulin, were selected as representative for soybean and mustard, respectively. The identified quantifier marker of Glycinin G1 was VLIVPQNFVVAAR (m/z 713.4312+), while FYLAGNQEQEFLK (m/z 793.8962+) and VFDGELQEGR (m/z 575.2802+) were designated as qualifier markers. The selection of specific marker peptides for mustard proved challenging due to the high structural similarity among proteins from Sinapis alba and other members of the Brassicaceae family. For 11S Globulin, FNTLETTLTR (m/z 598.3192+) was recognized as the quantifier marker, with VTSVNSYTLPILQYIR (m/z 934.0192+) serving as the qualifier marker. The developed method underwent thorough validation for linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, repeatability, and reproducibility, as well as potential matrix and processing effects. This strategy successfully facilitated the identification and quantification of soybean and mustard allergenic proteins in complex, processed food matrices, including naturally contaminated flour and cookies. These findings enhance food safety monitoring and regulatory compliance, thereby helping to mitigate allergen-related risks in wheat-based products
Lipidomics of the edible brown alga wakame (Undaria pinnatifida) by liquid chromatography coupled to electrospray ionization and tandem mass spectrometry
Full text linkThe lipidome of a brown seaweed commonly known as wakame (Undaria pinnatifida), which is grown and consumed around the world, including Western countries, as a healthy nutraceutical food or supplement, was here extensively examined. The study was focused on the characterization of phospholipids (PL) and glycolipids (GL) by liquid chromatography (LC), either hydrophilic interaction LC (HILIC) or reversed-phase LC (RPLC), coupled to electrospray ionization (ESI) and mass spectrometry (MS), operated both in high and in low-resolution mode. Through the acquisition of single (MS) and tandem (MS/MS) mass spectra more than 200 PL and GL of U. pinnatifida extracts were characterized in terms of lipid class, fatty acyl (FA) chain composition (length and number of unsaturations), and regiochemistry, namely 16 SQDG, 6 SQMG, 12 DGDG, 5 DGMG, 29 PG, 8 LPG, 19 PI, 14 PA, 19 PE, 8 PE, 38 PC, and 27 LPC. The FA (C16:0) was the most abundant saturated acyl chain, whereas the monounsaturated C18:1 and the polyunsaturated C18:2 and C20:4 chains were the prevailing ones. Odd-numbered acyl chains, i.e., C15:0, C17:0, C19:0, and C19:1, were also recognized. While SQDG exhibited the longest and most unsaturated acyl chains, C18:1, C18:2, and C18:3, in the sn-1 position of glycerol, they were preferentially located in the sn-2 position in the case of PL. The developed analytical approach might pave the way to extend lipidomic investigations also for other edible marine algae, thus emphasizing their potential role as a source of bioactive lipids
Targeted analysis of ceramides and cerebrosides in yellow lupin seeds by reversed-phase liquid chromatography coupled to electrospray ionization and multistage mass spectrometry
No full textCeramides (Cer) and cerebrosides are important sphingolipids (SL) involved in many biological processes. Herein, the SL content of yellow lupin seeds (Lupinus luteus) was determined by liquid–liquid extraction, mild alkaline hydrolysis (1 h at 37 °C) and reversed-phase liquid chromatography with negative electrospray ionization coupled to either an orbital-trap (Fourier-transformed, FT) or linear ion-trap (LIT) mass spectrometry (RPLC-ESI/MS). The chemical identity of SL including the sugar residues and sphingoid backbone (SB) was inferred by collision-induced dissociation multiple-stage mass spectrometry (MSn, n = 2,3). Up to 52 Cer and 47 cerebrosides were successfully recognized and quantified in sample extracts of L. luteus seeds also counting isobaric species. As reported for other vegetables, a hydroxylated SB was observed whereby the N-acyl chains showed a high occurrence of very-long-chain moieties; phytosphingosine and 4-hydroxy-8-sphingenine were the predominant SB paired mainly with oleic acid (C18:1), hydroxylated behenic acid (C22:0;1) and hydroxylated lignoceric acid (C24:0;1)
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