LC/MS analysis of storage-induced plasmalogen loss in ready-to-eat fish

Application of UV-Vis-NIR and FTIR spectroscopy coupled with chemometrics for quality prediction of katsuobushi based on the number of smoking treatments

Katsuobushi, a smoked, dried skipjack tuna, is a traditional Japanese food additive with a unique flavor and taste. Gas chromatography mass spectrometry (GC-MS), fourier transform infrared (FTIR), and ultraviolet-visible-near infrared spectroscopy (UV-Vis-NIR) combined with chemometric methods were evaluated the quality of katsuobushi according to the number of smoking treatments. Using GC-MS, 46 metabolites were identified and five metabolites were selected as key compounds. All samples were classified according to their smoking number via principal component analysis (PCA), partial least squares-discriminate analysis (PLS-DA) and hierarchical cluster analysis (HCA) of the FTIR and NIR spectra. Partial least squares regression (PLSR) analysis revealed that the FTIR and NIR spectra were highly correlated with the metabolites by GC-MS. These results demonstrated the potential of using the FTIR and NIR spectroscopy combined with chemometrics to assess the quality of katsuobushi based on the smoking treatments, with NIR spectroscopy showed particularly promising.

Marine Plasmalogens: A Gift from the Sea with Benefits for Age-Associated Diseases

Aging increases oxidative and inflammatory stress caused by a reduction in metabolism and clearance, thus leading to the development of age-associated diseases. The quality of our daily diet and exercise is important for the prevention of these diseases. Marine resources contain various valuable nutrients, and unique glycerophospholipid plasmalogens are found abundantly in some marine invertebrates, including ascidians. One of the major classes, the ethanolamine class (PlsEtn), exists in a high ratio to phospholipids in the brain and blood, while decreased levels have been reported in patients with age-associated diseases, including Alzheimer's disease. Animal studies have shown that the administration of marine PlsEtn prepared from marine invertebrates improved PlsEtn levels in the body and alleviated inflammation. Animal and human studies have reported that marine PlsEtn ameliorates cognitive impairment. In this review, we highlight the biological significance, relationships with age-associated diseases, food functions, and healthcare materials of plasmalogens based on recent knowledge and discuss the contribution of marine plasmalogens to health maintenance in aging.

Plasmalogen Profiling in Porcine Brain Tissues by LC-MS/MS

Plasmalogen, a functional glycerophospholipid, is known for its beneficial nutritional effects, such as anti-oxidation and anti-inflammation. As the porcine brain is a plasmalogen-rich resource, this study aimed to explore its potential for plasmalogen-based health food product development, with special attention on whether and how the industrial production processes influence the plasmalogen content and composition. In the present work, plasmalogens from different porcine brain products were investigated using liquid chromatography-tandem mass spectrometry. The results indicated that all the porcine brain products showed abundant total plasmalogens, of which more than 95% were ethanolamine plasmalogen species. Acetone precipitation, ethanol extraction, and drying did not significantly affect the plasmalogen content, whereas repeated freeze-thaw cycles in the production process led to noticeable loss. The chemometric investigation suggested that raw products and glycerophospholipid products exhibited different profiles; furthermore, the concentration step seemed to impact the plasmalogen composition. The nutritional assessment revealed that porcine brain products showed favorable values of multiple indexes, including PUFA/SFA ratio, n-6/n-3 ratio, thrombogenicity index, and unsaturation index, suggesting a health-beneficial value. The current study not only shows the feasibility of producing porcine brain-derived plasmalogens, but also provides possible strategies for developing and quality-controlling dietary plasmalogen supplements and healthcare products.

Lipidomic fingerprinting of plasmalogen-loaded zein nanoparticles during in vitro multiple-stage digestion using rapid evaporative ionization mass spectrometry

Plasmalogens (Pls) as the hydrophobic bioactive compound have shown potential in enhancing neurological disorders. However, the bioavailability of Pls is limited because of their poor water solubility during digestion. Herein, the hollow dextran sulfate/chitosan - coated zein nanoparticles (NPs) loaded with Pls was prepared. Subsequently, a novel in situ monitoring method utilizing rapid evaporative ionization mass spectrometry (REIMS) coupled with electric soldering iron ionization (ESII) was proposed to assess the lipidomic fingerprint alteration of Pls-loaded zein NPs during in vitro multiple-stage digestion in real time. A total of 22 Pls in NPs were structurally characterized and quantitatively analyzed, and the lipidomic phenotypes at each digestion stage were evaluated by multivariate data analysis. During multiple-stage digestion, Pls were hydrolyzed to lyso-Pls and free fatty acids by phospholipases A2, while the vinyl ether bond was retained at the sn-1 position. The result revealed that the contents of Pls groups were significantly reduced (p < 0.05). The multivariate data analysis results indicated that the ions at m/z 748.28, m/z 750.69, m/z 774.38, m/z 836.58, and etc. were the significant candidate contributors for monitoring the variation of Pls fingerprints during digestion. Results demonstrated that the proposed method exhibited potential for real-time tracking the lipidomic characteristics of nutritional lipid NPs digestion in the human gastrointestinal tract.

Regulation of plasmalogen metabolism and traffic in mammals: The fog begins to lift

Due to their unique chemical structure, plasmalogens do not only exhibit distinct biophysical and biochemical features, but require specialized pathways of biosynthesis and metabolization. Recently, major advances have been made in our understanding of these processes, for example by the attribution of the gene encoding the enzyme, which catalyzes the final desaturation step in plasmalogen biosynthesis, or by the identification of cytochrome C as plasmalogenase, which allows for the degradation of plasmalogens. Also, models have been presented that plausibly explain the maintenance of adequate cellular levels of plasmalogens. However, despite the progress, many aspects around the questions of how plasmalogen metabolism is regulated and how plasmalogens are distributed among organs and tissues in more complex organisms like mammals, remain unresolved. Here, we summarize and interpret current evidence on the regulation of the enzymes involved in plasmalogen biosynthesis and degradation as well as the turnover of plasmalogens. Finally, we focus on plasmalogen traffic across the mammalian body - a topic of major importance, when considering plasmalogen replacement therapies in human disorders, where deficiencies in these lipids have been reported. These involve not only inborn errors in plasmalogen metabolism, but also more common diseases including Alzheimer's disease and neurodevelopmental disorders.