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• Oxidation and Maillard-like reaction together cause krill oil color changes. • UV–vis spectroscopy is more suitable for quantifying color changes of krill oil. • α-Dicarbonyl compounds were formed during storage of krill oil. • Hydrophilic pyrroles associated with PEs was detected in krill oil. Antarctic krill oil (AKO) is reddish-orange in color but undergoes changes during storage. To investigate the color deterioration and potential mechanisms involved, the changes in color, endogenous components (astaxanthin, fatty acids, and phospholipids), and reaction products (aldehydes, α-dicarbonyl compounds, and pyrroles) of AKO upon storage were determined. Although the visual color of AKO tended to darken upon storage, the colorimetric analysis and ultraviolet–visible spectrum analysis both indicated a fading in red and yellow due to the oxidative degradation of astaxanthin. During storage of AKO, lipid oxidation led to the formation of carbonyl compounds such as aldehydes and α-dicarbonyls. In addition, phosphatidylethanolamines (PEs) exhibited a faster loss rate than phosphatidylcholines. Moreover, hydrophobic pyrroles, the Maillard-like reaction products associated with primary amine groups in PEs accumulated. Therefore, it is suggested that the Maillard-like reaction between PEs and carbonyl compounds formed by lipid oxidation contributed to color darkening of AKO during storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • The health-enhancing properties of Camellia japonica L. have been neglected. • Triterpenoid saponins (tea saponins) serve as an important class of active substances in C. japonica. • A strategy involved LC-Q-TOF untargeted analysis and spectrum similarity networking was applied. • The enrichment, structural prediction, isolation, and anticancer properties of tea saponins are carried. Camellia japonica L. is rich in bioactive compounds, but its health-enhancing potential is often overshadowed by its ornamental value. Notably, triterpenoid saponins are prominent due to their surfactant properties. MolNetEnhancer revealed 537 compounds in C. japonica leaves water extract, classified into 32 categories, including 38 triterpenoid saponins. To enrich triterpenoid saponins, the process of D101 resin chromatography was employed. Molecular networking analysis based on UPLC-Q-TOF and quantitative analysis based on HPLC revealed saponins concentrated in fractions 3 and 4 (68.3% transfer). MS2LDA and NAP predicted structures for 38 triterpenoid saponins, revealing nearly half of them are potential new compounds. Comprehensive chromatographic and spectroscopic methods were used for purification and structural illustration of triterpenoid saponins, yielding 13, including 7 new compounds. Statistical analysis and in vitro assays revealed the cytotoxic and anti-inflammatory activities of these triterpenoid saponins played a crucial role in the anticancer effects. [ABSTRACT FROM AUTHOR]

[Display omitted] • Both polyphenol oxidase and β-glucosidase were involved in VBP formation. • Vaccinoside played as a unique bifunctional precursor to form VBPs. • 15 Amino acids helped to give VBPs (λmax 581–590 nm) of different hues. • Two synthesis pathways were proposed to interpret formation of VBPs. Since Tang dynasty in China, the fresh leaves of Vaccinium bracteatum (VBL) have been applied as natural pigment to produce black rice. However, detailed information on its biosynthetic mechanism still remained unclear. Following rice dyeing capacity assay, vaccinoside, one of iridoid glycosides, was identified as the key active compound. Increased methodical research demonstrated vaccinoside as a distinct bifunctional precursor, which could be catalyzed by polyphenol oxidase or β-glucosidase independently, followed by reaction with 15 amino acids to give blue pigments (VBPs; λmax 581–590 nm) of different hues. Two synthetic pathways of VBPs were proposed, using multiple techniques such as HPLC, HPSEC, UV–Vis spectrum and colorimeter as analysis tools. Black rice was interpreted to be prepared by cooking, using vaccinoside, intrinsic enzymes from fresh VBL and rice protein in combination. These findings promote the understanding of VBP formation mechanisms and provide an efficient method of producing novel Vaccinium blue pigments. [ABSTRACT FROM AUTHOR]

• A pseudotargeted lipidomics method was used for identifying alkylglycerols in foods. • A new Dart package termed FFIMA was developed to facilitate data processing. • Mild acid hydrolysis was employed to assist in analyzing ether phospholipid species. • A total of 156 alkylglycerol-type ether lipids and 35 plasmalogens were identified. Alkylglycerols (1-O-alkyl- sn -glycerols) are microscale but critical lipids in foods. Conventional lipidomics analysis often loses sight of alkylglycerol analysis. In this study, we developed a high coverage pseudotargeted lipidomics method for analyzing alkylglycerols. The developed method integrated the advantages of GC–MS and LC–MS to profile alkylglycerol-type ether lipids comprehensively, with the help of a data processing Dart package termed FFIMA (Feature Fragments Information Matching Algorithm). The developed method exhibited competitive superiority to conventional lipidomics, such as wider coverage and higher accuracy. The validated method was assessed by three aquatic products and three milks. A total of 25 alkylglycerols, 107 diacylglycerol ethers, 21 monoacylglycerol ethers, 28 alkylglycerol-type ether phospholipids, and 35 plasmalogens were identified in the six foods. The results demonstrated that this method offers a comprehensive analysis of a wide spectrum of alkylglycerols. [ABSTRACT FROM AUTHOR]