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Triacylglycerol (TAG) components in human milk during different lactation periods, infant formulas with different fat sources, other mammalian milk (cow, goat, donkey, and yak milk), and plant oil (sunflower, rapeseed, corn, soybean, palm, palm kernel, and coconut oil) were analyzed and compared using ultraperformance supercritical fluid chromatography and quadrupole time-of-flight mass spectrometry (UPSFC-Q-TOF-MS). We identified 191 TAGs (86, 102, 101, and 54 TAGs in human milk, infant formula, mammalian milk, and plant oil, respectively). TAGs esterified with palmitic acid (16:0) were major TAG structures in human milk (59.08% of total TAGs) and contained 30 TAG types. The sn-O/P/O regioisomer constituted more than 80% of the O/P/O content of human milk, whereas the sn-O/O/P levels were higher in other samples. The carbon number (CN) 52 content was higher than the CN 54 content in human milk, with the opposite observed in infant formula. TAGs with CN < 40 content were abundant in cow, goat, and yak milk; donkey milk was rich in CN 52 content. TAGs composed of medium-chain fatty acids (MCFAs) and long-chain fatty acids (LCFAs) were rich in human milk, while TAGs with three MCFAs were rich in infant formula. The TAG characteristics of infant formula were directly related to its fat resource. TAGs with fewer double bonds were abundant in the plant oil formula; however, highly unsaturated TAGs were prominent in the cow and goat milk formulas, similar to plant oil and mammalian milk. Significant differences in the TAG distribution were observed among the different species.

This study aims to find the targets that may influence the production of bacitracin based on RNA sequencing in

In order to establish an efficient detection method to evaluate the formation of Amadori compounds (ACs) in food products and study the potential health effects, an ultra-high performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method using caffeine as internal standard was developed to determine eight ACs. The detection limits ranged from 0.0179 to 0.0887 mg/L for the ACs. The accuracy of the method was tested through measuring recovery of the spiked samples that varied from 81.90 ± 2.98% to 108.74 ± 2.34%. This method was further applied to detect ACs in 10 food products. Results showed that dry fruits and vegetables were rich in ACs, the total content of ACs varied from 1.36 ± 0.26 to 3415.91 ± 147.96 mg/100 g. The total amount of ACs in tomato juice heated under vacuum condition showed significant increment (P < 0.05) in 25 min at 80 °C comparing with that under atmospheric pressure due to the rapid loss of water. Besides, the amino acid content shows positive correlation with the corresponding AC formation in Maillard reaction during food drying. After heated at fixed water activity (Aw) for 4 hr by sous-vide process, the ACs content in tomato powder increased significantly and the antioxidant activity improved as well. PRACTICAL APPLICATION: Results of this study provided a valuable tool to evaluate the formation of ACs in complex dry food products, facilitated the quality control of food products. The knowledge obtained will offer useful information to food processors. The synthesized ACs would facilitate further study into the antioxidant activities and potential health effects of specified AC.

Triacylglycerol (TAG) regioisomers containing palmitic acid (16:0) was identified using ultra-performance supercritical fluid chromatography and quadrupole time-of-flight mass spectrometry (UPSFC-Q-TOF-MS) and quantified using calibration curve method and calculation equation method. There were negative linear correlation between [R

This study aimed to determine α-tocopherol (α-T) and its thermal oxidation products simultaneously. A novel method based on an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed. This approach was achieved by means of a BEH C18 analytical column under gradient elution conditions with eluents of acetonitrile/isopropanol (1:9, v/v) and acetonitrile/water (4:6, v/v). Compounds were elucidated through exact molecular mass and fragmentation ions obtained from the Q-TOF-MS detector. Two oxidation products, α-tocopheryl quinone and 5-formyl-γ-tocopherol, were identified, and one new compound was determined. This approach offered a simple, precise, and reliable method to determine oxidation products of α-T, which may give a way to understand the mechanism of the thermal oxidative process of α-T.

Polar lipids in milk are receiving increasing interest due to their bioactivities. However, milk polar lipids present a wide range of physical-chemical properties at different concentrations, making their analysis challenging. In this study, we presented a comprehensive lipidomic method using ultraperformance supercritical fluid chromatography (UPSFC)-quadrupole-time of flight-mass spectrometry (Q-TOF-MS), which enabled the separation of 18 lipid classes (including nonpolar lipids, cholesterol, ceramide, glycerophospholipids, sphingomyelin, and gangliosides) within 10 min. The method was used to analyze the polar lipids in seven samples, including human milk, other mammalian milk and milk fat globule membrane ingredients, identifying 14 lipid classes containing 219 lipid molecular species. A mass spectrometry data processing strategy applicable for high-throughput studies was also developed and validated.

Chitooligosaccharides (COSs) have a widespread range of biological functions and an incredible potential for various pharmaceutical and agricultural applications. Although several physical, chemical, and biological techniques have been reported for COSs production, it is still a challenge to obtain structurally defined COSs with defined polymerization (DP) and acetylation patterns, which hampers the specific characterization and application of COSs. Herein, we achieved the de novo production of structurally defined COSs using combinatorial pathway engineering in Bacillus subtilis. Specifically, the COSs synthase NodC from Azorhizobium caulinodans was overexpressed in B. subtilis, leading to 30 ± 0.86 mg/L of chitin oligosaccharides (CTOSs), the homo-oligomers of N-acetylglucosamine (GlcNAc) with a well-defined DP lower than 6. Then introduction of a GlcNAc synthesis module to promote the supply of the sugar acceptor GlcNAc, reduced CTOSs production, which suggested that the activity of COSs synthase NodC and the supply of sugar donor UDP-GlcNAc may be the limiting steps for CTOSs synthesis. Therefore, 6 exogenous COSs synthase candidates were examined, and the nodCM from Mesorhizobium loti yielded the highest CTOSs titer of 560 ± 16 mg/L. Finally, both the de novo pathway and the salvage pathway of UDP-GlcNAc were engineered to further promote the biosynthesis of CTOSs. The titer of CTOSs in 3-L fed-batch bioreactor reached 4.82 ± 0.11 g/L (85.6% CTOS5, 7.5% CTOS4, 5.3% CTOS3 and 1.6% CTOS2), which was the highest ever reported. This is the first report proving the feasibility of the de novo production of structurally defined CTOSs by synthetic biology, and provides a good starting point for further engineering to achieve the commercial production.

The correlation between potato components and Maillard reaction derivative harmful products (MRDHPs) formation during heat-processing was assessed in nine commercial potato varieties in China. Principal component analysis (PCA) combined with canonical correlation analysis (CCA) approach was performed to explore their relationships. The variables contributing most to the PCA results were extracted for CCA, and the results indicated that several amino acids, including lysine, tryptophan, alanine, phenylalanine, aspartate, and glutamate, have significant impacts on acrylamide and β-carboline heterocyclic amine formation. Moreover, 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, α-solanine, and α-chaconine were also important factors associated with acrylamide and β-carboline heterocyclic amine formation. Optimally using raw potato varieties based on the impacts of these factors can help control MRDHP formation during thermal processing. For the first time, such approach was applied, which may be a useful tool for discovering the correlation of food components and MRDHPs.

Chinese water chestnut [Eleocharis dulcis (Burm. f.) Trin. ex Hensch] peels (CWCPs) were a kind of vegetable waste and the present work was focusing on its comprehensive exploitation and utilization. Enzyme-assisted ultrasonic-microwave synergistic extraction (EAUMSE) of flavonoids from CWCPs was investigated, along with their qualitative and quantitative analysis using a combination of ultra-performance liquid chromatography-photodiode array (UPLC-PDA) and quadrupole-time-of-flight mass spectrometry (QTOF-MS). An optimal yield of 1.48% (w/w) was achieved with a 2:1 ratio (w/w) of cellulase and pectinase, 1.5% enzyme concentration, 5.0 pH, 50 °C hydrolysis temperature, 2 h hydrolysis time, with ethanol and 0.1 mol/L NaH2PO4 buffer (2:1, v/v) mixture as solvent, ultrasound and microwave power was 50 and 200 W, respectively, and 60 s extraction time. The flavonoid yield by EAUMSE was 26.50%, 22.31% and 12.98% higher than that by solvent extraction (SE), ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), respectively. Sixteen flavonoids were characterised, including four new ones, with the major flavonoids being luteolin (249 mg/100 g DW), eriodictyol (97 mg/100 g DW), 6-methylluteolin (74 mg/100 g DW) and fisetin (46 mg/100 g DW). The EAUMSE was an effective and green method for flavonoid extraction in the functional food and pharmaceutical industries.

Phytosterols are important beneficial compounds found in rice bran (RB) and rice bran oil (RBO). Although relationships have been confirmed between the forms of phytosterols and their bioactivities, the analysis of different forms of phytosterols in RB and RBO has been lacking. In this study, high temperature gas chromatography-mass spectrometry (HTGC-MS) was combined with the single standard to determine multi-components (SSDMC) method to determine free sterols (FSs) and steryl glycosides (SGs) in RB and RBO. High-performance liquid chromatography (HPLC) was used to determine steryl ferulates (SFs). There was clear variation in the composition of FS, SF and SG, indicating that different forms of phytosterols can discriminate between different RB and RBO. The developed method may be also useful for the detection of other compounds of interest in oils, oil seeds or cereals.

The levels of Ne-(carboxymethyl)lysine (CML) and Ne-(carboxyethyl)lysine (CEL) in 99 tea samples from 14 geographic regions, including 44 green, 7 oolong, 41 black, and 7 dark teas were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CML and CEL contents varied from 11.0 to 1701μg/g tea and 4.6 to 133μg/g tea, respectively. Dark tea presented the highest levels of CML and CEL, whereas green and oolong teas presented the lowest levels. Five kinds of catechins in the tea were also analyzed, and spearman's correlation coefficients showed that all the catechins negatively correlated with CML and CEL. The results suggested that withering, fermentation and pile fermentation may facilitate the formation of CML and CEL. Catechins might inhibit the formation of CML and CEL, but their inhibitory effects may be affected by tea processing. The results of this study are useful for the production of healthier tea.

In this study, UPLC-MS/MS combined with principal component analysis (PCA) with the help of scores, loadings, and contribution plots was used to investigate the inhibition of the profiles of carcinogenic and mutagenic heterocyclic amines (HAs) in roast beef patties by different levels of black pepper (0.05, 0.10, and 0.15%, g/g) or piperine (0.005, 0.010, and 0.015%, g/g). Six HAs from three categories, imidazopyridine (PhIP), imidazoquinoxaline (IQx, MeIQx, and 4,8-DiMeIQx), and β-carboline (harman and norharman), were detected and quantified in the roast beef patties. The PCA results demonstrated that both black pepper and piperine can significantly suppress the HA profiles and that lower levels of black pepper or piperine lead to better inhibition of HA formation, except the HA profiles of beef patties with 0.005% and 0.01% piperine were similar. In comparison, piperine inhibited HA formation better than did black pepper for all six HAs, as shown by the contribution plot. The total HAs were inhibited by all levels of black pepper (42%, 34%, 25%) and piperine (62%, 60%, 56%) in a dose-dependent manner, although black pepper suppressed only PhIP, IQx, MeIQx, and 4,8-DiMeIQx, whereas piperine inhibited all six HAs. The results show that UPLC-MS/MS in conjunction with PCA is a powerful tool for screening the inhibitory effects of spices and their components along with their relationship to HAs and can thus be used for safety control in food processing procedures.

Phospholipids (PLs) are increasingly considered as nutrients with putative health benefits. Mammalian milk is a prominent source of phospholipids. In this study, PLs from different mammalian milk powders (buffalo, camel, bovine, goat, and ewe) purchased from supermarkets were enriched by solid-phase extraction cartridges, and subsequently separated and analyzed with ultra-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS). Phospholipid classes were separated using hydrophilic interaction liquid chromatography (100 × 1 mm, 1.7 μm particle size BEH column) by gradient elution with acetonitrile/ammonium formate as a mobile phase. 22 molecular species of phosphatidylcholine (PC) were detected in the five types of milk powders, and PC (C16:0–C18:1) was the most abundant species with relative abundances of 10.93, 9.35, 9.35, 12.92, and 11.14%, respectively. While, 15 molecular species of phosphatidylethanolamine (PE) were detected, and PE (C18:0–C18:2) was the most abundant species making up 32.70, 16.45, 31.39, 29.88, and 27.24%, respectively. Furthermore, 9 molecular species of sphingomyelin (SM) were also detected, and the predominant species was SM (d18:1/16:0). This method of analysis was rapid, sensitive and precise for the identification of milk PLs. Also, it can be suggested as an application for studying specific technology markers in the dairy processing industry, and exploring novel applications of milk phospholipids.

Flavonoids are an important type of natural tyrosinase inhibitor, but their inhibitory activity and mechanism against tyrosinase are very different because of their different structures. In this study, the inhibitory activity and mechanism differences between norartocarpetin and luteolin for tyrosinase were investigated by a combination of kinetic studies and computational simulations. The kinetic analysis showed that norartocarpetin reversibly inhibited tyrosinase in a competitive manner, whereas luteolin caused reversible noncompetitive inhibition. Both norartocarpetin and luteolin showed a single type of quenching and a static-type quenching mechanism. A computational simulation indicated that the hydroxyl groups of the B ring of norartocarpetin interacted with tyrosinase residues Asn81 and His85 in the active pocket, while the hydroxyl groups of the B ring of luteolin bound residues Asn81 and Cys83. HPLC and UPLC-MS/MS further confirmed that luteolin acted as a substrate or a suicide inhibitor, yet norartocarpetin acted as an inhibitor.

Schizochytrium limacinum sp. was commercially utilized to produce single cell oil (SCO), but its detailed lipid profile remains unknown. In order to analyze the composition and structure of SCO produced by Schizochytrium limacinum SR31, the SCO extracted at stationary growth phase was separated into neutral lipids (NL), polar lipids and glycolipids by using silica gel column chromatography. The result of lipid classes in NL revealed that triacylglycerol (TAG) was the primary glyceride (93.81 %). Fatty acid (FA) analysis by gas chromatography–mass spectrometer (GC–MS) proved that palmitic acid (29.78 %) and docosahexaenoic acid (25.64 %) were the major FA. Quadrupole time of flight mass spectrometry in electrospray ionization mode coupled with ultra-performance liquid chromatography was carried out to investigate TAG structures. More than 80 species were identified. Positional distribution of FA in TAG might contribute to further study of the FA shifts during the lipid turnover stage and nutritional evaluation of the SCO.

Phospholipids are the main constituent of cell membranes and play multiple roles in cells, in forming the permeability barrier, supporting matrix, surfaces for many catalytic processes, and precursors of signal processing and macromolecular synthesis. Hydrophilic interaction (HILIC) ultra-performance liquid chromatography (UPLC) coupled with quadrupole time of flight (Q-TOF) mass spectrometry (MS) was used to analyze the composition of phospholipids from Schizochytrium sp. S31. Phosphatidyl-cholines, -ethanolamines, -inositoles, and -glycerol, and phosphatidic acid were separated by using an acetonitrile/ammonium formate gradient mobile phase. The structures of 70 phospholipids were identified by LC-MS/MS measurements in negative ion mode. The main phospholipid in Schizochytrium sp. S31, phosphatidylcholine, accounted for 49.8% of the total phospholipids, and the major phospholipid fatty acids were C16 : 0 and DHA.

The inhibitory effect of caffeic acid on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) was investigated in chemical model systems under microwave heating (MW). A mechanistic study was subsequently carried out to identify the inhibitory mechanism. The results showed that both for conductive heating (CV) and MW, the inhibition of PhIP increased with the concentration of caffeic acid but decreased with the prolongation of heating time. The inhibition on PhIP under MW was always higher than under CV, which were dominated by the difference in dielectric loss (e″). UPLC-MS analysis showed that caffeic acid releases a CO2 molecule to produce 4-vinylcatechol which can form adducts with phenylacetaldehyde, thus reducing its availability for PhIP formation. The structure of adduct was characterized as 3-(3,4-dihydroxyphenyl)-2-phenylbutanal with a molecular weight of 256. The findings indicate that trapping of phenylacetaldehyde by 4-vinylcatechol is a key mechanism of caffeic acid in inhibiting PhIP formation.

An ultra-performance convergence chromatography (UPC2) method coupled with quadrupole time-of-flight mass spectrometry (Q-TOF-MS), was developed for the determination of complicated triacylglycerols (TAGs) in human milk fat. The use of supercritical carbon dioxide as the mobile phase improved the chromatographic separation of the TAGs significantly. By optimizing the scan modes of Q-TOF-MS and selecting parent ions for MS/MS ionization, the fragment ions of each TAG including TAG isomers with overlapping retention time were adequately resolved for identification and quantification. A total of 95 different TAGs were identified in the human milk samples from Chinese mother volunteers, with O-P-L representing the main TAG, followed by O-P-O and O-L-L. In addition, the compositions and contents of TAGs in different fats and oils were successfully measured. The developed method can serve as an advanced and reliable analytical tool for the determination of complicated TAGs in various biological samples.

Pseudomonas putida KT2442 is an important bacterium for producing various types of polyhydroxyalkanoate polymers. Phospholipids and lipid A in membranes of P. putida play important roles in stress responses, but detailed structural information of these lipids is not known. In this study, phospholipids and lipid A were isolated from P. putida KT2442, and their structures were analyzed using thin layer chromatography, high performance liquid chromatography and electrospray ionization/mass spectrometry. Major phospholipids in P. putida KT2442 were phosphatidylethanolamine (79.9%), phosphatidylglycero1 (12.7%) and cardiolipin (7.4%), with C16:1 and/or C18:1 acyl chains. Four lipid A species were found in P. putida KT2442: two are hexa-acylated and the other two are penta-acylated. Compared with lipid A of P. aeruginosa, P. putida lipid A has less hydroxylation on the secondary acyl chains and less modification. Therefore, P. putida lipid A could be used as a base structure to investigate lipid A modification of P. aeruginosa for understanding its pathogenesis.

To discriminate and investigate the inhibitory patterns of different categories of ingredients from natural origin such as spice is necessary to elucidate the inhibitory mechanism of them on heterocyclic amines (HAs) formation. In this work, the inhibitory patterns of flavonoids (naringenin, quercetin, luteolin and rutin) and phenolic acids (chlorogenic acid, ferulic acid, p-coumaric acid and protocatechuic acid) on HAs in a mixed chemical model system were discriminated and examined by UPLC-MS profiling combined with principal component analysis (PCA) method with the interpretation of scores, loadings, contribution and biplots. Seventeen HAs from seven categories were profiled by UPLC-MS; furthermore, the precision for most of these HAs upon three repeated samples was between 4.2 and 13.9 %, and their recoveries were between 58.4 and 97.1 %. Seven HAs: norharman, harman, DMIP, PhIP, IQx, MeIQx and 4,8-DiMeIQx were detected and quantified in all of the samples without and with flavonoids (phenolic acids), thus employed in the subsequent multivariate analysis. The PCA results show that the inhibitory patterns of the two groups are different; moreover, flavonoids have inhibitory potential to norharman, PhIP, 4,8-DiMeIQx, while phenolic acids have possible capability of inhibiting DMIP formation. The results have demonstrated that the proposed UPLC-MS profiling method may be a useful tool for differentiating and exploring inhibitory patterns of different categories of ingredients from natural origin on HA formation.

An ultra-performance liquid chromatography-quadrupole time-of-flight-based metabolomic approach was developed to study influence of salidroside, an anti-fatigue ingredient from Rhoiola rosea, on urinary metabolic profiling of rats to a single dose of 180 mg/kg per day. Unsupervised principal component analysis (PCA) and supervised orthogonal pre-projection to latent structures discriminate analysis (OPLS-DA) on metabolite profiling revealed obvious differentiation between the salidroside treated groups and controls in both positive and negative ion modes. Eleven urinary metabolites contributing to the differentiation were identified as anti-fatigue biomarkers: N-acetylserotonin, 2-Methoxyestrone 3-glucuronide, Taurine, Melatonin, Sorbitol, Geranyl diphosphate, Z-nucleotide, Cortisone, Dihydrocortisol, Sebacic acid, Pregnenolone sulfate. The physiological significance of these biomarkers is discussed. The work showed that metabolomics is a powerful tool in studying the anti-fatigue effects of natural compound salidroside on multiple targets in vivo.

The levels of N

A new preparation procedure, allowing the analysis of 11 polar heterocyclic aromatic amines (HAAs) in meat samples, is proposed and applied to commercial meat products. It is based on ultrahigh-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). The procedure involves a one-step extraction using hydrochloric acid coupled with a solid-phase extraction clean-up using Oasis MCX cartridges. Significantly higher recoveries were obtained (ranging from 58.2% to 107.6%) for every target polar HAAs from roasted pork samples prepared in a laboratory compared with a commonly used reference method based on multiple extractions. The UHPLC-MS/MS parameters were optimized to simultaneously analyze all the 11 HAAs within 17 min with the limits of quantification (LOQs) < 4.3 μg L−1 using standard solutions. The LOQs for the spiked meat extract (0.026–0.659 ng g−1) and adequate day-to-day precision ranging from 6.17% to 12.03% (N = 15) were obtained. Five commercial meat products (smoked fish, roasted chicken wing, roasted pork, grilled beef, and sausage) were spiked with three concentrations (low, medium and high) of the HAAs standards. Satisfactory recoveries (about 50–110%) were obtained, which verify the applicability and advantage of the proposed method.

Triacylglycerols (TAGs) are an important source of dietary lipids that constitute an essential part of a healthy diet. The TAG profiles of vegetable oils are not arbitrary, and they are recently reported to be associated with lipid absorption and metabolism. In the present study, the TAG composition, FA composition, and their distributions in 18 commonly edible vegetable oils were analyzed and compared. The TAGs were quantified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (Q-ToF-MS). A total of 48 TAGs were identified. The composition of FAs and their distribution on the glycerol backbone of vegetable oils were determined by gas chromatography. The TAG compositions of different types of vegetable oils were found to be significantly different. Unique patterns of the TAG profiles of vegetable oils were obtained. Linoleic acid showed a clear difference between the total fatty acid and sn-2 position of the TAGs. This study will aid the investigation of the association of TAGs in dietary lipid and human health, and the development of novel lipid-based matrixes.

Analysing the products of ozone-treated aflatoxin B1 (AFB1) is essential in order to study the practical use of ozone treatment. In this paper, the products of AFB1 were investigated using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC Q-TOF MS). The products were well separated using UPLC, and the accurate masses of all the products were determined using Q-TOF MS. Finally, the possible pathways of fragmentation ion generation from the products of AFB1 and the structures of four products were proposed. From the view of the proposed structures of products, the C8-C9 double bond in the terminal furan ring was destroyed. According to the structure-activity relationship, the toxicity of products was significantly reduced compared with that of AFB1. The result indicated that ozone was an effective agent for degrading AFB1, and UPLC Q-TOF MS was a useful analytical tool for proposing and identifying a series of unknown products.

Background Transglutaminase (TGase) is secreted as a zymogen (Pro-TGase) and is then processed by removal of its N-terminal region through exogenous proteolytic activity. In this study it was discovered that the Pro-TGase from Streptomyces hygroscopicus was also activated by its TGase (processed through exogenous proteolytic activity), resulting in a different active form. Results The two TGases exhibited different ionic strengths, hydrophobicities, Km values and stabilities. Circular dichroism spectral analysis showed that the two enzymes had non-identical secondary structures, while liquid chromatography/mass spectrometry (LC-MS) analysis indicated that they differed in molecular mass by 111 Da. The formation of the TGase activated from Pro-TGase by TGase was delayed compared with that of TGase processed through exogenous proteolytic activity. Furthermore, it was found that the TGase activated from Pro-TGase by TGase did not activate Pro-TGase. Conclusion Two TGases derived from the same zymogen from S. hygroscopicus were discovered. These two active forms of TGase may be due to different activation processes: one of them is catalysed by its own active TGase, while the other is activated by an exogenous protease. © 2013 Society of Chemical Industry

The twigs of Morus alba L. were found to show strong tyrosinase inhibition activity, and the responsible active components in the extract were further investigated in this study. A flavone, named morusone (1), and sixteen known compounds 2–17 were isolated from M. alba twigs and their structures were identified by interpretation of the corresponding ESI-MS and NMR spectral data. In the tyrosinase inhibitory test, the compounds steppogenin (IC50 0.98 ± 0.01 µM), 2,4,2′,4′-tetrahydroxychalcone (IC50 0.07 ± 0.02 µM), morachalcone A (IC50 0.08 ± 0.02 µM), oxyresveratrol (IC50 0.10 ± 0.01 µM), and moracin M (8.00 ± 0.22 µM) exhibited significant tyrosinase inhibition activities, much stronger than that of the positive control kojic acid. These results suggest that M. alba twig extract should served as a good source of natural tyrosinase inhibitors for use in foods as antibrowning agents or in cosmetics as skin-whitening agents.

Egg phospholipids (PLs) are currently the products of greatest commercial interest with major area of importance in various fields. Therefore, in this study, duck, hen and quail egg yolk PLs were isolated by solvent extraction with chilled acetone precipitation, and subsequently separated and identified by using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Egg PLs were separated on hydrophilic interaction liquid chromatography (HILIC) with ethylene bridged hybrid (BEH) column by gradient elution using acetonitrile/ammonium formate as a mobile phase, and detected by mass spectrometry (MS) under electrospray ionization in positive and negative ion mode. Structural characterizations of 57 molecular species of egg yolk PLs were identified based on MS/MS fragment ion information and elemental composition in MassLynx 4.1 software. The obtained results showed that phosphatidylcholine (16:0-18:1), phosphatidylethanolamine (18:0-20:4), phosphatidylinositol (18:0-18:2), phosphatidylserine (18:0-18:2), sphingomyelin (d18:1/16:0) and lysophosphatidylcholine (16:0) were the predominant species among the different classes of egg yolk phospholipids.

The inhibitory profiles of chilli pepper and capsaicin, as well as their relationship to the formation of heterocyclic amines (HAs) in roast beef patties were investigated using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with principal component analysis (PCA). HAs including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-1,6-dimethylimidazo[4,5-b]pyridine (DMIP), 2-amino-1,5,6-trimethylimidazo[4,5-b]pyridine (1,5,6-TMIP), 2-amino-3-methyl-3H-imidazo[4,5-f]quinoxaline (IQx), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 1-methyl-9H-pyrido[3,4-b]indole (harman) and 9H-pyrido[3,4-b]indole (norharman) were detected and quantified in beef patties. Different levels of chilli pepper and capsaicin had different inhibitory profiles on HA formation, but had no significant (P>0.05) effect on the texture of the patties. Furthermore, all levels of chilli pepper and capsaicin reduced total HA and PhIP concentrations dose-dependently, with the highest inhibitions of 80% and 98% at 2mg of capsaicin. Moreover, capsaicin inhibited all HAs more than chilli pepper, implying that ingredients other than capsaicin in chilli pepper may promote the formation of HAs. These results could be useful for the reduction of HA, during food processing procedures, by spices.

A novel non-targeted isoflavone profiling method was developed using the diagnostic fragment-ion-based extension strategy, based on ultra-high performance liquid chromatography coupled with photo-diode array detector and electrospray ionization-mass spectrometry (UPLC-PDA-ESI-MS). 16 types of isoflavones were obtained in positive mode, but only 12 were obtained in negative mode due to the absence of precursor ions. Malonyldaidzin and malonylgenistin glycosylated at the 4'-O position or malonylated at the 4″-O position of glucose were indicated by their retention behavior and fragmentation pattern. Three possible quantification methods in one run based on UPLC-PDA and UPLC-ESI-MS were validated and compared, suggesting that methods based on UPLC-ESI-MS possess remarkable selectivity and sensitivity. Impermissible quantitative deviations induced by the linearity calibration with 400-fold dynamic range was observed for the first time and was recalibrated with a 20-fold dynamic range. These results suggest that isoflavones and their stereoisomers can be simultaneously determined by positive-ion UPLC-ESI-MS in soymilk.

The fatty acyl residues composition and molecular species of phosphatidylcholines (PCs) in soy lecithin powder were studied and characterized using ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC–ESI-MS/MS) via a two-step procedure. ESI-MS/MS by precursor ion scan (PIS) m/z 184.1 in positive ion mode first detected isobaric PCs, and further identified positional isomers and fatty acyl residue composition in negative ion mode. The results showed that the fatty acyl residue composition was in strong agreement with that detected by the classical analysis method. Likewise, ten peaks of isobaric PCs were obtained by ESI-MS/MS analysis in positive ion mode, and 20 positional isomers of PCs were characterized in negative ion mode. Thus, this study presents a simple and powerful way to analyze fatty acyl residue composition and molecular species of PCs without destroying chemical structure.

The identification and quantitation of the anthocyanins in 12 purple-fleshed sweet potato (PFSP) cultivars ('Jihei 1', 'Xuzi 3', 'Xuzi 6', 'Zhezi 4', 'Ningzi 1', 'Ningzi 2', 'Ningzi 3', 'Ning 2-2', 'Ning 6-8', 'Guangzi 1', 'Ziluolan', and 'Qinzi 1') in China were carried out using a combination of ultraperformance liquid chromatography-photodiode array (UPLC-PDA), quadrupole-time-of-flight mass spectrometry (QTOF-MS), and tandem mass spectrometry (MS/MS) analyses. Thirteen acylated anthocyanins were tentatively characterized, including two new PFSP anthocyanins, cyanidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside and peonidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside. The quantitative analyses of these anthocyanins were conducted using cyanidin 3-O-glucoside as a standard. The total anthocyanin content of the PFSPs depended on the cultivar. The five PFSP cultivars with the highest content of anthocyanins were 'Jihei 1', 'Xuzi 3', 'Zhezi 4', 'Ziluolan', and 'Qinzi 1'. This is the first report of the 'Ningzi 2', 'Ningzi 3', and 'Ning 2-2' PFSP cultivars containing only diacylated anthocyanins and of the 'Xuzi 6' cultivar containing single anthocyanidin-based anthocyanins.

Recently correlation studies between dietary advanced glycation end products (AGEs) and the progression of chronic diseases have attracted much attention. To explore the impact of dietary AGEs on the health risk of people consuming a high-fat diet (HFD), male Sprague-Dawley rats were used as the research subject. Under HFD, free N(e)-(carboxymethyl)lysine (CML, a major AGE, 60 mg/kg body weight/day) was administered by gavage for 12 consecutive weeks. The results indicated that protein-bound CML accumulation in the kidney, heart, lung, pancreas, and muscle significantly increased to 178 ± 36, 161 ± 2, 106 ± 11, 39 ± 8, and 141 ± 20 μg/g dry matter, respectively, compared to HFD control levels of 86 ± 9, 127 ± 10, 89 ± 6, 23 ± 2, and 95 ± 3 μg/g dry matter, whereas no statistical increase was found in the liver and spleen. An increase of the protein-bound CML might be due to free CML binding to proteins in tissues by covalent bonds. Moreover, the rats' serum low-density lipoprotein cholesterol concentration, fasting blood glucose levels, and energy expenditure also increased obviously. These findings indicated that long-term intake of high-dose free CML might be a health risk factor for rats with HFD. This could provide valuable information for further study on the possible effects of long-term consumption of CML-rich fatty foods on human health, involving the progression of chronic disease.

A photodegradation study of Aflatoxin B(1) (AFB(1)) in water solution was performed under UV irradiation at different AFB(1) initial concentrations and UV irradiation intensities. The effect of UV intensity on the AFB(1) photodegradation ratio is dominative, when compared with AFB(1) initial concentration. The photodegradation of AFB(1) was proved to follow first-order reaction kinetics (R(2) > or = 0.99). Three photodegradation products, i.e. P(1) (C(17)H(14)O(7)), P(2) (C(16)H(14)O(6)) and P(3) (C(16)H(12)O(7)), were identified on the basis of low mass error and high matching property by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF MS), and the degradation pathway was proposed. This study first reports the appearance of these photodegradation products and the proposed degradation pathway in aqueous media.

s The effects of non-treated and modified dried egg yolk on the rheological properties of flour dough were investigated. It indicated that farinograph dough development time, dough stability, and farinograph quality number of the dough increased with the incorporation of the dried egg yolk, while the dough softness decreased. The incorporation of PLA2-treated dried egg yolk into flour has more significant effect on farinograph than that of the non-treated dried egg yolk. Extensograph resistance to extension, and area below the curve (energy) significantly increased with the addition of dried egg yolk, while extensibility decreased and the water adsorption was unchanged. The addition of dried egg yolk lead to the increase of G' (the storage modulus) and G” (loss modulus) under frequency sweep from 0.1 to 20 Hz at 1.5% strain and temperature sweep from 20 to 90 °C at 1 Hz. The microstructure of the dough showed great difference when non-treated or PLA2-treated dried egg yolk was incorporated into wheat dough. Starch granules flowed into the continuous matrix compared to the blank wheat dough. The gluten network structure of the dough was increased when PLA2-treated dried egg yolk was added.

UV irradiation of a solution of aflatoxin B1 in acetonitrile resulted in three major degradation products which have been identified by LC–MS. Accurate masses and proposed molecular formulas of the degradation products—315.0868 (C17H15O6), 285.0758 (C16H13O5), and 275.0553 (C14H11O6)—were obtained with low mass error and high matching property by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF MS). Structural formulas of the photodegradation products, and the degradation pathways leading to the compounds, are proposed on the basis of the molecular formulas and MS–MS spectra. UPLC–Q-TOF MS has been recognized as a powerful analytical tool for qualitative analysis of trace materials and degradation products.

A novel synthesis method of methyl-3-quinoxaline-2-carboxylic acid (MQCA) and the preparation of its hapten were described. MQCA was synthesised involving in two steps with a high purity. For improving the sensitivity of detection, five different haptens were synthesised and corresponding immunogens and coating antigens were prepared. After comparing the sensitivity of immunoassay with different pairs of antibody and coating antigen, a specific immunoassay was obtained using an antibody raised against hapten (four-atom spacer arm) – BSA and a suitable coating antigen with a heterologous spacer arm group. The 50% inhibitory concentration of MQCA by indirect competitive enzyme-linked immunosorbent assay with optimised antibody and coating antigen was 3.84 ng/ml and the limit of detection was 0.25 ng/ml.

Eicosapentaenoyl trehalose was transesterified with eicosapentaenoic acid ethyl ester and trehalose in tert-butanol using microbial lipase. Reversed phase high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (RPHPLC-DAD–ESI-MS) analysis showed that the monoester and diester existed in the reaction mixture. Silica gel column chromatography was adopted to pretreat the reactive mixture then the eluted monoeicosapentaenoyl trehalose was further purified using semi-preparative HPLC. The structure of the compound was confirmed by ESI-MS and nuclear magnetic resonance (NMR) as 6-O-monoeicosapentaenoyl trehalose. Subsequently, the surface properties of monoeicosapentaenoyl trehalose were investigated. The results indicated that the surface tension, CMC, γCMC and ΔG mic o decreased with increasing temperature, however, the area occupied per molecule increased very little.

Triacylglycerols (TGs) in the seed oil of Momordica charantia L. var. abbreviata Ser. (MCV) were separated by non-aqueous reversed-phase (NARP)-HPLC. Many of the TGs contain two different fatty acyl chains, such as palmitic (P), stearic (S), oleic (O), linoleic (L), and conjugated linolenic acid (CLn). Seven pairs of AAB/ABA-type TGs might present in the seed oil of MCV, namely CLnCLnP/CLnPCLn, CLnCLnS/CLnSCLn, CLnCLnO/CLnOCLn, CLnCLnL/CLnLCLn, SSCLn/SCLnS, OOCLn/OCLnO and LLCLn/LCLnL. The positional isomers of a AAB/ABA-type TGs pair yielded mass spectra showing a significant difference in relative abundance ratios of the fragment ions [AA]+ to [AB]+, which were produced by preferred losses of the fatty acid from the 1/3-position compared to the 2-position of the glycerol backbone. The precise stereospecific structures of the predominant regioisomers of TGs in AAB/ABA pairs were identified by atmospheric pressure chemical ionization mass spectrometry (APCI-MS) according to the special relative abundance ratios of the fragment ions [AA]+ to [AB]+. TGs with CLn occupying the sn-2 position in seven pairs of AAB/ABA might be major constituents of the oil, such as CLnCLnS, LCLnL, CLnCLnP, and so on. Some of the TGs which were isolated and collected as fractions from the seed oil of MCV by NARP-HPLC were further analyzed by 13C-NMR. 13C-NMR data of type-AAA TGs containing α-eleostearic acyl have been complemented.

Rhodiola L. has a long history as traditional Chinese medicine (TCM) with a medicinal efficacy similar to Ginseng and Manyprickle Acathopanax roots. There exist three classes of important active constituents, i.e., phenylethanoids (salidroside, p-tyrosol), phenylpropanoides (rosarin, rosavin, rosin), and monoterpene (rosiridin) in this TCM. In this study, by optimizing the extraction, separation and analytical conditions, a sensitive and accurate high performance liquid chromatographic method has been developed for the simultaneous determination of the six active compounds in the different species of Rhodioa L. for the first time. The analysis was performed on a Purospher STAR C18 column at 30 °C using 20 mmol L−1 aqueous ammonia acetate/methanol gradient system at a flow rate of 1.0 mL min−1 and photodiode array detection (DAD ) at wavelengths 276, 250 and 205 nm, respectively. The optimized method provided good linear relation (r2 > 0.9993 for all the target compounds), satisfactory precision (RSD values less than 1.53%) and good recovery (from 96.3–104.8%). The limits of detection ranged between 0.012 and 0.047 μg mL−1 for the different analytes. The developed method has been successfully applied to analysis and quality control of Rhodiola L.

Corn gluten meal (CGM) was hydrolyzed by Alcalase after starch removal of CGM was applied as a pretreatment. A new inhibitory peptide for angiotensin I-converting enzyme (ACE) was isolated from the hydrolysate of CGM with the use of Bio-Rad P-2 gel filtration and followed by reverse-phase high-performance liquid chromatography (RP-HPLC). The sequence of the active peptide was determined to be Ala-Tyr after the application of amino acid analysis and HPLC/MS. The IC50 of the peptide was 14.2 microM, and it was not affected by preincubation with 30 mU of ACE at 37 degrees C for 3 h. Ala-Tyr also exerted antihypertensive effects after oral administration to spontaneously hypertensive rats. A maximal reduction of systolic blood pressure of 9.5 mmHg was observed 2 h after oral administration of Ala-Tyr at doses of 50 mg/kg.

The effects of high pressure homogenization processing (HPHP), thermal treatment (TT) and milk matrix (soy, skimmed and whole milk) on the phenolic bioaccessibility and the ABTS scavenging activity of apple, grape and orange juice (AJ, GJ and OJ) were investigated. HPHP and soy milk diminished AJ's total phenolic bioaccessibility 29.3%, 26.3%, respectively, whereas TT and bovine milk hardly affected it. HPHP had little effect on GJ's and OJ's total phenolic bioaccessibility, while TT enhanced them 27.3-33.9%, 19.0-29.2%, respectively, and milk matrix increased them 26.6-31.1%, 13.3-43.4%, respectively. Furthermore, TT (80 °C/30 min) and TT (90 °C/30 s) presented the similar influences on GJ's and OJ's phenolic bioaccessibility. Skimmed milk showed a better enhancing effect on OJ's total phenolic bioaccessibility than soy and whole milk, but had a similar effect on GJ's as whole milk. These results contribute to promoting the health benefits of fruit juices by optimizing the processing and formulas in the food industry.

The aim of this work was to study the effect of dynamic high pressure microfluidization (DHPM) on extracting total flavonoids from Cyperus esculentus L. (C. esculentus L.) leaves and to evaluate the antioxidant activity and antibacterial property of these flavonoids. In all the assays, pretreatment with DHPM was found to not only efficiently improve the yield of total flavonoids but also strengthen the antioxidant activity of the total flavonoids. C. esculentus L. leaves flavonoids had pronounced antioxidant activity in vivo that could significantly elevate the content of superoxide dismutase (SOD) without increasing the malondialdehyde (MDA) levels, and could also improve total antioxidant capacity in mice with a dose-dependent fashion. C. esculentus L. leaves flavonoids inhibited the growth of both Gram positive and Gram negative bacteria while no obvious inhibitory effect on Penicillium and Aspergillus could be observed. Our studies indicate that flavonoids from C. esculentus L. leaves can be taken as a natural antioxidant and bacteriostatic substance in food and pharmaceutical industry.