Simultaneous mitigation of heterocyclic aromatic amines and advanced glycation end products in roasted beef patties by plasma-activated water: Effects and mechanisms.

Heterocyclic aromatic amines (HAAs) and advanced glycation end products (AGEs) are hazardous substances produced when food is heated. In this study, the ability of plasma-activated water (PAW) to simultaneously mitigate production of HAAs and AGEs in roasted beef patties was investigated. Assays of free radicals, lipid peroxidation, and active carbonyls were used to analyze the mechanisms. PAW treatment decreased the contents of free HAAs, free AGEs, bound HAAs, and bound AGEs to 12.65 ng/g, 0.10 µg/g, 297.74 ng/g, and 4.32 µg/g, with the inhibition rates of 23.88%, 23.08%, 11.02%, and 8.47%, respectively. PAW treatment decreased HAAs and AGEs and mitigated their increase during storage. The decrease of HAAs and AGEs in PAW-treated samples was correlated with the enhancement of antioxidant capacity. The increase of free radical scavenging ability by PAW treatment led to the decrease of lipid peroxidation and the decrease of active carbonyls, HAAs, and AGEs in meat products.

Influence of soybean isolate on the formation of heterocyclic aromatic amines in roasted pork and its possible mechanism.

In this paper, the effects of soybean protein isolate (SPI) on the formations of five heterocyclic aromatic amines (HAAs) in roasted pork were investigated. The levels of all five HAAs improved upon addition of 2.5% of SPI (P < 0.05). With higher SPI dosage, the levels of HAA decreased after seeing an increase. Two HAAs (MeIQx and 4,8-DiMeIQx) were inhibited by 10.0% of SPI, with the inhibitory efficiencies of 7.0 % and 85.7%, respectively. After being heated, the levels of both the free amino acids and carbonyl groups in the SPI were observed significantly increased, from 55.04 µg g·SPI-1 to 91.66 µg g·SPI-1 and from 123.85 ± 13.07 to 931.78 ± 32.56, respectively (P < 0.05). Therefore, the possible promotion mechanism of the SPI was speculated that the heated SPI would provide both the HAA precursors and carbonyls, which significantly promoted the Strecker degradation and generated more HAA intermediates (P < 0.05).

Evaluating the effects of temperature and time on heterocyclic aromatic amine profiles in roasted pork using combined UHPLC-MS/MS and multivariate analysis.

In this study, ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) combined with principal component analysis (PCA) were used to investigate the effects of process conditions on the profiles of carcinogenic and mutagenic heterocyclic aromatic amine (HAA) in the pork roasted at 175 °C, 200 °C, 225 °C and 250 °C for 10, 15, 20, 25, 30, 35 and 40 min. Twelve HAAs from four categories, including carboline (Norharman, Harman, and Phe-p-1), imidazopyridine (PhIP, 4'-OH-PhIP, DMIP, and 1,5,6-TMIP), imidazoquinoline (IQ, IQ [4,5-b], and MeIQ), and imidazoquinoxaline (MeIQx and 4,8-DiMeIQx), were detected, quantified and used to compose the HAA profiles in roasted pork. After being Analyzed by PCA, the distributions of HAA profiles from different temperature on the PCA score plot demonstrated that there are significant differences among the HAA profiles from different temperatures. The loading plot also showed that PhIP, 4'-OH-PhIP, IQ[4,5-b], and MeIQ were mainly responsible for the difference. The profiles from higher temperature distribute more scattered than the lower ones, illustrating that the time effects on the HAA profiles from higher temperature are stronger than the lower ones. Comparing the score and loading plots of different heating times, the diversities of the HAA profiles at different temperatures increased under prolonged heating because of the changingpyridines levels. The results of PCA that comparing the HAA from different categories displayed that the formation features of four categories HAAs were significantly differed because of their formation discrepancy under low temperatures and short-term roasting. Using HAA profiles as an entirety, these findings obtained in this study are more close to the real process of HAA formation in roasted pork, and make the complex effects of temperature and time on multiple HAA formations more simply to be concluded.

Acetonitrile extraction coupled with UHPLC-MS/MS for the accurate quantification of 17 heterocyclic aromatic amines in meat products.

This study proposed a simple and accurate acetonitrile extraction pretreatment method coupled with ultrahigh-performance liquid chromatography with tandem mass spectrometry for the simultaneous determination of 17 heterocyclic aromatic amines (HAAs) in meat products. With this new method, all 17 HAAs, including 11 polar and 6 nonpolarHAAs, were simultaneously extracted by acetonitrile and purified by one-step Oasis MCX cartridge purification. Compared with two different improved reference methods, the acetonitrile method could obtain higher recoveries (in the range of 42.5% to 99.0%) and better repeatability (lower than 12.2%). The limits of quantification were calculated between 0.028ngg-1and0.648ngg-1 with high correlation coefficients (r>0.9976) in wide linear ranges. The proposed acetonitrile method was successfully applied to the analysis of the HAAs levels in 10 commercial meat products with satisfactory recoveries.

A novel isoflavone profiling method based on UPLC-PDA-ESI-MS.

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.

Preparation of tyrosinase inhibitors and antibrowning agents using green technology.

Chalcones and their derivatives have attracted great interests in recent years for their comprehensive biological activities. In this study, 2,4,2',4'-tetrahydroxychalcone and its two derivatives, 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione (new compound) and 7,2',4'-trihydroxyflavanone, were synthesized through one-pot green procedure catalyzed by boric acid in polyethylene glycol 400. Their structures were identified by ESI-MS and NMR spectral. Tyrosinase inhibitory activity and antibrowning test results showed that compounds 1-3 exhibited strong tyrosinase inhibitory activities and significant antibrowning effects on the fresh-cut lotus root slices at room temperature in 48 h. Among them, 0.01% 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione combined with 0.5% VC showed the best antibrowning ability. In brief, this study offers a protocol for one-pot green synthesis of high efficiency tyrosinase inhibitors which may be suitable as antibrowning agents for fresh-cut vegetables. More important, this study developed a new type of 1,5-dione derivative which may serve as new lead structures for novel tyrosinase inhibitors discovery.

Simultaneous analysis of PhIP, 4'-OH-PhIP, and their precursors using UHPLC-MS/MS.

A novel method allowing simultaneous analysis of PhIP, 4'-OH-PhIP, and their precursors (phenylalanine, tyrosine, creatine, creatinine, glucose) has been developed as a robust kinetic study tool by using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A direct hydrochloric acid (HCl) extraction was applied to achieve the simultaneous extraction of all seven analytes, with the mean recoveries ranging from 60% to 120% at two concentration levels. Then, an Atlantis dC18 column selected from four different chromatographic columns was ultimately used to separate these compounds within 15 min. The limits of detection range of allseven analytes were calculated as 0.14-325.00 µg L(-1). The intra- and interday precision of the proposed method were less than 15.4 and 19.9%, respectively. The proposed method was successfully applied to depict the kinetic profiles of PhIP, 4'-OH-PhIP, and their precursors in pork model, reducing the analysis time and cost in the kinetic study.

A novel kernel Fisher discriminant analysis: constructing informative kernel by decision tree ensemble for metabolomics data analysis.

Large amounts of data from high-throughput metabolomics experiments become commonly more and more complex, which brings an enormous amount of challenges to existing statistical modeling. Thus there is a need to develop statistically efficient approach for mining the underlying metabolite information contained by metabolomics data under investigation. In the work, we developed a novel kernel Fisher discriminant analysis (KFDA) algorithm by constructing an informative kernel based on decision tree ensemble. The constructed kernel can effectively encode the similarities of metabolomics samples between informative metabolites/biomarkers in specific parts of the measurement space. Simultaneously, informative metabolites or potential biomarkers can be successfully discovered by variable importance ranking in the process of building kernel. Moreover, KFDA can also deal with nonlinear relationship in the metabolomics data by such a kernel to some extent. Finally, two real metabolomics datasets together with a simulated data were used to demonstrate the performance of the proposed approach through the comparison of different approaches.

A new strategy of exploring metabolomics data using Monte Carlo tree.

Large amounts of data from high-throughput metabolomics experiments have become commonly more and more complex, which brings a number of challenges to existing statistical modeling. Thus there is a need to develop a statistically efficient approach for mining the underlying metabolite information contained by metabolomics data under investigation. In this work, we provide a new strategy based on Monte Carlo cross validation coupled with the classification tree algorithm, which is termed as the MCTree approach. The MCTree approach inherently provides a feasible way to uncover the predictive structure of metabolomics data by the establishment of many cross-predictive models. With the help of the sample proximity matrix such obtained, it seems to be able to give some interesting insights into metabolomics data. Simultaneously, informative metabolites or potential biomarkers can be successfully discovered by means of variable importance ranking in the MCTree approach. Two real metabolomics datasets are finally used to demonstrate the performance of the proposed approach.

Comparison of the volatile constituents of different parts of Cortex magnolia officinalis by GC-MS combined with chemometric resolution method.

Volatile compositions of different parts (stem, branch and root barks) of cortex Magnolia officinalis, cultivated in China, were investigated for the first time by GC-MS with the help of heuristic evolving latent projection (HELP). Identification of components was conducted by similarity matching to NIST mass library but also assisted by comparison of temperature-programmed retention indices (PTRIs) with the data web available. A total of 90, 82 and 76 volatile compounds in the essential oils of the three samples taken from the same batch aforementioned were qualitatively and quantitatively determined, representing 84.03, 83.68 and 83.10% of the total content, respectively. Among the constituents determined, there were 50 components coexisting. Eudesmol and its isomers were shown to be the principal compounds in the studied samples, accounting for 47.66, 36.74 and 36.31%, respectively. The three kinds of isomers (alpha-, beta- and gamma-eudesmol) in houpo volatile oils have been tentatively qualified and quantified simultaneously for the first time. By comparative analysis, significant qualitative and semi-quantitative differences and similarities were observed among the three samples. The results achieved provide a scientific evidence for further exploitation of Magnolia bark and clinical medication.

Interaction of glycyrrhetinic acid, furosemide and hydrochlorothiazide with bovine serum albumin and their displacement interactions: capillary electrophoresis and fluorescence quenching study.

Licorice is the most widely used crude drug in traditional Chinese medicine. Glycyrrhetinic acid (GA) is the metabolite of glycyrrhizic acid, which is the main bioactive ingredient of licorice. In this work, capillary electrophoresis-frontal analysis (CE-FA) was applied to study the binding of bovine serum albumin with GA and two diuretics: furosemide (FU) and hydrochlorothiazide (HZ). The binding parameters of GA were determined by Scatchard analysis, which showed that there are two kinds of binding sites in bovine serum albumin for GA. However, the results showed that the CE-FA method was not suitable for the interaction study of FU and HZ. Therefore, utracentrifugation-CE was used to probe the binding characteristic of these two drugs and the results showed only one kind of binding site for them under the studied conditions. Displacement interactions between these drugs were also investigated by utracentrifugation-CE method and the results showed that GA hardly displaces HZ while it can slightly displace FU and FU can slightly displace HZ. For comparison, the binding of these drugs was also studied by the fluorescence quenching method and the data were processed by the Stern-Volmer quenching equation. Results showed that the binding constants were basically consistent for two methods for all drugs studied. The number of binding sites on one protein molecule was well consistent for FU and HZ while it was quite different for GA.