Triacylglycerol regioisomers containing palmitic acid analyzed by ultra-performance supercritical fluid chromatography and quadrupole time-of-flight mass spectrometry: Comparison of standard curve calibration and calculation equation.

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 [RA-A]+/[RA-A]++[RA-B]+ and content of sn-A-B-A (%) for AAB/ABA type TAGs, [Rsn-1 FA-sn-3 FA]+/[RB-C]++[RA-C]++[RA-B]+ and content of fatty acid (FA) at sn-2 position (%) for BAC/ABC/ACB type TAGs. The difference between calculation equation and standard curve method was acceptable. The TAG regioisomers in human milk, mammalian milk, lard and fish oil were identified and quantified using the developed methods. This study provided a reliable and facile method for analysis of the TAG regioisomers, which was capable of the selection of oil materials for infant formula production.

Identification and Quantification of Triacylglycerols Using Ultraperformance Supercritical Fluid Chromatography and Quadrupole Time-of-Flight Mass Spectrometry: Comparison of Human Milk, Infant Formula, Other Mammalian Milk, and Plant Oil.

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.

Exploring the relationship between potato components and Maillard reaction derivative harmful products using multivariate statistical analysis.

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 ß-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 ß-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.

Characterization and determination of free phytosterols and phytosterol conjugates: The potential phytochemicals to classify different rice bran oil and rice bran.

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.

Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine in tea and the factors affecting their formation.

The levels of Nε-(carboxymethyl)lysine (CML) and Nε-(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.

Investigating the inhibitory activity and mechanism differences between norartocarpetin and luteolin for tyrosinase: A combinatory kinetic study and computational simulation analysis.

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.

High pressure homogenization processing, thermal treatment and milk matrix affect in vitro bioaccessibility of phenolics in apple, grape and orange juice to different extents.

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.

Dynamic high pressure microfluidization-assisted extraction and bioactivities of Cyperus esculentus (C. esculentus L.) leaves flavonoids.

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.

Identification and Quantitation of Anthocyanins in Purple-Fleshed Sweet Potatoes Cultivated in China by UPLC-PDA and UPLC-QTOF-MS/MS.

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.

Effects of Long-Term Exposure to Free Nε-(Carboxymethyl)lysine on Rats Fed a High-Fat Diet.

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(ε)-(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.

Separation of four flavonoids from Rhodiola rosea by on-line combination of sample preparation and counter-current chromatography.

Purification of four flavonoids from Rhodiola rosea was developed by on-line combination of sample preparation and counter-current chromatography (CCC). Flavonoid sample was prepared by dynamic ultrasonic-assisted and solid-phase extraction using ion liquids as extractant. The preparation conditions were optimized by D-optimal design as follows: 2mol/L of 1-ethyl-3-methylimidazolium bromide concentration, 360W of ultrasonic power, 1.5mL/min of flow rate, 35min of extraction time and 0.5mL (absorbent) per g (material) of absorbent amount. The prepared sample solution (20mL) was loaded and injected directly into CCC column for final separation. As a result, four flavonoids, herbacetin-3-O-ß-d-glucopyranosyl-7-O-α-l-rhamnopyranoside 1 (40.1mg), kaempferol-3-O-ß-d-glucopyranosyl-7-O-α-l-rhamn-opyranoside 2 (4.6mg), kaempferol 3-O-ß-d-glucopyranoside-(2→1)-ß-d-xylopyranoside 3 (20.2mg) and herbacetin-8-O-ß-d-glucopyranoside 4 (22.5mg), were obtained from 20g of R. rosea material using ethyl acetate-n-butanol-H2O as solvent system at a ratio of 4:1:5 by CCC. Their structures were identified by ESI-MS/MS, NMR methods. Their purities determined by UPLC were 98.5%, 95.4%, 98.1% and 97.5%, respectively. Kaempferol-3-O-ß-d-glucopyranosyl-7-O-α-l-rhamnopyranoside 2 and herbacetin-8-O-ß-d-glucopyrano-side 4 were isolated for first time from R. rosea. The purification method was simple, efficient and evaded tedious sample preparation process.

Preparation of human milk fat substitutes from palm stearin with arachidonic and docosahexaenoic acid: combination of enzymatic and physical methods.

Human milk fat substitutes (HMFSs) were prepared by a two-step process, namely, Lipozyme RM IM-catalyzed acidolysis of interesterified high-melting palm stearin with fatty acids from rapeseed oil and blending of the enzymatic product with the selected oils on the basis of the calculation model. The optimum conditions for the enzymatic reaction were a mole ratio of palm stearin/fatty acids 1:10, 60 °C, 8% enzyme load (wt % of substrates), 4 h, and 3.5% water content (wt % of enzyme); the enzymatic product contained 39.6% palmitic acid (PA), 83.7% of the fatty acids at sn-2 position were PA (sn-2 PA), and the distribution probability of PA at the sn-2 position among total PA (% sn-2 PA) was 70.5%. With the fatty acid profiles of human milk fat (HMF) as a preferable goal, a physical blending model was established for the second step to guarantee the maximum addition of selected oils. Based on the model prediction, a desirable formula constituted enzymatic product/rapeseed oil/sunflower oil/palm kernel oil/algal oil/microbial oil at a mole ratio of 1:0.28:0.40:0.36:0.015:0.017, and the final product had PA content, sn-2 PA, and %sn-2 PA at 23.5, 43.1, and 61.1%, respectively. The contents of arachidonic and docosahexaenoic acids were 0.4 and 0.3%, respectively. Relying on the total and sn-2 fatty acid compositions of HMF and "deducting score" principle, the score for the similarity between the final product and HMF was scaled as 89.2, indicating the potential as a fat substitute in infant formulas.