•A-type proanthocyanidin-rich cranberry concentrate has promising anti-aging effect.•Cranberry concentrate is capable of improving glutathione peroxidase activity.•Grape seed extract is able to increase superoxide dismutase activity.•Both products regulate malonaldehyde, monoamine oxidase and 8-isoprostane levels.•Neither of products generates any positive effect on catalase activities.We investigated the anti-aging and redox state regulation effects by A-type proanthocyanidins (PACs)-rich cranberry concentrate (CBC) and its comparison with B-type PACs-rich grape seed extract (GSE). Using the Q-Extractive mass spectrometry, PACs dimer A and B were identified as predominant phenolic compounds of CBC and GSE, respectively, while epicatechin was present in both extracts. Using the d-galactose-induced aging mice model, effects were investigated via an 8-week oral gavage considering water-soluble vitamin E as the positive control. Both CBC and GSE reduced hepatic and brain thiobarbituric acid reactive substances, and plasma 8-isoprostane levels by 30–57%, 24–30% and 11–62%, respectively, and decreased brain and plasma monoamine oxidase activities by 27–59% and 65–71%, respectively. CBC could improve hepatic glutathione peroxidase activity by 42%, while GSE increased hepatic superoxide dismutase activity by 13%. Therefore, both extracts exerted anti-aging effects probably via regulating in vivo redox state. However, neither generated any effect on catalase activities.

•AA aggravates existing obesity and modifies adipocyte browning.•AA may sex-dependently affect obesity-driven inflammation by altering microbiota.•AA exacerbates male inflammation and obesity-induced complications.•AA ameliorates female fatty liver and insulin resistance with GPR41 up-regulation.Unraveling the role of dietary lipids is beneficial to treat obesity and metabolic dysfunction. Nonetheless, how dietary lipids affect existing obesity remains unknown. Arachidonic acid (AA), a derivative of linoleic acid, is one of the crucial n-6 fatty acids. The aim of this study was to investigate whether AA affects obesity through associating microbiota-driven inflammation with hypothalamus-adipose-liver axis. Four-week old C57BL/6 J mice were fed with a high-fat diet (HFD, 45% fat) for 10 weeks to induce obesity, and then fed a HFD enriched with 10 g/kg of AA or a continuous HFD in the following 15 weeks. Systemic adiposity and inflammation, metabolic profiles, gut microbiota composition, short-chain fatty acids production, hypothalamic feeding regulators, browning process of adipocytes, hepatosteatosis, and insulin resistance in adipose were investigated. The results indicated that AA aggravates obesity for both genders whereas sex-dependently affects gut microbiota composition. Also, AA favors pro-inflammatory microbiota and reduces butyrate production and circulating serotonin, which augments global inflammation and triggers hypothalamic leptin resistance via microglia accumulation in male. AA exacerbates non-alcoholic steatohepatitis along with amplified inflammation through TLR4-NF-κB pathway and induces insulin resistance. Reversely, AA alleviates obesity-related disorders via rescuing anti-inflammatory and butyrate-producing microbiota, up-regulating GPR41 and GPR109A and controlling hypothalamic inflammation in female. Nevertheless, AA modifies adipocyte browning and promotes lipid mobilization for both genders. We show that AA affects obesity likely through a gut-hypothalamus-adipose-liver axis. Our findings formulate recommendations of n-6 fatty acids like AA from dietary intake for obese subjects preferably in a sexually dimorphic way.Download high-res image (83KB)Download full-size image

Acrylamide is classified as a probable carcinogen to humans and generated from Maillard reaction. Currently, the short-term exposure to acrylamide was evaluated via external diet sources in vitro or two main mercapturic acid metabolites: N-acetyl-S-(2-carbamoylethyl)-l-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-l-cysteine (GAMA) in vivo. In the present work, we comprehensively profiled four mercapturic acid metabolites and evaluated their internal exposure in rats and Chinese adolescents. The cumulative excretion of mercapturic acid metabolites contributes 38.4–73.0 and 43.8–63.6 % of total in vivo metabolites of acrylamide in male and female rats, respectively, when 1, 10, and 50 mg/kg bw of acrylamide were orally administered. Toxicokinetic study revealed that the conversion of acrylamide into glycidamide and glutathione coupling process is highly related to the gender and oral gavage dose via evaluating kinetic parameters, accumulative excretion percentages, and molar ratios of oxidative to reductive metabolism. In human study, a total of 101 Chinese adolescents (41 men and 60 women) were enrolled and served with a meal of potato chips, corresponding to a single-dose (12.6 μg/kg bw) exposure to acrylamide. Toxicokinetic work showed that AAMA is an early and predominant metabolite appearing as a biomarker in urine. N-acetyl-S-(2-carbamoylethyl)-l-cysteine-sulfoxide (AAMA-sul), an oxidative product from AAMA, exhibits a higher peak concentration than GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-l-cysteine (iso-GAMA) during the whole 48-h toxicokinetic period. The internal exposure via four mercapturic acid metabolites is associated with the gender and body mass index characteristics. Thus, current study aims at mercapturic acid metabolites as urinary biomarkers and provides comprehensive insights into the short-term internal exposure to acrylamide.

•Dose-dependent reduction of acrylamide by flavonoids shows bell-shaped correlation.•Phenolic hydroxyls instead of alcoholic hydroxyls contribute to reduction effect.•Number and position of phenolic hydroxyls correlates the reduction effect by QSAR.•The study broadens understanding of acrylamide chemoprevention on a structural basis.We reported a structure–activity relationship study on unravelling phenolic hydroxyls instead of alcoholic hydroxyls contribute to the reduction of acrylamide formation by flavonoids. The dose-dependent study shows a close correlation between the number of phenolic hydroxyls of flavonoids and their reduction effects. In view of positions of hydroxyls, the 3′,4′(ortho)-dihydroxyls in B cycle, 3-hydroxyl or hydroxyls of 3-gallate in C cycle, and 5,7(meta)-dihydroxyls in A cycle of flavonoid structures play an important role in the reduction of acrylamide. Flavone C-glycosides are more effective at reducing the formation of acrylamide than flavone O-glycosides when sharing the same aglycone. The current multiplex quantitative structure–activity relationship (QSAR) equations effectively predict the inhibitory rates of acrylamide using selected chemometric parameters (R2: 0.835–0.938). This pioneer study opens a broad understanding on the chemoprevention of acrylamide contaminants on a structural basis.

•The addition of flavonoids could effectively reduce acrylamide formation.•Acrylamide reduction was related to the number of phenolic hydroxyls of flavonoids.•Non-linear dose–response relationship was observed during microwave food processing.•Acrylamide reduction was in correlation with antioxidant activity of products.•Both ANN and MLR models could effectively predict acrylamide reduction.The aim of this study was to investigate the applicability of artificial neural network (ANN) and multiple linear regression (MLR) models for the estimation of acrylamide reduction by flavonoids, using multiple antioxidant capacities of Maillard reaction products as variables via a microwave food processing workstation. The addition of selected flavonoids could effectively reduce acrylamide formation, which may be closely related to the number of phenolic hydroxyl groups of flavonoids (R: 0.735–0.951, P < 0.001). The rate of inhibition of acrylamide formation correlated well with the change of trolox equivalent antioxidant capacity (ΔTEAC) measured by DPPH (R2 = 0.833), ABTS (R2 = 0.860) or FRAP (R2 = 0.824) assay. Both ANN and MLR models could effectively serve as predictive tools for estimating the reduction of acrylamide affected by flavonoids. The current predictive model study provides a low-cost and easy-to-use approach to the estimation of rates at which acrylamide is degraded, while avoiding tedious sample pretreatment procedures and advanced instrumental analysis.

Acrylamide is mainly generated from asparagine and reducing sugars. The comprehensive kinetic profile of acrylamide and Maillard reaction products (MRP) is important for understanding the control of acrylamide. We unraveled the role of flavonoids in the kinetic process of acrylamide via a potato-based asparagine–glucose microwave heating system. Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was employed for the simultaneous determination of asparagine, glucose, fructose and acrylamide. The multi-response non-linear regression models were used for kinetic parameter estimation. The results indicated a positive role of flavonoids in the fructose-participating (k3: 0.461–0.674; P < 0.05, P < 0.01, compared to the control) instead of the glucose-participating Maillard reaction (k1: 0.128–0.148; P > 0.05). The addition of flavonoids significantly reduces the formation of acrylamide during the advanced stage (k4: 2.311–4.327; P < 0.05, P < 0.01) but did not affect its elimination process (k6: 0.076–0.113; P > 0.05). Treatment of flavonoids has no significant impact on the formation of melanoidins (k5: 3.645–4.368; P > 0.05) and retains the original sensory attributes of MRP. These findings favor thinking mitigation strategies via the use of additives during food processing.

The reduction effect of catechins and esterified catechins on the kinetic behavior of acrylamide formation and its correlation with the change in antioxidant properties of Maillard reaction products in an equimolar asparagine–glucose microwave heating model system was investigated. Results indicated that both catechins and esterified catechins could effectively reduce the formation of acrylamide and could achieve a maximum inhibitory rate when their addition levels were 10−9 mol L−1. Furthermore, 5′-phenolic hydroxyl and/or 3-gallate groups in the chemical structure of catechins and/or their derivatives played an important role in the reduction of acrylamide formation. Also, the reduction effect of esterified catechins was better than that of catechins. Meanwhile, inhibitory rates of acrylamide affected by either catechins or esterified catechins correlated well (R2: 0.757–0.940) with the Trolox equivalent antioxidant capacity (ΔTEAC) of Maillard reaction products measured by three different antioxidant evaluation methods, i.e. 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), or the ferric reducing antioxidant power (FRAP) assay. The kinetic study revealed that the processes of the conversion from glucose into fructose, the asparagine–fructose reaction and the generation of acrylamide in Maillard reaction systems were all significantly suppressed, which may help to elucidate the mode of action of catechins and esterified catechins in reducing the formation of acrylamide during the Maillard reaction.

In this paper we describe a multiplex time-reducing quantitative polymerase chain reaction (qPCR) method for determination of telomere length. This multiplex qPCR assay enables two pairs of primers to simultaneously amplify telomere and single copy gene (albumin) templates, thus reducing analysis time and labor compared with the previously established singleplex assay. The chemical composition of the master mix and primers for the telomere and albumin were systematically optimized. The thermal cycling program was designed to ensure complete separation of the melting processes of the telomere and albumin. Semi-log standard curves of DNA concentration versus cycle threshold (Ct) were established, with a linear relationship over an 81-fold DNA concentration range. The well-performed intra-assay (RSD range 2.4–4.7%) and inter-assay (RSD range: 3.1–5.0%) reproducibility were demonstrated to ensure measurement stability. Using wild-type, Lewis lung carcinoma and H22 liver carcinoma C57BL/6 mouse models, significantly different telomere lengths among different DNA samples were not observed in wild-type mice. However, the relative telomere lengths of the tumor DNA in the two strains of tumor-bearing mice were significantly shorter than the lengths in the surrounding non-tumor DNA of tumor-bearing mice and the tissue DNA of wild-type mice. These results suggest that the shortening of telomere lengths may be regarded as an important indicator for cancer control and prevention. Quantification of telomere lengths was further confirmed by the traditional Southern blotting method. This method could be successfully used to reduce the time needed for rapid, precise measurement of telomere lengths in biological samples.

We developed an automated microwave digestion labstation (MDL) combined with ultra high-performance liquid chromatography−tandem mass spectrometry (UHPLC−MS/MS) method under the control of positive−negative ion switching as a robust kinetic study tool for rapid and simultaneous quantification of asparagine, glucose, fructose, and acrylamide in Maillard reaction products. Maillard reactions were conducted in a potato model via MDL. The two-step simple pretreatment procedures included the addition of isotope internal standards 15N2-asparagine, 13C6-glucose, and D3-acrylamide, followed by appropriate dilution with the mobile phase and filtration. Analytes were separated on a Hypercarb column and monitored by MS/MS. Study of matrix effects indicated Maillard reaction products induce an ionization suppression of both positive and negative precursor ions, but quantitative results are corrected through the use of isotopically labeled internal standards. Using this method, the limit of detection (LOD) and limit of quantification (LOQ) ranges of all analytes were calculated as 0.04−0.6 and 0.1−1.1 μM, respectively. Excellent repeatability (RSD < 9.6%) and acceptable within-laboratory reproducibility (RSD < 9.2%) substantially supported the use of this method for sample analysis. The present kinetic tools, with 10−50 min mimic of Maillard reactions and short instrumental run time (5.5 min per sample), were successfully validated and applied to simultaneous determination of acrylamide and its precursors and intermediates during Maillard reactions and kinetic elucidation. Furthermore, current tools of MDL combined with simple sample treatment procedures and UHPLC−MS/MS analysis reduce sample analysis time and labor in the kinetic study.

Microwave heating can be regarded as a possible way to produce a considerable amount of acrylamide. The present study investigated the formation of acrylamide in asparagine–glucose, asparagine–fructose and asparagine–sucrose microwave heating systems by the response surface methodology (RSM) and the orthogonal array methodology (OAM). The acrylamide content was rapidly quantified by a validated ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. Results of RSM study indicated that in the asparagine–glucose system, the acrylamide content increased in the combined condition of high temperature accompanying with short heating time (>190 °C, <20 min) or low temperature accompanying with long heating time (<180 °C, >30 min). In the asparagine–fructose system, the similar conclusion was made in the combined condition of high temperature accompanying with short heating time (>175 °C, <20 min) or low temperature accompanying with long heating time (<170 °C, >25 min). In the asparagine–sucrose system, the amount of acrylamide enhanced with the increase of both heating temperature and heating time. The fitted mathematic models were successfully applied to the quantification of acrylamide formation when the heating temperature and heating time fell into the ranges of 120–240 °C and 5–35 min simultaneously. OAM study showed that acrylamide is readily formed via heating binary precursors 5 min at 180 °C in the asparagine–glucose and asparagine–fructose systems. However, acrylamide is readily generated when the binary precursors are heated 15 min at 180 °C in the asparagine–sucrose system.

The present study investigated a robust method for the preparation of four flavone C-glycosides, i.e. orientin, homoorientin, vitexin and isovitexin, which were prepared from an ethanol aqueous extract, i.e. antioxidant of bamboo leaves (AOB), by AB-8 resin-based column chromatography and preparative high-performance liquid chromatography (HPLC) using a mobile phase consisting of 10% and 15% (v/v) of acetonitrile and 1% acetic acid. These flavone C-glycosides were further purified by the drowning-out crystallization method using methanol and water as drowning-out anti-solvents and salting-out agents, respectively. The purity was assessed by analytical HPLC and the confirmation of chemical structures was performed by IR, MS, NMR and UV spectroscopy. Orientin (49 mg), homoorientin (142 mg), vitexin (15 mg) and isovitexin (62 mg) were prepared from 6.5 g of crude column chromatography fraction obtained from 5 L of AOB concentrated solution. The present method is robust and suitable for preparing available quantities of pure flavone C-glycosides and the quantification of orientin, homoorientin, vitexin and isovitexin in bamboo leaves.

The present study developed two analytical methods for quantification of acrylamide in complex food matrixes, such as Chinese traditional carbohydrate-rich foods. One is based on derivatization with potassium bromate and potassium bromide without clean-up prior to gas chromatography with micro-electron capture detector (GC-MECD). Alternatively, the underivatized acrylamide was detected by high-performance liquid chromatography coupled to quadrupole tandem mass spectrometry (HPLC-MS/MS) in the positive electrospray ionization mode. For both methods, the Chinese carbohydrate-rich samples were homogenized, defatted with petroleum ether and extracted with aqueous solution of sodium chloride. Recovery rates for acrylamide from spiked Chinese style foods with the spiking level of 50, 500 and 1000 μg kg−1 were in the range of 79–93% for the GC-MECD including derivatization and 84–97% for the HPLC-MS/MS method. Typical quantification limits of the HPLC-MSMS method were 4 μg kg−1 for acrylamide. The GC-MECD method achieved quantification limits of 10 μg kg−1 in Chinese style foods. Thirty-eight Chinese traditional foods purchased from different manufacturers were analyzed and compared with four Western style foods. Acrylamide contaminant was found in all of samples at the concentration up to 771.1 and 734.5 μg kg−1 detected by the GC and HPLC method, respectively. The concentrations determined with the two different quantitative methods corresponded well with each other. A convenient and fast pretreatment procedure will be optimized in order to satisfy further investigation of hundreds of samples.

An improved method was validated for the determination of acrylamide in foods using ultra-performance liquid chromatography (UPLC) coupled to eletrospray ionization tandem mass spectrometry (MS/MS) in the present study. This improved method supplies a rapid quantitative procedure of acrylamide with a run time of only 3 min. Results showed a good repeatability (RSD ≤ 4.5%) with 50, 100, 250, 500 and 1000 μg/kg spiked concentrations in potato crisps in within-day (n = 5) and day-to-day (n = 10) precision tests. Meanwhile, good recoveries (81.6–99.0%) were obtained with the same spiked concentrations in acrylamide-free cereal samples (n = 3). The excellent method validation data and proficiency test results (Z-score: −0.1) of the official Food Analysis Performance Assessment Scheme (FAPAS) suggested that the present quantitative method could be applied for rapid determination of acrylamide in many investigations.

The formation of acrylamide under three asparagine–sugar low-moisture systems were analyzed by the response surface methodology (RSM) and orthogonal array methodology (OAM) in the present work. The acrylamide content was quantified by a novel validated ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS). Results of RSM study showed that in the asparagine–glucose system, the acrylamide content achieved a maximum level (442.7 μmol/mol Asn) when the system was heated 18 min at about 199 °C; in the asparagine–fructose system, the acrylamide content increases in the combined condition of higher temperature and shorter heating time (>200 °C, <15 min) or lower temperature and longer heating time (<150 °C, >35 min); in the asparagine–sucrose system, the amount of acrylamide enhanced with the increase of temperature and the decrease of time, but declined with the decrease of temperature and the increase of heating time. The coefficients of determination (R2) of the model indicated that all the three models adequately represented the real relationship among the parameters chosen. OAM study indicated that the molar quantity of asparagine monohydrate became the most important parameter contributing to the formation of acrylamide. Meanwhile, acrylamide was readily formed via heating binary precursors 15 min at 180 °C in the glucose and fructose system while acrylamide was readily generated when the binary precursors were heated 15 min at 210 °C in the sucrose system.

Tricin (5,7,4′-trihydroxy-3′,5′-dimethoxyflavone) occurs in its glycosidic form in rice bran and other grass species such as wheat, barley, and maize. Tricin is considered sufficiently safe for clinical development as a cancer chemopreventive agent, therefore it can be used for cancer prevention. This study established a new method for the preparation of tricin from bamboo leaves as an alternative to traditional methods such as chemical synthesis via the Baker−Venkata−Raman reaction between acetylsyringic acid and phloroacetophenone. Tricin was prepared from an antioxidant product that was derived from bamboo leaves (AOB) by extraction with aqueous ethanol. A concentrated solution of this product was obtained and then processed by polystyrene (AB-8) resin column chromatography and preparative high-performance liquid chromatography (HPLC) with 30% (v/v) acetonitrile in 1% (v/v) acetic acid as the mobile phase. The collected tricin-rich fraction was further sequentially purified by dialysis membrane separation and drowning-out crystallization methods. The purity was assessed by analytical HPLC with 25% (v/v) acetonitrile in 1% (v/v) acetic acid as the mobile phase, and the chemical confirmation was evaluated by infrared, mass, nuclear magnetic resonance, and ultraviolet spectroscopies. Tricin (3.09 g) was prepared from 174 g of a crude column chromatography fraction obtained from 5 L of AOB concentrated solution. The present method is appropriate for preparing quantities of pure tricin, which can be used for the quantification of tricin in various plant herbs and further for pharmaceutical/biomedical applications and evaluation.

Gas chromatography coupled with electron capture detector (GC–ECD) was successfully developed and applied for the rapid determination of acrylamide in conventional fried foods, such as potato crisps, potato chips, and fried chicken wings. The method included defatting with n-hexane, extraction with aqueous solution of sodium chloride (NaCl), derivatization with potassium bromate (KBrO3) and potassium bromide (KBr), and liquid–liquid extraction with ethyl acetate. The final acrylamide extract was analyzed by GC–ECD for quantification and by GC–MS for confirmation. The chromatographic analysis was performed on the HP-INNOWax capillary column, and good retention and peak response of acrylamide were achieved under the optimal conditions (numbers of theoretical plates N = 83,815). The limit of detection (LOD) was estimated to be 0.1 μg kg−1 on the basis of ECD technique. Recoveries of acrylamide from conventional samples spiked at levels of 150, 500 and 1000 μg kg−1 (n = 4 for each level) ranged between 87 and 97% with relative standard deviations (RSD) of less than 4%. Furthermore, the GC–ECD method showed that no clean-up steps of acrylamide derivative would be performed prior to injection and was slightly more sensitive than the MS/MS-based methods. Validation and quantification results demonstrated that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide.

Isotope dilution liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC–MS/MS) was successfully applied to the quantification of acrylamide (2-propene-amide) in infant rice cereals (with nutrients) and other cereal-based foods (fastfood nutrient cake, teething cookie, hi-protein milk wheat and vegetable teething rusk). The method included defatting with petroleum ether, extraction with 2 M aqueous solution of sodium chloride, further liquid–liquid extraction with ethyl acetate and clean-up by solid-phase extraction (SPE) with OASIS HLB 6 cc cartridges. Acrylamide was detected with an Atlantis dC18 5 μm; 210 mm × 1.5 mm column using 10% methanol/0.1% formic acid in water as mobile phase. The analytical method in the present study was well validated and good results were obtained with respect to repeatability (R.S.D. < 6.5%) and recovery (87–96%) which fulfilled the requirements defined by European Union (EU) legislation. The acrylamide levels in infant rice cereals and other cereal-based foods were 3.3–37.1 μg kg−1 and 10.9–1568.9 μg kg−1, respectively. This validated method might need to be modified under some special conditions. For instance, an additional deproteinating step should be operated during the sample treatment process as for the analysis of some protein-rich infant cereals.

In early 2002, Swedish National Food Administration (SNFA) and University of Stockholm together announced that certain foods that are processed or cooked at high temperature contain relatively high levels of acrylamide. The occurrence of acrylamide is derived from heat-induced reactions between the amino group of asparagine and the carbonyl group of reducing sugars during baking and frying. Corresponding chromatographic methods are used to determine various structural groups present during this process. Gas chromatography (GC)–mass spectrometry (MS) and liquid chromatography with tandem mass spectrometry (LC–MS/MS) analysis are both acknowledged as the major useful and authoritative methods for the acrylamide determination and other chromatographic methods are also briefly introduced. The aim of this review is to summarize the state-of-the-art about the occurrence, analytical methods, and extraction and clean-up procedures of acrylamide. Special attention is given to chromatographic techniques applied for the occurrence and determination of acrylamide.

Reversed-phase high-performance liquid chromatography (RP-HPLC) with ultraviolet diode array detection (UV-DAD) was used for the simultaneous determination of four flavone C-glucosides, i.e. orientin, homoorientin, vitexin and isovitexin in several food systems fortified by the antioxidant of bamboo leaves (AOB), such as high temperature sterilized milk, sunflower seed oil and extruded rice cake for the first time. The method included extraction of flavone C-glucosides from AOB-fortified foods by methanol aqueous solution, deproteinating with saturated lead acetate solution and potassium oxalate, defatting with n-hexane and clean-up by solid-phase extraction (SPE) with Phenomenex C18 cartridges. Analytes were separated with Luna C18 5 μm 250 mm × 4.6 mm column using acetonitrile and 1% (v/v) acetic acid (pH 3.0) as mobile phase. Good results were obtained with respect to repeatability (relative standard deviation (RSD) < 2.2%) and recovery (81.4–91.8%) which fulfilled the requirements defined by European Union (EU) legislation. The total amounts of four flavone C-glucosides were 12.56 μg/100 mL, 881.08 μg/100 mL and 1420.83 μg/100 g dry weight in AOB-fortified sterilized milk, sunflower seed oil and extruded rice cake, respectively. The method was successfully applied to the analysis of flavone C-glucosides in AOB-fortified samples. The optimized procedure could also be referenced for the separation of flavone C-glucosides in other fortified foodstuffs.

An improved method has been developed for the determination of acrylamide in infant powdered milk and baby foods in jars, a particular class of foodstuffs which represent an important source of nutrition for young infants and babies. This method uses isotope dilution liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization and is significantly more sensitive than previous published methods with a limit of quantification estimated at 1 μg kg−1. The new method offers effective sample preparation procedures including defatting with petroleum ether, extraction with aqueous solution of sodium chloride, further liquid–liquid extraction with ethyl acetate and clean-up by solid-phase extraction (SPE) with HLB 200 mg cartridges. The analytical method was well validated and good results were obtained with respect to repeatability (RSD < 5%) and recovery (86–97%) which fulfilled the requirements defined by European Union (EU) legislation. The acrylamide level in infant powdered milk and baby foods in jars were 3.01–9.06 μg kg−1 and 6.80–124.93 μg kg−1, respectively. Especially, this new method is successfully applied to the trace quantification of acrylamide in infant/baby foods, the content of which is less than 10 μg kg−1.

The present study investigated the effect of two natural antioxidants, i.e. antioxidant of bamboo leaves (AOB) and extract of green tea (EGT), on the mitigation and the kinetic behavior of acrylamide in an equimolar asparagine–glucose model system (pH 6.80). The substrates with addition of AOB or EGT were oven-heated at 180 °C under low-moisture conditions and the acrylamide content in final reaction products was quantified by ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS). Results of mitigation effect on the generation of acrylamide showed that both AOB and EGT could effectively reduce the formation of acrylamide and achieve a maximum reduction rate (74.4% for the use of AOB and 74.3% for the use of EGT) when the addition levels of AOB and EGT were both 10−4 mg. Such mitigation effect in the model system was further confirmed by addition of homoorientin and epigallocatechin gallate (EGCG), the representative components in AOB and EGT. To describe the kinetic behavior of acrylamide, a logistic-exponential model was selected among three kinetic model candidates while relative kinetic rate constants were calculated by the Marquardt non-linear regression method. Results indicated that there were significant differences on kinetic parameters (kg and tcg) between AOB/EGT-spiked and non-spiked model system studies, which suggested that addition of AOB or EGT could reduce the formation of acrylamide during the formation-predominant kinetic stage and prolong the formation progress of acrylamide in the low-moisture reaction system. However, such addition method was not able to reduce the acrylamide content during the elimination-predominant kinetic stage of acrylamide.

•Support vector regression model predicts acrylamide formation.•Flavanols and derivatives exhibit dual effects in a low-moisture system.•The inhibition and promotion effects are non-linear and bell-shaped dose-dependent.•Flavanols and derivatives with more phenolic hydroxyls both show greater effects.•Both effects are related to antioxidant changes of low-moisture heating products.This study investigated the effect of flavanols and their derivatives on acrylamide formation under low-moisture conditions via prediction using the support vector regression (SVR) approach. Acrylamide was generated in a potato-based equimolar asparagine–reducing sugar model system through oven heating. Both positive and negative effects were observed when the flavonoid treatment ranged 1–10,000 μmol/L. Flavanols and derivatives (100 μmol/L) suppress the acrylamide formation within a range of 59.9–78.2%, while their maximal promotion effects ranged from 2.15-fold to 2.84-fold for the control at a concentration of 10,000 μmol/L. The correlations between inhibition rates and changes in Trolox-equivalent antioxidant capacity (ΔTEAC) (RTEAC-DPPH = 0.878, RTEAC-ABTS = 0.882, RTEAC-FRAP = 0.871) were better than promotion rates (RTEAC-DPPH = 0.815, RTEAC-ABTS = 0.749, RTEAC-FRAP = 0.841). Using ΔTEAC as variables, an optimized SVR model could robustly serve as a new predictive tool for estimating the effect (R: 0.783–0.880), the fitting performance of which was slightly better than that of multiple linear regression model (R: 0.754–0.880).