Effect of Angelica dahurica, Angelica dahurica polysaccharides, and imperatorin on free and bound heterocyclic amine generation in roasted beef patties and release profiles of bound heterocyclic amines during in vitro digestion.

This study explored the suppressive activity of Angelica dahurica (AD), AD polysaccharides, and imperatorin on free and bound heterocyclic amine (HA) formation in roast beef patties and release profiles of bound HAs during in vitro digestion. The suppressive effects and potential mechanisms associated with free radical quenching were explored using UPLC-MS/MS, multivariate statistical analysis, and electron paramagnetic resonance (EPR). AD (0.5%, 1.0%, and 1.5%) and imperatorin (0.005%, 0.010%, and 0.015%) showed a dose-dependent inhibition for both free and bound HAs, with AD polysaccharides showing a slight inhibitory capacity. The maximum inhibition of free and bound HAs was 36.31% (1.5% AD) and 35.68% (0.015% imperatorin). The EPR results demonstrated that alkyl radicals and 1O2 were the pivotal free radicals for HAs. Furthermore, AD and imperatorin dose-dependently decreased the level of these radicals. Intriguingly, after in vitro digestion, only AD polysaccharides significantly inhibited the release of bound HAs, with imperatorin even facilitating the release process. In this study, the capacity of the AD polysaccharide to suppress the release of bound HAs and the ability of AD and imperatorin to inhibit free and bound HAs in beef patties were identified for the first time.

Quercetin 3-O-glucuronide-rich lotus leaf extract promotes a Brown-fat-phenotype in C3H10T1/2 mesenchymal stem cells.

Lotus (Nelumbo nucifera Gaertn.) is an aquatic perennial crop planted worldwide and its leaf (also called "He-Ye") has therapeutic effects on obesity. However, whether the underlying mechanism leads to increased energy expenditure by activation of brown adipocytes has not been clarified. Here, murine C3H10T1/2 mesenchymal stem cells (MSCs) were employed to investigate the effects of ethanol extracts from lotus leaf (LLE) on brown adipocytes formation and the underlying molecular mechanisms. The results showed LLE was rich in polyphenols (383.7 mg/g) and flavonoids (178.3 mg/g), with quercetin 3-O-glucuronide (Q3G) the most abundant (128.2 µg/mg). In LLE-treated C3H10T1/2 MSCs, the expressions of lipolytic factors (e.g., ATGL, HSL, and ABHD5) and brown regulators (e.g., Sirt1, PGC-1α, Cidea, and UCP1) were significantly upregulated compared to that in the untreated MSCs. Furthermore, LLE promoted mitochondrial biogenesis and fatty acid ß-oxidation, as evidenced by increases in the expression of Tfam, Cox7A, CoxIV, Cox2, Pparα, and Adrb3. Likewise, enhanced browning and mitochondrial biogenesis were also observed in Q3G-stimulated cells. Importantly, LLE and Q3G induced phosphorylation of AMPK accompanied by a remarkable increase in the brown fat marker UCP1, while pretreatment with Compound C (an AMPK inhibitor) reversed these changes. Moreover, stimulating LLE or Q3G-treated cells with CL316243 (a beta3-AR agonist) increased p-AMPKα/AMPKα ratio and UCP1 protein expression, indicating ß3-AR/AMPK signaling may involve in this process. Collectively, these observations suggested that LLE, especially the component Q3G, stimulates thermogenesis by activating brown adipocytes, which may involve the ß3-AR/AMPK signaling pathway.

Accumulation of Heterocyclic Amines and Advanced Glycation End Products in Various Processing Stages of Plant-Based Burgers by UHPLC-MS/MS.

The accumulation of heterocyclic amines (HAs) and advanced glycation end products (AGEs) during different processing stages was investigated in commercial raw materials to plant-based hamburger meats (PBHMs). Principal component analysis (PCA) was performed to explore the difference between the samples of each processing stage. The total free HA level accumulated from 4.74-6.63 ng/g in raw plant proteins to 5.81-20.23 ng/g in textured vegetable proteins after extrusion. The concentration of MeAαC increased from 29.23 ± 3.50 to 59.44 ± 0.26 ng/g, resulting in an accumulation of the total protein-bound HAs after cooking at 160 °C for 6 min, but the MeAαC content decreased to 42.26 ± 0.11 ng/g when the heating duration was prolonged to 12 min. An evident accumulation of AGEs was observed during the thermal home-processing of PBHM. The total levels for all HAs were 381.30 and 160.30 ng/g in roast beef patty (RBP) and PBHM, respectively, with RBP having a better amino acid composition pattern. These results may reveal the target processing stage, which should be paid attention to for the inhibition of Maillard reaction derivative harmful products (MRDHPs) in plant-based meat products.

Synergistic Inhibitory Effects of Selected Amino Acids on the Formation of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in both Benzaldehyde- and Phenylacetaldehyde-Creatinine Model Systems.

Although various inhibitors have been employed to react with phenylacetaldehyde to form adducts and thus interrupt the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), high concentrations of PhIP remain in the final system. It remains unknown whether other critical aldehyde or ketone intermediates are involved in the generation of PhIP, and scavenging these reactive carbonyls simultaneously may achieve higher inhibitory efficiency of PhIP. In this study, reactive carbonyls in a glucose/creatinine/phenylalanine model system were first identified by gas chromatography-mass spectrometry (GC-MS), and then the single and synergistic effects of nonprecursor amino acids (cysteine, methionine, proline, histidine, arginine, and leucine) on scavenging reactive carbonyls were investigated to find out promising combination partners. The obtained results showed that the concentrations of benzaldehyde and phenylacetaldehyde in the glucose/creatinine/phenylalanine model system reached 0.49 ± 0.01 and 6.22 ± 0.21 µg/mL, respectively. Heating these carbonyl compounds in the presence of creatinine resulted in the quantity of PhIP produced increasing linearly with the added quantity of benzaldehyde (r = 0.9733, P = 0.0002) and phenylacetaldehyde (r = 0.9746, P = 0.0002), indicating that both compounds are key intermediates for PhIP generation. Among the investigated amino acids, histidine produced the maximum inhibition of PhIP formation (78-99%) in the benzaldehyde/creatinine model system, and proline produced the maximum inhibition of PhIP formation (13-97%) in the phenylacetaldehyde/creatinine model system, where both compounds decreased PhIP formation in a dose-dependent manner. Histidine in combination with proline enhanced the inhibitory effect against PhIP formation at a low addition level, where the highest inhibitory efficiency was obtained using a 1:3 mass ratio of histidine to proline (2 mg/mL in total), reducing PhIP formation by 96%. These findings suggest that histidine-proline combinations can scavenge benzaldehyde and phenylacetaldehyde simultaneously, enhancing the suppression of PhIP formation.

Metabolic perturbations and health impact from exposure to a combination of multiple harmful Maillard reaction products on Sprague-Dawley rats.

The present study aimed to investigate the metabolic perturbations and health impact of the co-accumulation of Maillard reaction products (MRPs), including acrylamide, harmane, and Nε-(carboxymethyl)lysine (CML), via serum biochemical and histopathological examinations as well as metabolomic analysis. Sprague-Dawley rats were treated with acrylamide (2 mg per kg body weight [bw]), harmane (1 mg per kg bw), CML (2 mg per kg bw), and combinations of these MRPs. Harmane did not cause adverse effects on the health of rats, whereas acrylamide and CML resulted in significantly (P < 0.05) decreased insulin sensitivity (HOMA-IR > 1), increased oxidative stress levels, and pathological injuries to the pancreas, liver, and gastrocnemius. Owing to the antioxidant and anti-diabetic activities of harmane, the effects of the combination of the MRPs on oxidative stress levels, blood glucose metabolism, and pathological injuries to the pancreas and gastrocnemius were relieved. However, new health problems, including pathological injury of the kidneys and increased cancer risk, were observed. Metabolomic analysis revealed that this may be related to the effects of MRPs on the arginine biosynthesis pathway, which resulted in the abnormal metabolism of fumaric acid and the tricarboxylic acid cycle. These results indicated that the mechanisms of the combined effect of MRPs and their effects on health cannot be predicted from the effects of individual MRPs.

Unraveling inhibitory effects of Alpinia officinarum Hance and curcumin on methylimidazole and acrylamide in cookies and possible pathways revealed by electron paramagnetic resonance.

The synchronous mitigative effects of Alpinia officinarum Hance (AOH) and curcumin on the generation of methylimidazole and acrylamide in cookies were investigated. Possible mechanisms related to quenching free radicals, reducing lipid oxidation and eliminating carbonyl intermediates were explored by electron paramagnetic resonance (EPR) and HPLC. The total methylimidazole and acrylamide contents raised with an increase in heating temperature and time, and reached a maximum at 200 °C for 11 min. AOH and curcumin reduced methylimidazole and acrylamide simultaneously; the maximum inhibition rates for methylimidazole and acrylamide were 51.55% (0.015% curcumin) and 73.66% (1.5% AOH). Alkyl free radicals and HO· were proved to be the critical free radicals for methylimidazole and acrylamide, AOH and curcumin quenched these radicals in a dose-dependent manner. The lipid oxidation, active carbonyl intermediates glyoxal, methylglyoxal, and acrylaldehyde were also reduced by AOH and curcumin simultaneously, which may be resulted from the quenching of free radicals.

Release profiles of beef myofibril protein-bound heterocyclic amines and effects of dietary components on in vitro digestion.

The release profiles of protein-bound heterocyclic amines (HAs) in beef myofibril protein (MP) model systems were investigated after different enzyme dosage or stages of digestion were simulated in vitro. The effects of co-digestion of pepper, apple, and onion with bound HAs on the release rate of bound HAs were also explored. The results showed that, at a constant ratio of substrate to enzyme, the bound HAs were not completely converted into free HAs. Most bound HAs were enzymatically released after intestinal digestion, resulting in a significant increase of free HAs. ß-Carbolines were more easily hydrolyzed compared with other HAs. Pepper, apple, and onion promoted the release of bound HAs, and the total free HAs was increased 20.44, 41.56, and 33.28 times by 1.0% pepper, 150% apple, and 150% onion. The sensitivity of HAs to different additives was variable, with the most significant changes observed in harman and norharman.

Mitigative capacity of Kaempferia galanga L. and kaempferol on heterocyclic amines and advanced glycation end products in roasted beef patties and related mechanistic analysis by density functional theory.

The capacity of Kaempferia galanga L. (KG) and kaempferol to mitigate the formation of free and bound heterocyclic amines (HAs) and advanced glycation end products (AGEs) in roast beef patties was explored. Electron paramagnetic resonance (EPR) and density functional theory (DFT) were used to reveal the possible mechanisms involved in quenching the free radicals. KG (0.5%, 1.0%, 1.5%) and kaempferol (0.005%, 0.010%, 0.015%) reduced HAs and AGEs in a dose-dependent manner. Alkyl free radical, HOO·, and 1O2 were critical to the formation of HAs, and 1O2 was pivotal to AGEs. They were quenched by KG and kaempferol in a dose-dependent manner. DFT indicated that the 3-OH group of kaempferol was most pivotal and quenched the HOO· mainly via H-atom transfer. The active carbonyl intermediates phenylacetaldehyde, glyoxal, and methylglyoxal can also be reduced by KG and kaempferol in a dose-dependent manner, which may be result from the quenching of free radicals.

Release mechanism between sarcoplasmic protein-bound and free heterocyclic amines and the effects of dietary additives using an in-vitro digestion model.

In this study, the release mechanism between free and sarcoplasmic protein-bound heterocyclic amines (HAs) in an in-vitro digestion model were investigated by comparing changes in the amount of HAs between groups with different enzyme dosages and at different digestion stages. The effects of the addition of onions, peppers, and apples on the release mechanism were also studied. We found that bound HAs cannot be completely converted to free HAs under normal enzyme dosages and that a significant increase in HAs occurred in the intestines. The release rate of bound HAs was 5.99%-43.84%, and the total release rate of HAs was 36.67%. Furthermore, the release rate of ß-carbolines was the highest (34.41%-43.84%). The addition of onions, peppers, and apples significantly increased the number of free HAs, with growth rates reaching 56.06%, 43.43%, and 54.44%, respectively. These additives mainly promoted the generation of free harman and norharman.

Processed potatoes intake and risk of type 2 diabetes: a systematic review and meta-analysis of nine prospective cohort studies.

The current cohort study shows the inconsistent association between potato consumption and the risk of type 2 diabetes mellitus (T2DM). Therefore, we conducted a systematic review and dose-response meta-analysis of published prospective cohort studies to quantitatively estimate this association. We searched PubMed, Embase, MEDLINE, Web of Knowledge, and the Cochrane Library up to September 2019 for all published articles. Seven of the articles reported nine cohort studies with 383,211 participants, with 23,189 T2DM cases that met the inclusion criteria and were included for our analysis. The results of random effects model pooled relative risk (RR) showed an association between potato intake and the risk of T2DM (pooled RR = 1.13, 95% CI: 1.02-1.26, p > 0.01). In the subgroup analysis, French fries, long-term follow-up, large sample size, and high-quality studies were associated with an increased T2DM risk. Further, a linear dose-response analysis indicated that 100 g/day increment of total potato (RR = 1.05, 95% CI: 1.02-1.08) and French fries (RR = 1.10, 95% CI: 1.07-1.14) consumption may increase the risk of T2DM by 5% and 10%, respectively. Our meta-analysis showed that potato consumption, especially French fries consumption, was associated with increased T2DM risk.

The inhibitory effects of yellow mustard (Brassica juncea) and its characteristic pungent ingredient allyl isothiocyanate (AITC) on PhIP formation: Focused on the inhibitory pathways of AITC.

The effects of yellow mustard (Brassica juncea) and its characteristic component allyl isothiocyanate (AITC) on the formation of 2-amino-y1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) in roast beef patties and PhIP-producing model systems were investigated. The probable inhibitory pathways of AITC on PhIP formation were also investigated in the model systems. The results revealed that yellow mustard and AITC can reduce PhIP in roast beef patties up to 41.7% and 60.2%, respectively. The rate of inhibition of PhIP also reached 64.8% in the PhIP-producing model systems. Furthermore, AITC could react with creatinine and phenylalanine in the model system (reducing each by 15.0%%-23.7% and 31.4%-55.8%, respectively). AITC showed the great scavenging ability of free radical scavenging (up to 64.2%). AITC also reacted with the intermediate phenylacetaldehyde (16.9%-30.8%) and the final product PhIP (7.0%-24.6%). It is speculated that AITC can inhibit PhIP through competitive inhibition of precursors, blocking intermediate, free radical scavenging, and direct elimination of PhIP.

Simultaneous determination of the PhIP-proline adduct and related precursors by UPLC-MS/MS for confirmation of direct elimination of PhIP by proline.

The effect and elimination pathway of proline on reducing PhIP and the effect of processing temperature, duration, and proline addition on the PhIP-proline adduct and its precursors were investigated. The results have demonstrated that PhIP and proline could condense to produce the adduct by direct heating, which could also be detected in the PhIP-producing model system and in beef patties with proline. The analytical method was optimized and has a good limit of detection (0.006-73 ng/mL), limit of quantification (0.021-245 ng/mL), recovery rate (about 80%-120%), and precision (below 15%). A high dose of proline (5.0%, w/w) promoted the formation of the adduct and reduction of PhIP; long heating duration and high temperature were not conducive to the formation of the adduct in beef patties. With increased addition of proline, creatine and creatinine decreased in a dose-dependent manner; phenylalanine and glucose did not show the same trend.

Assessment the influence of salt and polyphosphate on protein oxidation and Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine formation in roasted beef patties.

The impact of NaCl and tripolyphosphate (TPP)/pyrophosphate (PP) on protein oxidation and Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) formation in roasted beef patties was investigated. The content of CML and CEL in patties treated with salts was approximately 1.1-1.7 and 1.2-3.2 times higher than that of the control samples, respectively. An increase in salt content caused higher oxidation of tryptophan and protein carbonylation with a decrease in Schiff bases (P < 0.05) and a slight decrease in lipid oxidation (P < 0.05). Significant correlations (P < 0.05) between CML, CEL, and protein oxidation measurements was found. The higher salts content, causing less cooking loss and higher moisture content, significantly correlated (P < 0.05) with CML, CEL content, and protein oxidation of the patties. The increase in CML and CEL content and protein oxidation in roasted patties with salts might be related to the pro-oxidation of salts, and also partly due to the temperature changes caused by the water-holding capacity of salts.

Generation of Sarcoplasmic and Myofibrillar Protein-Bound Heterocyclic Amines in Chemical Model Systems under Different Heating Temperatures and Durations.

The protein-bound heterocyclic amines (HAs) and their generation pattern are still unclear. Generation of sarcoplasmic (SP)- and myofibrillar protein (MP)-bound HAs under different heating conditions was investigated in chemical model systems using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that eight types (387.01 ± 37.50 ng/100 mg MP) and six types (452.06 ± 33.32 ng/100 mg SP) of protein-bound HAs were generated at 180 °C/40 min, respectively. MP system can generate either more types or amounts of bound HAs at 90-150 °C. The main categories of protein-bound HAs in two systems were almost the same: ß-carbolines, α-carbolines, pyridines, and quinolines, among which nonpolar HAs dominated by ß-carbolines (at least 69.2%) are most easily formed. Principal component analysis revealed no significant difference in bound HAs at 90-120 °C but showed a significant increase at 150-180 °C. The higher the temperature, the more significant the differences between samples with different durations at the same temperature.

Metabolic changes from exposure to harmful Maillard reaction products and high-fat diet on Sprague-Dawley rats.

Rats were fed a high-fat diet and treated with acrylamide (21 mg/kg BW), harmane (7 mg/kg BW), NƐ-(carboxymethyl)lysine (CML; 10 mg/kg BW), or the co-accumulation of the three chemicals to investigate the effects of harmful Maillard reaction products (MRPs) generated by heat processing of potatoes. Damage to the liver, kidney, gastrocnemius, and nervous system was confirmed by serum biochemical testing and histopathology examination after six weeks of feeding. Serum metabolomic analysis was performed using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). The metabolites detected by GC-TOF-MS were processed using chemometric techniques, and the results were evaluated using a t-test (p < 0.05) and calculated variable importance in projection (VIP) value (>1.5). Significant changes (increase or decrease) were identified in 13 metabolites, compared with the control. These metabolites were gluconolactone, tyrosol, 5-hydroxytryptophan, erythrose 4-phosphate, quinolinic acid, 2-ketobutyric acid, tyrosine, 3-hydroxy-3-methylglutaric acid, desaminotyrosine, L-cysteine, ribonic acid, cysteamine, and tryptophan. Among these, cysteamine and tryptophan are metabolites unique to the co-accumulation of all three test compounds in the treated rats. This study demonstrates that these harmful MRPs exert toxic effects on the liver, kidney, and nervous system via different metabolic pathways. Moreover, co-accumulation of these harmful MRPs caused differing toxic effects and changes in a variety of metabolites. These changes may contribute to the interaction of those harmful MRPs and also affect toxicity at the metabolic level.

Western Dietary Patterns, Foods, and Risk of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Prospective Cohort Studies.

An increasing number of epidemiological studies suggest that adherence to Western dietary patterns (WDPs) is associated with risk of gestational diabetes mellitus (GDM), but results remain inconsistent. Therefore, we conducted a systematic review and meta-analysis of the effect of WDPs and typical Western dietary foods on GDM. A literature search was performed in PubMed, Embase, Web of Knowledge, and the Cochrane Library up to December 2019. Cohort studies investigating the combined associations of WDPs with incidence of GDM were included. Reviewers were paired, and they independently reviewed and assessed studies, extracted data, and evaluated study quality. Pooled HRs were calculated using random-effects models. Heterogeneity and publication bias tests were also conducted. Twenty-one prospective cohort studies with 191,589 participants, including 12,331 women with GDM, were included in our analysis. The pooled risk ratio (RR) of WDPs was 1.52 (95% CI: 1.21, 1.91), indicating a significant association with GDM risk in Western countries. Potatoes (pooled RR: 1.12; 95% CI: 0.93, 1.35) showed a nonsignificant (P > 0.05) relation to GDM risk. However, consumption of animal meat (pooled RR: 1.35; 95% CI: 1.16, 1.57) and fast food (pooled RR: 1.75; 95% CI: 1.41, 2.19) showed a positive association with the risk of developing GDM. Subgroup analysis demonstrated that the consumption of red meat and processed red meat increased the risk of GDM more than either poultry or fish intake. Our study provides further evidence for understanding the relation between dietary factors and increased GDM risk and contributes to reducing the incidence of GDM through healthy diets.

The Effect of Exogenous Free Nε-(Carboxymethyl)Lysine on Diabetic-Model Goto-Kakizaki Rats: Metabolomics Analysis in Serum and Urine.

The current study investigated the effects of exogenous free Nε-(carboxymethyl) lysine (CML) from daily diet on diabetic-model Goto-Kakizaki rats. Rats were fed with free CML (2 mg/kg body weight) for 8 weeks, then metabolomics evaluation was performed on serum and urine, and biochemical and histopathologic examinations were conducted to verify metabolic results. Diabetic rats fed with free CML showed significantly increased (P < 0.05) fasting blood glucose (11.1 ± 1.07 mmol/L) and homeostasis model assessment values (homeostatic model assessment of insulin resistance: 16.0 ± 4.24; homeostatic model assessment of beta cell function: 6.66 ± 2.01; and modified beta cell function index: 11.5 ± 2.66) and a significantly altered (P < 0.05) oxidative stress level when compared to the control group. Serum and urine metabolomics showed a significantly altered (P < 0.05) level of aminomalonic acid, 2-oxoadipic acid, l-malic acid, ß-alanine, 2-oxoglutaric acid, d-threitol, N-acetyl-leucine, methylmalonic acid, l-cysteine, thymine, glycine, l-alanine, 4-hydroxyproline, hexadecane, succinic acid, l-ornithine, gluconolactone, maleic acid, l-lactate, tryptophan, 5-methoxyindoleacetate, γ-aminobutyric acid, homoserine, maltose, and quinolinic acid. Our results indicated that these metabolites altered by exposure to exogenous free CML were mapped to the citric acid cycle and amino acid and carbohydrate metabolism, which might be related to increased progression of diabetes and some other diabetic complications, including diabetic brain and neurological diseases, retinopathy, nephropathy, and impaired wound healing.

Simultaneous generation of acrylamide, ß-carboline heterocyclic amines and advanced glycation ends products in an aqueous Maillard reaction model system.

The simultaneous formation of acrylamide; ß-carboline heterocyclic amines (HAs): harmane and norharmane; and advanced glycation end products (AGEs) (Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL)) was analyzed based on an aqueous model system. The model systems included lysine-glucose (Lys/Glu), asparagine-glucose (Asn/Glu), tryptophan-glucose (Trp/Glu), and a mixture of these amino acids (Mix/Glu). Only AGEs were generated when heated at 100 °C, Asn and Trp competed with Lys for glucose and methylglyoxal (MGO), and glyoxal (GO) decreased AGE content. The k value of CML, CEL, and acrylamide decreased when heated at 130 °C, whereas that of harmane increased in the Mix/Glu, owing to the competition between Lys and Asn for glucose, GO, and MGO. Harmane preferably formed via the Pictet-Spengler condensation between Trp and acetaldehyde, which further reduced acrylamide formation via the acrolein pathway.

Non-precursors amino acids can inhibit ß-carbolines through free radical scavenging pathways and competitive inhibition in roast beef patties and model food systems.

The aim of this study was to investigate the inhibitory effect of non-precursors amino acids (histidine, leucine, proline and methionine) which have advantages of safety, inexpensiveness and high standardization on the formation of ß-carbolines in roast beef patties and glucose/creatine/creatinine/tryptophan model system, and the possible pathway of inhibition by monitoring the scavenging of free radicals by electron paramagnetic resonance (EPR) spectroscopy and the consumption of tryptophan by HPLC in a glucose/tryptophan model system. Almost all amino acids can inhibit ß-carbolines in roast beef patties (up to 80.62%) and model system (up to 67.01%). Histidine showed an excellent alkyl radical scavenging ability (up to 82.59%) and a highly competitive inhibition ability (up to 65.60%) against ß-carbolines generation. The corresponding abilities of leucine and methionine were less remarkable. Proline could only suppress ß-carbolines through competitive inhibition. The results could shed light on the reduction of ß-carbolines during meat processing.

Effects of amides from pungent spices on the free and protein-bound heterocyclic amine profiles of roast beef patties by UPLC-MS/MS and multivariate statistical analysis.

Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), principal component analysis (PCA) and orthogonal projection to latent structure-discriminant analysis (OPLS-DA) were used to explore the effects of the amide components (capsaicin, sanshoamide, piperine) of pungent spices widely consumed in China (chili pepper, Sichuan pepper and black pepper) on the profiles of 17 heterocyclic amines (HAs) from seven categories in roast beef patties. Four groups of HAs were detected and quantified in both free and protein-bound states: imidazopyridines (DMIP, 1,5,6-TMIP), imidazoquinolines (MeIQ), imidazoquinoxalines (IQx, 4,8-MeIQx) and ß-carbolines (norharman, harman). Notably, different amounts of added capsaicin, sanshoamide and piperine had significant inhibitory effects on free DMIP, MeIQx, 4,8-DiMeIQx and harman formation in roast beef patties. Additionally, all three amide components significantly inhibited the formation of protein-bound MeIQ, 4,8-DiMeIQx, harman, norharman and MeAαC. In general, amide ingredients inhibited the formation of ß-carbolines and total HAs by approximately 70%. Furthermore, the addition of 0.005% and 0.010% capsaicin suppressed imidazopyridine formation by 44% and 35%, respectively, and 0.015% capsaicin inhibited imdazoquinoxaline formation by 33%. These findings shed light on the effects of amide ingredients on the formation of free and protein-bound HAs.