Inhibitory effect of Chrysanthemum morifolium flower extract on the formation of heterocyclic amines in goat meat patties cooked by various cooking methods and temperatures

Edible flowers' flavor, safety and their utilization as functional ingredients: a review

Edible flowers have been a part of various traditional dishes around the world. The consumption of edible flowers has been rising due to their nutritional properties, minerals, antioxidants, phenolic and bioactive compounds, therapeutic properties, and also aesthetic appeal. Along with the nutrients, some antinutrients and other chemical, biological, microbial hazards may render flowers non-edible. The components responsible for flavor in edible flowers are different from species to species. Bioactive compounds play a major role in sensory attributes of edible flowers. Various functional food products such as bakery items, dairy products, beverages etc. can be developed by incorporating edible flowers. Understanding various properties of edible flowers, their safe consumption, and utilization as functional ingredients in the development of various food products is not only useful but also necessary to popularize edible flowers for novel applications. It is important for food safety experts to recognize and reduce the risks connected with edible flowers.

Graphical abstract

A comprehensive review of structure-activity relationships and effect mechanisms of polyphenols on heterocyclic aromatic amines formation in thermal-processed food

Heterocyclic aromatic amines (HAAs) are potent carcinogenic substances mainly generated in thermal-processed food. Natural polyphenols have been widely used for inhibiting the formation of HAAs, whereas the effect of natural polyphenols on HAAs formation is complex and the mechanisms are far from being clearly elucidated. In order to clarify the comprehensive effect of polyphenols on HAAs, this review focused on the structure-activity relationships and effect mechanisms of polyphenols on the formation of HAAs. In addition, the effects of polyphenols on HAAs toxicity were also first reviewed from cell, gene, protein, and animal aspects. An overview of the effect of polyphenol structures such as parent ring and exocyclic group on the mitigation of HAAs was emphasized, aiming to provide some valuable information for understanding their effect mechanism. The HAAs formation is inhibited by natural polyphenols in a dose-dependent manner largely through eliminating free radicals and binding precursors and intermediates. The inhibitory effect was probably affected by the quantity and position of hydroxyl groups in the aromatic rings, and polyphenols with m-hydroxyl group in the aromatic ring had the stronger inhibitory effect. However, the presence of other substituents and excessive hydroxyl groups in natural polyphenols might mitigate the inhibitory effect and even promote the formation of HAAs. This review can provide theoretical reference for effectively controlling the formation of HAAs in thermal-processed food by natural polyphenols and reducing their harm to human health.

Formation and Reduction of Toxic Compounds Derived from the Maillard Reaction During the Thermal Processing of Different Food Matrices

Advanced glycation end products (AGEs), heterocyclic aromatic amines (HAAs), acrylamide (AA), 5-hydroxymethylfurfural (5-HMF), and polycyclic aromatic hydrocarbons (PAHs) are toxic substances that are produced in certain foods during thermal processing by using common high-temperature unit operations such as frying, baking, roasting, grill cooking, extrusion, among others. Understanding the formation pathways of these potential risk factors, which can cause cancer or contribute to the development of many chronic diseases in humans, is crucial for reducing their occurrence in thermally processed foods. During thermal processing, food rich in carbohydrates, proteins, and lipids undergoes a crucial Maillard reaction, leading to the production of highly active carbonyl compounds. These compounds then react with other substances to form harmful substances, which ultimately affect negatively the health of the human body. Although these toxic compounds differ in various forms of formation, they all partake in the common Maillard pathway. This review primarily summarizes the occurrence, formation pathways, and reduction measures of common toxic compounds during the thermal processing of food, based on independent studies for each specific contaminant in its corresponding food matrix. Finally, it provides several approaches for the simultaneous reduction of multiple toxic compounds.

Effects of Çemen pastes prepared in different formulations on physicochemical, microbiological, and textural properties of beef hamburger patties during refrigerated storage

This study aimed to investigate the effects of çemen pastes prepared in different formulations on physicochemical, microbiological, and textural properties of hamburgers during refrigerated storage (4°C; 60 d). Çemen pastes were produced by using different combination doses of fenugreek seed flour, sweet red pepper, and garlic powder. As a result of çemen paste usage in hamburgers, cooking losses and dimensional shrinkage decreased, whereas moisture and fat retention ratios increased (p < .05). The hardness, gumminess, and chewiness values of hamburgers containing çemen paste were generally lower than those of control (p < .05). Çemen paste addition to hamburgers generally did not cause a difference in terms of microbial growth and moisture, fat and ash contents. Protein contents of hamburgers containing çemen paste or breadcrumbs were generally higher than that of control (p < .05). Çemen paste usage in hamburgers generally decreased the L* values and increased the b* values (p < .05). In general, addition of 3.5% or higher doses of both sweet red pepper and garlic powder caused higher a* values in hamburger patties (p < .05). Lower oxidation levels were generally observed in hamburgers containing 3% or lower doses of fenugreek seed flour and 4.5% of garlic powder in çemen paste (p < .05). It was concluded that çemen paste usage in hamburger patty processing has the potential to improve the quality characteristics and delay oxidative changes.

Attenuation of heterocyclic amine formation and lipid and protein oxidation in air-fried fish fillets by marination with selected legume seed extracts

The present study aimed to investigate the potential of marination with extracts prepared from five legume seeds on heterocyclic amine (HA) formation in chemical models and air-fried fish fillets. In terms of total HAs, clove seed marinade (CSM) was found with the maximum inhibitory effect (43.98 %), followed by tamarind seed marinade (TSM) (40.26 %), fenugreek seed marinade (FSM) (39.07 %), acacia seed marinade (ASM) (37.99 %), and black bean seed marinade (BSM) (29.95 %). In particular, at higher levels (3 mg/mL, 4 mg/mL), CSM and FSM achieved the greatest mitigating effect against 4,8-DiMeIQx, 7,8-DiMeIQx, and MeIQx. Furthermore, all marinades were effective in lowering thiobarbituric acid-reactive substances (TBARS) and carbonyl and retaining thiol content relative to the control. PCA analysis revealed that higher levels of ASM, BSM, and FSM had better mitigating effect against IQ and MeIQx formation, whereas Pearson correlation shows that TBARS and carbonyl were positively correlated to HAs.

The construction of garlic diallyl disulfide nano-emulsions and their effect on the physicochemical properties and heterocyclic aromatic amines formation in roasted pork

Garlic diallyl disulfide (DAD) nano-emulsions consisting of soy proteins were constructed, and their effects on physicochemical properties and heterocyclic aromatic amines (HAAs) formation in roasted pork were investigated. DAD was well encapsulated by soy proteins with a mean particle of 400-700 nm. Applying DAD nano-emulsions to pork patties significantly altered the color and texture of roasted pork, with a slight increase in brightness and decreases in redness and yellowness. The flavor determination demonstrated that sulfur-containing compound levels in encapsulated DAD were significantly reduced, particularly 7S group compounds, indicating an effective shielding effect on the irritating odor of garlic oil by protein. The levels of three HAAs (MeIQx, PhIP, and Harman) were significantly reduced by DAD nano-emulsion exposure (51.84 %, 76.80 %, and 48.70 %, respectively). This study provides a new method for inhibiting HAA formation and improving the sensory qualities of meat products.

The Effect of Direct and Indirect Barbecue Cooking on Polycyclic Aromatic Hydrocarbon Formation and Beef Quality

Herein, the effect of direct and indirect barbecue cooking processes, including different cooking degrees (medium and well done), on the formation of polycyclic aromatic hydrocarbons (PAHs) and on certain quality parameters (water content, cooking loss, pH, lipid oxidation) of beef meat was examined. While no significant effect (p > 0.05) of the cooking method was detected on the water content, cooking loss, ∑PAH4 [the sum of benzo[a]pyrene (BaP), benzo[a]anthracene (BaA), chrysen (Chry), and benzo[b]fluoranthene (BbF)], and ∑PAH8 [the sum of BaP, BaA, Chry, benzo[k]fluoranthene (BkF), dibenzo[a,h]anthracene (DahA), benzo[g,h,i]perylene (Bghip), and indeno [1,2,3-cd]pyrene (IncdP)] content, it was determined that it had a significant effect on pH (p < 0.05) and lipid oxidation (TBARS, p < 0.01). While the cooking degree did not have a significant effect (p > 0.05) on the TBARS value, it had a significant effect (p < 0.05) on the water content and pH value, and a very significant effect (p < 0.01) on the cooking loss. While BaA and BaP compounds were detected in all barbecued samples, the DahA compound could not be detected in any of the samples. Varying levels of BaA (up to 5.62 ng/g), Chry (up to 0.43 ng/g), BbF (LOD-..-LOQ), BkF (LOD-..-LOQ), BaP (up to 0.49 ng/g), BghiP (up to 0.82 ng/g), and IncdP (up to 4.99 ng/g) compounds were determined in the samples. While the ∑PAH4 contents varied between 0.71 and 6.35 ng/g, the ∑PAH8 contents varied between 1.12 and 11.34 ng/g. While the increase in cooking level did not affect the ∑PAH4 content, it caused a significant increase in the ∑PAH8 content. The highest BaP (0.49 ng/g), ∑PAH4 (6.35 ng/g), and ∑PAH8 (11.34 ng/g) contents were detected in the meat samples that were well cooked on the barbecue by the direct method. The results have proven that PAHs are formed at varying levels in both meat samples cooked on the barbecue by the direct method and the indirect method. On the other hand, it has been determined that even if 100 g of the meat with the highest BaP and ∑PAH4 content is eaten, the exposure amount remains far below the limit values specified for PAHs. However, paying close attention to the barbecue cooking process is still recommended.

Advantageous Effects of Sumac Usage in Meatball Preparation on Various Quality Criteria and Formation of Heterocyclic Aromatic Amines

Heterocyclic aromatic amines (HAAs) are mutagenic/carcinogenic compounds that can be formed during the cooking process of proteinaceous foods such as meat. Therefore, it is needed to inhibit or reduce their formations in cooked meats. Hereby, the effects of sumac usage (0.5%, w/w) in beef meatball preparation on the formation of HAAs and some quality parameters (water, pH, cooking loss, and lipid oxidation values) of meatballs cooked at 150 and 250 °C were investigated. The sumac usage caused a reduction in pH (p < 0.01), cooking loss (p < 0.05), lipid oxidation level (TBARS, p < 0.01), and total HAA amount (p < 0.05) of the samples. In addition, increasing the cooking temperature significantly decreased the pH value (p < 0.01) and increased the cooking loss (p < 0.05) of the samples. Only one compound, 2-amino-3,8-dimethylimidazo [4,5-ƒ]quinoxaline (MeIQx), from nine different HAAs studied in this study, could be determined, and the levels of the other HAAs studied were lower than their detection limits. On the other hand, MeIQx was not detected in the samples cooked at 150 °C, it was only determined in the control group samples cooked at 250 °C. The sumac usage completely inhibited MeIQx formation in the samples. Due to its positive effect on cooking loss value, lipid oxidation level, and MeIQx formation, it can be suggested to use sumac powder in meatball preparation.

Application of High-Performance Liquid Chromatography with Fluorescence Detection for Non-Polar Heterocyclic Aromatic Amines and Acridine Derivatives Determination in Pork Loin Roasted in a Roasting Bag

Heat treatment of meat can lead to the formation of carcinogenic organic compounds. The influence of dried fruits on the formation of non-polar heterocyclic aromatic amines (carbolines) and nitrogen derivatives of polycyclic aromatic hydrocarbons (azaarenes) in roasted pork loin was elucidated. Two hundred grams of fruit per 1 kg of meat were used as stuffing. Carbolines, derivatives of pyridoimidazole and pyridoindole, and azaarenes (benzoacridines and dibenzoacridines) were determined by means of high-performance liquid chromatography with fluorescence detection. The total concentration of six δ-, γ- and α-carbolines in roasted pork loin was 1.3 ng/g. This content decreased by 64%, 58%, and 54% in pork loin stuffed with prunes, apricots, and cranberries, respectively. Concentrations of β-carbolines (harmane and norharmane) increased under the influence of added fruits. The norharmane content increased the most, from 2.2 ng/g in the control sample to 12.3 ng/g in meat prepared with cranberries. The harmane content increased from 1.0 ng/g to 3.6 ng/g in meat with prunes. The total concentration of azaarenes (two benzoacridines and dibenzo[a,c]acridine), which was close to 0.1 ng/g, decreased in dishes with prunes and apricots by 54% and 12%, respectively. Azaarenes were not found in samples of meat stuffed with cranberries.

Perilla frutescens seed meal as a fat substitute mitigates heterocyclic amine formation and protein oxidation and improves fatty acid profile of pan-fried chicken patties

Fatty acid profile, protein and fatty acid oxidation and flavor profile of pan-fried chicken patties formulated with various levels of Perilla frutescens seed meal (PSM) as a fat substitute was investigated in this study. The formation of heterocyclic amines (HCAs) in the chicken patties was also evaluated. The results showed that pan-fried patties formulated with 20% PSM (PSM4) had the highest ranges of oleic acid and ΣMUFA content and ΣPUFA/ΣSFA ratio. Low to medium levels of PSM (PSM1, 2, and 3 corresponding to 5, 10, and 15% of PSM, respectively) reduced the content of lipid peroxidation products, while high level (PSM4) increased it. All levels of PSM were also found to be effective against elevation in carbonyl content relative to the control. Moreover, the PSM effectively inhibited HCA formation in the chicken patties. The total contents of HCAs in PSM1, PSM2, PSM3, and PSM4 samples were significantly (P < 0.05) lower than that of the control sample, corresponding to 31.9, 46.1, 57.2, and 44.8% inhibition, respectively. PSM4, however, had no or very little effect on the formation of PhIP, 4,8-DiMeIQx and AαC, despite a strong inhibitory effect on MeIQx formation. These findings not only support the promising potential of PSM for application as a fat substitute to improve the fatty acid profile and reduce the content of harmful by-products in heat-processed chicken, but also highlight that appropriate addition level is a critical factor in optimizing the functional capacity of this natural agent.

Effect of Different Roasting Conditions and Coreopsis Extract on Heterocyclic Amine Formation in Roast Lamb Products

ABSTRACT

Heterocyclic amines (HCAs), which are known carcinogens in thermally processed foods, were investigated in roast lamb patties under various time and temperature conditions. HCAs in lamb products roasted at some temperatures increased with roasting time. An exponential model with a time factor fit well for the production of HCAs. The mean pH and cooking loss at various temperatures were also determined. The mean pH decreased as the temperature increased. Coreopsis extract was added to lamb patties roasted at 230°C for 15 min per side. The amount of coreopsis extract added had a significant effect on HCA development. A weak positive relationship was observed between the antioxidant activity of the lamb patty with the coreopsis extract and the inhibitory effect of coreopsis extract on various HCAs, with a correlation coefficient of 0.14 to 0.44 (P > 0.05). Coreopsis extract containing flavonoids can be a beneficial additive for production of barbecue meat.

HIGHLIGHTS

Conversion sweet sorghum biomass to produce value-added products

Currently, most biotechnological products are produced from sugar- or starch-containing crops via microbial conversion, but accelerating the conflict with food supply. Thus, it has become increasingly interesting for industrial biotechnology to seek alternative non-food feedstock, such as sweet sorghum. Value-added chemical production from sweet sorghum not only alleviates dependency and conflict for traditional starch feedstocks (especially corn), but also improves efficient utilization of semi-arid agricultural land resources, especially for China. Sweet sorghum is rich in components, such as fermentable carbohydrates, insoluble lignocellulosic parts and bioactive compounds, making it more likely to produce value-added chemicals. Thus, this review highlights detailed bioconversion methods and its applications for the production of value-added products from sweet sorghum biomass. Moreover, strategies and new perspectives on improving the production economics of sweet sorghum biomass utilization are also discussed, aiming to develop a competitive sweet sorghum-based economy.

Inhibitory Effect of Tamarix ramosissima Extract on the Formation of Heterocyclic Amines in Roast Lamb Patties by Retarding the Consumption of Precursors and Preventing Free Radicals

Tamarix ramosissima has been widely used as barbecue skewers for the good taste and unique flavor it gives to the meat, but the effects of T. ramosissima on heterocyclic amine (HA) formation in roast lamb are unknown. The influence of T. ramosissima extract (TRE) on HA formation, precursors’ consumption, and free radicals’ generation in roast lamb patties were elucidated by UPLC-MS, HPLC, and electron spin resonance (ESR) analysis, respectively. Six HAs were identified and compared with the control group; the total and polar HAs decreased by 30.51% and 56.92% with TRE addition at 0.30 g/kg. The highest inhibitory effect was found against 2-amino-1-methyl-6-phenylimidazo[4,5-f]pyridine (PhIP) formation (70.83%) at 0.45 g/kg. The addition of TRE retarded the consumption of HA precursors, resulting in fewer HAs formed. The typical signal intensity of free radicals in roast lamb patties significantly decreased with TRE addition versus the control group (p < 0.05), and the higher the levels of the TRE, the greater the decrease in signal intensity. We propose that the inhibitory effects of TRE on HA formation, especially on polar HAs, were probably achieved by retarding the consumption of precursors and preventing free radicals from being generated in roast lamb patties. These findings provide valuable information concerning TRE’s effectiveness in preventing HA formation through both the precursor consumption and free radical scavenging mechanisms.

Isolation and Identification of Polyphenols From Fresh Sweet Sorghum Stems and Their Antibacterial Mechanism Against Foodborne Pathogens

As a C4 energy crop widely planted all over the world, sweet sorghum is mainly used in sugar making and brewing. Fresh sweet sorghum stalks contain many natural ingredients that have antioxidant properties and can significantly inhibit the growth of foodborne pathogens. In this study, the polyphenols in sweet sorghum were extracted by acid ethanol and ion precipitation, and the types of polyphenols were determined by HPLC-MS. The polyphenol content in fresh sweet sorghum stalks was 5.77 mg/g after process optimization with 18 types of phenolic acids identified. The extract had a total antioxidant capacity of 9.4 μmol Trolox/mL. Polyphenol extract of sweet sorghum displayed antibacterial activity against Staphylococcus aureus, Escherichia coli, Listeria spp., and Salmonella spp. The extract increased the conductivity of cell suspensions by destroying the membrane structure, resulting in leakage of cell electrolytes. Changes in bacterial morphology and internal structure were indicated. The data describe an optimized process to extract polyphenols from sweet sorghum stalks and the methodology to identify the major components within the extract. The data provide a novel option for the comprehensive utilization of fresh sweet sorghum stalks.

Mitigation of heterocyclic amines by phenolic compounds in allspice and perilla frutescens seed extract: The correlation between antioxidant capacities and mitigating activities

The effect of different levels of allspice and perilla frutescens seed extract (ASE and PSE) on the formation of heterocyclic amines (HCAs) in pan-fried chicken meat patties and the bioactive components found in ASE and PSE that contribute to the mitigation of HCAs were investigated in this study. DPPH radical scavenging activity was evaluated and the results indicated that APSE (ASE + PSE) showed the highest capacity to scavenge free radicals, and the most effective inhibition of HCAs formation. Furthermore, Single and mixed phenolic compounds exhibited a positive effect in scavenging free radicals and mitigating HCAs. The radical scavenging activity and HCAs inhibition effect of single phenolic compounds were highly correlated, whereas mixed phenolic compounds exhibited poor correlation. PCA analysis indicated that phenolic compounds had the maximum inhibitory effect on IQ, followed by Norharman and harman and the minimal effect on PhIP and 7,8-DiMeIQx.

Schemes for enhanced antioxidant stability in frying meat: a review of frying process using single oil and blended oils

Deep-fried meat products are widely popular. However, harmful compounds produced by various chemical reactions during frying have been shown to be detrimental to human health. It is of great necessity to raise practical suggestions for improving the oxidation problem of frying oils and frying conditions in some aspects. Vegetable oils are not as thermally stable as saturated fats, and blended oils have higher thermal stability than single oil. In this review, we discussed the oxidation problems frying oils and meats are subject to during frying, starting from the oil oxidation mechanism, the effects of different oils and fats on the quality of different fried meats under different conditions were concluded to alleviate the oxidation problem, to highlight the necessity of applying blended oils for frying, and effective antioxidants added to frying oils are also introduced, that would provide more convenient and practical options for obtaining higher quality of fried meat products and offer better understanding of the potential of blended frying oils for frying meat products.

Heterocyclic amines in cooked meat products, shortcomings during evaluation, factors influencing formation, risk assessment and mitigation strategies

At this point in time, the evidence of a link between well-done meat intake and the incidence of cancer is stronger than it was 20 years ago. Several cohort and case-control studies have confirmed this evidence, and have shown a higher odd ratio and increased exposure to heterocyclic amines (HCAs) among those who frequently consume red meat. However, in most epidemiological studies, dietary assessment, combined with analytical data, is used to estimate the intake of HCAs, which has many inconsistencies. In addition, there is a lack of findings indicating a substantial correlation between various factors, like types of raw meat, types of meat products, and cooking methods that directly or indirectly influence the occurrence of cancer. Although numerous mitigation strategies have been developed to reduce HCAs levels in meat, there is still a high prevalence of carcinogenesis caused by HCAs in humans. The aim of this review is to summarise conflicting reports, address shortcomings and identify emerging trends of cutting-edge research related to HCAs.

Inhibitory effects of hyperoside and quercitrin from Zanthoxylum bungeanum Maxim. leaf on 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine formation by trapping phenylacetaldehyde

2-amino-1-methyl-6-phenylimidazole[4,5-b]pyridine (PhIP) is one of the most abundant Heterocyclic amines (HAs) in meat products. Zanthoxylum bungeanum Maxim. leaf (ZML) extract has been shown to be rich in polyphenols, which are gaining increasing interest as efficient tools for inhibiting the formation of HAs. In the present work, the effects of ZML extract, major polyphenols, chlorogenic acid, hyperoside and quercitrin on the formation of PhIP in both roast beef patties and chemical model systems were investigated. UPLC-MS showed that ZML extract and those three polyphenols effectively inhibited PhIP formation. Additionally, GC-MS analysis showed that those three polyphenols significantly reduced the content of phenylacetaldehyde in the model systems, a key intermediate involved in PhIP formation. The subsequent UPLC-MS and TOF-MS/MS analysis found that hyperoside and quercitrin reacted with phenyacetaldehyde to form those four adducts, 8-C-(E-Phenylethenyl)hyperoside, 6-C-(E-Phenylethenyl)hyperoside, 8-C-(E-Phenylethenyl)quercitrin and 6-C-(E-Phenylethenyl)quercitrin, respectively. The results revealed that hyperoside and quercitrin could trap phenylacetaldehyde to form adducts, thereby, retarding the reaction of phenylacetaldehyde and creatinine, blocking the generation of PhIP.

Gut inflammation exacerbates hepatic injury in C57BL/6J mice via gut-vascular barrier dysfunction with high-fat-incorporated meat protein diets

AIM

Meat and its derivatives provide nutrients essential for human health. However, meat consumption, along with excessive fat intake, has been associated with gut inflammation, intestinal barrier dysfunction and alterations in gut microbiota. Herein, we investigated whether and how these changes in the intestinal barrier system affect the gut liver axis and hepatic injury and eventually lead to the progression of liver syndrome such as NAFLD.

METHODS

Mice were fed with high fat (60% kcal) or low fat (12% kcal) along with soybean (control), chicken and pork proteins (HFCH, HFP, LFCH, and LFP) for 12 weeks. The biomarkers for liver injury were investigated after meat protein intake along with the high fat.

FINDINGS

Greater amount of fat vacuoles visible in the H&E staining increased the inflammatory cell infiltration and disorganized liver structures were observed in the HFP-fed mice. Oil Red O staining revealed that the HFP-fed and HFCH-fed mice showed more lipid droplets, confirming the increased hepatic lipid accumulation. Potential serum markers for NAFLD, ALT and AST were increased in the HF meat diet groups. Key genes responsible for hepatic inflammation and lipogenesis, such as MCP-1, IL1-β and TNF-α were upregulated. HF meat protein diet-fed mice exhibited signs of compromised liver with increased levels of endotoxin in the liver and its binding protein in serum, upregulation of TLRs in the liver, and significant increase in TG, TC, LDL-C and HDL-C concentrations.

SIGNIFICANCE

Intestinal inflammation and barrier dysfunction aggravate liver injury and fibrosis due to the intake of HF meat protein diets in mice, which may contribute to the progress of liver injury and associated complications. Gut inflammation may directly contribute to the development of NAFLD, especially of the gut vascular barricade dysfunction.

Heterocyclic Aromatic Amines in Meat: Formation, Isolation, Risk Assessment, and Inhibitory Effect of Plant Extracts

Heterocyclic aromatic amines (HAAs) are potent carcinogenic compounds induced by the Maillard reaction in well-done cooked meats. Free amino acids, protein, creatinine, reducing sugars and nucleosides are major precursors involved in the production of polar and non-polar HAAs. The variety and yield of HAAs are linked with various factors such as meat type, heating time and temperature, cooking method and equipment, fresh meat storage time, raw material and additives, precursor’s presence, water activity, and pH level. For the isolation and identification of HAAs, advanced chromatography and spectroscopy techniques have been employed. These potent mutagens are the etiology of several types of human cancers at the ng/g level and are 100- to 2000-fold stronger than that of aflatoxins and benzopyrene, respectively. This review summarizes previous studies on the formation and types of potent mutagenic and/or carcinogenic HAAs in cooked meats. Furthermore, occurrence, risk assessment, and factors affecting HAA formation are discussed in detail. Additionally, sample extraction procedure and quantification techniques to determine these compounds are analyzed and described. Finally, an overview is presented on the promising strategy to mitigate the risk of HAAs by natural compounds and the effect of plant extracts containing antioxidants to reduce or inhibit the formation of these carcinogenic substances in cooked meats.

Changes in moisture, colour, residual nitrites and N-nitrosamine accumulation of bacon induced by nitrite levels and dry-frying temperatures

The effects of different nitrite levels (50, 100, and 150 mg/kg meat) and dry-frying temperatures (100, 150, 200 and 250 °C) on the moisture movement, colour, sensory variables and residual nitrite and N-nitrosamine levels in smoked bacon were investigated. Increasing the dry-frying temperatures significantly increased the cooking loss and decreased the moisture content (P < 0.05). The bacon L*-values showed an increasing trend at first and then decreased, with the highest value of the bacon with 150 mg/kg nitrite was obtained at 100 °C and 150 °C. In addition, a*-values were significantly affected by the nitrite level and dry-frying temperature (P < 0.05), with the highest value of the bacon samples with 100 and 150 mg/kg nitrite observed at 250 °C. The residual nitrite content level initially increased (from unheated control to 150 °C) and then decreased (from 150 to 250 °C) sharply with increasing dry-frying temperatures in the bacon samples with the same sodium nitrite levels. N-methyl-N-nitrosoaniline (NMPhA) and N-nitrosomorpholine (NMOR) were measured in a number of smoked bacon samples, and a significant positive correlation (R² = 0.772) was found for N-nitrosamines (NA) contents and nitrite levels (P < 0.05). The maximum levels of NMPhA and NMOR were detected when the bacon with 150 mg/kg sodium nitrite was pan-fried at 200 °C and 150 °C, respectively.

Using Adinandra nitida leaf extract to prevent heterocyclic amine formation in fried chicken patties

Adinandra nitida leaf extract (ANE) is rich in phenols and flavonoids. In this study, the effects of ANE as an additive on the formation of major heterocyclic amines (HCAs), namely, PhIP, norharman and harman, in both chemical model systems and fried chicken patties were explored. In model systems, treatment with various amounts of ANE (0, 15, 30, 45, 60 mg) led to the most effective inhibition of PhIP, norharman and harman, with levels reduced by 47.88%, 49.73% and 29.63% when treated with 45 mg, 60 mg and 60 mg, respectively. Further, the effect of diverse dosages of ANE (0, 0.2, 0.4, 0.6%, w/w) on the formation of HCAs in chicken patties fried at 170 °C and 190 °C was evaluated. Statistics showed that the temperature significantly increased the formation of HCAs. Total HCA contents of patties fried at 170 °C and 190 °C ranged from 1.52 ng g-1 to 2.52 ng g-1 and from 6.05 ng g-1 to 13.76 ng g-1, respectively. The inhibitory efficacy of various concentrations of ANE on the total HCA content was higher (38.95-56.03%) in patties fried at 190 °C than at 170 °C (18.65-40.08%). External parts of the meat patties showed higher HCA contents than the interior. The current study presents evidence that ANE at moderate dosages can reduce the formation of HCAs in fried chicken. By extension it suggests that ANE has potential applications as a natural antioxidant for preventing the formation of HCAs in foods.

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.

A novel potent inhibitor of 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) formation from Chinese chive: Identification, inhibitory effect and action mechanism

Differential solvent extraction and phytochemical profiling of Chinse chive were employed to identify its principal PhIP-formation inhibitory constituents. Six compounds (mangiferin, isorhamnetin, luteolin, rosmarinic acid, 6-methylcoumarin, and cyanidin-3-glucoside) were further analyzed in a PhIP-producing chemical model to identify the dominant inhibitor. Its inhibitory mechanism was investigated by assessing the contribution of antioxidation and scavenging of key PhIP precursor/intermediate. No significant correlation was observed between PhIP inhibition rates and antioxidant activities. Further evaluation of the novel potent inhibitor mangiferin revealed a highly significant correlation between its dose-dependent inhibition of PhIP formation and phenylacetaldehyde scavenging. Finally, the proposed mechanism was corroborated through organic synthesis and structural elucidation of the mangiferin-phenylacetaldehyde adduct. This study has identified a potent novel inhibitor of the most abundant HA in heat-processed food and characterized its action mechanism. These findings may provide insight for future studies on mitigation of dietary exposure to toxic Maillard products by polyphenolic phytochemicals.

Inhibitory effects of Portulaca oleracea L. and selected flavonoid ingredients on heterocyclic amines in roast beef patties and Density Function Theory calculation of binding between heterocyclic amines intermediates and flavonoids

The inhibitory effects of Portulaca oleracea L. (PO) and its flavonoid ingredients on the formation of heterocyclic amines (HAs) in roast beef patties were investigated. Ten HAs were found in control patties, and the total content was 212.73 ± 7.13 ng/g. With the addition of PO (1%, 5%, and 10%, w/w), HAs decreased by 62.39%, 68.03%, and 73.75%, respectively. The main flavonoid ingredients (rutin, hesperidin, and flavanone) also present a similar inhibitory effect. The Density Function Theory (DFT) methods were adopted to investigate the inhibitory mechanism. These ingredients bonded with the intermediate to block the formation of norharman. Both experimental and calculated data of the ingredients were analyzed on their HAs inhibitory capacity. Our results provide a novel and valuable strategy to reduce HAs via a low additive level of medicinal and edible plants. And the correlation between experimental and calculated data could be applied to predict the inhibitory ability of inhibitors.

Revealing a key inhibitory mechanism of 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline via trapping of methylglyoxal

The inhibitory effects of vitamins (nicotinic acid, pyridoxamine [PM], and l-ascorbic acid) and phenolic acids (ferulic acid and p-coumaric acid) on the formation of 2-amino-3,8-dimethylimidazo [4,5-f] quinoxaline (MeIQx) were studied in a glycine/glucose/creatinine model system and fried tilapia cakes. The results showed that PM was the most potential inhibitor and the inhibition rates reached 82.72% and 78.54% in model system and fried tilapia cakes, respectively. Detailed formation mechanism of MeIQx was put forward to find the inevitable species in the non-free radical formation mechanism of MeIQx. Dose-dependent analysis of PM on methylglyoxal (MGO ) and MeIQx formation were studied by using model systems and the results showed that MGO and MeIQx were both reduced about 60% in reaction mixtures when the molar ratio of PM to glycine was 1:16, which indicated that MGO is a key intermediate on the pathway of MeIQx formation. Quantum chemistry calculations showed that PM can act as a useful inhibitor to inhibit the formation of MeIQx and react with MGO to form new compounds. A pathway for the inhibitory activity of PM against MeIQx formation was proposed. PRACTICAL APPLICATION: Pyridoxamine was the most effective inhibitor against heterocyclic aromatic amines (HAAs) and could be applied to a variety of food systems. While the inhibitory mechanism is still unclear. Detailed formation mechanism of MeIQx was put forward first and suggested methylglyoxal as an inevitable species in the non-free radical formation mechanism of MeIQx in this study. Pyridoxamine trapping methylglyoxal is likely a key mechanism against the generation of MeIQx was demonstrated by quantum chemistry calculation and experimental demonstration. These findings may provide effective suggestions for reducing HAAs and similar toxicants in daily cuisine.

Antioxidant potential of chrysanthemum morifolium flower extract on lipid and protein oxidation in goat meat patties during refrigerated storage

Flavonoid and phenolic acid profile of chrysanthemum morifolium flower extract (CME) was analyzed by using ultra-performance liquid chromatography (Q-TOF-MS, Xevo G2-S; Milford, MA, USA, Waters) system in tandem with a quadruple time-of-flight mass spectrometer. The effect of CME on lipid and protein oxidation was investigated in goat patties during 9 days of refrigerated storage (4 ± 1 °C). Patties were prepared from freshly minced meat with the addition of 0.1% and 0.2% CME and compared with the butylated hydroxytoluene (BHT) (0.01%) and control. High level of thiol and lower level of thiobarbituric acid reactive substances and carbonyl content were observed in CME-treated samples compared to control during storage period. The incorporation of CME in patties reduced the pH and water activity values markedly, but no effect was found on color and sensory analyses. These results show that increased level of CME is more effective against lipid and protein oxidation and therefore can be used as a natural antioxidant in meat products without affecting product acceptability. PRACTICAL APPLICATION: Chrysanthemum morifolium flower belongs to the family "Asteraceae" and is a novel natural antioxidant for meat processing industry. It possesses strong antioxidant activities having many phenolic compounds including gallocatechin, apigenin, rosmarinic acid, caffeic acid, rhamnetin, and quercetin, and can be used for development and production of functional food as a natural antioxidant agent.