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

Theoretical exploration of the phenolic compounds' inhibition mechanism of heterocyclic aromatic amines in roasted beef patties by density functional theory

The ability of spices (bay leaf, star anise, and red pepper) and their characteristic phenolic compounds (quercetin, kaempferol, and capsaicin) to inhibit Heterocyclic aromatic amines (HAAs) in roasted beef patties were compared. Density functional theory (DFT) was used to reveal phenolic compounds interacting with HAAs-related intermediates and free radicals to explore possible inhibitory mechanisms for HAAs. 3 % red chili and 0.03 % capsaicin reduced the total HAAs content by 57.09 % and 68.79 %, respectively. DFT demonstrated that this was due to the stronger interaction between capsaicin and the β-carboline HAAs intermediate (Ebind = -32.95 kcal/mol). The interaction between quercetin and phenylacetaldehyde was found to be the strongest (Ebind = -17.47 kcal/mol). Additionally, DFT indicated that capsaicin reduced the carbonyl content by transferring hydrogen atoms (HAT) to eliminate HO·, HOO·, and carbon-centered alkyl radicals. This study provided a reference for the development of DFT in the control of HAAs.

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.

Citrus Peel Extracts: Effective Inhibitors of Heterocyclic Amines and Advanced Glycation End Products in Grilled Pork Meat Patties

In the present study, citrus peels were extracted using various conventional and deep eutectic solvents (DESs). Compared to other citrus peel extracts, the DES extract based on choline chloride showed notably higher total phenolic and flavonoid content levels, along with superior antioxidant activity, among these extracts. Consequently, this study aimed to further investigate the inhibitory effects of the choline chloride based DES extract on the production of both free and bound heterocyclic amines (HAs) and advanced glycation end products (AGEs) in roast pork meat patties. The results indicated that the addition of choline chloride-based DES extracts, particularly the choline chloride-carbamide based DES extract, can effectively reduce the oxidation of lipids and proteins by quenching free radicals. This approach proves to be the most efficient in reducing the formation of both HAs and AGEs, leading to a significant reduction of 19.1-68.3% and 11.5-66.5% in free and protein-bound HAs, respectively. Moreover, the levels of free and protein-bound AGEs were reduced by 50.8-50.8% and 30.5-39.8%, respectively, compared to the control group. Furthermore, the major phenolics of citrus peel extract identified by UHPLC-MS were polymethoxylated flavonoids (PMFs) including hesperidin, isosinensetin, sinensetin, tetramethoxyflavone, tangeretin, and hexamethoxyflavone, which inferring that these compounds may be the main active ingredients responsible for the antioxidant activity and inhibition effects on the formation of HAs and AGEs. Further research is needed to explore the inhibitory effects and mechanisms of PMFs with different chemical structures on the formation of HAs and AGEs.

Response differences of gut microbiota in oligofructose and inulin are determined by the initial gut Bacteroides/Bifidobacterium ratios

Prebiotics are known to modulate the gut microbiota, but there is host variability, mainly due to differences in carbohydrate-utilisation by gut microbiota. Bifidobacterium and Bacteroides are powerful carbohydrate-utilising bacteria, and the ratio of both is closely related to the utilisation of prebiotics. However, the differential impact of prebiotics on the composition and function of the gut microbiota and its metabolites in participants with different Bacteroides/Bifidobacterium (Ba/Bi) ratios have not been studied. Here, we conducted a 4-week randomised double-blind, parallel four-arm trial using two prebiotics (oligofructose and inulin) in two populations with high Ba/Bi (H) and low Ba/Bi (L). The response to prebiotics in both populations was influenced by the baseline microbiota background specificity. Notably, at an overall level, FOS was slightly better than inulin in modulating the gut microbiota. Difference in gut microbiota regulation by FOS across microbiota contexts were significant between the two groups. Butyric acid-producing bacteria were significantly more abundant in H and further elevated butyric acid and related metabolite levels, with H more likely to benefit from the FOS intervention. The two groups showed only metabolic differences in their response to inulin, with L showing a significant increase in propionic acid and being enriched in glycolysis functions, whereas H was enriched in amino acids and aminoglycolysis functions. Overall, these results provide a basis for selecting appropriate prebiotics for participants with different gut backgrounds.

Characterization of aroma profiles of chinese four most famous traditional red-cooked chickens using GC-MS, GC-IMS, and E-nose

The aroma profile of the four most popular types of red-cooked chickens in China was analyzed using a combination of gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), and electronic nose (E-nose). Principal component analysis (PCA) demonstrated that the E-nose could successfully distinguish between the four types of red-cooked chickens. Additionally, a fingerprint was created using GC-IMS to examine the variations in volatile organic compounds (VOCs) distribution in the four chicken types. A total number of 84 and 62 VOCs were identified in the four types of red-cooked chickens using GC-MS and GC-IMS, respectively. Odor activity value (OAV) showed that 1-octen-3-ol, heptanal, hexanal, nonanal, octanal, eugenol, dimethyl trisulfide, anethole, anisaldehyde, estragole, and eucalyptol were the key volatile components in all samples. Furthermore, partial least squares-discriminant analysis (PLS-DA) demonstrated that (E, E)-2,4-decadienal, dimethyl trisulfide, octanal, eugenol, hexanal, (E)-2-nonenal, 1-octen-3-ol, butanal, ethyl acetate, ethyl acetate (D), nonanal, and heptanal could be used as markers to distinguish aroma of the four types of red-cooked chickens. Also, it is worth noting that levels of VOCs varied between chicken breast muscle and skin. The obtained results offer theoretical and technological support for flavor identification and control in red-cooked chickens to enhance their quality and encourage consumer consumption, which will be advantageous for the red-cooked chicken production chain.

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.

Advanced Glycation End Products and Nitrosamines in Sausages Influenced by Processing Parameters, Food Additives and Fat during Thermal Processing

Advanced glycation end products (AGEs) and nitrosamines (NAs) in sausage are associated with pathogenic and carcinogenic risks. However, the multiple reaction parameters affecting the production of AGEs and NAs during sausage processing remain unclear. This experiment evaluated the effects of processing parameters, food additives and fat ratios on the formation of AGEs and NAs in sausages. The results showed a 2-3-fold increase in N^ε-(carboxymethyl)lysine (CML) and N^ε-(carboxyethyl)lysine (CEL) when the sausage processing temperature was increased from 90 °C to 130 °C, and N-nitrosodimethylamine (NDEA) increased from 3.68 ng/g to 6.41 ng/g. The addition of salt inhibited the formation of AGEs and NAs, and the inhibitory ability of 2 g/100 g of salt was 63.6% for CML and 36.5% for N-nitrosodimethylamine (NDMA). The addition of 10 mg/kg nitrite to sausages reduced CML formation by 43.9%, however, nitrite had a significant contribution to the formation of NAs. The addition of fat only slightly contributed to the production of CML. In addition, the relationship between α-dicarbonyl compounds and the formation of AGEs was investigated by measuring the changes in α-dicarbonyl compounds in sausages. The results showed two trends of AGEs and α-dicarbonyl compounds: AGEs increased with the increase in α-dicarbonyl compounds and AGE level increased but α-dicarbonyl compound level decreased.

Strategies for the content determination of capsaicin and the identification of adulterated pepper powder using a hand-held near-infrared spectrometer

To achieve the goals of rapid content determination of capsaicin and adulteration detection of pepper powder. The method based on the hand-held near-infrared spectrometer combined with ensemble preprocessing was proposed. DoE-based ensemble preprocessing technique was utilized to develop the partial least squares regression models of red pepper [Capsicum annuum L. var. conoides (Mill.) Irish] powders. The performance of final models was evaluated using coefficient of determination (R²), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD). Model development using selective ensemble preprocessing gave the best prediction of capsaicin in Yanjiao pepper powder (R² = 0.9800, RPD = 7.090, RMSEP = 0.00689) and Tianying pepper powder (R² = 0.8935, RPD = 3.017, RMSEP = 0.06154). Moreover, the potential of grey wolf optimizer-support vector machine (GWO-SVM) to detect adulterated pepper powder was investigated. The samples were composed of two authentic products and three different adulterants with different adulteration levels. The results showed that the classification accuracy of GWO-SVM model for Yanjiao peppers was over 90 %, which realized the adulteration detection of Yanjiao pepper. And GWO-SVM showed better performance in detecting adulterated Tianying pepper compared to hierarchical cluster analysis, orthogonal partial least squares discriminant analysis and random forest. In summary, the quality control strategy established in this paper can provide a solution for the adulteration detection and quality evaluation of pepper powder in a rapid and on-site way.

A Coding Basis and Three-in-One Integrated Data Visualization Method 'Ana' for the Rapid Analysis of Multidimensional Omics Dataset

With innovations and advancements in analytical instruments and computer technology, omics studies based on statistical analysis, such as phytochemical omics, oilomics/lipidomics, proteomics, metabolomics, and glycomics, are increasingly popular in the areas of food chemistry and nutrition science. However, a remaining hurdle is the labor-intensive data process because learning coding skills and software operations are usually time-consuming for researchers without coding backgrounds. A MATLAB^® coding basis and three-in-one integrated method, 'Ana', was created for data visualizations and statistical analysis in this work. The program loaded and analyzed an omics dataset from an Excel^® file with 7 samples * 22 compounds as an example, and output six figures for three types of data visualization, including a 3D heatmap, heatmap hierarchical clustering analysis, and principal component analysis (PCA), in 18 s on a personal computer (PC) with a Windows 10 system and in 20 s on a Mac with a MacOS Monterey system. The code is rapid and efficient to print out high-quality figures up to 150 or 300 dpi. The output figures provide enough contrast to differentiate the omics dataset by both color code and bar size adjustments per their higher or lower values, allowing the figures to be qualified for publication and presentation purposes. It provides a rapid analysis method that would liberate researchers from labor-intensive and time-consuming manual or coding basis data analysis. A coding example with proper code annotations and completed user guidance is provided for undergraduate and postgraduate students to learn coding basis statistical data analysis and to help them utilize such techniques for their future research.

The Influence of Deep Eutectic Solvents Extract from Ginger on the Formation of Heterocyclic Amines and Advanced Glycation End Products in Roast Beef Patties

Heterocyclic amines (HAs) and advanced glycation end products (AGEs) are important harmful products formed simultaneously during the thermal processing of food. In order to develop a green, efficient method that can be used to control the production of two harmful products simultaneously in food processing. In the present study, deep eutectic solvents (DESs) were used to extract ginger, and this method produced significantly higher levels of total phenolic and flavonoid content as well as an antioxidant activity than ginger extracted using conventional solvents. Herein, we further investigated the inhibitory effects of DES extracts from ginger on the generation of HAs and AGEs in roast beef patties. All the nine DES extracts reduced the formation of HAs and AGEs, and the application of choline chloride–lactic-acid-based DES extract caused a signification reduction of 44.33%, 29.38%, 50.95%, 78.61%, 21.94%, and 17.52% of the PhIP, MeIQx, MeIQ, 4,8-DiMeIQx, Harmane, and Norhamane content, and those for Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) were 49.08% and 58.50%, respectively. Furthermore, the proximate and texture profile changes of beef patties as well as the precursors (creatine, creatinine, and glucose) of HAs and AGEs were evaluated to determine the mechanism of ginger DES extracts on the formation of HAs and AGEs and the physical/chemical changes of ginger DES extracts on beef patties. This study develops a new method for reducing the amount of HAs and AGEs in meat, which will help food manufacturers produce healthier meat products.

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.

Formation of Carcinogens in Processed Meat and Its Measurement with the Usage of Artificial Digestion—A Review

Meat is a rich source of various nutrients. However, it needs processing before consumption, what in turn generates formation of carcinogenic compounds, i.a., polycyclic aromatic hydrocarbons (PAH), nitrosamines (NOCs), and the most mutagenic heterocyclic aromatic amines (HAAs). It was widely found that many factors affect the content of carcinogens in processed meat. However, it has recently been discovered that after digestion free HAAs are released, which are not detectable before enzymatic treatment. It was established that the highest percentage of carcinogens is released in the small intestine and that its amount can be increased up to 6.6-fold. The change in free HAAs content in analyzed samples was dependent on many factors such as meat type, doneness, particle size of meat, and the enzyme concentration used for digestion. In turn, introduction of bacteria naturally occurring in the human digestive tract into the model significantly decreases total amount of HAAs. Contrary, the addition of food ingredients rich in polyphenols, fiber, and water (pepper powder, onions, apples) increases free HAAs’ release up to 56.06%. Results suggests that in vitro digestion should be an integral step of sample preparation. Artificial digestion introduced before chromatographic analysis will allow to estimate accurately the content of carcinogens in processed meat.

Hierarchical Porous Nanocellulose Aerogels Loaded with Metal-Organic Framework Particles for the Adsorption Application of Heterocyclic Aromatic Amines

This work overcomes the long-standing challenge of cumbersome pretreatment methods in the detection of heterocyclic aromatic amines (HAAs). A UiO-66/nanocellulose composite aerogel (CMC-CNC-UiO-66) with layered pores and low density prepared by a self-cross-linking method is applied as a simple and rapid adsorbent for capturing 14 HAAs via strong electrostatic interactions, van der Waals force, and the steric effect. The adsorption capacity of CMC-CNC-UiO-66 to 14 HAAs reached 98.00-188.00 nmol/mg at equilibrium within 10 min. The adsorption and desorption abilities of CMC-CNC-UiO-66 were retained with values of 93.36 and 97.34% after two cycles. In the meantime, the kinetics study demonstrated the chemisorption between HAA molecules and CMC-CNC-UiO-66 due to the excellent agreement with the pseudo-second-order adsorption models. The fit with the Freundlich isotherm models suggested a multilayer adsorption mechanism between HAA molecules and materials with heterogeneous surfaces. Moreover, coupled with the ultrahigh-performance liquid chromatography-tandem mass spectrometry detection, the CMC-CNC-UiO-66 extraction process can be completed with a high average recovery ranging from 86.68 to 115.33%, indicating a potential application of CMC-CNC-UiO-66 in HAA adsorption for further quantitative analysis.

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 β-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.

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.

High-throughput quantification of eighteen heterocyclic aromatic amines in roasted and pan-fried meat on the basis of high performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry

Triple quadrupole mass spectrometry has been the main technique for HAAs analysis in recent decade, while it requires extensive optimization of compound-dependent parameters. A novel method based on HPLC-Q-Orbitrap-HRMS was developed firstly for simultaneous determination of eighteen HAAs. Extraction and purification conditions were optimized and the developed method was validated in terms of linearity, accuracy and precision. Results indicated eighteen HAAs and two internal standards could be separated in 12 min using a gradient elution program. The full MS/dd-MS² scan was adopted for analysis, which indicated favorable recoveries (71.3-114.8%) along with LODs and LOQs in the ranges of 0.02-0.6 and 0.05-2.0 μg/kg, respectively. Internal standards used for calibration could effectively reduce quantification errors produced by matrix effects. The validated method was successfully applied for HAAs analysis in roasted and pan-fried meat and was confirmed to be an alternative method when triple quadrupole mass spectrometry is absent in lab.

Shrimp as a substantial source of carcinogenic heterocyclic amines

In the present work, fifteen mutagenic/carcinogenic heterocyclicamines (HAs)were studied in cooked Caridean shrimp (pink) and Penaeid shrimp (tiger, white and brown). The cooking methods were used as stir-frying, broiling and steaming under controlled temperature and time, and HAs determination was performed by SPE/UPLC-ESI-MS/MS. HAs 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-Amino-1,6-dimethyl-imidazo[4,5-b]pyridine (DMIP), 1-Methyl-9H-pyrido[3,4-b]indole (Harman) and 9H-pyrido[3,4-b]indole (Norharman) were identified (0.05-22.48 ng/g) in all stir-fried and broiled shrimp, whereas 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) was only found (0.08-0.35 ng/g) in stir-fried shrimp. HAs 2-Amino-3,7,8-trimethyl-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) and, α-carbolines 2-Amino-9H-pyrido[2,3-b]indole (AαC) and 2-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), γ-carbolines 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-Amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and δ-carbolines 2-Amino-6-methyldipyrido[1,2-α:3́,2́-d]imidazole (Glu-P-1) and 2-Aminodipyrido[1,2-α:3́,2́-d]imidazole (Glu-P-2) were not detected or found below quantification limit. Brown shrimp (stir-fried) appeared to be more contaminated which constitutes total HAs (81.93 ng/g) followed by pink (70.41 ng/g), tiger (53.02 ng/g) and white (33.57 ng/g). Steaming method does not yield any HAs, and the cause might be elucidate that shrimp were not directly in contact with cooking pan or fire which affect the HAs formation. Food precursors (protein, moisture, fat, creatine and glucose) were also measured in raw and cooked shrimp to investigate the influence on HAs formation. Creatine (3.85 mg/g) and glucose (0.43 mg/g) were found at higher concentrations in brown shrimp, generates high amounts of HAs. Our findings have illustrated that the cooking method, shrimp types and precursors are the main contributors to the formation of HAs. The outcomes from this work could be applied to estimate the HAs human intake globally and add to steaming cooking method in such types of food products that diminish the risk of HAs exposure, and thus to get healthier food quality and security.

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 review on β-carboline alkaloids and their distribution in foodstuffs: A class of potential functional components or not?

Pharmacologically active β-carboline alkaloids (βCs) such as harman, norharman and some others are naturally present in plants and occur in many foodstuffs. They have a lot of pharmacological properties, including antitumor, antioxidant, anti-inflammatory and antimicrobial effects, and possess the potential for treating Alzheimer's disease, Parkinson's disease, depression and other central nervous system diseases. Dietary intake is proven to be an important source of βCs. Therefore, it is important to know the amounts of βCs that can be gotten from daily diets. This review summarizes the pharmacological activities, toxicology and formation of βCs, and gives collective information on contents of βCs in different foodstuffs.