Monitoring the contents of biogenic amines in sufu by HPLC with SPE and pre-column derivatization

Determination of biogenic amines in chicken, beef, and mutton by dansyl chloride microwave derivatization in Malaysia

In this study, an improved dansyl-chloride derivatization technique using a microwave synthesizer was used for the qualitative and quantitative analyses of biogenic amine in the fresh meat samples. The derivatization technique was optimized in terms of temperature, reaction time, and spinning speed. The derivatization method together with a validated reversed-phase HPLC-DAD method was used for the determination of biogenic amines in chicken, beef, and mutton sold in the wet market. The results of the analyses showed that tryptamine, putrescine, and histamine were generally detected in all the three types of meat. Higher levels of histamine were found in chicken and beef. However, low levels of histamine were observed in mutton. Tyramine was either detected low or moderate in all the three types of meat. The biogenic amines of the fresh meat sold in the wet market is generally higher than the reported values. The mechanisms of biogenic amines-dansyl-chloride formation were investigated and proposed. PRACTICAL APPLICATION: The biogenic amine derivatization method was improved. The improved derivatization method can be potentially used for various food products beside meats for routine biogenic amine analyses due to its fast analysis time and simplicity. High levels of biogenic amines were generally found in the meat sold in the wet markets. However, proper handling of the raw meat can reduce the risk of infection.

Development of a High Performance Liquid Chromatography with Diode Array Detector (HPLC-DAD) Method for Determination of Biogenic Amines in Ripened Cheeses

Biogenic amines (BAs) are organic, basic nitrogenous compounds formed during the decarboxylation of amino acids. A method for the determination of eight biogenic amines (tryptamine, 2-phenyletylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine) in ripened cheeses was developed and validated. Cheese samples with the addition of internal standards were extracted with 0.2 M perchloric acid and pre-column derivatized with dansyl chloride at 60 °C for 15 min, purified with toluene and dried under a stream of nitrogen. The samples were analyzed using high performance liquid chromatography with diode array detector (HPLC-DAD). The method was validated with the BAs at three concentration levels: 50, 100, and 200 mg/kg, respectively. The obtained values of correlation coefficient (R2) ranged at 0.9997−0.9998 for all of compounds. The limits of detection (LOD) and quantification (LOQ) were in ranges 1.53−1.88 and 5.13−6.28 mg/kg, respectively. The recovery for all of biogenic amines ranged from 70 to 120% and the precision (RSDr) value were <20%. The validated method was applied to analysis of 35 real ripened cheese samples purchased in Poland.

Evaluation of Nitrite, Ethyl Carbamate, and Biogenic Amines in Four Types of Fermented Vegetables

Nitrite, ethyl carbamate, and biogenic amines in fermented vegetables are considered harmful compounds. In this study, the concentration of the nitrite, ethyl carbamate, and biogenic amines in four different varieties of fermented vegetables in China was determined. The results show that the nitrite concentration in the fermented cabbage was the highest, followed by fermented mustard, fermented bamboo, and fermented radish. Additionally, nitrite concentration in two fermented cabbage samples and one fermented mustard sample exceeded the maximum allowed residue limit (20 mg/kg) suggested by China’s National Food Safety Standards. However, only one fermented cabbage sample had a very low level of ethyl carbamate (<10 μg/kg). Otherwise, higher biogenic amines were found in the samples of fermented cabbage, fermented bamboo, and fermented mustard. Additionally, the concentration of biogenic amines in some samples exceeded the recommended limit. On the contrary, biogenic amines in fermented radish samples were relatively low. Therefore, the concentration of nitrite and biogenic amine should be closely monitored and controlled during the vegetable fermentation processes, especially for the fermentation processes of bamboo, cabbage, and mustard.

Metagenomic insights into the bacteria responsible for producing biogenic amines in sufu

Harmful levels of biogenic amines (BAs) are frequently identified in sufu. The microorganisms and mechanisms responsible for BA production in sufu, however, are not well documented. In this study, sufu samples were randomly obtained from various regions of China. Putrescine, tyramine, and histamine were quantitated as the most abundant BAs. According to the metagenome sequencing, the abundances and diversities of genes encoding the critical enzymes in BA production were acquired. The results showed that genes encoding arginine-, ornithine-, tryptophan-, and histidine decarboxylases were the predominant amino acid decarboxylase genes. Furthermore, 34 metagenome-assembled genomes (MAGs) were generated, of which 23 encoded at least one gene involved in BA production. Genetic analysis of MAGs indicated genera affiliated with Enterococcus, Lactobacillus-related, and Lactococcus were the major histamine-synthesizing bacteria, and tyrosine may be utilized by Bacillus, Chryseobacterium, Kurthia, Lysinibacillus, Macrococcus, and Streptococcus to product tyramine. The critical species involved in two putrescine-producing pathways were also explored. In the ornithine decarboxylase pathway, Lactobacillus-related and Veillonella were predicted to be the main performers, whereas Sphingobacterium and unclassified Flavobacteriaceae were the dominant executors in the agmatine deiminase pathway. The present study not only explained the BAs formation mechanism in sufu but also identified specific bacteria used to control BAs in fermented soybean products.

Comparative analysis of the microbial community and nutritional quality of sufu

Sufu is a type of fermented food with abundant nutrients and delicious taste. It is made from the fermentation of tofu by various microorganisms. In this study, three types of sufu were prepared through natural fermentation: (NF), single-strain fermentation (SF), and mixed-strain fermentation (MF). Microbial species, amino acids, and fatty acids were identified to investigate dynamic changes in nutritional quality and microbial flora in sufu. The results showed that the number of microbial species in NF sufu was the highest (n = 284), whereas that in SF sufu was the lowest (n = 194). Overall, 153 microbial species were found in all three types of sufu. Relative abundance analysis also revealed that Tetragonococcus, Bacillus, Acinetobacter, and Staphylococcus were the main bacteria in sufu. However, there was a large number of harmful bacteria such as Enterococcaceae in NF sufu. The levels of various nutrients were low in SF sufu, whereas the contents of protein and soy isoflavones were higher in NF and MF sufu. Seventeen kinds of amino acids were detected, comprising seven essential amino acids and ten other amino acids. The contents of essential amino acids and essential fatty acids were higher in MF sufu than the other two types, resulting in its high nutritional value. The sufu produced through the three fermentation methods differed significantly (p < .05) in terms of microbial flora and nutritional quality.

Portable molecularly imprinted polymer-based platform for detection of histamine in aqueous solutions

Histamine, which is a naturally occurring chemical in seafood, is known to cause undesirable inflammatory response when consumed in large amounts. Histamine is produced in unsafe amounts in colored seafood when improperly stored for just a few hours. Food and health regulatory bodies across the world have guidelines limiting the amount of histamine in fresh as well as processed seafood. Conventional histamine detection is performed in testing labs, which is a slow process and results in bottlenecks in the seafood supply-chain system. A system to rapidly detect the seafood histamine levels on site is very desirable for seafood suppliers. Herein, we describe an impedance-based histamine detection sensor built on a flexible substrate that can detect histamine in the range of 100-500 ppm. Moreover, our sensor discriminates histamine in the presence of DL-histidine and other biogenic amines, with the selectivity provided by molecular imprinting technology. As a proof of concept, a smartphone controlled, portable semi-quantitative histamine sensing device was fabricated that gave out reliable testing results for histamine in different test solutions as well as for real seafood. We believe this technology can be extended towards determination of other food contaminants in aqueous solutions.

Ratiometric Cataluminescence Sensor of Amine Vapors for Discriminating Meat Spoilage

The freshness of meat has always been the focus of attention from consumers and suppliers for health and economic reasons. Usually, amine vapors, as one of the main components of the gas produced in the process of meat spoilage, can be used to monitor meat spoilage. Here, a new ratiometric cataluminescence (CTL) sensor based on energy transfer was developed to identify amine vapors and monitor meat freshness. After Tb doping, amine vapors exhibit a dual-wavelength (490 and 555 nm) property of CTL signals when reacted on the surface of Tb-doped La₂O₂CO₃, and the ratio of I₅₅₅ to I₄₉₀ (R_555/490) is a unique value for a given analyte within a wide range of concentrations. To illustrate the new sensor, 15 amine vapors were successfully identified using R_555/490, including homologues and isomers. Besides, this sensor was used to monitor four meats, and the freshness of meats can be distinguished by cluster analysis successfully. Moreover, further discussion of energy-transfer phenomena and influence factors has facilitating effects on exploring the mechanism of energy transfer at the gas-solid interface.

Bioactive compounds in cherry tomatoes (Solanum Lycopersicum var. Cerasiforme): Cultivation techniques classification by multivariate analysis

This study aimed to assess bioactive compounds contents in cherry tomatoes and classify samples according to cultivation techniques. Simple and cost-effective analyses were conducted on 128 samples cultivated using hydroponic, organic, and conventional practices. An HPLC-FD method was validated in-house for eight biogenic amines while antioxidants were evaluated using total phenolic content and anti-radical activity assays (DPPH^• and ABTS^•+ assays). Chemometric evaluation was applied to extrapolate significant information from data-sets. Variable selection using correlation matrix and the Fisher test was performed. Principal component analysis and linear discriminant analysis were used to construct a mathematical model to classify samples. Correct classifications were achieved in training (95.2%), validation (98.5%), and testing (100%). The results showed that cherry tomatoes cultivated using different techniques could be discriminated based on bioactive profiles using chemometric approaches.

Determination of Biogenic Amines in Different Parts of Lycium barbarum L. by HPLC with Precolumn Dansylation

The aim of this work was to characterize biogenic amines (BAs) in different parts of Lycium barbarum L. using HPLC with dansyl chloride derivatization, and jointly, to provide referential data for further exploration and utilization of Lycium barbarum L. The linear correlation coefficients for all BAs were above 0.9989. The limits of detection and quantification were 0.015-0.075 and 0.05-0.25 μg/mL, respectively. The relative standard deviations for the intra-day and inter-day precision were 0.66-2.69% and 0.91-4.38%. The described method has good repeatability and intermediate precision for the quantitative determination of BAs in different parts of Lycium barbarum L. Satisfactory recovery for all amines was obtained (79.3-110.3%). The result showed that there were four kinds of BAs. The highest putrescine content (20.9 ± 3.2 mg/kg) was found in the flower. The highest histamine content (102.7 ± 5.8 mg/kg) was detected in the bark, and the highest spermidine (13.3 ± 1.6 mg/kg) and spermine (23.7 ± 2.0 mg/kg) contents were detected in the young leaves. The high histamine (HIS) content in the bark may be one of the reasons why all of the parts of Lycium barbarum L., except the bark, are used for medicine or food in China. Meanwhile, the issue of the high concentration of HIS should be considered when exploiting or utilizing the bark of Lycium barbarum L.

The effect of different starter cultures on biogenic amines and quality of fermented mutton sausages stored at 4 and 20°C temperatures

The biogenic amines (BAs), water activity, pH, thiobarbituric acid-reactive substances (TBARS), and nitrite were, respectively, tested in dry fermented sausage with starter cultures (37x-6 Lactobacillus plantarum, x3-3b L. plantarum, 30x-11 Staphylococcus pentosans, and 37x-8 S. pentosans), during storage of room temperature (20°C) and refrigeration storage (4°C). Tryptamine (TRM), 2-phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD), histamine (HIM), and tyramine (TYM) contents of all samples were increased storage at 20°C, and the content of TRM, PUT, CAD, and HIM of all samples storage at 20°C was higher than that storage at 4°C after 42 days. The content of BA with 37x-6, x3-3b, and 37x-8 was obviously decreased at 4°C storage. The storage temperature has a significant effect on BA content (p < .05) for TYM and other BAs tested. Finally, x3-3b, 37x-6, and 37x-8 should be used to produce fermented sausages on the basis of the concentration of BAs.

Characterization of 10 Biogenic Amines in Male Silkworm Moth by HPLC with Precolumn Derivatization

Background:

Biogenic Amines (BAs) are biologically active nitrogenous organic compounds of low molecular weight, which are frequently found in a wide variety of foods, beverages and herbs due to their toxic potential in humans. Male Silkworm Moth (MSM), a Traditional Chinese Medicine (TCM), has been exploited and utilized as nutritious liquor based on its traditional effects in the Chinese community.

Objective:

The objective of this study was to develop an HPLC with Dns-Cl derivatization method for characterizing overall BAs in MSM and providing data for further evaluating its activities and safety profiles.

Methods:

The method has acceptable sensitivity, precision, accuracy, selectivity and recovery, and was successfully applied to the determination of the BAs contents in MSM for the first time.

Results:

In the analysis of 10 batches of MSM samples, serotonin and dopamine were not found in detectable concentrations in any samples, and the most abundant amine found was putrescine. The mean values of tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine determined in the samples were found to be 34.7 mg/ kg, 16.1 mg/ kg, 218.3 mg/ kg, 37.9 mg/ kg, 12.1 mg/ kg, 18.2 mg/ kg, 4.5mg/ kg, and 0.9 mg/ kg, respectively.

Conclusion:

The contents of BAs in 10 batches of MSM were below the maximum recommended limits, and MSM can be used safely.

Reduction in biogenic amines in douchi fermented by probiotic bacteria

Ecology studies showed that esophageal and gastric cancers are directly correlated with the consumption of processed foods. The carcinogenicity of traditional Chinese fermented foods such as douchi (fermented black beans or fermented black soybeans) is due to the presence of carcinogenic N-nitroso compounds, which are derived from biogenic amines. Among the various biogenic amines that can act as precursors of N-nitroso compounds, histamine and tyramine are considered to be the most toxic and are of public health concern when present in food. We have examined some douchi products on the market, and significant amounts of histamine and tyramine were found. The use of fermentation starters generated by subculturing fermented products with unknown microbiota would induce the risk of biogenic amines. As the microbiota used in fermentation is a crucial factor in determining the biogenic amines of fermented food, it is hypothesized that the possible harmful effects of douchi can be minimized through the use of fermentation starters composed of probiotic bacteria. This is the first study to investigate the potential of using probiotic bacteria in manufacturing douchi. Lactobacillus rhamnosus GG (LGG), Lactobacillus casei Shirota (LcS) and Escherichia coli Nissle 1917 (EcN) were used to ferment black beans in this study, and no tyramine was detected in black bean samples incubated with these three strains anaerobically at 37°C or 20°C. The starter culture strains, temperature and presence of oxygen during the incubation period were found to be critical to the generation of biogenic amines. The findings of this study can provide evidence-based insights and warrant further investigations on the potential of reducing the harmful compounds in food fermented with probiotic bacteria as well as the sensory evaluation of douchi fermented with probiotic bacteria.

Simultaneous quantification of five biogenic amines based on LC-MS/MS and its application in honeybee venom from different subspecies

The use of honeybee venom in traditional medicine is increasing due to its unexpected beneficial effects in the treatment of diseases. In this study, a simple and environmentally friendly sample preparation procedure was developed to quantify five biogenic amines-histamine, 5-hydroxytryptamine, dopamine, adrenaline, and noradrenaline-in honeybee venom using high-performance liquid chromatography tandem mass spectrometry. The instrument and sample preparation method were optimized to achieve stable, sensitive, and accurate quantification of the five biogenic amines. The peak purities of five biogenic amines in bee venom were examined using a diode array detector to ensure that endogenous impurities will not interfere with biogenic amines during the chromatographic separation procedure. The correlation coefficient of each compound was higher than 0.998 in the range of 0.5-1000 ng/mL. The limits of detection and quantification of the developed method ranged between 0.09 and 0.17, and 0.3 and 0.59 μg/g, respectively. The average recoveries of spiked biogenic amines with different concentrations were higher than 70.95%, and the intra- and intermediate-day precisions were lower than 7.51% and 10.17%, respectively. The carry-over between each injection and the stability of the target analytes were also evaluated to ensure the effectiveness of this method. The data obtained are presented in various formats, including boxplot, heat map, and principal component analysis diagram, to visualize the differences in the biogenic amine contents of the honeybee venoms from different subspecies. This method hopes to provide the opportunity to distinguish the bee venom produced by different subspecies.

Occurrence and reduction of biogenic amines in traditional Asian fermented soybean foods: A review

Biogenic amines are harmful substances generated during the fermentation process. Regulations on biogenic amine content in fermented foods are currently insufficient in comparison to the popularity of fermented food consumption in Asian countries. The current review evaluated the biogenic amine content of fermented soybean-based Asian foods to determine whether the food products are safe for consumption. Though the reported ranges of biogenic amine content in fermented soybean foods varied widely, most products contained biogenic amine concentrations at potentially hazardous levels. To ensure the safety of fermented soybean food products, further efforts are required in the improvement of the food manufacturing process, as well as the establishment of regulations on managing biogenic amine content.

Occurrence of biogenic amines in sufu obtained from Chinese market

This study aims at examining the level of biogenic amines (BAs) in different kinds of sufu commonly consumed in China. The correlation between different BAs and physical and chemical index in sufu samples was also investigated. The results proved that different processing technologies altered the distribution of BAs in commercial sufu. Total BA level was significantly correlated with salt content and pH. Some of the sufu samples in this survey contained higher levels of BAs, of which 26.6% of the samples might induce histamine poisoning, 15.6% might induce headache in virtue of phenylethylamine, and 23.4% might cause migraine and headache in virtue of tyramine. Moreover, 6.3% of the sufu samples with total BA content over 1000 mg/kg may be harmful to human health. From the food safety perspective, some sufu should not be excessively consumed daily and should be processed under strict sanitary conditions to decrease the BA level.

Biogenic amines analysis and microbial contribution in traditional fermented food of Douchi

Biogenic amines (BAs) have been reported to threaten the Douchi safety, while the BAs formation mechanism and corresponding control method have not been clarified for Douchi. The present study aims to investigate the microbial contribution to BAs in Douchi, and to find the beneficial strain for BAs control. Firstly, the BAs profiles of 15 Douchi samples were analyzed, and common 6 kinds of BAs were detected from different samples. All the samples showed the total BAs contents within the safe dosage range, while the histamine concentrations in 2 samples and β-phenethylamine in 6 samples were above the toxic level. Then, the bacterial and fungal communities were investigated by high-throughput sequencing analysis, and Bacillus and Candida were identified as the dominant bacteria and fungi genus, respectively. Furthermore, nineteen strains were selected from the dominant species of Douchi samples, including 14 Bacillus strains, 2 Staphylococcus strains, 1 Enterococcus strain and 2 Candida strains, and their BAs formation and degradation abilities were evaluated. B. subtilis HB-1 and S. pasteuri JX-2 showed no BAs producing ability, and B. subtilis GD-4 and Candida sp. JX-3 exhibited high BAs degradation ability. Finally, fermented soybean model analysis further verified that B. subtilis HB-1 and S. pasteuri JX-2 could significantly reduce BAs. This study not only contributed to understanding the BAs formation mechanism in Douchi, but also provided potential candidates to control the BAs in fermented soybean products.

A facile molecularly imprinted polymer-based fluorometric assay for detection of histamine

Histamine is a biogenic amine naturally present in many body cells. It is also a contaminant that is mostly found in spoiled food. The consumption of foods containing high levels of histamine may lead to an allergy-like food poisoning. Analytical methods that can routinely screen histamine are thus urgently needed. In this paper, we developed a facile and cost-effective molecularly imprinted polymer (MIP)-based fluorometric assay to directly quantify histamine. Histamine-specific MIP nanoparticles (nanoMIPs) were synthesized using a modified solid-phase synthesis method. They were then immobilized in the wells of a microplate to bind the histamine in aqueous samples. After binding, o-phthaldialdehyde (OPA) was used to label the bound histamine, which converted the binding events into fluorescent signals. The obtained calibration curve of histamine showed a linear correlation ranging from 1.80 to 44.98 μM with the limit of detection of 1.80 μM. This method was successfully used to detect histamine in spiked diary milk with a recovery rate of more than 85%.

Biogenic amines in foods

Biogenic amines are produced by bacterial decarboxylation of corresponding amino acids in foods. Concentration of biogenic amines in fermented food products is affected by several factors in the manufacturing process, including hygienic of raw materials, microbial composition, fermentation condition, and the duration of fermentation. Intake of low amount of biogenic amines normally does not have harmful effect on human health. However, when their amount in food is too high and detoxification ability is inhibited or disturbed, biogenic amines could cause problem. To control concentration of BAs in food, decarboxylase activity for amino acids can be regulated. Levels of BAs can be reduced by several methods such as packaging, additives, hydrostatic pressure, irradiation, pasteurization, smoking, starter culture, oxidizing formed biogenic amine, and temperature. The objective of this review paper was to collect, summarize, and discuss necessary information or useful data based on previous studies in terms of BAs in various foods.

A Double-Stimuli-Responsive Fluorescent Center for Monitoring of Food Spoilage based on Dye Covalently Modified EuMOFs: From Sensory Hydrogels to Logic Devices

Unsafe food is a huge threat to human health and the economy, and detecting food spoilage early is an ongoing and imperative need. Herein, a simple and effective strategy combining a fluorescence sensor and one-to-two logic operation is designed for monitoring biogenic amines, indicators of food spoilage. Sensors (methyl red@lanthanide metal-organic frameworks (MR@EuMOFs)) are created by covalently modifying MR into NH₂ -rich EuMOFs, which have a high quantum yield (48%). A double-stimuli-responsive fluorescence center is produced via energy transfer from the ligands to Eu³⁺ and MR. Portable sensory hydrogels are obtained by dispersing and solidifying MR@EuMOFs in water-phase sodium salt of carboxy methyl cellulose (CMC-Na). The hydrogels exhibit a color transition upon "smelling" histamine (HI) vapor. This transition and shift in the MR-based emission peak are closely related to the HI concentration. Using the HI concentration as the input signal and the two fluorescence emissions as output signals, an advanced analytical device based on a one-to-two logic gate is constructed. The four output combinations, NOT (0, 1), YES (1, 0), PASS 1 (1, 1), and PASS 0 (0, 0), allow the direct analysis of HI levels, which can be used for real-time food-freshness evaluation. The novel strategy suggested here may be a new application for a molecular logic system in the sensing field.

Reduction of biogenic amines in sufu by ethanol addition during ripening stage

The aim of this study was to investigate the content of biogenic amines (BAs) in different types of sufu samples obtained from different producers, and the effect of ethanol in reducing BA levels during sufu ripening. The results showed that different manufacturing processes altered the distribution of BAs in commercial sufu. Putrescine, cadaverine, histamine, and tryptamine were the main and common BAs in red, white and grey sufu. The contents of putrescine, cadaverine, tryptamine, β-phenylethylamine and tyramine in the grey sufu of all producer brands were significantly (p<0.05) higher than those in the white and red sufu. The addition of ethanol to the dressing mixture had a significant influence in reducing the total content of BAs in laboratory-made sufu. The slight increase in polypeptide and amino nitrogen contents after the addition of ethanol indicated a reduction in the degradation of water soluble protein.

Simultaneous Determination of Food-Related Biogenic Amines and Precursor Amino Acids Using in Situ Derivatization Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

A simple, rapid, sensitive, selective, and environmentally friendly method, based on in situ derivatization ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) using multiple reaction monitoring (MRM) mode has been developed for the simultaneous determination of food-related biogenic amines and amino acids. A new mass-spectrometry-sensitive derivatization reagent 4'-carbonyl chloride rosamine (CCR) was designed, synthesized, and first reported. Parameters and conditions of in situ DUADLLME and UHPLC-MS/MS were optimized in detail. Under the optimized conditions, the in situ DUADLLME was completed speedily (within 1 min) with high derivatization efficiencies (≥98.5%). With the cleanup and concentration of microextraction step, good analytical performance was obtained for the analytes. The results showed that this method was accurate and practical for quantification of biogenic amines and amino acids in common food samples (red wine, beer, wine, cheese, sausage, and fish).

Low-temperature derivatization followed by vortex-assisted liquid-liquid microextraction for the analysis of polyamines in Nicotiana Tabacum

Polyamines are ubiquitous polycationic molecules that play a key role in many biological processes such as nucleic acid metabolism, protein synthesis, cell growth, and nicotine synthesis precursors. This work describes a rapid, sensitive, convenient, green, and cost-effective method for the determination of polyamines in Nicotiana tabacum by ultra high performance liquid chromatography with photodiode array detection. The analytes were derivatized with 3,5-dinitrobenzoyl chloride at low temperature (about 4°C) and then extracted with vortex-assisted liquid-liquid microextraction. The experimental designs based on quarter-fractional factorial design and Doehlert design were used to screen and optimize the important factors in microextraction process. Under the optimal conditions, the method was linear over 0.05-8.00 μg/mL with an r(2) ≥ 0.992 and exhibited good repeatability and reproducibility less than 6.0 and 6.9%, respectively. The limit of detection ranged between 0.013 and 0.029 μg/g. The newly developed method was successfully employed to analyze different leaf samples of Nicotiana tabacum, among which the polyamines contents were found to be very different. Moreover, tyramine, 1,3-diaminopropane, homospermidine, and canavalmine were tentatively identified with the electrospray ionization quadrupole time-of-flight mass spectrometry. To our knowledge, this is the first report of identification of canavalmine in Nicotiana Tabacum.

Rapid analysis of biogenic amines from rice wine with isotope-coded derivatization followed by high performance liquid chromatography-tandem mass spectrometry

A pair of isotope-coded derivatization reagents, d0-10-methyl-acridone-2-sulfonyl chloride (d0-MASC, light form) and d3-10-methyl-acridone-2-sulfonyl chloride (d3-MASC, heavy form), were used for labeling biogenic amines (BAs). On basis of the isotope-coded derivatization, a global isotope internal standard quantitative method for determining seven BAs by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The d0-MASC and d3-MASC can easily label BAs under mild conditions within 15 min at 50 °C. The obtained light and heavy labeled BAs were monitored by the transitions of [M+H](+) → 208 and [M+H](+) → 211, respectively. Relative quantification of BAs was achieved by calculation of the peak area ratios of d0-MASC/d3-MASC labeled derivatives. Excellent linear responses for relative quantification were observed in the range of 1/10-10/1. The developed method has been successfully applied to the quantification of BAs in Chinese rice wine with recoveries ranging from 94.9% to 104.5%.

A sensitivity-enhanced heterologous immunochromatographic assay based on a monoclonal antibody for the rapid detection of histamine in saury samples

An immunochromatograhic strip for rapid detection of histamine based on a sensitive monoclonal antibody against p-nitrobenzoylated histamine was firstly reported.

A novel, colorimetric method for biogenic amine detection based on arylalkylamine N-acetyltransferase

We developed a novel colorimetric method for rapid detection of biogenic amines based on arylalkylamine N-acetyltransferase (aaNAT).

Biologically active amines in fermented and non-fermented commercial soybean products from the Spanish market

Biologically active amines were determined in commercial soybean products. The antioxidant polyamines were found in both non-fermented and fermented soybean products. Natto and tempeh showed the highest content of polyamines (75-124 and 11-24 mg/kg of spermidine and spermine, respectively). On the other hand, the bacterial-related biogenic amines, tyramine, histamine, tryptamine and β-phenylethylamine, were detected in practically all fermented products with a high variability. The highest contents were found in sufu, tamari and soybean paste. Extremely high tyramine and histamine contents, 1700 and 700 mg/kg, respectively, found in some sufu samples could be unhealthy. However, biogenic amines observed in the other soybean products should not be a risk for healthy consumers. However, individuals who take monoamine and diamine oxidase inhibitors drugs should be strongly recommended to avoid this kind of products in order to suffer no adverse health effects. These biogenic amines were not detected in non-fermented soybean products.

Safety assessment of the biogenic amines in fermented soya beans and fermented bean curd

To evaluate the safety of biogenic amines, high performance liquid chromatography (HPLC) was used to evaluate the levels of biogenic amines in fermented soya beans and fermented bean curd. In fermented soya beans, the total biogenic amines content was in a relatively safe range in many samples, although the concentration of histamine, tyramine, and β-phenethylamine was high enough in some samples to cause a possible safety threat, and 8 of the 30 samples were deemed unsafe. In fermented bean curd, the total biogenic amines content was more than 900 mg/kg in 19 white sufu amples, a level that has been determined to pose a safety hazard; putrescine was the only one detected in all samples and also had the highest concentration, which made samples a safety hazard; the content of tryptamine, β-phenethylamine, tyramine, and histamine had reached the level of threat to human health in some white and green sufu samples, and that may imply another potential safety risk; and 25 of the 33 samples were unsafe. In conclusion, the content of biogenic amines in all fermented soya bean products should be studied and appropriate limits determined to ensure the safety of eating these foods.

Development and application of quartz crystal microbalance sensor based on novel molecularly imprinted sol-gel polymer for rapid detection of histamine in foods

To rapidly detect histamine (HA) in foods, a novel material for HA-specific recognition was synthesized by a sol-gel process and coated on a quartz crystal microbalance (QCM) sensor. The Scatchard model was used to evaluate the adsorption performance of the material; high affinity for HA was demonstrated. Based on QCM frequency change, the sensor exhibited linear behavior for HA concentrations of 0.11 × 10(-2) to 4.45 × 10(-2) mg L(-1), a detection limit of 7.49 × 10(-4) mg kg(-1) (S/N = 3), high selectivity for HA (selectivity coefficient >4) compared with structural analogues, good reproducibility, and long-term stability. The sensor was used to determine the concentration of HA in spiked fish products; the recovery values were satisfactory (93.2-100.4%) and compared well with those obtained by high-performance liquid chromatography (correlation coefficient, r(2) = 0.9965).

Health effects and occurrence of dietary polyamines: a review for the period 2005-mid 2013

This review continues a previous one (Kalač & Krausová, 2005). Dietary polyamines spermidine and spermine participate in an array of physiological roles with both favourable and injurious effects on human health. Dieticians thus need plausible information on their content in various foods. The data on the polyamine contents in raw food materials increased considerably during the reviewed period, while information on their changes during processing and storage have yet been fragmentary and inconsistent. Spermidine and spermine originate mainly from raw materials. Their high contents are typical particularly for inner organs and meat of warm-blooded animals, soybean and fermented soybean products and some mushroom species. Generally, polyamine contents range widely within the individual food items.

A review of the liquid chromatographic methods for the determination of biogenic amines in foods

Biogenic amines (BAs) are biologically active molecules which have aliphatic (putrescine, cadaverine, spermine, spermidine), aromatic (tyramine, phenylethylamine) or heterocyclic (histamine, tryptamine) structures. They can be detected in raw and processed foods which are formed and degraded through several pathways during the metabolic processes of animals, plants and microorganisms. The identification and quantitation procedures of BAs in food samples are very important, because BAs are considered as the indicators of food quality and freshness. The determination of BAs are commonly achieved by separation techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC) and capillary electrophoresis (CE). In this article, analysis of BAs in foods were reviewed from 2007 to present.

Electrochemical sensor based on molecularly imprinted film at polypyrrole-sulfonated graphene/hyaluronic acid-multiwalled carbon nanotubes modified electrode for determination of tryptamine

An imprinted electrochemical sensor based on polypyrrole-sulfonated graphene (PPy-SG)/hyaluronic acid-multiwalled carbon nanotubes (HA-MWCNTs) for sensitive detection of tryptamine was presented. Molecularly imprinted polymers (MIPs) were synthesized by electropolymerization using tryptamine as the template, and para-aminobenzoic acid (pABA) as the monomer. The surface feature of the modified electrode was characterized by cyclic voltammetry (CV). The proposed sensor was tested by chronoamperometry. Several important parameters controlling the performance of the molecularly imprinted sensor were investigated and optimized. The results showed that the PPy-SG composites films showed improved conductivity and electrochemical performances. HA-MWCNTs bionanocomposites could enhance the current response evidently. The good selectivity of the sensor allowed three discriminations of tryptamine from interferents, which include tyramine, dopamine and tryptophan. Under the optimal conditions, a linear ranging from 9.0×10(-8) mol L(-1) to 7.0×10(-5) mol L(-1) for the detection of tryptamine was observed with the detection limit of 7.4×10(-8) mol L(-1) (S/N=3). This imprinted electrochemical sensor was successfully employed to detect tryptamine in real samples.