Analysis of acrylamide in food products by in-line preconcentration capillary zone electrophoresis

Detection of Acrylamide in Foodstuffs by Nanobody-Based Immunoassays

Acrylamide is toxic aliphatic amide formed via the Maillard reaction between asparagine and reducing sugars during thermal processing of food. Herein, a specific nanobody termed Nb-7E against the acrylamide derivative xanthyl acrylamide (XAA) was isolated from an immunized phage display library and confirmed to be able to detect acrylamide. First, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for acrylamide with a limit of detection (LOD) of 0.089 μg/mL and working range from 0.23 to 5.6 μg/mL. Furthermore, an enhanced electrochemical immunoassay (ECIA) was developed based on the optimized reaction conditions. The LOD was as low as 0.033 μg/mL, threefold improved compared to that of ic-ELISA, and a wider linear detection range from 0.39 to 50.0 μg/mL was achieved. The average recoveries ranged from 88.29 to 111.76% in spiked baked biscuits and potato crisps. Finally, the analytical performance of the ECIA was validated by standard ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Comprehensive Study on the Acrylamide Content of High Thermally Processed Foods

Acrylamide (AA) formation in starch-based processed foods at elevated temperatures is a serious health issue as it is a toxic and carcinogenic substance. However, the formation of more AA entangles with modern-day fast food industries, and a considerable amount of this ingredient is being consumed by fast food eaters inadvertently throughout the world. This article reviews the factors responsible for AA formation pathways, investigation techniques of AA, toxicity, and health-related issues followed by mitigation methods that have been studied in the past few decades comprehensively. Predominantly, AA and hydroxymethylfurfural (HMF) are produced via the Maillard reaction and can be highlighted as the major heat-induced toxins formulated in bread and bakery products. Epidemiological studies have shown that there is a strong relationship between AA accumulation in the body and the increased risk of cancers. The scientific community is still in a dearth of technology in producing AA-free starch-protein-fat-based thermally processed food products. Therefore, this paper may facilitate the food scientists to their endeavor in developing mitigation techniques pertaining to the formation of AA and HMF in baked foods in the future.

Food safety and quality assessment: comprehensive review and recent trends in the applications of ion mobility spectrometry (IMS)

Ion mobility spectrometry (IMS) is an analytical separation and diagnostic technique that is simple and sensitive and a rapid response and low-priced technique for detecting trace levels of chemical compounds in different matrices. Chemical agents and environmental contaminants are successfully detected by IMS and have been recently considered to employ in food safety. In addition, IMS uses stand-alone or coupled analytical diagnostic tools with chromatographic and spectroscopic methods. Scientific publications show that IMS has been applied 21% in the pharmaceutical industry, 9% in environmental studies and 13% in quality control and food safety. Nevertheless, applications of IMS in food safety and quality analysis have not been adequately explored. This review presents the IMS-related analysis and focuses on the application of IMS in food safety and quality. This review presents the important topics including detection of traces of chemicals, rate of food spoilage and freshness, food adulteration and authenticity as well as natural toxins, pesticides, herbicides, fungicides, veterinary, and growth promoter drug residues. Further, persistent organic pollutants (POPs), acrylamide, polycyclic aromatic hydrocarbon (PAH), biogenic amines, nitrosamine, furfural, phenolic compounds, heavy metals, food packaging materials, melamine, and food additives were also examined for the first time. Therefore, it is logical to predict that the application of the IMS technique in food safety, food quality, and contaminant analysis will be impressively increased in the future. HighlightsCurrent status of IMS for residues and contaminant detection in food safety.To assess all the detected contaminants in food safety, for the first time.Identified IMS-related parameters and chemical compounds in food safety control.

Thiol-ene Click Derivatization for the Determination of Acrylamide in Potato Products by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection

The development of analytical methods for acrylamide formed during food processing is of great significance for food safety, but limited by its inherent characteristics, the analysis of acrylamide is a continuing challenge. In this study, an efficient derivatization strategy for acrylamide based on thiol-ene click reaction with cysteine as derivatization reagent was proposed, and the resulting derivative was then analyzed by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C⁴D). After systematic investigation including catalyst dosage (0-20 mM), reaction temperature (30-90 °C) and time (1-60 min), and cysteine concentration (0.2-3.6 mM), acrylamide could be efficiently labeled by 2.0 mM cysteine at 70 °C for 10 min using 4 mM n-butylamine as catalyst. Application of 10 mM triethylamine as separation buffer, the labeled acrylamide was analyzed within 2.0 min, and the relative standard deviations of migration time and peak area were less than 0.84% and 5.6%, indicating good precision. The C⁴D signal of acrylamide derivative showed a good linear relationship with acrylamide concentration in the range of 7-200 μM with the correlation coefficient of 0.9991. The limit of detection and limit of quantification were calculated to be 0.16 μM and 0.52 μM, respectively. Assisted further by the QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample pretreatment, the developed derivatization strategy and subsequent CE-C⁴D method were successfully applied for the determination of acrylamide in potato products.

Analysis of Three Compounds in Flos Farfarae by Capillary Electrophoresis with Large-Volume Sample Stacking

The aim of this study was to develop a method combining an online concentration and high-efficiency capillary electrophoresis separation to analyze and detect three compounds (rutin, hyperoside, and chlorogenic acid) in Flos Farfarae. In order to get good resolution and enrichment, several parameters such as the choice of running buffer, pH and concentration of the running buffer, organic modifier, temperature, and separation voltage were all investigated. The optimized conditions were obtained as follows: the buffer of 40 mM NaH₂P0₄-40 mM Borax-30% v/v methanol (pH 9.0); the sample hydrodynamic injection of up to 4 s at 0.5 psi; 20 kV applied voltage. The diode-array detector was used, and the detection wavelength was 364 nm. Based on peak area, higher levels of selective and sensitive improvements in analysis were observed and about 14-, 26-, and 5-fold enrichment of rutin, hyperoside, and chlorogenic acid were achieved, respectively. This method was successfully applied to determine the three compounds in Flos Farfarae. The linear curve of peak response versus concentration was from 20 to 400 µg/ml, 16.5 to 330 µg/mL, and 25 to 500 µg/mL, respectively. The regression coefficients were 0.9998, 0.9999, and 0.9991, respectively.

Hapten synthesis and development of a competitive indirect enzyme-linked immunosorbent assay for acrylamide in food samples

The high level of acrylamide in widely consumed processed foods poses a potentially significant risk to human health, which has led to an increasing demand for rapid, simple, and selective analytical methods. In the present work, several haptens for acrylamide were designed in an attempt to prepare antibodies with acrylamide affinity, but they failed their purpose. However, a polyclonal antibody was produced against 4-mercaptophenylacetic acid (4-MPA)-derivatized acrylamide, which showed high binding affinity to the derivative. As acrylamide easily reacted with 4-MPA at high derivation yield, a competitive indirect enzyme-linked immunosorbent assay (ciELISA) for acrylamide via a preanalysis derivatization was developed. The derivatization and ELISA conditions were fully optimized to produce a method for acrylamide assay that exhibited an IC50 of 2.86 μg/kg, limit of detection at 0.036 μg/kg, and linear range of 0.25-24.15 μg/kg. The results of preanalysis recovery tests of acrylamide-spiked food samples and screening of blind food samples by both ciELISA and HPLC-MS/MS indicated the proposed ciELISA's good accuracy and reliability. This method was thus deemed suitable for routine acrylamide screening in food samples at low cost.

Evaluation of acrylamide in food from China by a LC/MS/MS method

Acrylamide is potential carcinogenic compound that possesses neurotoxicity activity. In this study, the levels of acrylamide in 123 selected food samples from China was evaluated using a LC/MS/MS method. One hundred and fifteen (115) out of 123 samples showed positive levels of acrylamide in the range of 0.41 to 4,126.26 µg/kg. Generally, the highest acrylamide levels were found in fried products, such as potato, prawn strips and rice crust, with average values of 604.27, 341.40, and 201.51 µg/kg, respectively. Heated protein-rich food also showed some acrylamide content (ranging from 2.31 to 78.57 µg/kg). The results revealed that a potential acrylamide public health risk occurred in processed snacks, as well as the food consumed daily. This study supplied new information on acrylamide content of a variety of heat-treated foods from China.

New trends in quantification of acrylamide in food products

Methods applied in acrylamide quantification in foods have been reviewed in this paper. Novel analytical techniques like capillary electrophoresis (CE), immunoenzymatic test (ELISA) and electrochemical biosensors, which can replace traditional methods like high performance liquid chromatography (HPLC) and gas chromatography (GC) were presented. Short time of analysis and high resolution power of electrophoretic techniques caused that they became routinely used in food analysis apart from high performance liquid chromatography and gas chromatography. Application of modern chromatography methods like ultra performance liquid chromatography (UPLC) in acrylamide quantification considerably shortened the time of analysis and decreased the consumption of indispensable reagents. The most promising approaches to acrylamide quantification in foods are electrochemical biosensors and immunoenzymatic tests. In contrast to chromatography and electrophoretic methods they require neither expensive equipment nor time consuming sample preparation and allow for fast screening of numerous samples without the usage of sophisticated apparatuses. Because of many advantages such as miniaturization, rapid and simple analysis, and high sensitivity and selectivity, biosensors are thought to replace conventional methods of acrylamide quantification in food.

Development of an enhanced chemiluminescence ELISA for the rapid detection of acrylamide in food products

In this work, a polyclonal antibody for acrylamide (AA) was obtained by immunization of rabbits with N-acryloxysuccinimide (NAS) and keyhole limpet hemocyanin (KLH) conjugate. A direct enzyme-linked immunosorbent assay (ELISA) based on this antibody was developed with enhanced chemiluminescent (ECL) detection of AA in food samples. Assay conditions, such as concentrations of antibody and enzyme conjugate and competition time, were optimized. The effects of ionic strength and pH value were investigated. The optimized ECL-ELISA system allowed AA determination in a linear working range of 26.3-221.1 ng mL(-1) with an IC(50) value of 60.6 ng mL(-1) and a limit of detection of 18.6 ng mL(-1). Good recoveries with spiked food samples were obtained with a recovery range from 74.4 to 98.1%, and these results correlated well with those obtained using an HPLC method. This indicates that ECL-ELISA is applicable to the specific detection and routine monitoring of AA in food samples.

Contemporary sample stacking in CE

Sample stacking techniques remain an important tool for enhancement of the selectivity and sensitivity of analyses in contemporary CZE. This contribution reviews new knowledge on this topic published since 2006. It is organized according to the operational principles used, which include concentration adjustment, application of a pH step, MEKC and sweeping, and transient ITP. Techniques combining several of these principles and comparative studies are also included.

CE: a useful analytical tool for the characterization of Maillard reaction products in foods

The Maillard reaction (MR) is a complex series of nonenzymatic reactions between reducing compounds and amines, amino acids, peptides, or proteins that play an important role in the formation of flavors and colors in foods during processing and storage. Also, the antioxidant properties of some Maillard reaction products (MRP) was an additional benefit reported. On the other hand, these reactions decrease the nutritional quality of foods and may result in the formation of toxic MRP. Although, research to assess the risks and benefits associated with the consumption of MRP in the diet is still awaiting for new analytical methodologies to be developed. Structural characterization of MRP has been very challenging due to the chemical diversity of these compounds which present a wide range of polarities and molecular weights, making analyses difficult. CE is a technique that has gained popularity for the separation of complex mixtures that have otherwise proved difficult to analyze. Thus, the purpose of this overview is to give the reader an appreciation of some of the CE analytical developments on the analysis of MRP in model systems and foods, and to address the potential of CE on the characterization of this complex group of compounds.

Analysis of heat-induced contaminants (acrylamide, chloropropanols and furan) in carbohydrate-rich food

Heat-induced food contaminants have attracted attention of both the scientific community and the public in recent years. The presence of substances considered possibly or probably carcinogenic to humans has triggered an extensive debate on the healthiness of even staple foods. In that respect, acrylamide, furan and chloropropanols are the main substances of concern. Their widespread occurrence in processed food, which concomitantly causes considerable exposure to humans, led either to the setting of maximum limits (for some chloropropanols) or at least the initiation of monitoring programmes in order to put risk assessment on a solid data basis. Acrylamide, furan and chloropropanols are small molecules with physicochemical properties that make their analysis challenging. Their amount in food ranges typically from below the limit of detection to hundreds of micrograms per kilo or even milligrams per kilo. However, a number of recently published scientific reports deal with the analysis of these substances in different kinds of food. The aim of this publication is to give an overview of analytical approaches for the determination of acrylamide, furan and chloropropanols in foodstuffs.

Field amplified sample injection–capillary electrophoresis–tandem mass spectrometry for the analysis of acrylamide in foodstuffs

This paper shows the applicability of capillary electrophoresis (CE) coupled to mass spectrometry (MS) for the analysis of acrylamide (AA) in foodstuffs. In order to obtain an ionisable compound amenable to be analysed by CE, acrylamide was derivatised with 2-mercaptobenzoic acid. Spectra in positive and negative modes were studied in order to select the best ionisation mode and multistep tandem mass spectrometry was used to obtain structural information. Maximum signal was observed when negative mode was used and MS/MS and MS3 were selected for quantitation and confirmation, respectively. For the separation, a fused-silica capillary of 80 cm and 50 microm I.D. and 35 mM ammonium formate/ammonia solution at pH 10 as running electrolyte were used. The applicability of field amplified sample injection (FASI) in reversed polarity was evaluated in order to decrease detection limits. The developed FASI-CE-MS/MS method provided a detection limit of 8 ng g(-1) and good linearity (r=0.999) and precision (day-to-day lower than 15%). The method has been applied to the analysis of different representative food products and the results were compared with those obtained by LC-MS/MS.