Aflatoxin B1 Concentration Research Articles

A preliminary study on the degradation of AFB1 by Tenebrio molitor, Rhizopus oryzae and Trichoderma reesei

Abstract Recently, genus Aspergillus, a fungus capable of producing aflatoxins, secondary highly toxic metabolites, has spread to new areas. These areas became suitable habitats due to the recent climate changes. The use of aflatoxin-contaminated crops is a cause of great concern in guaranteeing food safety and is responsible for major economic losses along the supply chain. For this reason, several strategies have been investigated to utilize these contaminated products as a possible food or feed resource by reducing or eliminating their aflatoxin content, but with limited relevant success. The presented study was aimed to evaluate a combination of biological processes to use aflatoxin B1 contaminated crops for their reintroduction into the production chain. The high tolerance to AFB1 and the apparent lack of accumulation in yellow mealworm larvae, reared on wheat bran substrates, spiked with increasing AFB1 concentration (0, 125, 250, 500 μg/kg) to obtain proteins of high biological value. Subsequently, the aflatoxin-degrading capacity of Rhizopus oryzae and Trichoderma reesei was applied to insect breeding waste (frass) in a fermentation process to ensure further utilization of biohazardous frass as soil conditioner. Individually, each process proven to be able to reduce the AFB1 present by about 80%, while the combination of the two approaches ensured the total degradation of aflatoxin B1-contaminated substrate and frass, which resulted in the possible production of biomass, that could be used for the feed and agricultural industry.

AFB1-responsive mesoporous silica nanoparticles for AFB1 quantification based on aptamer-regulated release of SERS reporter

In this study, we propose a novel surface-enhanced Raman scattering (SERS) method for quantifying aflatoxin B1 (AFB1). This method relies on the target-triggered release of a SERS reporter from aptamer-sealed aminated mesoporous silica nanoparticles (MSNs). These MSNs were synthesized to accommodate 4-mercaptophenylboronic acid (4-MPBA) within their well-defined micropores, which were subsequently sealed with AFB1 aptamers. Upon specific binding of AFB1 to its aptamer, the conformational change in the aptamer is regulated by the presence of the target. Consequently, a positive linear relationship between the AFB1 concentration and the 4-MPBA SERS signal was observed. Under optimal conditions, the method exhibited a good linear relationship over the range of 0.1 to 5 ng/mL AFB1, with a limit of detection (LOD) of 0.03 ng/mL. This strategy was validated using wheat samples, yielding results comparable to high performance liquid chromatography-fluorescence detector (P > 0.05), confirming its reliability for detecting AFB1 in complex food matrices.

Graphene coated optical microfiber for aflatoxin B1 detection

We proposed a graphene coated microfiber-based sensor for enhancing Aflatoxin B1 detection at room temperature. The heat-and-pull technique was used to fabricate the microfiber while the graphene layer was coated using a drop-casting technique. Aflatoxin samples are used as a sensor sensing area soaking solution, whereby the prepared graphene-coated microfiber was used as a sensor probe. The sensing is based on the modulation of transmission intensity and wavelength shift induced by the alteration of concentration of aflatoxin B1 from 0 ppm to 10 ppm. There is an increase in sensitivity from 0.129 dBm/ppm to 0.187 dBm/ppm and an increase in resolution from 0.17 ppm to 0.037 ppm by coating graphene on the microfiber sensor. For the graphene coated microfiber-based sensor, the wavelength shift from 1525.37 nm to 1525.19 nm was obtained when the aflatoxin B1 concentration was increased from 0 to 10 ppm. It reveals a sensitivity of 0.018 nm/ppm with a linearity of more than 90 %. This finding shows that the proposed sensor can be used to detect various concentration of Aflatoxin sample with the ability to offer real time measurement.

Laser-induced CdS/TiO2/graphene dual photoanodes for ratiometric self-powered photoelectrochemical sensor: an innovative approach for aflatoxin B1 detection.

A ratiometric self-powered photoelectrochemical sensor based on laser direct writing technology was constructed to address the problem that the conventional single-signal detection mode was susceptible to the influence of instrumentation and environmental factors, which interfered with the detection results. Laser-induced CdS/TiO2/Graphene was prepared as dual photoanodes (PA1 and PA2), which were controlled by multiplexed switches to form a photocatalytic fuel cell with Pt cathode. By modifying the aptamer of aflatoxin B1 (AFB1) on the photoanode surface, the target was specifically captured to the electrode surface to form a biological complex, which increased the steric hindrance and affected the electron transfer, thus reducing the output signal of the sensor. Targets with different concentrations were incubated on the surface of PA1, and targets with fixed concentrations were incubated on the surface of PA2. Under the control of the multiplex switch, the output signals of the two photoanodes were recorded, and the ratio of these two signals was used as the basis for the quantitative detection of AFB1. The sensor output was linearly increasing with the logarithm of AFB1 concentration from 1.0 to 150ngmL-1 and the detection limit was 0.0974ngmL-1. Additionally, this method had good stability, fast response, and good selectivity to real samples, providing an effective method for food safety monitoring.

The effect of dielectric barrier discharge (DBD) cold plasma treatment on the reduction of aflatoxin B1 and the physicochemical properties of oat

Cold plasma is an emerging technology that has increased in demand because of consumers’ desire for fresh, safe and minimally processed food products. Aflatoxin B1 is one of the main mycotoxins that is usually found in cereals, especially oats. This study was conducted to determine the effect of DBD cold plasma on aflatoxin B1 and the physicochemical characteristics of oats. Whole oat grains were subjected to DBD plasma treatment for 1, 3, and 6 min at powers of 32, 37, and 42 W. Untreated samples were also evaluated as controls. The results showed that DBD treatment had the greatest reduction in 6 min and power 37, which reduced AFB1 concentration by 82%. Furthermore, there was no significant difference for some qualitative parameters such as protein and pH compared with the control sample, whereas the peroxide value and β-glucan increased and alpha-tocopherol decreased. The farinograph test showed that the improvement in water absorption capacity, dough stability, dough development time, and the degree of softening decreased. In addition, the viscosity of treated sample was reduced compared with that of the control sample. This study showed that DBD plasma had an effective reduction in aflatoxin AFB1, and it also improved the technological properties.

First evidence on the occurrence of multi-mycotoxins and dietary risk exposure to AFB1 along the cassava value chain in Uganda

This study investigated the occurrence and distribution of multiple mycotoxins (aflatoxin B1, B2, G1, G2, fumonisins B1, B2, ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEN), and citrinin (CIT)) in cassava products and as assessed the potential risk of aflatoxin B1 (AFB1) exposure among cassava consumers. A total of 192 samples of cassava products (96 flour and 96 chips, each with 48 samples from farmer and 48 from wholesaler) were analysed using LC/MS–MS. All positive samples irrespective of their origin (flour or chips) exhibited AFB1 levels exceeding the EU regulatory threshold of 5 µg/kg. The sum of fumonisins (FB1 + FB2), ZEN, and DON were significantly (P < 0.05) higher in cassava flour (14.3 µg/kg; 3.71 µg/kg; 25.1 µg/kg) compared to chips (6.54 µg/kg; 1.25 µg/kg; 0.25 µg/kg), respectively. Aflatoxins G2 was not detected in any of 192 samples. Cassava flour samples from farmers exhibited significantly (P < 0.05) higher mean concentrations of AFB1 (27.1 µg/kg), total aflatoxins (78.2 µg/kg), and ochratoxin A (79.6 µg/kg) in contrast to wholesalers, whose mean levels were notably lower at 8.91, 5.79 µg/kg, and 2.44 µg/kg, respectively, pointing the likely critical source of mycotoxin contamination. Cassava consumers in Northern Uganda are at a higher risk, with an estimated 2.06 cancer cases per 100,000 individuals per year compared to those in Eastern Uganda at 0.25. This study underscores the urgent need for interventions to manage aflatoxins in cassava flour, particularly at farm level in Northern Uganda. It accentuates a shift market to household-level sampling and the need for analytical methods targeting multiple mycotoxins.

Sanitary and Chemical Analysis of Drinking Water and Laboratory Control of the Content of Toxic Elements of Pesticides and Mycotoxins in Food Products

Relevance of the study: nutrition is the most important factor in maintaining health, normal growth and development of children and adolescents, preventing a number of diseases, maintaining high performance of the adult population, maintaining active longevity. Drinking water and food are necessary for the existence of humans and all life on Earth. Issues related to increasing responsibility for the effectiveness and objectivity of quality control of drinking water and food products are relevant in guaranteeing their safety for the health of consumers. Objectives of the study: to study the quality of drinking water and the efficiency of the water supply system in Osh in the period from 2020 to 2023; analysis of compliance of drinking water quality with sanitary and chemical standards; development of recommendations for improving the quality of water and the water supply system in Osh. Determination of toxic elements, pesticides and mycotoxins in food products, determination of physicochemical indicators and toxic elements in drinking water, pesticides and mycotoxins in food products was carried out in accordance with regulatory documents of GOST and the maximum permissible concentration. The test results showed the normal and permissible levels of pH, total iron, fluorides, hardness, dry residue, ammonia, nitrates, etc. in water, and the content of aflatoxin B1, the mass concentration of cadmium and lead, hexachlorane, dichlorodiphenyltrichloroethane in food products. For a more in-depth analysis, it is recommended to use additional data on climatic conditions, geological features of the region, as well as the demographic situation in Osh.

Effect of lactic acid bacteria inoculation on the aflatoxin B1 contamination and the diversity of yeast communities in Aspergillus flavus-contaminated experimental corn silage

AbstractThe present work aimed to study the yeast communities of whole crop corn silages (CS) that were previously contaminated with aflatoxin-producing Aspergillus flavus (CSCA). In addition, the effect of lactic acid bacterium (LAB) inoculation on the aflatoxin B1 (AFB1) content, genotoxicity, yeast load, and diversity of yeast communities were also investigated. In A. flavus contaminated silages, after two months, the AFB1 content was 40% lower with LAB inoculation, also a lower level of genotoxicity was determined. The number of yeasts cultured from the initial mixture of chopped whole crop corn was 4.8 × 107 CFU g−1 wet mass, while only 2.4 × 106 CFU g−1 from the CSCA and 7.1 × 105 CFU g−1 from the LAB-inoculated CSCA could be cultured. Based on 144 randomly isolated strains, the yeast community of the initial mixture consisted of 8 species. In contrast, the yeast community of CSCA consisted only of 4 species determined by 132 randomly selected isolates. LAB-inoculated CSCA consisted also of 4 species based on 158 randomly isolated strains. Saccharomyces cerevisiae and Pichia kudriavzevii proved to be predominant in the CSCA, while S. cerevisiae and Meyerozyma guilliermondii were the most abundant in the LAB-inoculated CSCA. The species richness was also confirmed by alpha diversity values (1.827, 1.188, and 1.123 as Shannon's indices for CS, CSCA, and LAB-inoculated CSCA, respectively). In response to LAB inoculation, the species diversity decreased considerably.

Pathogen producing aflatoxin in contaminated sandwich: Identification and preservation

The toxicity of the contaminated powder contributed to toxic aflatoxins has been well-known in the literature. However, before this study, the specific fungal strain behind aflatoxin production remained unidentified. Our research aimed to isolate and identify fungi from the tainted sandwiches while also assessing the preservation of sandwiches in ambient conditions. The study pinpointed Aspergillus flavus as the fungus responsible for aflatoxin production. Analysis revealed that the sandwich samples contaminated with pure A. flavus exhibited a significant Aflatoxin B1 (AFB1) concentration of 55.2 ± 0.21 ng/g, accompanied by a spore count of 2 × 106 Colony-Forming Unit (CFU)/g after ten days. In contrast, sandwich samples contaminated with the unspecified fungi displayed a lower AFB1 content of 16.21 ± 0.42 ng/g, with a spore count of 2.2 × 102 CFU/g after the same duration. In the prevention study, the efficacy of the ethanol spray method for inhibiting aflatoxin from A. flavus was investigated. Results demonstrated that a 70 % ethanol concentration at a ratio of 2.0 % total weight of the sandwich proved highly effective, significantly impeding fungal growth. This method extended the preservation time by sevenfold compared to the control. Importantly, tests at 2.0 % ethanol of the sandwich weight did not detect aflatoxin presence.

Exposure and knowledge on peanut aflatoxin B1 among urban consumer in Jakarta, Indonesia

Groundnut (Arachis hypogaea L), an important food in the Indonesian diet, has been reported to be contaminated with the carcinogenic Aflatoxin B1. However, research on consumer knowledge and exposure to AfB1 from peanuts in Indonesia is still limited. This study aimed to assess the exposure to aflatoxin B1 (AfB1) from peanuts consumed by urban Jakarta and their knowledge of aflatoxin risk. This observational study was cross-sectional in design, involving 192 randomly selected respondents. Peanut intake frequency was measured using a semi-quantitative FFQ instrument. Questionnaires were used to collect data regarding knowledge and income. The AfB1 content was analyzed by HPLC. Pearson Chi-Square test was used for analysis. The results showed that AfB1 contaminants were present in all samples. Respondents who frequently consumed high amounts of peanuts and processed products were exposed to AfB1 with a median of 22.55 ppb bb/day. There was no significant relationship between knowledge and AfB1 exposure (p= 0.874), age (p= 0.884), or income (p= 0.355). In conclusion, aflatoxin B1 exposure was still high in urban areas. There was no relationship between knowledge and exposure to AfB1 peanuts. Inter-sectoral strengthening of the empowerment and control of aflatoxin exposure is needed, as are economic and health impact studies related to AfB1 exposure.

Development of a Voltammetric Methodology Based on a Methacrylic Molecularly Imprinted Polymer-Modified Carbon-Paste Electrode for the Determination of Aflatoxin B1

Aflatoxin B1 (AFB1) is one of the most dangerous mycotoxins found in food, necessitating the development of precise and reliable methodologies for its detection. In this study, a novel electrochemical sensor based on a molecularly imprinted polymer (MIP) integrated with a carbon-paste electrode was developed for the voltammetric determination of AFB1. The innovative aspect of this work lies in the use of methacrylic acid (MAA) as the functional monomer, which enhances the sensor’s selectivity and binding affinity. The developed electrochemical sensor exhibited a linear response range from 20.8 to 80 ng/L, with a limit of detection (LOD) of 2.31 ng/L and a sensitivity of 19.83 µA (ng/L)−1 cm−2. The sensor demonstrated outstanding analytical performance, with reproducibility and repeatability yielding relative standard deviations (RSDs) of 3.24% and 1.41%, respectively. To validate the sensor’s practical applicability, its performance was tested in real samples of corn and wheat using the standard addition method. Samples were prepared following official Mexican standard methods. Detected AFB1 concentrations were 0.0147 μg/L and 0.0138 μg/L for corn and wheat, respectively. A statistical comparison using the Student’s t-test confirmed no significant matrix effects, underscoring the high selectivity and accuracy of the MIP-modified sensor. This work introduces a highly selective, sensitive, and reproducible methodology for AFB1 detection, which could significantly advance food safety monitoring.

A biosensor integrating the electrochemical and fluorescence strategies for detection of aflatoxin B1 based on a dual-functionalized platform

BackgroundAflatoxin B1 (AFB1), is a potent hepatic carcinogen which causes cancer by inducing DNA changes in the liver cells. Variety of methods have been developed for detection of AFB1 which are based on single mode detection strategy. Fabrication of novel platform which are compatible for multimodal detection of AFB1 provide robust performance for reliable detection of AFB1. In this study, we aimed to develop a robust biosensing platform that combines electrochemical and fluorescence techniques for the sensitive and specific detection of Aflatoxin B1. ResultsThe sensing platform includes the magnetic core-shell Fe3O4@AuNPs and zeolitic imidazolate framework-8 (ZIF-8). In electrochemical mode, the applied voltametric approach was used through functionalization of glassy carbon electrode and exhibited a linear range between 0.5 and 10000 pg mL−1 with LOD of 0.32 pg mL−1. Fluorescence analysis was based on the FRET on/off status of FAM-functionalized aptamer deposited on the same platform. The FAM emission recovered by the addition of AFB1 concentration in the range of 6–60 fg mL−1 with the LOD of 0.20 fg mL−1. The real sample analysis demonstrated satisfactory relative recoveries in the range of 92.81–105.32 % and 91.66–106.66 % using the electrochemical and fluorescence methods, respectively, and its reliability was confirmed by the HPLC technique. SignificanceThe experimental results affirm that the proposed aptasensor serves as a sensitive, efficient, and precise platform for monitoring AFB1 in both electrochemical and fluorescence detection approaches. Proposed strategy showed efficient selectivity among different analytes and was reproducible. Furthermore, the applicability of biosensor was confirmed in food and biological samples.

Fluorescence/visual aptasensor based on Au/MOF nanocomposite for accurate and convenient aflatoxin B1 detection.

Adual-mode fluorescence/visual aptasensor was developed for straightforward and accurate determination of aflatoxin B1 (AFB1) based on an Au/metal-organic framework (Au/MOF) composite. Aptamer-modified Au/Fe3O4 (Apt/Au/Fe3O4) served as the recognition element, and Au/MOF modified with complementary chains and 3,3',5,5'-tetramethylbenzidine (cDNA/TMB/Au/MOF) acted as the fluorescence and visual probes. These components are integrated to form conjugates (Apt/Au/Fe3O4-cDNA/TMB/Au/MOF). Upon the introduction of AFB1, some cDNA/TMB/Au/MOF dissociated from Apt/Au/Fe3O4, enabling the use of detached probes for visual detection. The undecomposed conjugates were isolated magnetically for use in fluorescence detection. As the AFB1 concentration increases, the visual signal intensifies and fluorescence intensity diminishes. Thus, the proposed aptasensor achieves the simultaneous fluorescence and visual determination of AFB1, obviating the need for material and reagent substitutions. The detection limits were established at 0.07ngmL-1 for the fluorescence mode and 0.08ngmL-1 for the visual mode. The effectiveness of the aptasensor was further validated by quantifying AFB1 in real samples.

Bidirectional hybridized hairpin DNA fluorescent aptasensor based on Au-Pd NPs and CDs for ratiometric detection of AFB1.

Anovel and simple ratiometric fluorescent aptasensor was developed for the sensitive detection of aflatoxin B1 (AFB1). A hairpin DNA (h-DNA) was independently synthesized as the basic skeleton, and the bidirectional hybridization of h-DNA can increase the load of aptamer and signal probes, thereby realizing signal amplification. The high-efficiency fluorescence resonance energy transfer interaction between gold-palladium nanoparticles (Au-Pd NPs) and the self-synthesized fluorescent probe carbon dots (CDs) was utilized. Moreover, the label-free probe SYBR Green I (SG I) dye was introduced to form a double-signal probe with CDs, and a ratiometric sensor with FCDs/FSG I as a response signal was constructed. The ratio strategy can eliminate the fluctuation of external factors, thus improving the accuracy and reliability of the sensor. The quenching effect of Au-Pd NPs on CDs was 1.4 times that of AuNPs and 3.4 times that of Pd NPs, respectively. In the range 1-100ng/mL, FCDs/FSG I showed a good linear relationship with the logarithm of the concentration of AFB1, and the limit of detection was as low as 0.07ng/mL. The sensor was used to detect AFB1 in spiked peanuts and wine samples, and the recovery was between 91 and 115%, indicating that the sensor has high application potential in real sample analysis.

X-ray Irradiation Reduces Live Aspergillus flavus Viability but Not Aflatoxin B1 in Naturally Contaminated Maize.

Food crops around the world are commonly contaminated with Aspergillus flavus, which can produce the carcinogenic mycotoxin aflatoxin B1 (AFB1). The objective of this study is to test an X-ray irradiation sterilization method for studying AFB1 in contaminated maize samples in the laboratory. Maize that had been naturally contaminated with 300 ppb AFB1 by the growth of aflatoxigenic A. flavus was ground and then irradiated at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kGy. A. flavus was quantified by dilution plating on potato dextrose agar (PDA) and modified Rose Bengal media (MDRB) for viability and qPCR for gene presence. AFB1 was quantified by HPLC and ELISA. A. flavus viability, but not gene copies, significantly decreased with increasing doses of radiation (PDA: p < 0.001; MDRB: p < 0.001; qPCR: p = 0.026). AFB1 concentration did not significantly change with increasing doses of radiation (HPLC: p = 0.153; ELISA: p = 0.567). Our results imply that X-ray irradiation is an effective means of reducing viable A. flavus without affecting AFB1 concentrations. Reducing the hazard of fungal spores and halting AFB1 production at the targeted dose are important steps to safely and reproducibly move forward research on the global mycotoxin challenge.

A novel biomass carbon dots ratiometric fluorescence probe coupled with molecularly imprinted polymer for selective detection of aflatoxin B1

The accumulation of Aflatoxin B1 (AFB1) in food and crops can pose significant hazards to human health. Consequently, there has been extensive attention paid to the development of a rapid and reliable method for detecting AFB1 in food. In this context, a ratiometric fluorescence probe (DE-MIPs) was prepared using dual-emission fluorescent carbon dots (CDs) coupled with the molecular imprinting technique for visual detection of AFB1. The dual-emission CDs consisted of red fluorescence biomass CDs (R-CDs) wrapped by molecularly imprinted cavities (R-CDs@MIPs), which served as a response signal, and pure blue emission biomass CDs (B-CDs) as a reference signal. Due to the specific quenching effect of AFB1 on red fluorescence while leaving blue fluorescence unaffected, there was a gradual decrease in the fluorescence intensity ratio (I670/I437) and a distinct shift in fluorescence color from red to blue as the concentration of AFB1 increased. The ratiometric probe demonstrated excellent linearity in detecting AFB1 within the concentration range of 0.1–200 ng/mL, with a detection limit (LOD) of 0.05 ng/mL. Furthermore, the practicality of DE-MIPs was validated by successfully detecting AFB1 in vegetable oil, with desirable recoveries from 89.0% to 107.4%. Furthermore, the integration of a smartphone as colorimetric reader enabled rapid AFB1 detection by capturing changes in fluorescence color. Overall, the development of this ratiometric probe offers a novel perspective for the facile and efficient identification of AFB1 in complex food samples.

Aflatoxins, fumonisins, citrinin, and zearalenone contents and health risk estimates in bee products in Turkey

Food contamination is an important global food safety issue. This study aimed to detect aflatoxins (AFB1, AFB2, AFG1, AFG2), fumonisins (FB1, FB2), citrinin (CIT), and zearalenone (ZEA) in four bee product groups (honey, royal jelly, bee pollen, propolis) in Turkey. Additionally, exposure and risk assessments were made for mycotoxins detected in these products. Mycotoxin analyzes in bee products were carried out by high-performance liquid chromatography-ultraviolet (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC/MS-MS) methods. The most frequently detected mycotoxins in all bee products were ZEA (37.5%) and AFB2 (36.6%). The analysis showed that the average concentrations of FB2 (2.091 μg/kg), AFB1 (0.595 μg/kg), and ZEA (0.009 μg/kg) in all bee products were above the detection limit levels, while the levels of AFB2, AFG1, AFG2, FB1, and CIT were below the limit of detection. When comparing bee products, it was found that honey samples were more exposed to AFB2 and FB1, bee pollen to FB1, propolis to AFB2, and royal jelly to ZEA contamination. AFG1 and CIT were not detected in propolis and bee pollen, respectively. All mycotoxins analyzed in the study pose no health risks when bee products are consumed daily.

Establishment of an amplification strategy - specific binding - convenient processing integrated aflatoxin B1 detection method based on Fe3O4-NH4/AuNPs/apt-S1

Aflatoxin B1 (AFB1) is a potent toxin in food, necessitating rapid, instant, and sensitive detection. We have engineered an electrochemical sensor to monitor AFB1 using a system composed of Fe3O4-NH4/AuNPs/apt-S1. The aptamer specifically recognizes AFB1, while ‘S1’ is functionalized with methylene blue to enhance the current. The RecJf exonuclease promotes the formation of the electrochemical strategy. The Fe3O4 component, with its magnet properties, enables a rapid separation of solids and liquids without the need for instrumentation. The sensor exhibits a linear range for AFB1 ranging from 1 ng to 10 μg. The regression equation is I(nA) = 446.8 × logc+2085 (where I and c represent the peak current and AFB1 concentration, respectively). The correlation coefficient is 0.9508, and the detection limit is 3.447 nM. The relative standard deviation of AFB1 in peanut oil ranges from 4.80% to 6.80%. These results demonstrate that the sensor has high sensitivity, stability, repeatability, and specificity for AFB1 detection.

Colorimetric detection of the potent carcinogen aflatoxin B1 based on the aggregation of L-lysine-functionalized gold nanoparticles in the presence of copper ions.

L-lysine functionalized gold nanoparticles (AuNPs-Lys) have been widely used for the detection of worldwide interest analytes. In this work, a colorimetric assay for the detection of the carcinogen aflatoxin B1 (AFB1) based on the aggregation of AuNPs-Lys in the presence of copper ions was developed. For this purpose, AuNPs were synthesized in citrate aqueous solution, functionalized, and further characterized by UV-Vis, fluorescence, Fourier transform infrared spectroscopy (FTIR), nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), and transmission electron microscopy (TEM). In general, AuNPS-Lys (~2.73 × 1011 particles) offered a clear colorimetric response in the presence of AFB1 and Cu2+ ions showing linearity in the range of 6.25 to 200 ng AFB1/mL, with a detection limit of 4.18 ng AFB1/mL via photometric inspection. Moreover, the performance of the proposed methodology was tested using the 991.31 AOAC official procedure based on monoclonal antibodies in maize samples artificially contaminated with AFB1. There was a good agreement between the measured AFB1 concentrations in both assays, the average recoveries for the colorimetric and immunoaffinity assays were between 91.2-98.4% and 96.0-99.2%, respectively. These results indicated that the colorimetric assay could be used as a rapid, eco-friendly, and cost-effective platform for the quantification of AFB1 in maize-based products.

Solid‐state fermentation by Aspergillus niger and Lactobacillus plantarum improved the nutritional and physicochemical properties of wheat bran and whole wheat bread

SummarySolid‐state fermentation (SSF) is an economically viable processing technique to improve the bioactive content from agricultural by‐products. The impacts of SSF by Aspergillus niger (AN) and Lactobacillus plantarum (LP) on the physicochemical and functional properties of wheat bran and whole wheat bread were investigated in this study. Compared with unfermented wheat bran, the pH of fermented wheat bran decreased significantly, and the titrated acidity increased significantly. The water absorption index, water solubility index and swelling capacity of wheat bran were significantly increased after fermentation. Besides, the free‐radical scavenging activities for DPPH, ABTS and the total antioxidant capacity of wheat bran were notably increased after SSF. Moreover, the content of alkylresorcinols (ARs), total phenolics and flavonoids compounds in wheat bran were enhanced by 137.85%, 52.87% and 95.6%, respectively, after fermentation. The content of aflatoxin B1, deoxynivalenol, zearalenone and ochratoxin A were decreased by 76.34%, 18.67%, 34.48% and 20.46%, respectively. SSF enhanced the content of ARs, total phenols and flavonoids in the reconstituted whole wheat bread by 136.55%, 54.55% and 97.74%, respectively. Whereas, the hardness and chewiness of the bran‐rich bread were decreased by 75.2% and 92.41%, respectively. Additionally, the sensory evaluation score, specific volume and the overall score of reconstituted bread were significantly improved. Taken together, SSF by AN and LP could improve the processing value of wheat bran and might be a feasible solution to upgrade whole wheat product quality.