Cereal Samples Research Articles

Quantitative determination of four mycotoxins in cereal by fluorescent microsphere based immunochromatographic assay.

Mycotoxins are secondary metabolites produced by fungi, which have serious effects on humans and animals. In this study, we selected the monodispersed polystyrene fluorescent microspheres with good luminescence performance and strong stability as markers to conjugate with four mycotoxins antibodies for preparing fluorescent probes. We have developed a fluorescent microsphere based immunochromatographic assay (FMICA) to detect sensitively and quickly zearalenone (ZEN), aflatoxin B1 (AFB1 ), fumonisin B1 (FB1 ), and ochratoxin A (OTA) in cereal. Under optimal experimental conditions, the procedure of this method can be completed within 10min. The limit of detection (LOD) of FMICA for ZEN, AFB1 , FB1 , and OTA is 0.072, 0.093, 0.32, and 0.19 μg L-1 , respectively. And FMICA has good specificity and no cross-reactivity with other mycotoxins. Four mycotoxins in naturally contaminated cereal samples (corn, rice, and oat) are detected by this method, and the results are highly consistent with that of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The developed FMICA has good accuracy, high sensitivity, simplicity, convenience, rapidity, and low cost, and it could be employed for sensitive and quantitative detecting of mycotoxins in cereal on-site. © 2022 Society of Chemical Industry.

Microbial quality and physicochemical property changes of Anggun sweet potato breakfast cereal during storage

Studies on quality changes of Anggun sweet potato breakfast cereal had been conducted for a 6-month storage period. Freshly prepared breakfast cereal samples were packed in Ony/Al/PE pouches (28 cm × 21.5 cm with 0.10 mm thickness) and stored at 27±3°C with relative humidity (RH) of 70-75%. Results showed that the lightness (L*) and red colour (a*) values were not significantly different, yellow colour (b*) values decreased, while the moisture content was in the range for the cereal products category during the storage period. The mesophilic bacteria, yeast and mould counts were within the acceptable limits for direct consumption. There was less than 1.0 log CFU/g for coliform bacterium and Bacillus cereus counts in the samples throughout the storage period. The anthocyanin content of the sample was 12.04±0.04 mg/100g at the end of storage. Anggun sweet potato cereal packed in Ony/Al/PE was found to be of an acceptable quality for up to 6 months when stored at 27±3°C (70-75% RH) and has the potential to be used as an alternative healthy breakfast cereal.

Determination of the Level of Heavy Metals in the Selected Cereals from Debre Markos Local Market, Amhara Region, Ethiopia

Environmental contamination by heavy metals has become a worldwide problem in recent years because of industrial and agricultural development which causes cereal crop contamination via their wastes. The presence of toxic heavy metals in cereal crops accumulate in the body for a prolonged period of time which poses acute and chronic health risks. The aim of the study was to assess the level of heavy metals in selected cereals sold at Debre Markos local market, in Ethiopia. The samples were prepared for analysis by using the dry ashing method, and their cadmium, lead, chromium, and copper contents were analyzed by using microwave-induced plasma-atomic emission spectroscopy (MP-AES) and were expressed in mgkg-1 dry weight. The accuracy of the method was analyzed by the spike recovery test. The percentage recovery for Cr, Cu, Pb, and Cd in each sample ranged from 85.6 to 112.8%. The levels of heavy metals (mean ± SD) were as follows: chromium, 2.20 ± 0.072, 2.22 ± 0.061, 1.57 ± 0.48, and 1.84 ± 0.26; copper, 2.94 ± 0.19, 2.31 ± 0.06, 1.28 ± 0.13, 1.52 ± 0.035, and 2.31 ± 0.06; lead, 0.49 ± 0.031, 0.34 ± 0.121, 0.52 ± 0.029, and 0.37 ± 0.15; and cadmium, 2.01 ± 1.73, 1.84 ± 1.60, 1.95 ± 1.69, and 1.93 ± 1.67 for barley, teff, wheat, and maize, respectively. This study revealed that the levels of Cr and Cu are generally below the permissible limit. However, the levels of Pb and Cd in all cereal samples were found to be above the permissible limit set by FAO/WHO, 0.2 and 0.1 mg kg-1, respectively. The findings of the study suggest that most of the analyzed crops contained unsafe levels of lead and cadmium that exceeded the WHO permissible limits. Therefore, regular monitoring of these toxic metals in cereal crops should be carried out to prevent heavy metal toxicity associated with the consumption of some cereal crops marketed in the Debre Markos local market, Ethiopia.

Co-occurrence and estimation of the risk of total aflatoxins (B1, B2, G1, and G2) and ochratoxin A in agri-food products consumed in Chile

The consumption of agri-foods contaminated with mycotoxins poses a serious threat to human health. In this study, we evaluated the presence of total aflatoxins (AFs) and ochratoxin A (OTA) in various agri-food products of national and imported origin in Chile that are consumed daily. A total of 653 samples of cocoa (22), oats (50), ginger (62), pepper (131), coffee (42), raisins (34), turmeric (60), nutmeg (30), cereals (60), flour (47), walnuts (16), dried fruits (18), pistachios (10), hazelnuts (7), almonds (20), peanuts (35), and tea (9) were collected from 2018 to 2020 in markets and supermarkets in Chile by the Mycotoxin Monitoring Program of the Ministry of Health of Chile. Contamination by AFs occurred mainly in nutmeg, pepper, and ginger in 2018, as these compounds were not detected in 2020. The detection frequency for OTA was higher than that of the AFs, and it was mainly present in turmeric, ginger, and pepper. The Estimated Daily Intake (EDI) in nutmeg for AFs and OTA does not exceed the tolerable weekly or daily intake levels proposed by international bodies.

Validation of the Assurance® GDS for Cronobacter Tq II in Infant Formulas, Infant Cereals, Ingredients, and Environmental Samples Collaborative Study: First Action 2021.08.

The Assurance® GDS for Cronobacter Tq II assay is a nucleic acid amplification system for the qualitative detection of Cronobacter. The method uses an upfront concentration of the target organism from the enrichment by immunomagnetic separation (IMS) using the PickPen®device. The Assurance GDS for Cronobacter Tq II method was evaluated for Official Methods of AnalysisSM certification. The matrix was compared to the ISO 22964:2017: Microbiology of the Food Chain-Horizontal Method for the Detection of Cronobacter spp. standard and using an alternative confirmation procedure. The alternative method was evaluated using 10 g test portions in an unpaired study design for powdered infant formula (milk based with iron and DHA) containing probiotics. Eleven technicians from eight laboratories located within the United States and Europe participated in the collaborative study. Statistical analysis was conducted according to the probability of detection (POD) statistical model as presented in the AOAC validation guidelines. The difference in laboratory POD (dLPODC) values with 95% confidence intervals across collaborators was calculated for each level between the candidate and reference method results and between the candidate presumptive and confirmed results. Results obtained for the low inoculum level test portions produced a dLPOD value with a 95% confidence interval of 0.03 (-0.18, 0.15). The dLPOD results indicate equivalence between the candidate method and reference method for the matrix evaluated. The method also demonstrated acceptable inter-laboratory reproducibility as determined in the collaborative evaluation. There were no false negative results; the false positive rate was determined and produced a value of <2%. Based on the data generated, the method demonstrated Assurance GDS for Cronobacter Tq II assay produced acceptable interlaboratory reproducibility data and statistical analysis. The Assurance GDS for Cronobacter Tq II method is suitable for the rapid qualitative detection of Cronobacter in infant formulas, infant cereals, ingredients, and environmental samples.

Geographic tracing of cereals from South Tyrol (Italy) and neighboring regions via 87Sr/86Sr isotope analysis

The protection and promotion of agricultural niche products can be supported by the application of analytical techniques able to link food to its territory. This study aimed at exploring the possibility to discriminate between cereal samples from South Tyrol (Italy) and the neighboring regions (Trentino, East Tyrol, and North Tyrol) by their 87Sr/86Sr ratios. Soil and grain (different species) samples were collected from around 100 fields in two sampling campaigns. No difference in the 87Sr/86Sr ratios among different cereal species (p < 0.05) was found when cultivated on the same field. A high correlation between 87Sr/86Sr ratios in cereal grains and soil samples was found, with results in line with the local geology characteristics. Cereal samples from South Tyrol showed relatively high 87Sr/86Sr values (0.716 – 0.721, mean 50%), separating them from the other regions investigated and many cereal production areas of global importance.

Diagnosis and Determination of Phosphine by Dynamic Headspace/ICP/AES in Biological Samples

Objective: Inductively coupled plasma atomic emission spectroscopy (ICP/AES) has been used for the determination of phosphine residues in cereal and tissue biological samples. Methods: The method used is based on the reaction of phosphine residue with H2SO4 in a headspace vial, determining the phosphor of the liberated phosphine gas by ICP/AES at 213.6 nm. At this wavelength, there is a linear relationship between emission and concentration of phosphine in the range of 0.10 up to 0.50 μg g-1 (R2 = 0.990). The method is rapid and sensitive with the detection limit of 3.1 μg (S/N =3), and the precision expressed as relative standard deviations (RSD %) is below 12% for 10 replicates. Results: The obtained results showed good agreement with the GC/NPD method. Conclusion: In this study, we develop a rapid analysis, inexpensive, easier handling, simple, repeatable, and sensitive method for the determination of phosphine residue in various samples.

Simultaneous heptamerization of nanobody and alkaline phosphatase by self-assembly and its application for ultrasensitive immunodetection of small molecular contaminants in agro-products

Antibody affinity and enzyme loads are two critical factors in determining the sensitivity of enzyme-linked immunosorbent assay for small molecular contaminants in food. Multimerization is considered an effective strategy to improve antibody affinity and enzyme loads. Herein, we selected ochratoxin A (OTA) as the model antigen and constructed a nanobody-alkaline phosphatase (Nb-ALP) heptamer fusion for OTA, where the Nb and ALP were simultaneously heptamerized via the self-associating peptide from the α-chains of C4 binding protein (C4bpα). The heptamer was used to develop an enhanced colorimetric enzyme immunoassay for OTA. Under the optimal experimental parameters, the proposed method has a half maximal inhibitory concentration of 0.081 ng/mL for OTA, which is 12.5-fold lower than the Nb-ALP-based method. Negligible cross-reaction was observed with OTA analogs and other common cereal mycotoxins. Moreover, good recovery rates and repeatability were obtained in the spiked cereal samples. The developed method was then applied to the analysis of OTA in real agro-products, and the results correlated well with that of the LC-MS/MS method. Overall, this work demonstrated that the simultaneous heptamerization of nanobody and alkaline phosphatase by self-assembly is an effective strategy for improving antibody affinity and enzyme loads. It also showed the great potential of Nb–C4bpα-ALP heptamer as a robust dual-functional probe for sensitive, selective, and rapid detection of mycotoxin and other small molecular contaminants in food. • Dual-functional nanobody-alkaline phosphatase heptamer (Nb–C4bpα-ALP) for OTA. • Simultaneous heptamerization of Nb and ALP by the self-assembly strategy. • Nb–C4bpα-ALP shows better binding affinity and enzyme activity than Nb-ALP. • Nb–C4bpα-ALP-based enzyme immunoassay for small molecules was first reported. • The developed method has an IC 50 of 0.081 ng/mL with the assay time of 20 min.

Temporal and spatial dynamics of Fusarium spp. and mycotoxins in Swedish cereals during 16 years

We analysed the dynamics of Fusarium spp. and mycotoxin contamination in Swedish cereals during 2004–2018. More than 1400 cereal samples from field trials were included, collected in a monitoring programme run by the Swedish Board of Agriculture. Five Fusarium mycotoxins were quantified with LC-MS/MS and fungal DNA from four species was quantified using quantitative real-time PCR. Correlation analyses revealed that deoxynivalenol (DON) and zearalenone (ZEN) were mainly associated with Fusarium graminearum, but stronger correlations with F. culmorum was seen some years. Nivalenol (NIV) was associated with F. poae and the HT-2 and T-2 toxins with F. langsethiae. Clear differences in mycotoxin contamination between different cereal crops and geographical regions were identified. The highest levels of DON and ZEN were found in spring wheat in Western Sweden. For NIV, HT-2 and T-2 toxins, the levels were highest in spring oats and spring barley. Regional differences were not detected for NIV, while HT-2 and T-2 toxins were associated with the northernmost region. We found that delayed harvest was strongly associated with increased levels of DON and ZEN in several crops. However, harvest date did not influence the levels of NIV or HT-2 and T-2 toxins. Our results suggest similar distribution patterns of DON and ZEN, in contrast to NIV and HT-2 and T-2 toxins, probably mirroring the differences in the ecology of the toxin-producing Fusarium species. Timely harvest is important to reduce the risk of DON and ZEN contamination, especially for fields with other risk factors.

The Potential of Traditional ‘Gaja’ and New Breed Lines of Waxy, Blue and Purple Wheat in Wholemeal Flour Fermentation

The aim of this study was to analyse and compare the acidity, microbiological and colour characteristics, fatty (FA) and amino (AA) acid profiles, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations, and macro- and microelement contents in non-treated (non-fermented) and fermented wholemeal cereal flours of ‘Gaja’ (traditional wheat) and new breed lines DS8888-3-6 (waxy wheat), DS8548-7 (blue wheat) and DS8535-2 (purple wheat). Independent fermentations were undertaken with selected strains of Pediococcus acidilactici, Liquorilactobacillus uvarum and Lactiplantibacillus plantarum. The results revealed that all the wholemeal cereal flours of the analysed wheat varieties are suitable for fermentation with the selected strains because all the fermented samples showed lactic acid bacteria (LAB) viable counts higher than 8.00 log10 CFU/g and desirable low pH values. In most of the cases, fermentation increased the concentration of essential amino acids in the wholemeal cereal samples, and the LAB strain used for fermentation proved to be a significant factor in all the essential amino acid content of wholemeal wheat (p ≤ 0.0001). When comparing the non-fermented samples, the highest GABA content was found in ‘Gaja’ and waxy wheat samples (2.47 µmol/g, on average), and, in all the cases, fermentation significantly increased GABA concentration in the wholemeal cereals. On the other hand, total levels of biogenic amines in wholemeal samples ranged from 22.7 to 416 mg/kg. The wheat variety was a significant factor in all the analysed macro- and microelement contents (p ≤ 0.0001) in the wholemeal cereals. Furthermore, fermentation showed to be a significant factor in most of the FA content of the wholemeal cereal samples. Finally, fermentation can also contribute to improving the biological and functional value of wholemeal wheat flours (by increasing essential amino acids and GABA concentrations); however, safety parameters (e.g., biogenic amines) also should be taken into consideration when optimizing the most appropriate technological parameters.

"One-pot" preparation of aminated carbon nanotube-modified magnetic nanoparticles and their application to the quantification of phenoxyacetic acid herbicides in cereal and vegetable samples

有效萃取是分析复杂样品中苯氧羧酸类除草剂(PAs)残留的关键步骤。为此,该文利用“一锅法”水热技术快速、简便地制备了氨基碳纳米管功能化磁性纳米粒子(NH2-CNTs@M)并作为磁固相萃取(MSPE)的萃取介质,用于萃取谷物和蔬菜样品中痕量PAs。研究利用多种手段对NH2-CNTs@M的形貌、尺寸、磁性性质等进行了表征,结果表明Fe3O4的粒径、氨基化碳纳米管的直径以及NH2-CNTs@M的磁饱和值分别为30 nm、40 nm和44.2 emu/g。详细考察了制备条件和萃取参数对NH2-CNTs@M/MSPE萃取性能的影响,结果表明,NH2-CNTs@M/MSPE可通过π-π、疏水和氢键作用有效富集目标化合物,最佳萃取条件如下:吸附剂用量为30 mg,解吸溶剂为含2.0%(v/v)甲酸的乙腈溶液,吸附时间和解吸时间分别为8.0 min和3.0 min,基底pH值为6.0,不调节基底的离子强度。将NH2-CNTs@M/MSPE与高效液相色谱-二极管阵列检测技术(HPLC-DAD)联用,建立了谷物和蔬菜中PAs的灵敏检测方法。谷物和蔬菜基质中苯氧羧酸类除草剂的检出限(LOD, S/N=3)分别为0.32~1.6 μg/kg和0.53~1.6 μg/kg,定量限(LOQ, S/N=10)分别为0.94~4.8 μg/kg和1.6~4.8 μg/kg。在两种实际样品中不同浓度下的加标回收率分别为73.1%~112%和72.3%~113%。与现有方法相比,所建方法具有萃取速度快、灵敏度高和环境友好等特点。

Zearalenone and Its Masked Forms in Cereals and Cereal-Derived Products: A Review of the Characteristics, Incidence, and Fate in Food Processing.

Zearalenone (ZEA) is known as a Fusarium-produced mycotoxin, representing a risk to cereal food safety with repercussions for economies and worldwide trade. Recent studies have reported the co-occurrence of ZEA and masked ZEA in a variety of cereals and cereal-based products, which may exert adverse effects on public health due to additive/synergistic interactions. However, the co-contamination of ZEA and masked ZEA has received little attention. In order to minimize the threats of co-contamination by ZEA and masked ZEA, it is necessary to recognize the occurrence and formation of ZEA and masked ZEA. This review focuses on the characteristics, incidence, and detection of ZEA and its masked forms. Additionally, the fate of ZEA and masked ZEA during the processing of bread, cake, biscuits, pasta, and beer, as well as the ZEA limit, are discussed. The incidence of masked ZEA is lower than that of ZEA, and the mean level of masked ZEA varies greatly between cereal samples. Published data showed a considerable degree of heterogeneity in the destiny of ZEA during cereal-based food processing, mostly as a result of the varying contamination levels and complicated food processing methods. Knowledge of the fate of ZEA and masked ZEA throughout cereal-based food processing may reduce the likelihood of severe detrimental market and trade ramifications. The revision of legislative limits of masked ZEA may become a challenge in the future.

Ion mobility-mass spectrometry to extend analytical performance in the determination of ergot alkaloids in cereal samples

This work evaluates the potential of ion mobility spectrometry (IMS) to improve the analytical performance of current liquid chromatography-mass spectrometry (LC-MS) workflows applied to the determination of ergot alkaloids (EAs) in cereal samples. Collision cross section (CCS) values for EA epimers are reported for the first time to contribute to their unambiguous identification. Additionally, CCS values have been inter-laboratory cross-validated and compared with CCS values predicted by machine-learning models. Slight differences were observed in terms of CCS values for ergotamine, ergosine and ergocristine and their corresponding epimers (from 3.3 to 4%), being sufficient to achieve a satisfactory peak-to-peak resolution for their unequivocal identification. A LC-travelling wave ion mobility (TWIM)-MS method has been developed for the analysis of EAs in barley and wheat samples. Signal-to-noise ratio (S/N) was improved between 2.5 and 4-fold compared to the analog LC-TOF-MS method. The quality of the extracted ion chromatograms was also improved by using IMS.

First step in development and evaluation simultaneous determination of mycotoxins in cereals by liquid chromatography - mass spectrometry

Currently, solid phase extraction (SPE) with immunoaffinity columns is applied in&amp;nbsp;most standardized methods for mycotoxin determination to purify extracts and analysis by&amp;nbsp;HPLC-FLD, HPLC-UV/VIS or LC-MS/MS. Therefore, sample preparation and analysis by&amp;nbsp;instruments are time-consuming and high operating costs. The novel method allow&amp;nbsp;simultaneously identify nine mycotoxin compounds with selective, stable and accurate&amp;nbsp;results. The new method has been evaluated through three stages including validation as&amp;nbsp;requirements of CEN/TR 16059:2010 (phase 1), comparison with current standard methods&amp;nbsp;(phase 2), evaluate the method using an interlaboratory comparison program (phase 3). Cereal samples were extracted by QuEChERS and analyzed by LC-MS/MS. The limit&amp;nbsp;of quantitation (LOQ) was 0,5 &amp;mu;g/kg for each aflatoxin compound and 40 &amp;mu;g/kg, 25 &amp;mu;g/kg,&amp;nbsp;1 &amp;mu;g/kg, 75 &amp;mu;g/kg for&amp;nbsp;deoxynivalenol, zearalenone, ochratoxin A, each toxin fumonisin (B1&amp;amp;B2), respectively. The recovery is in the range of 70-120%, relative standard deviation&amp;nbsp;RSD &amp;lt; 20%. The novel method also gives the same results compared to the individual&amp;nbsp;standardized methods, using the immunoaffinity column in the extraction stage. At the&amp;nbsp;present, the method is being evaluated through an interlaboratory comparison program with&amp;nbsp;two rounds: round 1 (for survey) and round 2 (official round), which is expected to be&amp;nbsp;implemented in 2022. &amp;nbsp;

Quantum-Dot-Bead-Based Fluorescence-Linked Immunosorbent Assay for Sensitive Detection of Cry2A Toxin in Cereals Using Nanobodies.

In this study, a quantum-dot-bead (QB)-based fluorescence-linked immunosorbent assay (FLISA) using nanobodies was established for sensitive determination of the Cry2A toxin in cereal. QBs were used as the fluorescent probe and conjugated with a Cry2A polyclonal antibody. An anti-Cry2A nanobody P2 was expressed and used as the capture antibody. The results revealed that the low detection limit of the developed QB-FLISA was 0.41 ng/mL, which had a 19-times higher sensitivity than the traditional colorimetric ELISA. The proposed assay exhibited a high specificity for the Cry2A toxin, and it had no evident cross-reactions with other Cry toxins. The recoveries of Cry2A from the spiked cereal sample ranged from 86.6–117.3%, with a coefficient of variation lower than 9%. Moreover, sample analysis results of the QB-FLISA and commercial ELISA kit correlated well with each other. These results indicated that the developed QB-FLISA provides a potential approach for the sensitive determination of the Cry2A toxin in cereals.

Behaviour of deep eutectic solvent based on terpenoid and long-chain alcohol during dispersive liquid-liquid microextraction: Determination of zearalenone in cereal samples

In recent years, the numerous articles have been devoted to the application of hydrophobic deep eutectic solvents based on natural terpenoids and long-chain alcohols as extraction solvents in dispersive liquid–liquid microextraction. Typically, the microextraction procedure assumes injection of deep eutectic solvent solution in a dispersive solvent (polar organic solvent) into aqueous phase. The decomposition of deep eutectic solvent in the extraction system can be observed due to the partial dissolution of its precursors in aqueous phase containing the dispersive solvent. In this work, the process of dispersive liquid–liquid microextraction with the use of deep eutectic solvents based on terpenoids and long-chain alcohols was investigated. The extraction systems were applied to the mycotoxin (zearalenone) determination in cereal samples as a model analytical task. The solvent based on dl-menthol and 1-hexanol provided high extraction recovery (93 ± 4) % and satisfactory enrichment factor (15.8 ± 0.7). The limit of detection evaluated from the signal-to-noise ratio was 2 μg/kg. The stability of the deep eutectic solvent in acetonitrile–water mixture was studied using gas chromatography-flame ionization detection and Karl Fisher method. It was shown that the formation of terpenoid-rich phase (60 % (m/m) of menthol) took place during the dispersive liquid–liquid microextraction, and the deep eutectic solvent based on terpenoid and long-chain alcohol cannot be considered as the extraction solvent.

The effects of exogenous fibrolytic enzymes on the in vitro generation of xylooligosaccharides and monosaccharides is dependent upon cereal type

Fibrolytic enzymes are routinely added to non-ruminant livestock feeds to help degrade the non-starch polysaccharide (NSP) contents and thereby improve feed efficiency. This study investigated the range of xylooligosaccharides (XOS) and monosaccharides produced from four cereal samples (barley, maize, oats and wheat) over a 72 h in vitro incubation using 3 commercially available (AB Vista, Marlborough, Wiltshire, United Kingdom) fibrolytic enzymes, Econase XT, Econase MP1000 and Barley P700, all containing endo-xylanase with other combinations of enzymes. Complete non-starch acid hydrolysis showed there were differences between cereals in the total monosaccharide (P < 0.01). There was a cereal x enzyme x incubation time 3-way interaction in the generation of XOS (xylotetraose, xylotriose and xylobiose) (P < 0.01) indicating the generation of XOS varies dependent on both the cereal and the enzyme used. The enzymes failed to generate any detectable xylose from maize. For xylose there was also a cereal x enzyme x incubation time 3-way interaction (P < 0.05). Econase XT generated the greatest quantity of xylose, with 38% of available xylose from wheat being released after 72 h, 11% from barley and 9% from oats, whilst no xylose was detected from maize using any of the 3 commercial enzyme preparations. For arabinose and galactose production there was a cereal x enzyme x incubation time 3-way interaction (P < 0.01), whilst glucose release was only significantly affected by cereal (P < 0.05) or time (P < 0.05). These findings suggest that the fibrolytic enzymes tested have some specificity for certain cereals and therefore it might be possible to optimise the combinations used in animal feeds, to help maximise the feed efficiency of livestock.

Development of a simple and rapid fluorescent aptasensor based on DNA tweezer

AbstractUtilizing the flexible spatial structure and dynamic conformational change of DNA tweezer (DT), a simple and fast fluorescent aptasensor based on fluorescence resonance energy transfer (FRET) was designed. The hinge region and the overhang region were optimized to obtain the satisfied flexibility and controllably conformational change. Using ochratoxin A (OTA) as a simulation target, the established aptasensor showed a simple and time‐saving procedure, higher sensitivity, good selectivity, and good stability with a detection limit of 0.024 ng/ml. Besides, the aptasensor exhibited favorable accuracy with recoveries of 95–103% for spiked cereal samples. The proposed fluorescent aptasensor has a promising potential for the rapid and reliable detection of targets.

A green miniaturized QuEChERS based on an electrospun nanofibrous polymeric deep eutectic solvent coupled to gas chromatography-mass spectrometry for analysis of multiclass pesticide residues in cereal flour samples

A new polymeric deep eutectic solvent (DES) composed of poly (2-hydroxyethyl methacrylate):1-tetradecanol ([PHEMA]:[TD]) was prepared through thermally-induced free-radical polymerization using azobisisobutyronitrile (AIBN) as initiator. The [PHEMA]:[TD] DES was mixed with polyamide 6 (PA6) and electrospun into a composite fibrous scaffold for the first time. The PA6/[HEMA]:[TD] nanofibers were characterized by ATR-FTIR, SEM, BET, and BJH techniques and applied as a sorbent in the micro-solid phase extraction (µSPE) step of pesticide residues from cereal flour samples. The analyses were carried out with the GC–MS technique. The effect of sorbent mass, desorption solvent (kind and volume), pH, and ionic strength was investigated to establish the optimal conditions. Besides, the factors influencing the performance of the electrospinning process, such as electrospinning voltage, polymer solution feed rate, syringe needle tip-to-collector distance, and electrospinning duration, were also optimized. Matrix-matched calibration curves showed good linearity (r2 = 0.9803–0.9984) in the concentration range of 0.016–250 μg kg−1. The obtained limits of quantification (0.016–1.805 μg kg−1) were lower than the maximum residue levels (MRLs) established by the European Union and the Food and Agriculture Organization (0.01–0.05 mg kg−1) for the pesticide residues in cereal samples. The intra-day and inter-day precision based on relative standard deviation (RSD) were obtained as 1.1–5.8% and 2.4–8.5%, respectively. The method was applied to the detection of multiclass pesticide residues in maize, rice, wheat, and pastry flour samples, and the obtained relative recoveries were in the range of 71–118% (RSD%<7.5). Finally, the procedure greenness was evaluated based on Complex Green Analytical Procedure Index (Complex GAPI) and the Analytical Eco-Scale (AEC) approaches. This paper also suggests the first application of green hydrophobic PA6/[PHEMA]:[TD] electrospun nanofibers as sorbent for analyzing pesticides in different cereal samples.

Bio-derived solvent-based dispersive liquid-liquid microextraction followed by smartphone digital image colorimetry for the detection of carbofuran in cereals

Bio-derived solvent-based dispersive liquid-liquid microextraction coupled with smartphone digital image colorimetry (BDS-DLLME with SDIC) was established to detect carbofuran in cereals. Carbofuran was hydrolyzed to benzofuranol by adding Na2CO3 solution. Bio-derived solvent p-cymene as the extractant and acetic acid as the dispersant were utilized in the DLLME process. The Na2CO3 and acetic acid reacted to generate CO2 bubbles, increasing the contact area between the extractant and sample solution. Thus, the rapid and efficient extraction of benzofuranol was achieved. Fe3O4 nanoparticles catalyzed the oxidative coupling reaction between benzofuranol and 4-aminoantipyrine in the presence of H2O2. Thus, the colorless solution was changed to purple-red which was captured using a smartphone and analyzed with an RGB system, achieving the quantitative detection of carbofuran. The concentration of carbofuran had a good linear relationship in the range of 0.02–20 mg kg−1. The limit of quantification was 0.018 mg kg−1, and the limit of detection was 0.005 mg kg−1. This method was successfully applied to analyze cereal samples with the recoveries of 91.1–113.8%. The BDS-DLLME with SDIC method was used to detect carbofuran with good sensitivity, selectivity, and reliability. The developed method has broad application prospects in rapid and efficient extraction and detection.