Pear Samples Research Articles

Unsupervised anomaly detection for pome fruit quality inspection using X-ray radiography

A novel fully convolutional autoencoder (convAE) was introduced to analyze X-ray radiography images of ‘Braeburn’ apples and ‘Conference’ pears with and without disorders for online sorting purposes. The model was solely trained on either apple or pear samples without disorders and outperformed a traditional autoencoder (AE) across multiple test sets. We evaluated our approach using the area under the curve (AUC) as an evaluation metric. A cross-test experiment further demonstrated consistent performance between a model trained on apple data for classifying pear fruit (accuracy: 71 %) and a pear-specific model (accuracy: 70 %). We also evaluated models trained on simulated X-ray radiographs with real ones, and vice versa. For instance, under scenario of training on real data and testing on simulated X-ray radiographs, an accuracy of 80 % for detecting disordered non-consumable pear was achieved. This work provides valuable insights into anomaly detection for apples and pears with several disorders.

Residue levels and risk assessment of pesticides in fruits from the Aqaba region in Jordan

Quantification and risk assessment of pesticide residues in fruits from the local market at Aqaba/Jordan were performed. To this end, the level of pesticide residue in fruits and the estimated intake (EI) of it resulting from the intake of fruits were quantified. Out of 130 samples, 34 (26 %) contain pesticides above the quantification limit: 10 samples of apple, 6 samples of peach, 10 samples of grape, 2 samples of pear, and 6 samples of cucumber. 13 samples have multiple residues; apples have the highest, with 7 out of 10 samples having multiple residues. All samples did not pose any hazard to public health since (acute Hazard Quotient) aHQ values were <1, except for four peach samples that showed aHQ values above one for the same pesticide (cypermethrin), and the aHQ values were 4.27, 3.14, 2.4, and 1.85. Because of that, training sessions for farmers about good agricultural practices about the use of pesticides with continuous monitoring by official authorities should be planned and well organized.

Оценка различных форм груши кавказской (P. caucasica Fed.) для селекции на декоративность

Abstract. The article describes the results of studying the morphological features of 93 forms of P. caucasica Fed. collected in various regions of the Caucasus. The research was carried out in the collection gardens score, and samples with lower scores, but having one or more attractive decorative features. The studied samples of the Caucasian pear had valuable decorative qualities to varying degrees: narrow pyramidal crown (index 2.16) – Kasp-69-59; rounded crown (index 0.88) – 67-Chr-249, 67-B-208, Ard-69-18; large flowers – Ter-69-77, 67-Ku-139, 67-BZ-37, B-69-111, 67-BZ-67, B-69-87, Kasp-69-59; abundant flowering – P. caucasica Fed. № 2, P. caucasica Fed. №3, P. caucasica Fed. №6, B-69-88, L-69-98, L-69-101, Shali-69-36; attractive appearance of leaves, absence of fungal diseases – Arg-69-34, 67-B-190, Ur-69-1, 67-Chr-250, B-69- 78; anthocyanin integumentary coloration of fruits – P. caucasica Fed. №4 and №5, B-69-108, Kasp-69-59. Frost resistance of plants was an important feature for the use in ornamental gardening. This property was noted in the samples of P. caucasica Fed. №4, B-69-78, Ard-69-18. Samples B-69-90, B-69-78 had edible sweet fruits. Selected forms of the Caucasian pear retained their decorative properties during the growing season. The forms B69-88, B-69-78, Kasp-69-59, L-69-96, 67-Ku-127 can have the greatest value for breeding in terms of the sum of points and the presence of valuable features. Keywords: the Caucasus, the Caucasian pear, decorativeness, morphology, diversity of features, selection, breeding Financing source: The research was carried out at the expense of a grant from the Federal State Budgetary Educational Institution «Maikop State Technological University» «Assessment of various forms of Caucasian pear (P. caucasica Fed.) for breeding for decorative purposes», registration number of the scientific project: NP 8-2024 of the Maikop Experimental Station – a branch of All-Union Research Institute of Plant Breeding (VIR) in 2021-2023s in accordance with modern methods of studying and assessing the decorative properties of research objects. Twenty-two samples were identified, including those with the highest total decorative

Research on the Maturity Detection Method of Korla Pears Based on Hyperspectral Technology

In this study, hyperspectral imaging technology with a wavelength range of 450 to 1000 nanometers was used to collect spectral data from 160 Korla pear samples at various maturity stages (immature, semimature, mature, and overripe). To ensure high-quality data, multiple preprocessing techniques such as multiplicative scatter correction (MSC), standard normal variate (SNV), and normalization were employed. Based on these preprocessed data, a custom convolutional neural network model (CNN-S) was constructed and trained to achieve precise classification and identification of the maturity stages of Korla pears. Additionally, a BP neural network model was used to determine the characteristic wavelengths for maturity assessment based on the sugar content feature wavelengths. The results demonstrated that the BP model, based on sugar content feature wavelengths, effectively discriminated the maturity stages of the pears. Specifically, the comprehensive recognition rates for the training, testing, and validation sets were 98.5%, 93.5%, and 90.5%, respectively. Furthermore, the combination of hyperspectral imaging technology and the custom CNN-S model significantly enhanced the detection performance of pear maturity. Compared to traditional CNN models, the CNN-S model improved the accuracy of the test set by nearly 10%. Moreover, the CNN-S model outperformed existing techniques based on partial least squares discriminant analysis (PLS-DA) and support vector machine (SVM) in capturing hyperspectral data features, showing superior generalization capability and detection efficiency. The superior performance of this method in practical applications further supports its potential in smart agriculture technology, providing a more efficient and accurate solution for agricultural product quality detection. Additionally, it plays a crucial role in the development of smart agricultural technology.

Cultivated plants and their wild relatives of Central Russia and the North Caucasus (results of a collecting mission of 2023)

In 2023, field explorations of cultivated plants and their wild relatives were carried out in the regions of the Volga Upland, the western part of the Caspian Lowland and the Stavropol Upland with the aim of further replenishing seed and herbarium collections of VIR.A total of 525 samples of CWR and cultivated plants were collected, including 200 are herbarium sheets, 323 seed samples of cultivated plants and CWR, and a couple of cuttings. The collected material encompasses 145 species, including 91 cultivars. Seeds of the cultivars were purchased at markets, in supermarket chains and from local residents. The following areas were examined in detail: the left bank of the Lower Volga (Peschany anabranch, Kigach anabranch, as well as the “Novaya Roshcha” protected area). In the Republic of Ingushetia the team collected samples of cherry plum, Caucasian pear, barberry, viburnum, Lonicera orientalis, sea buckthorn, raspberry, and Malus orientalis, which local residents use in their diet. Also, samples of spicy herbs such as savory, catnip, oregano, thyme, etc. were collected. Hops were sampled in the Tambov and Volgograd provinces, the Republics of Ingushetia, North Ossetia and Adygea, from abandoned household plots in Botanika village in Gulkevichi District (Krasnodar Territory). The exploration in vicinities of Derbent and of the wall of Naryn-Kala fortress in Derbent resulted in collecting a rare specimen of Secale sylvestre Host., which previously used to be a fairly common plant in the North Caucasus, but is very rare now. Vegetable crops were collected along the entire route of the collecting mission. It was not always possible to collect seeds, so a part of the material enriched the herbarium collection. The collected material reflects the use of a vast range of vegetable and spicy plant species by the local population.Collecting missions help to understand which species are of primary importance for the conservation of natural processes, biodiversity and the maintenance of local ecosystems. The genetic diversity of a region is a key object of research for geneticists and plant breeders. Landraces of vegetable, cereal and other crops may have unique properties, such as adaptation to local climate conditions or disease resistance. Work on the mobilization and conservation of the plant genetic diversity is the basis for modern breeding and genetic research.

NiFe2O4 nanoparticles grafted sulfonated melamine for rapid magnetic dispersive µ-solid phase extraction of pesticides in apple and pear samples: Greenness evaluation

In this research, a facile and rapid magnetic dispersive µ-solid-phase extraction technique based on novel and high-performance sulfonated melamine-modified NiFe2O4 nanoparticles was developed forsimultaneous extraction and separation of fifteen pesticides followed by gas chromatography-mass spectrometry. The characterization of the synthesized nano-adsorbent was carried out using scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FT-IR) techniques. The substantial factors including pH, the amount of nano-sorbent, ionic strength, sample volume, and desorption conditions (i.e. desorption solvent type and volume, and desorption time) on the extraction efficiencies of the interest pesticides from apple and pear samples were explored using the matrixed match method. Under the optimum conditions, the linear range of 0.2-500µg kg−1, LODs, and LOQs in the range of 0.065–0.077µg kg−1 and 0.22–0.26µg kg−1 for apple and 0.065–0.085µg kg−1 and 0.22–0.29µg kg−1 for pear were acquired. The intra-day and inter-day precisions were evaluated at three spiked concentration levels (10, 50, and 100 μg kg−1 of each analyte) on the same day and five distinct days, respectively. The RSD (%) values were ≤ 3.6 % for intra-day (n = 6) and ≤ 4.3 % for inter-day (5 days and n = 3) precisions. High relative recoveries of 92.5–98.9 % revealed high potential of the presented method for analysis of pesticides in complex matrixes. Moreover, Analytical Greenness metric approach was applied and consequently confirmed the greenness of the method which accompanied with the green analytical aspects.

Fruit grading system by reconstructed 3D hyperspectral full-surface images

Conducting hyperspectral imaging of fruit' entire surfaces while simultaneously evaluating their physical properties, such as volume and mass, can provide a richer dataset for comprehensive fruit classification. For this purpose, a fruit grading system using 3D hyperspectral full-surface images is developed, which is based on multi-view imaging of mirrors in the hardware structure design and relies on the virtual volume intersection (VI) algorithm and texture technology in software design. During the design process, a mathematical model for the mirror layout and system geometry parameters is established to determine the system's layout for scanning the entire surface of the sample. In practical applications, a prototype with 28 channels ranging from 400 to 1000 nm is developed for pear samples based on a sub-component control system, a spherical-cap cavity with flashing multi-color LEDs, and multiple side mirrors. The results obtained from this prototype reveal that the predicted volume (R2=96.18%) and mass (R2=98.18%) exhibit a high correlation with measured results and the hyperspectral data between bruised and normal pears is a significant difference. A dataset of pears of three qualities (large, small, and bruised) is prepared for comprehensive classification and resulting in an effective grading (95.33%), which shows that the proposed system is a potential solution for comprehensive fruit quality classification.

Development of a sensitive lateral flow immunoassay for the rapid detection of butralin in fruits

Butralin is a dinitrobenzene pesticide, has been widely used as a herbicide in many crops. Its high levels of residues threaten the ecological balance and human health. Therefore, establishment of a sensitive monoclonal antibody (mAb) for rapid detection of butralin residues is critical. In this study, special haptens were designed with good preservation of the characteristic structure of target compound. After mice immunization, a highly sensitive monoclonal antibody was produced. The half-maximum inhibitory concentration (IC50) was 1.936 ng/mL. And we applied it to develop a method of lateral flow immunoassay (LFIA), with vLOD value of the LFIA strip to be 10 ng/mL. In watermelon and pear samples, the cLOD values of the LFIA strip were 0.432 ng/mL and 0.426 ng/mL, respectively. The recoveries of the developed method ranged from 94.4% ± 2.1%–112.1% ± 3.4% and 89% ± 5.4%–103% ± 4.1% in watermelons and pears samples, with a CV of 2.9%–3.4% and 2.2%–5.2%, respectively. The results demonstrated that the developed method showed great prospect in the detection and monitoring of butralin in real food samples.

Drying Kinetics of Pear Slices in Greenhouse Solar Dryer

An experimental study was performed to determine the drying characteristics of pear using greenhouse based solar dryer and under open sun with natural convection. Prior to drying, sliced pear samples were pre-treated: i) control inside dryer i.e. with no dip, ii) blanching, iii) soaking in 2% KMS (Potassium Metabisulphite) solution, iv) blanching and soaking in 1% KMS solution, v) control outside dryer i.e. with no dip. The experimental drying data of pear were fitted to five different mathematical models viz. Exponential, Generalized exponential, Page’s, Logarithmic and Power law models, and drying rate constants and coefficient of models tested were determined by non-linear regression analysis. Among the various models tested to interpret the drying behaviour of pear, Page’s model was selected which gave best statistical indices of coefficient of determination (R2) and standard error of estimation (SEE) values.

First Report of Lasiodiplodia pseudotheobromae Causing Necrosis and Canker Disease on Pear Tree in China.

Pear ispopularamongpeople, which is an important pillar industry in China. In March of 2023, dark brown necrotic lesions were discovered on the trunks of Pyrus pyrofolia cv. Osmanthus pear in orchard, Liuzhou City, Guangxi Zhuang Autonomous Region. In August, field investigation and sample collection were conducted in orchard. Forty pear trees were selected for symptomatic observation, which of 21 had lesions ranging from 10 to 24 per tree, and 19 with 1 to 8 lesions, respectively. To isolate the pathogen, small tissue pieces of 3 diseased pear trunk samples were disinfected with 75% ethanol for 1 minute, rinsed with sterile water, and dried with filter paper. The tissue pieces were placed on potato dextrose agar (PDA) plates and cultured in a dark incubator at 25℃. Six isolates with the similar morphology were obtained. One of the six isolates was randomly selected as the representative strain and named as GX-3. Mycelium grows with an average rate of 4.26 cm/d. The hypha is highly aerial, and is initially white and then turns black. Subsequently, pycnidia formed and secreted black mucus on the PDA medium after 28 days. The immature conidia were ellipsoid, colorless, hyaline, and unicellular, mostly becoming brown bicellular with longitudinal stripes at maturity. The conidial size was 22.5 to 32.6×12.1 to 19.7μm, and the average size was 28.4±2.3×16.7±2.0 μm (n=50), respectively. GX-3 colony morphology was consistent with that of Lasiodiplodia pseudotheobromae (Alves et al.2008). For molecular identification, the internal transcribed spacer of rDNA (ITS), translation elongation factor 1-α (TEF1-α), and β-tubulin regions were amplified using the primers ITS1/4, EF1-728F/986R, and Bt2a/Bt2b, respectively (White et al.1990; Carbone and Kohn 1999; Glass and Donaldson 1995). The obtained sequences of GX-3 were deposited in NCBI with Accession numbers OR655421, OR661231, and OR661230, respectively. The sequences of ITS, TEF1-α, and β-tubulin from GX-3 are 99.44%、99.67% and 99.78% identities with those of L. pseudotheobromae CBS 447.62, respectively. The phylogenetic analysis was performed by maximum likelihood method, revealing that GX-3 is closely clustered with the isolates of L. pseudotheobromae. Therefore, the GX-3 strain was identified as L. pseudotheobromae. GX-3wasfurtheranalyzedforitspathogenicityonpear. Firstly, the GX-3 mycelium plugs and spraying spore suspension with the concentration of 1×107 conidia/ml were applied on the stems of 4-month-old healthy birch-leaf pear (Pyrus betulifolia Bunge) potted seedlings by acupuncture needle method, meanwhile PDA and sterile waterwere usedascontrols. After 3 days of inoculation, stem surface of the birch-leaf pear exhibited dark brown lesions with slight surface depression, obvious dryness, and canker symptoms, while the control treatment showed no symptoms. The GX-3 was also inoculated on in vitro branches of 'Hosui', 'Hongxiangsu', 'Bodoqing' and 'Xuehua', showing dark brown canker lesions. The same pathogen can be successfully isolated from diseased stems and branches but not from the controls, which accomplishes Koch's postulates. L. pseudotheobromae has been widely reported that it can cause rot and canker on apple, walnut, hackberry, and so on (Xue et al. 2019; Wang et al. 2023; Liang et al. 2020). This is the first report of necrosis and canker disease caused by L. pseudotheobromae on pear in China, which is a potential threat to pear industry.

Heterologous antigen selection of chicken single-chain variable fragments against thiamethoxam.

Single-chain variable fragments (scFvs) are valuable in the development of immunoassays for pesticide detection. In this study, scFvs specific to thiamethoxam (Thi) were successfully isolated from a library generated by chicken immunization through heterologous coating selection. These scFvs were subsequently expressed with fusion with an Avi tag and alkaline phosphatase. After combination and optimization, a scFv-biotin based enzyme linked immunosorbent assay (ELISA) was developed for the detection of Thi, demonstrating an impressive half-maximum signal inhibition concentration (IC50) of 30 ng mL-1 and a limit of detection (LOD) of 1.8 ng mL-1. The immunoassay exhibited minimal cross-reactivity with other neonicotinoid insecticides, except for 7.5% for imidacloprid and 6.7% for imidaclothiz. The accuracy of the assay was confirmed by testing spiked samples of apple, pear, cabbage, and cucumber, which resulted in average recoveries ranging between 82% and 119%, closely aligning with the results obtained through high-performance liquid chromatography. Therefore, the chicken scFv-biotin based assay showed promise as a high-throughput screening tool for Thi in agricultural samples.

Genome analysis of viruses of Phenuiviridae, Betaflexiviridae and Bromoviridae, and apple scar skin viroid in pear by high-throughput sequencing revealing host expansion of a rubodvirus and an ilarvirus

Pear (Pyrus spp.) is an important perennial fruit crop of India. During May 2022, pear leaf samples were collected from the orchard of ICAR-Indian Agricultural Research Institute, Regional Station, Dhanda, Shimla, Himachal Pradesh, India. RNA sequencing of two pooled samples, Pe1 and Pe2, was done using NovaSeq 6000. Host unaligned reads were de novo assembled into contigs and annotated through BLAST using the virus database. Near complete genome sequences of apple rubbery wood virus 1 (ARWV-1), apple necrotic mosaic virus (ApNMV), citrus virus A (CiVA), apple stem grooving virus (ASGV), apple stem pitting virus (ASPV), apple chlorotic leaf spot virus (ACLSV), and a genetic variant of ASGV named as ASGV-Shimla, and a partial sequence of apple scar skin viroid (ASSVd) were assembled. ARWV-1 and ApNMV belong to the genus Rubodvirus and Ilarvirus having tripartite negative sense and positive sense single stranded RNA genomes, respectively, and their presence in pear trees was observed for the first time indicating the host expansion. Presence of CiVA, ASGV and ACLSV in pear in India was also recorded for the first time in India. The fragments per kilobase of transcript per million reads mapped estimation showed the dominance of ASPV and CiVA in Pe1 and Pe2, respectively. Single nucleotide variants (SNVs) analysis revealed that ASPV had the highest number of SNVs (477), while ACLSV had the lowest number of SNVs (1). The presence of ARWV-1, ApNMV, CiVA, ASPV, ASGV, ACLSV, ASGV-Shimla, and ASSVd was also confirmed in pear samples through Sanger sequencing. The present study widens our understanding of the pear virome and host range expansion of viruses in the genus Rubodvirus and Ilarvirus. This information will be useful in biological study of these viruses and virus indexing programs in pear.

Acute and chronic exposure risks of insecticide residues in fresh commodities collected from Bursa province markets during winter season

This study shows the findings about pesticide residues and the associated acute and chronic exposure risks of different fresh commodities collected from different markets located in Bursa province during 2023 winter season. For this purpose, pesticide residue levels of the collected samples were analysed with LC-MS/MS. Highest levels of insecticide and acaricide residues were detected in some lettuce, parsley, dill, carrot, pear, mandarin and banana samples and they were exceeded the maximum residue limit (MRL). The acute and the chronic exposures to pesticides were assessed by using the highest and the average redidue levels of each pesticide respectively. Highest acute exposure was calculated as acute reference dose (ARfD) exceedance rate and it was 104.27% for indoxacarb in apples, 107.06% and 137.11% for lambda-cyhalothrin in pears and mandarins, and 158.2% for phosmet in pears. For all commodity types, none of the pesticide residues displayed chronic hazard. When the cumulative long-term exposure evaluated, none of the insecticides was found to be risky for adults. The findings showed that the levels of insecticide residues on lettuce, parsley, dill, carrot, apple, pear, mandarin, orange and banana samples collected from Bursa markets in winter 2023 could not be considered as an important public health risk.

Voltammetric nano-molar range quantification of agrochemical pesticide using needle-like strontium pyrophosphate embedded on sulfur doped graphitic carbon nitride electrocatalyst

The development of a viable sensor for agrochemical pesticides requires the assessment of trace levels. To achieve this, we developed a diphenylamine (DPA) sensor using needle-like strontium pyrophosphate embedded in sulfur-doped graphitic carbon nitride (SrPO/SCN). We obtained needle-like SrPO/SCN nanocomposite through co-precipitation followed by ultrasonication. The formation of the SrPO/SCN nanocomposite was verified through FT-IR, XRD, XPS, SEM-EDX, and HR-TEM analyses. Additionally, we explored their electrochemical behavior towards DPA using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The SrPO/SCN nanocomposite-modified electrode exhibited a higher anodic peak current (15.47 µA) than those of the other modified and unmodified electrodes. Under optimal experimental conditions, SrPO/SCN/GCE demonstrated a good limit of detection (0.009 µmol/L), dynamic linear range (0.05–98 µmol/L), and sensitivity (0.36 µAµM-1cm−2). Furthermore, the developed sensor exhibited excellent reproducibility, selectivity, and stability, and successfully detected DPA in real samples, including pear and apple samples, with good recoveries.

Comparative evaluation of greenhouse gas emissions and specific energy consumption of different drying techniques in pear slices

AbstractIn recent years, global warming, climate change, and carbon emissions have emerged due to the uncontrolled use of fossil fuels and the lack of widespread use of renewable energy sources on a global scale. This research investigated specific energy consumption (SEC) and greenhouse gases (GHG) emissions (carbon dioxide [CO2] and nitrogen oxides [NOX]) during the drying of pear samples by five different types of dryers, namely, convective (CV), infrared (IR), microwave (MW), combined IR/CV, and MW/CV. Moreover, the quality properties of dried pears, such as shrinkage, rehydration (RR), and color change were determined. The results showed that the highest shrinkage (72.53%) and color change (ΔE = 33.41) values were obtained in CV drying at 50 °C and thickness of 2 mm and IR dryer 1000 W and thickness of 6 mm, respectively. The greatest rehydration rate (4.25) was also determined in MW/CV drying at 450 W and an air temperature of 60 °C. The lowest SEC was observed for the MW/CV dryer with a power of 630 W and air temperature 70 °C (20.25 MJ/kg), while the highest SEC (267.61 MJ/kg) was obtained in the CV drying (50 °C, sample thickness of 6 mm). The highest CO2 and NOX emissions (GT-GO power plant) were 280.45 and 1.55 kg/kg water in the CV dryer at 50 °C and a thickness of 6 mm. In conclusion, the increases in IR and MW power and temperatures led to reduced CO2 and NOX emissions, while the increases in sample thickness led to increase CO2 and NOX emissions.

A robust electrochemical sensor based on AgNWs@MoS2 for highly sensitive detection of thiabendazole residues in food samples

Thiabendazole (TBZ), a highly toxic phosphorothioate insecticide commonly used in postharvest fruit management, has the potential to cause detrimental effects on human health as an endocrine disruptor. In this study, an electrochemical sensor was developed to detect TBZ by modifying MoS2 on silver nanowires (Ag NWs@MoS2) and integrating them onto a glassy carbon surface. Cyclic voltammetry revealed that TBZ underwent an irreversible, diffusion-controlled process on Ag NWs@MoS2, leading to a two-fold increase in peak current compared to unmodified MoS2. Square wave voltammetry facilitated TBZ detection, and the sensor exhibited a linear range of 0.05–10 μM with a high coefficient of determination (R2 = 0.9958) and a limit of detection (LOD) of 1.75 nM (signal-to-noise ratio = 3). The sensor's applicability for food safety monitoring was verified through TBZ analysis in pear and apple samples, achieving recoveries of 95.5–103.6% with RSDs in the range of 1.98–3.25%.

Bimetallic CoCu nanoparticles anchored on COF/SWCNT for electrochemical detection of carbendazim

Carbendazim (CBZ) is a widespread fungicide used in crop protection, but the CBZ residues in drinking water, fruits, and vegetables can also cause adverse impacts on public health due to direct exposure. In this paper, a ternary synergistic composite of bimetallic CoCu nanoparticles anchored on covalent organic framework/single-walled carbon nanotube (CoCu/COF/SWCNT) was prepared and further applied as an electrochemical sensing platform for detecting CBZ. The sensor showed a sensitive response performance toward CBZ oxidation, as a result of the enhanced charge transfer ability, large electrochemically active surface area, and high electro-catalytic activity from the rational integration of the ternary components in CoCu/COF/SWCNT. Under the optimal conditions, the proposed sensor exhibited a detection range of 0.001 to 10 μM and a limit detection of 0.65 nM for CBZ detection. In addition, the sensor displayed practical feasibility for the determination of CBZ in water and pear samples with a recovery of 96.1 % to 102.1 %.

A Colorimetric Sensor Enabled with Heterogeneous Nanozymes with Phosphatase-like Activity for the Residue Analysis of Methyl Parathion.

In this study, a colorimetric sensor was developed for the detection of organophosphorus pesticides (OPs) using a heterogeneous nanozyme with phosphatase-like activity. Herein, this heterogeneous nanozyme (Au-pCeO2) was obtained by the modification of gold nanoparticles on porous cerium oxide nanorods, resulting in synergistic hydrolysis performance for OPs. Taking methyl parathion (MP) as the target pesticide, the catalytic performance and mechanism of Au-pCeO2 were investigated. Based on the phosphatase-like Au-pCeO2, a dual-mode colorimetric sensor for MP was put forward by the analysis of the hydrolysis product via a UV-visible spectrophotometer and a smartphone. Under optimum conditions, this dual-mode strategy can be used for the on-site analysis of MP with concentrations of 5 to 200 μM. Additionally, it can be applied for MP detection in pear and lettuce samples with recoveries ranging from 85.27% to 115.87% and relative standard deviations (RSDs) not exceeding 6.20%, which can provide a simple and convenient method for OP detection in agricultural products.

Identification of quality markers for the geographical and botanical differentiation of Mediterranean prickly pears based on conventional physicochemical parameters, volatile compounds, sugars and colour

Seventy-four prickly pear samples grown in Mediterranean countries (Cyprus, Greece, Italy and Spain) and 43 prickly pear samples, from 3 different Cypriot varieties (Yellow, Red and Spineless), were characterized and differentiated according to geographical and botanical origin. Prickly pear conventional quality parameters (pH, electrical conductivity, titratable acidity, moisture content, crude fat and protein, total carbohydrates and ash) were determined using official methods of analysis. Colour parameters were determined using HunterLab tristimulus colorimetry and individual sugars using UPLC–MS/MS. Volatile compounds were identified and semi-quantified using solid-phase microextraction in combination with gas chromatography–mass spectrometry. Multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) were used to analyze the experimental data. Results showed that the combination of physicochemical parameters and volatiles gave a correct differentiation rate of 80.8% according to geographical origin while the combination of physicochemical parameters gave a correct differentiation rate 95.3% according to botanical origin using the cross-validation method.

Detection of neonicotinoids in agricultural products using magnetic molecularly imprinted polymers-surface enhanced Raman spectroscopy

In this paper, magnetic molecularly imprinted polymers-surface-enhanced Raman spectroscopy (MMIPs-SERS) for rapidly analyzing acetamiprid and thiacloprid in agricultural products has been firstly developed. The magnetic imprinted polymers were obtained by polymerizing the imprinted layers on the surface of magnetic nanoparticles. The polymers were detailed characterized by using series of analytical techniques, and their adsorption and recognition performance were validated by adsorption tests. The results showed that the magnetic molecularly imprinted polymers possessed typically core-shell structure and exhibited class-specific recognition, fast adsorption saturation (only 1 min), and good magnetic separation performance towards targets. The adsorption and desorption conditions for MMIPs-SERS detection system were carefully investigated. Under optimum conditions, the good linear detection range of 1∼20 μg/g with LODs of 23.7–68.8 ng/g for acetamiprid and thiacloprid in peach and pear samples was obtained. Through the reusable and spiked experiments, the developed MMIPs-SERS method based on Au NPs as enhanced substrate was validated to be highly sensitive, accurate, efficient and applicable in analyzing neonicotinoids from pear and peach samples. This study provided a rapid and simple detection method for neonicotinoids with effective separation and detection properties based on the synergistic effect of imprinted polymers and SERS. More importantly, this developed method have good application potential in rapid analyzing field for neonicotinoids due to the amazing rapid adsorption time for extracting targets from complex food matrix (only 1 min).