Pear Juice Samples Research Articles

Exploring Electrochemical Sensing for Fungicide Detection: Utilization of Newly Synthesized Oligomers.

The determination of thiabendazole is crucial for ensuring food safety, environmental protection, and compliance with regulatory standards. Accurate detection helps prevent harmful exposure, ensuring the safety of agricultural products and safeguarding public health. Therefore, this study investigates the electrochemical sensing capabilities of newly synthesized oligo 3-amino-5-mercapto-1,2,4-triazole (oligo AMTa) using hydrogen tetrachloroaurate (III) (HAuCl4) as an oxidizing agent at room temperature for thiabendazole (TBZ) detection, employing a simple electrode fabrication process. The prepared oligo AMTa was thoroughly characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution mass spectroscopy (HR-MS), and Fourier-transform infrared spectroscopy (FT-IR) to confirm its oligomerization structure and properties. The IR spectrum of oligo AMTa reveals a new peak at 1449 cm-1, indicating the conversion of -NH2 groups to -N=N- groups during oligomerization, unlike AMTa. Additionally, the disappearance of the -SH group peak at 2615 cm-1 in oligo AMTa suggests an S-S linkage involvement in the oligomerization process. In the oligo AMTa XPS spectrum, the presence of C=N is displayed by a small peak at 287.3 eV, and oligomerization via -NH and N=N is confirmed by the lack of a 284.0 eV peak for C-C or C=C. Gold nanoparticle formation is not demonstrated by the 84.8 eV peak, which implies that the gold atom is not in the Au0 state. The HR-MS spectrum of oligo AMTa shows a peak at m/z 564.08, indicating a chain of five monomers, and another peak at m/z 435.03, confirming the presence of a tetrameric form of AMTa. After that, the GC electrode was directly linked to the oligo AMTa by the potentiodynamic method. SEM, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were all employed to confirm the fabrication of oligo AMTa. The SEM image illustrates the formation of a particlelike structure with a uniform size of the oligomer after cycling in 0.1 M H2SO4. After electrocycling, the size of the oligomer was reduced from 2.6 μm to 30 nm. The oligo AMTa-modified electrode possesses the highest electroactive surface area and electrical conductivity due to several key factors. First, the presence of amino (-NH2) and thiol (-SH) functional groups in AMTa enhances the surface coverage and density of electroactive sites, increasing the electroactive surface area. Additionally, the conjugated structure of AMTa facilitates efficient electron transfer, resulting in enhanced electrical conductivity compared to unmodified electrodes. Eventually, the electrochemical oxidation of TBZ occurred using the fabricated electrodes. The GC/oligo AMTa electrode exhibited a four-fold increase in oxidation current for TBZ compared to unmodified GC electrodes. This enhancement is due to the improved surface properties from the oligo AMTa modification, which significantly boosts TBZ adsorption through strong interactions like hydrogen bonding and π-π stacking. These interactions, along with the increased surface area and catalytic properties, facilitate effective electron transfer, resulting in a higher oxidation current. As an outcome, the film was employed to determine the sensitivity level of TBZ, and a LOD of 1.8 × 10-11 M (S/N = 3) was found. The straightforward method's practical utility was proven by measuring TBZ in tap water, water spinach, and pear juice samples. The comprehensive characterization of oligo AMTa provided insights into its interaction mechanisms with thiabendazole, contributing to the development of a reliable, cost-effective, and efficient sensor.

A core-shell structured magnetic sulfonated covalent organic framework for the extraction of benzoylureas insecticides from water, pear juice and honey samples

Three magnetic covalent organic frameworks (named M-TpPa-SO3Na, M-TpPa-SO3H and M-TpPa) were prepared by the solvothermal synthesis method with 1,3,5-trimethylphenol (TP) and either 2-sulfo-1,4-phenylenediamine (Pa-SO3H) or p-phenylenediamine (Pa) as monomers. Among them, the M-TpPa-SO3Na possessed relatively high hydrophilicity, good magnetic responsiveness, and high affinity for the benzoylureas (BUs) insecticides. It was then explored as the magnetic solid-phase extraction adsorbent for the extraction of six BUs (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, flufenoxuron and chlorfluazuron) from water, pear juice and honey samples prior to high-performance liquid chromatography with ultraviolet detection. Under the optimized experimental conditions, a good linearity was achieved within the concentration range of 0.27-40.0 ng mL−1 for water sample, 0.47-30.0 ng mL−1 for pear juice sample, and 2.70-200.0 ng g−1 for honey sample. The limits of detection for the analytes were 0.08-0.11 ng mL−1 for water sample, 0.14-0.19 ng mL−1 for pear juice sample and 0.80-1.00 ng g−1 for honey sample. The method recoveries for spiked samples were in the range of 85.0%-111.0% with the relative standard deviations less than 8.8%. The developed method was successfully used for the determination of the BUs in water, pear juice and honey samples.

Target Quantification and Semi-Target Screening of Undesirable Substances in Pear Juices Using Ultra-High-Performance Liquid Chromatography-Quadrupole Orbitrap Mass Spectrometry.

Fruit juices are common products in modern diets due to the supply of vegetal nutrients combined with its tastiness. Nevertheless, potential contaminants, such as mycotoxins and pesticides, can be present in commercial products due to a potential carry-over. Therefore, the aim of this study was to investigate for the first time the presence of 14 Fusarium mycotoxins using a quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction followed by an ultra-high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry in 21 pear juice samples from Italian markets. Up to nine different mycotoxins were detected, particularly an extensive presence of zearalenone (67%, n = 21, mean value = 0.88 ng/mL). Emerging Fusarium mycotoxins enniatins B, B1, A, and A1 were also detected. Additionally, 77 pesticide residues were tentatively identified through a retrospective analysis based on a mass spectral library. The prevalent presence of some non-approved pesticides, such as ethoxyquin (64%, n = 21) and triazophos (55%, n = 21), must be highlighted. The results obtained indicate an extensive contamination of marketed pear juice with undesirable compounds, and they should be taken into consideration when performing risk assessment studies.

Valorization of Prickly Pear Juice Geographical Origin Based on Mineral and Volatile Compound Contents Using LDA.

In the present work the mineral content and volatile profile of prickly pear juice prepared from wild cultivars was investigated. Fruits used in the study originated from three areas of the Peloponnese Peninsula. Twenty-five macro- and micro-minerals (K, Na, P, Ca, Mg, Al, B, Ba, Be, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Sb, Se, Si, Sn, Ti, Tl, V, Zn) were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES). Furthermore, analysis of the mineral content of soil samples with ICP-OES showed a perfect correlation with those of fruit juices. Volatile compounds (alcohols, aldehydes, hydrocarbons, terpenoids, and others) were identified using an optimized headspace solid phase microextraction coupled to gas chromatography mass spectrometry (HS-SPME/GC-MS) method. Multivariate analysis showed significant differences (p < 0.05) among the investigated parameters with respect to juice geographical origin. Prickly pear juice samples were classified according to geographical origin by 85.7% and 88.9% using 7 minerals and 21 volatile compounds, respectively.

Hollow Fiber Stir Bar Sorptive Extraction Combined with GC–MS for the Determination of Phthalate Esters from Children’s Food

In this work, a zeolitic imidazolate framework-based graphene oxide composite (ZIF-8@GO) was prepared and used as the adsorbent in hollow fiber stir bar sorptive extraction. The stir bar was constructed of a small section of hollow fiber filled with 5 mg ZIF-8@GO and a thin stainless wire of 1.5 cm long in its lumen, and used to extract the trace levels of phthalate esters from children’s food samples prior to gas chromatography–mass spectrometric detection. The ZIF-8@GO showed a high adsorption efficiency for the compounds containing aromatic rings. The main experimental parameters that can impact the extraction efficiency including extraction temperature, extraction time, stirring rate, sample salinity, and desorption conditions were investigated. Under the optimized conditions, the limits of detection (LODs) for the five phthalate esters (diethyl phthalate, dipropyl phthalate, diisobutyl phthalate, butylbenzyl phthalate, and di(2-ethylhexyl) phthalate) were 0.15–0.6 µg L−1 for CiCi beverage and pear juice samples, and 0.75–2.2 µg kg−1 for jam samples. The limits of quantitation (LOQs) were 0.5–2.0 µg L−1 for CiCi beverage and pear juice samples, and 2.5–7.5 µg kg−1 for jam samples. Wide linear ranges of 0.5–500.0 µg L−1 and 2.5–2000 µg kg−1 were obtained for CiCi beverage, pear juice samples and jam samples, respectively, with good repeatability (RSD < 11%) and high method recoveries (72%–100%). The lifetime test results showed that the ZIF-8@GO-based hollow fiber stir bar can be reused for 120 extraction cycles without a significant loss of extraction efficiency, indicating its high durability and stability. The established method was applied successfully for the determination of the phthalate esters (PAEs) in children’s food samples.

Multilaboratory Validation of First Action Method 2016.04 for Determination of Four Arsenic Species in Fruit Juice by High-Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry.

Before being designated AOAC First Action Official MethodSM 2016.04, the U.S. Food and Drug Administration's method, EAM 4.10 High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometric Determination of Four Arsenic Species in Fruit Juice, underwent both a single-laboratory validation and a multilaboratory validation (MLV) study. Three federal and five state regulatory laboratories participated in the MLV study, which is the primary focus of this manuscript. The method was validated for inorganic arsenic (iAs) measured as the sum of the two iAs species arsenite [As(III)] and arsenate [As(V)], dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) by analyses of 13 juice samples, including three apple juice, three apple juice concentrate, four grape juice, and three pear juice samples. In addition, two water Standard Reference Materials (SRMs) were analyzed. The method LODs and LOQs obtained among the eight laboratories were approximately 0.3 and 2 ng/g, respectively, for each of the analytes and were adequate for the intended purpose of the method. Each laboratory analyzed method blanks, fortified method blanks, reference materials, triplicate portions of each juice sample, and duplicate fortified juice samples (one for each matrix type) at three fortification levels. In general, repeatability and reproducibility of the method was ≤15% RSD for each species present at a concentration >LOQ. The average recovery of fortified analytes for all laboratories ranged from 98 to 104% iAs, DMA, and MMA for all four juice sample matrixes. The average iAs results for SRMs 1640a and 1643e agreed within the range of 96-98% of certified values for total arsenic.

Oligosaccharide formation during commercial pear juice processing

The effect of enzyme treatment and processing on the oligosaccharide profile of commercial pear juice samples was examined by high performance anion exchange chromatography with pulsed amperometric detection and capillary gas chromatography with flame ionization detection. Industrial samples representing the major stages of processing produced with various commercial enzyme preparations were studied. Through the use of commercially available standards and laboratory scale enzymatic hydrolysis of pectin, starch and xyloglucan; galacturonic acid oligomers, glucose oligomers (e.g., maltose and cellotriose) and isoprimeverose were identified as being formed during pear juice production. It was found that the majority of polysaccharide hydrolysis and oligosaccharide formation occurred during enzymatic treatment at the pear mashing stage and that the remaining processing steps had minimal impact on the carbohydrate-based chromatographic profile of pear juice. Also, all commercial enzyme preparations and conditions (time and temperature) studied produced similar carbohydrate-based chromatographic profiles.

Occurrence of patulin in various fruit juice marketed in Tunisia

Patulin (PAT) is a secondary metabolite, which is mainly produced by certain species of Aspergillus and Penicillium fungi. The objective of this study is to investigate the presence of Patulin in various fruit products marketed and consumed in Tunisia. A total of 214 samples (30 concentrated juice samples, 42 apple juice samples, 42 pear juice samples, 34 mixed juice samples, 35 compote samples, 15 apple jams samples and 16 pear jam samples) were analyzed. The incidence of PAT contamination was 50% with a concentration ranging from 2 to 889 μg/l with an average of 89 μg/l and a median of 41 μg/l. Twenty two percent (22%) of total analyzed samples exceeded the limit recommended by the European Union. Our results showed that PAT seems to be a problem in fruit products marketed in Tunisia, which required and recommended a hard and fast surveillance of this toxin.

Preparation of parathion imprinted polymer beads and its applications in electrochemical sensing

Parathion imprinted polymer beads were prepared by free radical polymerization using parathion as template, methacrylic acid as functional monomer, divinyl benzene as cross-linking reagent and 2,2′-azobis(isobutyronitrile) as initiator. The obtained molecularly imprinted beads were characterized with transmission electron micrograph. The rebinding properties of these imprinted beads towards parathion were studied by saturation binding experiments using ultraviolet/visible spectroscopy. Effects of the template, functional monomer, cross-linking reagent and initiator on selective adsorption of parathion were investigated. The high selectivity of the imprinted beads was successfully demonstrated by their selective adsorption of free parathion from an ethanol–water (v/v = 1:5) solution. In addition, the parathion imprinted beads were dispersed into dihexadecyl hydrogen phosphate solution at the concentration of 1.0 mg mL −1. By coating this solution onto a glassy carbon electrode surface, a molecularly imprinted electrochemical sensor for parathion was obtained. The electrochemical sensor exhibited good selectivity and fast response to parathion. Under optimized experimental conditions, the peak currents were found linearly proportional to the parathion concentration in the range of 1.0 × 10 −7 mol L −1 to 1.0 × 10 −5 mol L −1 with a detection limit of 5.4 × 10 −8 mol L −1 (S/N = 3). The developed sensor was successfully employed for the determination of parathion in pear juice samples.

Simultaneous determination of cypermethrin and permethrin in pear juice by ultrasound-assisted dispersive liquid-liquid microextraction combined with gas chromatography

A new method was developed for simultaneous determination of cypermethrin and permethrin residues in pear juice with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and gas chromatography-flame ionization detection (GC-FID). 3.5 mL of methanol (dispersant) and 30 μL of C 2Cl 4 (extractant) were injected into 5.0 mL of pear juice sample and then emulsified by ultrasound for 2.0 min to forming the cloudy solution. Under the optimum condition, the enrichment factors for cypermethrin and permethrin were 344 and 351 fold respectively. Good linearity was observed in a range of 0.009-1.52 μg g −1 with the correlation coefficient ( r 2)≥0.9993. The limits of detection (LODs) were 3.1 and 2.2 μg kg −1 for cypermethrin and permethrin, respectively (S/N = 3). The recoveries of the method evaluated at three spiked levels were in the range of 92.1%-107.1%. The repeatability evaluated as intra-day and inter-day precision (RSDs) were less than 4.0% (n = 5). The developed method was successfully applied to determine the two pesticide residues in different pear juice samples.

Adulteration of Apple with Pear Juice: Emphasis on Major Carbohydrates, Proline, and Arbutin

Detection of juice-to-juice adulteration based on chemical composition studies is a common method used by government regulatory agencies and food companies. This study investigated the use of major carbohydrate (fructose, glucose and sucrose), polyol (sorbitol), proline, and phenolic profiles as indicators of pear adulteration of apple juice (PAAJ). For this work, a total of 105 authentic apple juice samples from 13 countries and 27 authentic pear juice samples from 5 countries were analyzed. Because the major carbohydrate ranges for these juices showed significant overlap their use as markers for PAAJ detection would be very limited. It was found that sorbitol and proline means for apple and pear were significantly different; however, their broad natural ranges would afford PAAJ at levels up to 30% without detection. In addition, careful selection of the pear juice used as the adulterant would further limit the usefulness of these markers for PAAJ detection. Arbutin was conclusively identified as a marker for pear juice on the basis of its presence in all 27 authentic pear samples and its absence (<0.5 microg/mL) in all 105 apple juice samples analyzed in this study. The application of the developed HPLC-PDA method for arbutin analysis to detect PAAJ at levels as low as 2% (v/v) was demonstrated. A confirmation method for the presence of arbutin in pure pear juice and apple adulterated with pear juice was introduced on the basis of the hydrolysis of arbutin to hydroquinone employing beta-glucosidase, with reactant and product monitoring by HPLC-PDA.

Phenolic compounds in pear juice from different cultivars

The phenolic contents of pear juice samples obtained from seven different varieties were analyzed by HPLC. The results indicated that chlorogenic acid ranged from 73.1 to 249 mg/l, epicatechin from 11.9 to 81.3 mg/l, caffeic acid from 2.4 to 11.4 mg/l and p-coumaric acid from 0.0 and 3.0 mg/l.