Food Analytical Methods最新文献

In this study, steady-state and time-resolved fluorescence spectroscopy techniques have been applied to determine fluorescence characteristics and fluorescence decay kinetics parameters (fluorescence lifetimes and their amplitudes) of available on the Polish market bee products, including several nectar honeys, royal jelly, bee bread in honey and in liquid artificial honey. The fluorescence properties of the tested bee products arise from the presence of a unique composition of aromatic amino acids, vitamins, phenolic compounds and Maillard reaction products. In the 300–550 nm region of the emission spectra (excited at 280 nm), each of the tested bee products exhibited (showed) a specific and distinctive vibronic structure, which was not observed in the spectrum of artificial honey. Quantitative and qualitative composition as well as specific interactions between fluorescent constituents determine the specific fluorescence characteristics of a given bee product providing a unique fingerprint that can be used in the identification of bee products of different botanical origin. Combination of stationary and time-resolved fluorescence techniques seems to be a promising approach in the identification, authentication and quality control of bee products to verify their health-beneficial properties.

Mycotoxin contamination in agri-food systems has been a serious global concern over the past few decades. Corn is easily contaminated by Ochratoxin A (OTA) and Zearalenone (ZEN), which seriously threaten the survival and health of humans and animals. Herein, a rapid and sensitive method of OTA and ZEN dual quantum dots (QDs) fluorescence immunochromatographic test strip was established in this study. OTA and ZEN fluorescence probes were prepared by carbodiimide. The OTA-OVA, ZEN-BSA and staphylococcal protein A were sprayed on the nitrocellulose filter membrane as the T1 line, T2 line and control line of the dual test strip, which exhibited high sensitivity, accuracy and specificity. For quantitative detection of OTA, the linear regression equation was y = 0.3222x + 0.3834 (R² = 0.9687), LOD and IC₅₀ were 0.132 ng/mL and 2.296 ng/mL, and the linear detection range was 0.269 ng/mL to 19.588 ng/mL. In addition, for quantitative detection of ZEN, its linear regression equation was y = 0.3077x + 0.3777 (R² = 0.9648), LOD and IC₅₀ were 0.125 ng/mL and 2.495 ng/mL, and the linear detection range was 0.264 ng/mL to 23.55 ng/mL. Briefly, the OTA and ZEN dual QDs immunochromatographic test strip was favored for the simultaneous detection of OTA and ZEN in corn.

Tetracyclines (TCs) are among the most widely used antibiotics worldwide for treating bacterial infections (both Gram-positive and Gram-negative) in humans and animals. In Brazil, chicken is one of the most produced and traded meats, with TCs being the primary antibiotics used in its production. This study applied two experimental designs to optimize the QuEChERS method for simultaneous quantitative analysis by HPLC–DAD of three TCs (tetracycline, chlortetracycline, and oxytetracycline) in chicken. The optimized conditions of the QuEChERS method for the preconcentration of TCs were 500 mg of sample, 1000 mg of Na₂SO₄, 700 mg of NaCl, 100 mg C18, 100 mg of PSA in 10 mL of the extracting solvent, vortex for 1 min, and centrifugation 4000 rpm for 5 min with a total run time of 10 min. LOQ values were lower than the MRL for all antibiotics established by ANVISA, precision in intra-day and inter-day ranged from 0.1 to 5.0%, and recovery ranged from 80 to 101%, greatly improving the work efficiency. The analytical method was applied to four commercial chicken breast samples and other proteins, one for beef and one for pork, of which no residues were found. The “GREEnness” of the optimized method demonstrated that the proposed approach made it possible to develop a “greener” method than traditional methods.

Lettuce (Lactuca sativa L.) is one of the most consumed vegetables worldwide and is considered a good source of health-promoting compounds. The objective of this work was to apply a multivariate design of experiments through a screening stage followed by optimization of factors that affect the extraction of phytochemicals present in lettuce. A response surface methodology was employed and, specifically, a central composite design model, for the optimization of the methods. The optimal conditions for the extraction of chlorophyll a, b, and total carotenoids were as follows: 4.8 mL of acetone:water (80:20 v/v) and 10 mg of sample with ultrasound-assisted extraction for 5 min. On the other hand, for anthocyanin and phenolic compounds, the optimal conditions were as follows: 5 mL of acetone:acidified water (80:20 v/v) and 20 mg of sample for 5 min with ultrasound-assisted extraction. The experimental model was followed by spectrophotometry methodology for a comprehensive characterization. Optimal conditions were applied for the simultaneous extraction and determination of the above-mentioned compounds in different lettuce cultivars. Both extraction methods successfully extract different phytochemicals by reducing the volume of solvent, sample mass, and extraction time compared to previously reported methods. The results obtained showed a significant variability in the content of phytochemicals; therefore, it could be estimated that the different cultivars of lettuce evaluated will exhibit different beneficial health effects.

This manuscript proposes a new extraction method for analyzing natural compounds in herbal supplements for weight loss and determining adulterants by a comprehensive two-dimensional gas chromatography system coupled to a quadrupole time-of-flight mass spectrometer (GCxGC/Q-TOFMS). In this new approach, a hydrophilic microporous cartridge (HMCart) was developed to enclose the samples, protecting the SPME (solid-phase microextraction) fibers. The cartridge is loaded with herbal supplement samples during direct immersion of SPME fiber in the aqueous phase to allow the analytes to be trapped. The new sample preparation method using chromatographic analyses enabled the detection of 650 compounds, including natural compounds, such as terpenes, aldehydes, ketones, and fatty acids. Adulterants found in other studies in the literature, such as sibutramine and ephedrine. The fluoxetine and caffeine were detected and quantified. The new method has achieved the goal of simple, effective, solvent-free, and versatile sample preparation that can be applied in future studies, including determining other compound classes in various matrix samples.

In the present study, cold atmospheric plasma (CAP) was employed as a pretreatment method for the extraction of phenolic compounds from spent coffee grounds (SCGs). The impact of CAP treatment conditions, i.e., thickness of the SCGs layer (mm), distance between the plasma source and the SCGs layer (mm) and duration of CAP treatment (min), on the total phenol content, in vitro antioxidant activity, as well as caffeine and chlorogenic acid content of SCGs, was investigated. The process parameters were optimized with the aid of response surface methodology (RSM). After optimizing the CAP pretreatment conditions, the CAP-treated SCGs were subjected to ultrasound-assisted extraction using ethanol as the extraction solvent. The optimum conditions for CAP treatment identified, i.e., thickness, 1 mm; distance, 16 mm; and duration, 15 min, led to a significant enhancement in the recovery of bioactive compounds from SCGs compared to those obtained from untreated SCGs. Total phenolic content and antioxidant activity significantly increased (i.e., TPC from 19.0 ± 0.7 to 24.9 ± 1.4 mg GAE/100 g dry SCGs, A_DPPH from 106.7 ± 5.01 to 112.3 ± 4.3 μmol Trolox/100 g dry SCGs, A_ABTS from 106.7 ± 5.01 to 197.6 ± 5.8 μmol Trolox/100 g dry SCGs, A_CUPRAC from 17938 ± 157 to 18299 ± 615 μmol Trolox/100 g dry SCGs). A significant increase in caffeine content from 799.1 ± 65.1 mg to 1064 ± 25 mg/100 g dry SCGs and chlorogenic acid content from 79.7 ± 15.3 mg to 111.3 ± 3.3 mg/100 g dry SCGs, was also observed. Overall, CAP pre-treatment can be used to enhance the recovery of bioactive compounds from SCGs.

This study delves into the electrochemical properties of ascorbic acid (AA) in garlic bulbs, employing both a glassy carbon electrode (GCE) and an activated glassy carbon electrode (AGCE). Cyclic voltammetry (CV) and square wave voltammetry (SWV) were utilized for the thorough characterization and detection of AA in freshly harvested garlic bulbs sourced from Debark, Ethiopia. The AGCE was meticulously prepared through a 200-s activation process at a potential of 1750 mV. Demonstrating remarkable electrocatalytic behavior towards AA, the AGCE exhibited enhanced peak current and a less positive shift in peak potential compared to the GCE. It demonstrated an increase with pH up to 6.5, followed by a decrease beyond pH 6.5, leading to the selection of pH 6.5 as the optimal value. The variation in scan rate indicated an adsorption-controlled process. The established calibration curve equation was Ip (μA) =  − 9.94 – 0.15CAA, presenting a high R² value of 0.999 within the linear range of 0.01 – 0.2 mM. The method demonstrated a low limit of detection (0.004 mM) and quantification (0.012 mM). A robust degree of recovery (102.2%) validated the method’s accuracy. The concentration of AA in fresh garlic bulbs was determined to be 192.8 mg/kg, affirming the method’s suitability for the analysis of real environmental samples.

This study evaluated the performance of two techniques – conventional solvent extraction (CSE) and ultrasound-assisted extraction (UAE) – using different solvents (50% methanol, 50% ethanol, 70% acetone) for the extraction of phenolics from mango peel. For each mango peel extract (MPE), a further purification step was performed on an OASIS HLB 6 cc VAC-packed column. Subsequently, the phenolic compound profile was quantified using Ultra Performance Liquid Chromatography accoupled with a Photodiode Array (UPLC-PDA), and the antioxidant activity was also assessed. The results indicated that using 50% methanol as an extraction solvent yielded more significant phenolics, such as mangiferin, gallic acid, quercetin, and rutin. Additionally, the extracts obtained by UAE with different solvents showed a higher phenolic compound content, with mangiferin being the most predominant, mainly when methanol was used (222.34 mg/100 g DW) and higher antioxidant activity than extracts obtained by CSE, especially when acetone was used (364.00 ± 13.00 µmol Trolox/g DW). Overall, the results indicate the potential use of these mango by-products as a source of natural ingredients for the development of functional food.

Pathogenic Shiga toxin–producing Escherichia coli (STEC) are an important cause of foodborne illness. The detection of STEC in finished products and during the manufacturing process has an important role as part of verification plans, to confirm that practices and procedures described in the food safety program are successfully applied to control STEC. The aim of this study is to evaluate the effect of temperature and pooling in detection and isolation of the major non-O157 STEC serogroups from meat samples with the use of alternative and standard methods. Bovine meat was experimentally inoculated with one of the “Top 6” non-O157 STEC strains (O26, O103, O111, O145, O45, and O121). Both ISO TS 13136:2012 and a novel alternative method were implemented to evaluate the impact of temperature and pooling. An increase of the enrichment temperature to 41.5 °C allowed the detection of the spiked strain in 10% more samples compared to enrichment at 37 °C. The use of 25- and 375-g sample tests demonstrated no statistically differences between both methods. And finally, this alternative method appears easy to use and time-saving for routine laboratory use.