Food Analytical Methods最新文献

This work describes the synthesis, characterization, and electrochemical application of innovative AgNP/carbon dot/MWCNT nanoarchitecture. Silver nanoparticles (AgNPs) have been obtained by directly reducing silver nitrate salt in carbon dot/MWCNT alcoholic solution. UV–vis spectroscopy, HR-TEM, XPS, and electrochemical techniques have characterized this nanoarchitecture. The AgNP/carbon dot/MWCNT nanoarchitecture has been dispersed on a gold-printed electrode surface, showing excellent electrocatalytic activity for fenitrothion determination in acetate buffer, pH 4.5, by impedance electrochemistry spectroscopy with a detection limit of 0.48 nmol L⁻¹. The fenitrothion pesticide detection was also performed in orange juice and did not suffer significant interference from other pesticides.

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Propolis is an apicultural product whose composition depends on the climate conditions, geographical region, source of the resinous substance, and bee species. It is rich in phenolic compounds with antioxidant potential. This study aimed to establish better extraction conditions of bioactive compounds from Melipona quadrifasciata (MQ) propolis using a central composite rotational design (CCRD) and multivariate statistical tools. The solvent concentration and extraction time effects on the phenolic compounds profile with antioxidant activity (AA) were evaluated. The total phenolic compounds (TPC) and AA varied from 20.43 to 56.03 mg GAE g⁻¹ (gallic acid equivalent) and 95.89 to 154.67 mmol Trolox g⁻¹, respectively. The best condition for TPC and AA was 50% ethanol and 60 min of the extraction. However, each phenolic compound identified had a different best extraction condition, probably due to the molecules’ polarity and solvent interaction. The cinnamic acid was the highest content identified, followed by ferulic acid, gallic acid, epicatechin, p-coumaric acid, and catechin. Anyway, more extended times of extraction and solvent concentration closer to 50% ethanol can maximise the extraction of compounds with antioxidant potential. Thus, the Brazilian stingless bee propolis could be considered a potential source of bioactive compounds with potent antioxidant capacity, which could be further explored for future applications as natural antioxidants in several products.

The aim of this work was to establish a cost-effective extraction procedure for simultaneous determination of pesticides and veterinary drugs in Chinese market preference fresh aquatic products based on MRLs in food of animal origin in China. Modified QuEChERS method coupled to UPLC-MS/MS for the simultaneous detection of 39 pesticides and veterinary drugs were developed. Six representative matrices of bulk fresh aquatic products in China’s coastal markets showed applicability with recoveries 60.3–119.0% and acceptable precision 4.3–20.8%. Experiments showed that for fresh aquatic product matrices, the addition of EDTA-Mcllvaine effectively improved the extraction efficiency, and 0.4-g C₁₈/0.4 g PSA/1.2-g MgSO₄ combination with n-hexane extraction three times can remove the matrix interference effectively. Furthermore, LOD and LOQ in the range of 1.0–5.0 μg/kg and 3.0–10.0 μg/kg for 39 pesticides and veterinary drugs upon six representative matrices of bulk fresh aquatic products, respectively, that providing a practical flexible screening method for production quality control before entering the market.

Ergot alkaloids (EAs) are toxins produced by Claviceps purpurea fungi that may infect cereals, particularly rye. The present study describes the comparison between ultra-high performance liquid chromatography coupled with mass spectrometry (UPLC-MS) and ELISA for the determination of twelve ergot alkaloids in rye flour. The sample preparation for LC–MS analysis was done by the QuEChERS method and clean-up via freeze-out. The analytical LC–MS method was fully validated, and the validation parameters such as linearity, limit of quantification (LOQ), precision, accuracy and matrix effect were tested. The calibration curves were linear (R² > 0.99) for all ergot alkaloids. The recoveries ranged from 74 to 104%, and the relative standard deviation under conditions repeatability (RSDr) did not exceed 17% for any analytes. The analytical LC–MS method and ELISA were applied to 27 samples of rye flour commercially available from retail shops in the Czech Republic. A positive correlation was found between the samples measured by ELISA and LC–MS. Ergot alkaloid concentrations measured by these methods were compared with the European legislation resulting in 5 samples exceeding the set limit of 500 µg/kg with 2 samples exceeding this limit 10 and 20 times, respectively. With the new legislative limit coming into effect in July 2024, more than half of the samples would not comply with the new established limit of 250 µg/kg.

Stingless bee honey (SBH) is gaining popularity for its unique flavour and potential nutritional and health benefits. Due to its low yield, SBH is usually more expensive than common honey. Moreover, SBH is also commonly sold as raw honey with higher moisture content, which could jeopardize its shelf life, quality, and safety if not stored properly. Therefore, a rapid method is required to characterize stingless bee honey for authentication and quality assurance. This study aimed to categorize SBH samples from Sarawak using two simple and rapid methods, namely the pollen or melissopalynological analysis and attenuated-total-reflectance Fourier-transform-infrared (ATR-FTIR). The melissopalynological analysis showed that all honey samples analyzed are multifloral honey. Principal Component Analysis (PCA) on the ATR-FTIR spectra clearly illustrated a clear separation between normal honey and SBH; and between raw SBH and processed SBH. Overall, this study provides important insights into the characterization of SBH from Sarawak using two simple and rapid methods. Further research could expand on these findings and contribute to the development of the SBH industry in Malaysia.

Soybeans have the characteristics of balanced amino acid species and high nutritional value and served as the main oil crop in the world. In order to investigate the potential of triacylglycerols (TAGs) for tracing geographic origin of imported soybeans in China, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used to profile TAGs in soybean oils. Orthogonal partial least-squares discrimination analysis(OPLS-DA) was applied to establish identification model based on the acquired MALDI-MS spectra to trace the soybean origin of four typical origins (Argentina, the USA, Brazil, and Canada). The models were verified through 40 samples of the test set, and the comprehensive identification accuracy rate of the OPLS-DA models reached 100%. The method and model in this study were accurate and reliable, and could accurately identify the geographic origin of soybean.

Curcumin (CUR) is a phytochemical widely used in food industries, cosmetics, and in the treatment of various ailments. It is a polyphenol derived from turmeric and is often considered the golden spice. CUR has a low solubility of less than 1 µg/ml and poor oral bioavailability which can be improved by co-amorphization with naringin (NRG). Analytical method to simultaneously quantify CUR and NRG is not reported in literature. This study aimed to develop a stability-indicating reverse phase HPLC method in gradient mode to simultaneously quantify CUR and NRG in co-amorphous system. The co-amorphous system of CUR and NRG in molar ratios 1:1 and 1:2 was prepared by quench cooling technique. The separation was attained on a Genesis C18, (4.6 mm × 150 mm, 4 µm) column with the mobile phase comprising of methanol and a 0.1% acetate buffer pH 3.8 at a single wavelength, 289 nm. CUR and NRG eluted at 5.1 and 11.1 min, respectively. For both the molecules, the linearity range was 0.125–16 µg/ml with LOD and LOQ of 0.063 and 0.125 µg/ml. The method developed was validated as per International Conference on Harmonization (ICH) guidelines for linearity, accuracy, precision, and robustness. The method was used to estimate CUR and NRG content in co-amorphous mixture and for in vitro evaluation.

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The synthesis of cobalt, nitrogen and sulfur co doped carbon quantum dots (Co-NS-CQDs) has become a subject of significant research interest. These CQDs were produced using a single-step microwave method, which is considered environmentally friendly, and the entire process was completed in just 90 seconds. In this synthesis, citric acid was utilized as the carbon source, methionine served as the source for both nitrogen and sulfur, and cobaltous acetate was used to introduce cobalt ions into the CQDs structure. The synthesized carbon quantum dots (CQDs) exhibit a narrow size distribution and a high quantum yield of 51.5%, which is notably superior to non-metal-doped CQDs with a yield of 38%. Characterization of these CQDs was performed using different techniques such as transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transformation infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The developed CQDs have blue luminescence at emission wavelength 438 nm after excitation at 350 nm. Different factors affecting the CQDs synthesis including dialysis duration, reaction time and reaction temperature. These CQDs were utilized as a probe for the detection of monosodium glutamate (MSG) in various food products. The intensity of the fluorescence of the CQDs showed a direct and linear increase with the concentration of MSG within the range of 25–250 µg/mL. The detection and quantitation limits for MSG were 2.78 µg/mL and 8.44 µg/mL, respectively. Additionally, the developed method is environmentally friendly, as confirmed by assessments using the analytical Eco scale, Green Analytical Procedure Index (GAPI), and Analytical Greenness calculator (Agree). The proposed method presents several advantages over other reported methods in terms of convenience, rapid response, and attainment of accurate and precise results.

Dummy molecularly imprinted polymers (DMIPs) were grafted on the surface of microspheres (CG161M) by surface imprinting and layer by layer self-assembling process and applied as adsorbent for the rapid and selective detection of phthalate compounds, such as diethyl phthalate (DEP), dibutyl phthalate (DBP) and dioctyl phthalate (DOP). Dioctyl phthalate (DOP) was chosen as a dummy template for diethyl phthalate (DEP) and dibutyl phthalate (DEP), allowing selective and specific identification of DEP and DBP and did not affect the accuracy of the analysis even if the template has not been eluted completely. The synthesized composites were characterized by Fourier transform infrared spectrometer, scanning electron microscope, static/kinetic adsorption, thermogravimetric analysis and nitrogen adsorption analysis. The maximum adsorption capacities of the MIPs for DEP, DBP and DOP were 0.006, 0.008 and 0.007 mg g⁻¹, respectively. The adsorption of phthalates reached equilibrium within 260 min and complied well with pseudo-second-order kinetic model and Langmuir model. Moreover, MIPs-based sorbents combined with hollow fibre stirring bar sorptive extraction followed by gas chromatography–mass spectrometry was applied to the recognition of DEP, DBP and DOP in several food samples. Under the optimum conditions, the limits of detection (LODs) for DEP, DBP and DOP were 0.0047, 0.0054 and 0.0031 mg L⁻¹, with spiked recoveries of 73.06–106.02% and relative standard deviations (RSDs) within 3.91–6.89%, exhibiting high adsorption capacity and good selectivity of DMIPs towards DEP, DBP and DOP. Since the template of surface molecularly imprinted polymers could be changed with the analytes, MIP-based molecularly imprinted polymers combining with hollow fibre stirring bar sorptive extraction can be a promising and selective method for recognition and separation of a certain series of analytes with similar skeleton in complicated samples without sample clean-up.

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A quantitative analysis of perceived saltiness was established by combining sensory perceived NaCl concentration with electronic tongue salty response. Saltiness index (SI) was defined as the ratio of perceived NaCl concentration to the actual NaCl concentration, and was proposed to evaluate the saltiness enchantment. Method validation of the saltiness sensor included assessments of linearity, repeatability, reproducibility, limit of detection, limit of quantitation, and recovery yield. A desirable linear relationship between the logarithm of perceived NaCl concentration and saltiness was observed at NaCl concentration ranging from 45 to 90 mM with a determination coefficient exceeding 0.99. A low relative standard deviation of less than 1% was achieved in the repeatability test. Through visual evaluation, the detection and quantitation limits of the saltiness sensor for NaCl solutions were determined to be 0.01 mM and 0.1 mM, respectively. A high recovery yield (97.6–108.3%) was obtained from the spike recovery test. Optional test solvents, including ultrapure water, distilled water, and pure water, were employed without interference. Upon adding 20–35 g/100 g potassium chloride, the salty response of the salt solution increased, while the linearity of NaCl solution remained unaffected. Saltiness enhancements of 37.20 ± 0.00% and 18.17 ± 0.18% were observed for the potassium-containing salt (30%, w/w) and oyster mushroom (Pleurotus ostreatus) peptides (0.3%, w/w), respectively. This evaluation method provided an effective and quantitative approach to advancing the development of salt reduction ingredients.