Food Analytical Methods最新文献

A novel and efficient analytical method was developed for the determination of 4-methylimidazole (4-MeI) in tea extracts using stir-bar sorptive extraction (SBSE) coupled with gas chromatography-mass spectrometry (GC-MS). Extraction parameters were optimized using ethylene glycol- and silicone-coated stir bars. The ethylene glycol-coated stir bar was used due to its higher extraction efficiency. The method demonstrated excellent linearity over the range of 2 µg/mL and 100 µg/mL (R² = 0.9982), with a limit of detection (LOD) of 1.19 µg/mL and a limit of quantification (LOQ) of 3.97 µg/mL. Method precision was confirmed with intra- and inter-day relative standard deviations of less than 1.6% and recoveries exceeding 102.26 ± 3.82%. The combined and expanded uncertainties were calculated as 0.0187 and 0.0373, respectively. Compared with liquid chromatography mass spectrometry (LC-MS/MS) and Quick, Easy, Cheap, Effective, Rugged and Safe-based (QuEChERS) methods, the developed SBSE-GC/MS protocol offers reduced matrix interference, simplified sample preparation, and comparable sensitivity. Real sample analyses validated the method’s applicability for routine monitoring of 4-MeI in commercial tea-based products. This approach offers a fast, reliable, and eco-friendly alternative for monitoring food safety and detecting thermally generated contaminants.

Aflatoxin B1 (AFB1) is one of the most hazardous foodborne toxins, posing a major risk to food safety and human health worldwide. Traditional detection techniques are often limited by lengthy procedures, high costs, and insufficient sensitivity for on-site applications. To overcome these challenges, we developed a portable, non-Faradaic electrochemical impedance spectroscopy (EIS) platform designed for rapid and highly sensitive detection of AFB1 in overnight-soaked corn samples. The working electrode was modified with a semiconducting-gold composite layer, followed by DTSSP crosslinker chemistry and antibody immobilization, which provided enhanced surface activity and stable biofunctionalization. This configuration enabled fast detection within 5 min, achieving an impressive detection limit of 0.005 ng/mL and a wide dynamic range of 0.01–40.96 ng/mL. The sensor demonstrated excellent reproducibility, with intra- and inter-study %CV consistently below 20%. Validation against laboratory benchtop systems showed a strong correlation (Pearson r = 0.977). Diagnostic evaluation further confirmed its robustness, yielding 90.6% accuracy and an AUC of 0.83. These results highlight the combined benefits of nanocomposite surface engineering and non-Faradaic EIS detection in achieving highly sensitive performance. Compact, user-friendly, and reliable, this sensing platform represents a promising solution for on-site toxin detection in food supply chains, thereby contributing to improved food safety monitoring and reduced public health risks associated with AFB1 exposure.

Graphical Abstract

This study presents a comprehensive approach for detecting and quantifying adulteration in minced meat products using image processing and colorimetric analysis techniques under both raw and cooked conditions. Common adulterants—including soy, chicken skin, sheep lung, gizzard, and bread dough—were added to minced meat at varying concentrations (0 to 80%), and their visual changes were tracked over time using red, green, blue (RGB)-based image analysis. Calibration curves were plotted, and linear regression models were developed for each adulterant. The method demonstrated high sensitivity, with the average slopes of the calibration curves being sheep lung (1.372), chicken skin (1.219), soy (1.067), gizzard (0.704), and bread dough (0.616). Corresponding relative standard deviation (RSD) values were 21.97%, 13.22%, 7.97%, 10.56%, and 10.70%, respectively, indicating reliable accuracy, particularly for soy and gizzard samples. Importantly, even at low adulteration levels, significant deviations in RGB values were detectable, confirming the reliability of the method for early-stage adulteration. Additionally, it was observed that increasing the temperature during cooking led to a reduction in RGB values, highlighting the thermal impact on color characteristics. The results confirm that the proposed hybrid method, combining image analysis, offers a rapid, low-cost, and highly sensitive solution for routine adulteration screening in meat products.

The rising concern regarding the consumption of the foods classified as “ultra-processed foods” (UPFs), linked to multiple health risks, underscores the need to explore a possible higher occurrence of process-induced contaminants and to develop new approaches to characterise the chemical profile of formulated and processed goods in order to improve their quality and safety. This study aims to develop untargeted approaches based on LC-HRMS and LC-HRMS/MS, coupled with feature-based molecular networking (FBMN), to explore, for the first time, the chemical profiles induced by thermal reactivity within a well-characterised UPF-like food matrix (sponge cake). Three controlled baking conditions were applied to the formulated cake to induce thermal reactivity and generate diverse chemical profiles. Principal component analysis and heatmap clustering of untargeted LC-HRMS data from cake extracts were able to effectively discriminate samples based on the thermal process intensity. Approximately 75% of the detected features were indeed involved in the reactivity. FBMN revealed different groups of compounds (including precursors and advanced products) associated with Maillard and caramelisation reactions and helped in the annotation of several reaction markers. This is the first application of FBMN on widely consumed processed foods such as baked products, opening new perspectives for generating high-throughput untargeted data to annotate reaction markers from complex food matrices.

The rise in demand for vegetable oils (VOs), especially sesame oil (SO), coupled with their economic value, has also increased the risk of adulteration by low-cost options, such as rice bran oil (RO) and mustard oil (MO). This study presents a laser-assisted method for detecting and characterizing such adulteration, emphasizing thermal diffusivity (D) as a sensitive and non-destructive marker for compositional changes. D reflects molecular mobility and heat transfer efficiency in oils and is quantified using the mode-mismatched dual-beam thermal lens (MMDBTL) technique. Adulteration levels ranging from 10 to 50% are analyzed, revealing that RO increases D due to its lower viscosity, while MO decreases D, indicating greater thermal resistance. Changes caused by adulteration are further examined with the help of Fourier transform infrared (FTIR), photoluminescence (PL), and UV–visible (UV–vis) absorption spectroscopy. FTIR spectroscopy exhibits limited sensitivity at low levels of adulteration. UV–vis spectroscopy indicates enhanced optical energy absorption with a red shift. PL spectra show a decrease in emission intensity with increasing adulterant levels, which is further validated using International Commission on Illumination (CIE) chromaticity coordinates and power spectral analysis. The inverse relationship observed between PL intensity and TL signal amplitude highlights the complementary nature of radiative and nonradiative pathways. The study confirms MMDBTL as a highly sensitive, non-destructive tool for detecting and distinguishing oil adulterants and suggests its potential for tailoring thermal properties for specific functional uses.

Astaxanthin, a natural red pigment belonging to the xanthophyll class, is widely found in microorganisms, algae, and crustaceans. This study addresses for the first time the challenge of efficiently extracting astaxanthin from shrimp by-products (Aristeus antennatus) using environmentally friendly GRAS solvents (acetone, ethanol, ethyl acetate, and isopropanol). For such a scope, astaxanthin content was identified and quantified by HPLC-DAD-APCI-MS, followed by the evaluation of the seasonal variation and the effect of thermal processing. Additionally, the antioxidant and antimicrobial potentials of the extracted astaxanthin were investigated to determine its functional value. Results demonstrated that acetone at a 1:20 solvent-to-solid ratio for 60 min at 30 °C achieved the highest extraction yield (1346.38 ± 37.31 µg/g). Astaxanthin content peaked in autumn and declined during summer, while cooking led to significant pigment loss. The extract exhibited strong antioxidant activity (EC₅₀ = 25.42 ± 1.43 µg/mL) and moderate antimicrobial effects (MIC range 25–1500 µg/mL). This study highlights the potential application of shrimp by-product-derived astaxanthin as a natural antioxidant and colorant in food industries, offering a sustainable valorization pathway for seafood waste.