Journal of AOAC International最新文献

Background: The BioSystems Gluten is an automated quantitative method based on immunoturbidimetry for quantification of the 33-mer peptidic immunotoxic fraction of gluten in food and beverages, crucial for ensuring safety for those with gluten-related disorders like celiac disease.

Objective: An AOAC Performance Tested Methods  SM validation study was performed to evaluate the BioSystems Gluten method for the quantification of gluten from wheat, barley, and rye flours across selected food and beverage commodities, including both non processed and processed products.

Methods: Validation covered non-processed (rice flour, corn flour, wine, sausage) and incurred matrixes (cornbread, rice cookies), spiked with wheat, barley, and rye gluten (0-30 mg/kg). Twelve test portions were analyzed for each matrix and contamination level using three different kit lots. The study evaluated linearity, bias, recovery, precision, limit of detection, and limit of quantification, selectivity and interferences, evaluated by recovering gluten in a defined gluten-free matrix group, stability studies of the kit components and method robustness following AOAC Guidelines for Quantitative Gluten Methods.

Results: The method met AOAC performance requirements for the quantitative determination of gluten from wheat, barley, and rye across a variety of representative food commodities and spiking levels. The validated working range spans from the limit of quantification (2.5 mg/kg) up to 200 mg/kg. The method achieved satisfactory recovery rates within the established acceptance limits, showed no evidence of analytical interferences, and yielded comparable results between the method developer and an independent laboratory, supporting its robustness and reproducibility.

Conclusions: The validation study conclusively establishes the test kit as an automated, precise, rapid, and user-friendly method for quantifying gluten concentrations in both food and incurred matrixes derived from wheat, barley, and rye flours.

Highlights: Novel automated method for gluten quantification based on spectrophotometric analysis in a Biosystems Y15 analyzer with ready-to-use and liquid reagents.

Background: Natamycin is a naturally occurring antimycotic used to prevent mold in a variety of foodstuffs, mainly processed meat, cheese and wine, and more recently certain fresh fruits.

Objective: The aim of the present study was to develop and validate a sensitive and selective method for the quantification of natamycin residues in blueberries.

Method: A methanolic extraction followed by solid phase extraction clean up and analysis by liquid chromatography coupled to high resolution tandem mass spectrometry validated for the analysis of natamycin residues in blueberries following the SANTE guidelines.

Results: The method was validated at 0.025, 0.25 and 11 mg/kg with average recoveries between 86 and 105%, and precision (%RSD) was below 15%. The detection limit for natamycin was below 0.010 mg/kg. Residues of natamycin in treated blueberries were found to range from 1 to 29 mg/kg and remained stable over 4 weeks of storage at 4 °C.

Conclusions: The LC-HRMS analysis reported here is shown to be an accurate and sensitive method for quantifying natamycin residues in blueberries.

Highlights: A method suitable for use in the regulatory and commercial monitoring of natamycin residues in blueberries is developed and presented.

Background: Water determination for plant materials generally uses loss on drying (LOD) methods. The azeotropic-toluene distillation (ATD) method is often used in pharmacopeial and food compendial monographs to determine the water content of plant materials containing volatile components because LOD will lose both water and volatile components. ATD is an environmentally hazardous method since it uses relatively large amounts of toluene with distillation.

Objective: To seek a greener approach for water determination in plant materials, USP <921> Water Determination, Method I, also known as the Karl Fischer (KF) test, is recommended due to its efficiency, specificity, and accuracy. However, it may be difficult to determine water content of plant materials using direct titration since water is tightly trapped in plant cells. An alternative approach is needed.

Methods: The United States Pharmacopeial Convention (USP) laboratory therefore developed and validated an alternative method-KF direct titration with extraction using formamide as the extraction solvent.

Results: The validation results demonstrated that the newly developed method met the required criteria for accuracy, repeatability and robustness8.

Conclusion: Using the newly established method, the water content in different species with different plant parts including fruit peel, root, rhizome, bark, cremocarp and bulb was effectively determined.

Highlights: The results generated using the KF direct titration with extraction were also compared with results of LOD applying different heating times and direct titration using different solvents (see Table 1). The differences in the results between the methods will be discussed.

Background: Polygonatum cyrtonema Hua (PCH) is widely used in traditional Chinese medicine. The components and activity are important for simultaneously quality evaluation in PCH.

Objective: This study aimed to establish an accurate, rapid and comprehensive quality evaluation method by near-infrared spectroscopy (NIR) for forecasting the total polysaccharides content (TPsC), total flavonoids content (TFC), and antioxidant activity (AA) in PCH.

Methods: PCH samples were used to establish model of TPsC, TFC, and AA in PCH by NIR combined with partial least squares regression (PLS). To enhance the accuracy of the models and remove non-essential variables, we used multiple spectral preprocessing methods and multiple chemometrics to analyze the processed full spectrum, such as competitive adaptive reweighted sampling-partial least squares regression (CARS-PLS), moving window-partial least squares regression (MW-PLS), and interval random frog-partial least squares regression (iRF-PLS). The remaining samples were used to complete external validation.

Results: Satisfactory prediction results of PLS models combined with chemometrics were obtained. The optimal chemometric of TPsC, TFC, and AA selected 157, 105, and 134 variables, respectively. For the TPsC, TFC, and AA models, which incorporated optimal spectral preprocessing and chemometric, the root mean square error of calibration (RMSEC, %) values were 0.743, 0.069, and 0.136, while the R2 values were above 0.95. The root mean square error of prediction (RMSEP, %) for these models were 1.00, 0.074, and 0.153, while R2 values were above 0.90. The remaining 20 samples were used to complete external validation, which confirmed the preeminent comparability and ability of the proposed method.

Conclusion: NIR combined with chemometrics provide an effective, fast, and nondestructive approach for evaluating quality via multiple indicators of PCH and provides a meaningful reference for evaluation of herbal medicine quality.

Highlights: NIR combined with chemometrics offers an effective, quick, nondestructive way to evaluate herbal medicine quality with multiple indicators.

Background: Aflatoxin B1 (AFB1) is widespread in various kinds of food and poses a serious threat to health when it enters the human body via the food chain.

Objective: This study aimed to establish a rapid and sensitive method for the detection of AFB1 and then combine it with HPLC for the quantitative analysis of AFB1 content.

Method: In this work, hydrothermal and sol-gel methods were employed to prepare aminoated magnetic nanoparticles featuring strong magnetism and excellent dispersion. Magnetic nanoparticles bound with antibodies can specifically capture AFB1 and then be combined with HPLC for the quantitative analysis of AFB1 content. Moreover, the key factors influencing the extraction efficiency, such as buffer type, adsorption time, elution time and volume, were optimized.

Results: The samples were spiked with AFB1 at low, medium, and high concentration levels of 5.0, 10.0, and 20.0 μg/kg, respectively. The established method exhibits good linearity within the range of 0.1-100 µg/kg, and the detection limit is as low as 0.09 µg/kg (S/N = 3). The recoveries in real samples ranged from 79.33% to 111.51%, with all relative standard deviations (RSDs) being less than 11.16% (n = 3 for each level).

Conclusions: In conclusion, a rapid and efficient analytical method for detecting AFB1 in corn, peanut and oat based on functionalized immunomagnetic beads (IMBs) coupled with HPLC-FLD have been successfully developed .The method exhibited excellent sensitivity, featuring a low method detection limit of 0.09 μg/kg, high accuracy, and remarkable precision. In comparison to traditional sample preparation techniques, this IMBs-based approach presents substantial advantages in terms of simplicity, rapidity (completing sample processing within approximately 30 minutes), and cost-effectiveness.

Highlights: The IMBs possess excellent magnetic separation capabilities, which effectively streamline the pre-processing steps.

Background: Bovine lactoferrin (bLF) has been supplemented to a variety of foods, particularly dairy products, to promote human health. Reliable analytical methods are required for accurate quantification of bLF in foods. Isolation of bLF from foods using a heparin column and quantification via HPLC have been reported (heparin method); however, its applicability remains limited.

Objective: To develop a broadly applicable method for determining bLF in dairy products by optimizing the extraction buffer conditions used in the heparin method.

Method: bLF was spiked into different dairy products and extracted using buffers with or without additives, such as urea, sodium chloride, EDTA, and Tween 20. These additives reduced interactions between bLF and dairy components and improved the interaction of bLF to the heparin column, with the buffer pH adjusted to 6.0. The extracted bLF was isolated using a heparin column and quantified via C4 reversed-phase HPLC using an external standard calibration curve.

Results: The optimized extraction buffer improved bLF recovery rates across all tested dairy product matrices.

Conclusions: An improved extraction buffer was developed that enhanced the applicability of bLF quantification using the heparin method. This optimized extraction buffer enabled reliable recovery of bLF from diverse and complex dairy product matrices.

Highlight: The optimized extraction buffer significantly improves the recovery and quantification of bLF in various dairy products, providing a versatile solution for accurate bLF analysis.

Background: Psilocybin-containing mushrooms are gaining the attention of the scientific community due to the potential benefits offered by their psychoactive phytochemicals in the treatment of addiction and various mental health conditions. Although there are hundreds of different Psilocybe species, only a handful have been successfully cultivated under indoor controlled conditions and chemically analyzed.

Objective: The goal of this publication is to describe Nammex's ongoing effort to cultivate poorly studied Psilocybe mushroom species and analyze them by high-performance thin-layer chromatography (HPTLC) to identify and quantify important psychoactive compounds.

Methods: Pure mycelium cultures of Psilocybe species were created from spore prints and tissue of mushrooms collected in the wild. From these mycelia, numerous cultivars were developed and then propagated on various substrates, based on nutritionally supplemented cellulosic materials. Using indoor growth chambers under strictly controlled conditions, mushrooms were produced and prepared for analysis.

Results: Six Psilocybe species (P. zapotecorum, P. natalensis, P. azurescens, P. subaeruginosa, P. cyanescens, and P. stuntzii) were successfully cultivated indoors. Species identity was confirmed through analysis of anatomical and microscopic features, as well as by DNA sequencing. HPTLC was successfully used to quantify psilocybin and psilocin and to identify norbaeocystin, baeocystin, and aeruginascin. P. zapotecorum had the highest psilocybin content (1.89%), and P. stuntzii the lowest (0.45%). Preliminary data showed that psilocybin concentrations remained stable across three successive flushes of P. stuntzii. Storage of fresh mushrooms in a -20 °C freezer prior to freeze-drying drastically reduced psilocybin and increased psilocin levels.

Conclusions: This study successfully demonstrated the cultivation and chemical profiling of multiple Psilocybe species under controlled conditions. The detailed HPTLC analysis revealed species-specific differences in psychoactive compound concentrations. Future research will incorporate advanced techniques, such as HPLC and mass spectrometry, to develop a more comprehensive chemical profile of these mushrooms.

Highlights: This study successfully cultivated and chemically analyzed six Psilocybe species, revealing species-specific differences in psychoactive compound concentrations. Storage conditions, differences between stem and cap, and mushroom developmental stage influenced the composition of psychoactive compounds.

Background: The determination of cobalt in water samples (test samples) is crucial, as it is an essential metal; yet, both deficiency and excessive intake may contribute to detrimental effects in humans and animals.

Objective: In this study, a dispersive solid-phase extraction (DSPE) procedure was developed for the determination of trace amounts of cobalt using flame atomic absorption spectrometry (FAAS).

Methods: The Mn3O4-MnOOH nanocomposite was synthesized to be used as a sorbent in the preconcentration of cobalt.

Results: The enhancement in the detection power of the developed analytical method was quantified by the ratio of the detection limits of the Mn3O4-MnOOH-DSPE-FAAS and FAAS systems, revealing a 15-fold increase with the Mn3O4-MnOOH-DSPE-FAAS method.

Conclusion: The recovery results obtained in tap water for the determination of trace amounts of cobalt demonstrated the applicability and accuracy of the developed method.

Highlights: A sensitive analytical strategy was developed for Co. High recovery results were obtained under optimum conditions.

Background: Chlorogenic acid (CGA), a plant-derived phenolic compound, possesses antioxidant, anti-inflammatory, and antimicrobial activities. Accurate quantification is essential due to its therapeutic value and potential toxicity at high doses.

Objective: To develop a rapid, sensitive electrochemical method for CGA detection using spinel-based catalysts with improved conductivity.

Methods: An electrochemical sensing platform was constructed based on a nanocomposite of ZnFe2O4 and boron, sulfur and nitrogen co-doped reduced graphene oxide (BSN-rGO). This hybrid material effectively addresses the intrinsic poor conductivity of spinel oxides by leveraging the synergistic effect between the catalytic activity of ZnFe2O4 and the superior charge transport capability of BSN-rGO. The resulting sensor enabled rapid and quantitative analysis of CGA within two minutes.

Results: The sensor showed a linear detection range of 1 × 10-4 -1 × 10-1 M and a low detection limit of 1 × 10-6 M (S/N = 3). Adding standard recovery reached 97.48% to 100.75%, with RSDs of 1.02% to 2.95%, indicating excellent accuracy and reproducibility in complex matrices.

Conclusion: The proposed method enables rapid and reliable CGA detection in natural products, offering potential for pharmaceutical and food analysis.

Highlights: BSN-rGO integration enhances spinel conductivity and boosts electrochemical sensing performance.

Background: The extensive use of imported commercial Saccharomyces cerevisiae active dry powder preparations has led to a serious homogenization of wine products in China.

Objective: In recent years, there has been growing interest in developing and applying indigenous non-Saccharomyces yeasts to enhance the diversity and distinctive character of wines.

Methods: In this study, a promising indigenous strain, Hanseniaspora uvarum BF-345, previously isolated from local grape juice, was investigated due to its desirable fermentation properties, robust stress tolerance, and high β-glucosidase activity. Response surface methodology (RSM) was employed to optimize the composition of a cryoprotectant formulation for the vacuum freeze-drying of BF-345.

Results: The optimal protectant formulation was determined as follows: 5.63% skim milk powder, 12.89% maltitol, and 7.02% sucrose. Under these conditions, the viability of the freeze-dried cells reached 85.2%, representing a 27.3% increase compared to the pre-optimized formulation.

Conclusion: The prepared active dry yeast complied with the Chinese national standard GB/T 20886.2-2021, and maintained a viability above 70% after 6 months of sealed storage at 4 °C.

Highlights: In micro-vinification trials with Cabernet Sauvignon, the fermentation system inoculated with the freeze-dried powder exhibited higher yeast cell counts and more favorable fermentation kinetics than that inoculated with a liquid seed culture.