ABSTRACT
Sample pretreatment is a vital step in the detection of mycotoxins, and traditional pretreatment methods are time-consuming, labor-intensive and generate much organic waste liquid. In this work, an automatic, high-throughput and environmentally friendly pretreatment method is proposed. Immunomagnetic beads technology and dispersive liquid-liquid microextraction technology are combined, and the zearalenone in corn oils is directly purified and concentrated under the solubilization effects of surfactant. The proposed pretreatment method allows for the batch pretreatment of samples without pre-extraction using organic reagents, and almost no organic waste liquid is produced. Coupled with UPLC-FLD, an effective and accurate quantitative detection method for zearalenone is established. The recovery of spiked zearalenone in corn oils at different concentrations ranges from 85.7 to 89.0%, and the relative standard deviation is below 2.9%. The proposed pretreatment method overcomes the shortcomings of traditional pretreatment methods and has broad application prospects.
Subject(s)
Liquid Phase Microextraction , Mycotoxins , Zearalenone , Zearalenone/analysis , Liquid Phase Microextraction/methods , Corn Oil , Zea mays , Mycotoxins/analysis , Chromatography, High Pressure Liquid/methodsABSTRACT
Sample pretreatment is an important step in the detection and analysis of mycotoxins. However, conventional pretreatment methods are complex, time-consuming, and labor-intensive; moreover, they generate a large amount of organic waste that pollutes the environment. An environmentally friendly and automated pretreatment method is proposed. Without extraction using organic solvents in advance, aflatoxins in peanut oil are directly cleaned and concentrated by immunomagnetic beads with the aid of a reaction solution containing surfactant Tween-20. Under optimal conditions, the proposed pretreatment method requires 40 min to simultaneously pretreat 10-24 samples without any centrifugation or filtering steps, and virtually no organic waste was produced. This pretreatment step was coupled with ultra-performance liquid chromatography-fluorescence detection to develop an effective detection method. The recovery of spiked aflatoxins in peanut oils at different concentrations ranged from 91.6 to 100.8%, and the relative standard deviation was below 5.3%. This reliable method overcomes the drawbacks of conventional methods and offers great application prospects.
Subject(s)
Aflatoxins , Aflatoxins/analysis , Arachis , Chromatography, High Pressure Liquid/methods , Chromatography, Liquid , Plant Oils/chemistry , Surface-Active AgentsABSTRACT
Blue honeysuckle rich in anthocyanins can inhibit starch-digesting enzyme activity. This study evaluated the inhibitory effect and mechanism of blue honeysuckle extract (BHE) on glycosidases (α-amylase and α-glucosidase). BHE was a mixed glycosidase inhibitor with an IC50 of 2.36 ± 0.14 and 0.06 ± 0.01 for α-amylase and α-glucosidase, respectively. Fourier transform infrared (FTIR) spectroscopy, multi-fluorescence spectroscopy, and isothermal titration calorimetry (ITC) confirmed that BHE caused the secondary structure change and static fluorescence quenching of glycosidases, and the interaction was an enthalpy-driven exothermic reaction. Molecular docking proved that the main anthocyanin monomers in BHE interacted with glycosidases through hydrogen bonds and van der Waals forces. Moreover, BHE changed the starch structure and prevented starch from being digested by glycosidases. In vivo, BHE and starch-BHE complexes effectively slowed postprandial hyperglycemia. This research provided a theoretical basis for BHE in antidiabetic healthy food research and development.
Subject(s)
Lonicera , alpha-Glucosidases , Anthocyanins , Digestion , Glycoside Hydrolases , Molecular Docking Simulation , Plant Extracts/chemistry , Starch/chemistry , alpha-Amylases , alpha-Glucosidases/chemistryABSTRACT
Coix seed is an important food and traditional Chinese medicine in China and other Asian countries. Notably, coix seed is currently being used as a traditional medicine for the treatment of COVID-19 in China. However, coix seeds are generally contaminated by mycotoxins, and this risk cannot be ignored. In this paper, we developed a method that involves direct extraction and UHPLC-HRMS analysis for the simultaneous detection of 24 mycotoxins in coix seeds. UHPLC-HRMS instrument and data acquisition parameters, and the sample pretreatment were optimised. One-step extraction showed several advantages compared to the three commercial solid-phase extraction clean-up methods, including ease of use, reduced time of sample preparation, low cost, good recovery, and acceptable matrix effect. The method validation results indicate that all mycotoxins have good linearity and sensitivity. Recoveries were between 74.2-101.1%, and RSD ranged from 0.1-5.8%. The LOQs for 24 mycotoxins were in the range of 0.5-100 µg/kg. To survey the contamination levels of these mycotoxins in commercial coix seeds, more than 70 samples were collected from Chinese markets and were analysed using the newly developed method. Zearalenone (positive ratio: 98.7%, range:1.1-1562 µg/kg), deoxynivalenol (positive ratio: 87%, range: 8.4-382.5 µg/kg), nivalenol (positive ratio: 85.7%, range: 26.8-828.2 µg/kg), fumonisin B1 (positive ratio: 84.4%, range:2.5-314.5 µg/kg), fumonisin B2 (positive ratio: 75.3%, range:1.6-72.8 µg/kg), fumonisin B3 (positive ratio: 48%, range:1.0-203.6 µg/kg), aflatoxin B1 (positive ratio: 29.9%, range: 0.39-14.7 µg/kg), sterigmatocystin (positive ratio: 29.9%, range: 1.4-51.6 µg/kg), and tenuazonic acid (positive ratio: 19.5%, range 36.1-105.7 µg/kg) were the most frequent mycotoxin contaminants. These results highlight the importance of routine monitoring and control of mycotoxins in coix seeds.