Melamine is one of the most frequently detected adulterants in dairy products. The current study proposes a surface-enhanced Raman spectroscopy (SERS)-based analytical tool for fast and reliable screening of melamine in bovine milk. A hand-held Raman spectrometer was used in conjunction with a substrate composed of silver nanoparticles (AgNPs) that was 2D printed onto glass fiber (GF) filter paper. Under optimized conditions, a sensitive and fingerprint-like signal at 674 cm⁻¹ was obtained. The AgNPs/GF substrate exhibited high sensitivity to melamine in milk down to 1.9498×10⁻⁵ mg/mL, which is well below the USA and EU safety limits (2.5×10⁻³ mg/mL). Remarkably, the proposed technology was also highly reproducible, showing spot-to-spot and block-to-block variations below 3.3% and 4.9% at 674 cm⁻¹ in Raman intensity, respectively. The characteristic peak intensity and concentration of melamine showed an acceptable linear relationship (R²=0.9909) within the range of 0.0001-1 mg/mL. Overall, the method established in this study can provide an efficient and effective method for the quantitative target screening and detection of melamine in dairy products.

Given severe health-hazardous effects of aflatoxin B1 (AFB1) widely occurring in cereal grains and animal feeds, it is highly urgent to develop analytical methods for its rapid screening. In this work, we proposed a simple and high-throughput method for the determination of AFB1 in millet and buckwheat samples using high performance thin layer chromatography (HPTLC) linked to fluorescence densitometry. The first step was to optimize the solid-liquid extraction for the crude clean-up of the samples. The QuEChERS (Quick, Easy, Cheap, Effective, Robust and Safe) extraction strategy was used and different solvent systems for their extraction efficiency of AFB1 from the samples were evaluated. Then, trichloromethane/ethyl acetate (7/3, v/v) was used as the mobile phase to realize the separation of the targeted compound from background noises on silica gel plates. Quantification was readily performed with densitometry in fluorescence mode. In order to fix the optimal excitation wavelength, spectra scanning from 250-400 nm was carried out, revealing that 364 nm light gave the highest signal. With the optimized optical system, high sensitivity to AFB1 was achieved, with a limit of detection (LOD) at 3 μg/kg. Apart from that, good linearity (0.999) was obtained within the range of 1-80 ng/band of AFB1. To assess the analysis accuracy, two levels of AFB1 (50 and 100 μg/kg) were spiked into real grain samples. The obtained results showed that the recovery rates were within the range of (81.6–114.0)%. The proof-of-concept results of this work evidenced that HPTLC is a promising analytical tool for the screening of mycotoxin in difficult samples.

Dietary phosphatidylcholine (PC) is an ideal source of bioactive lipids showing efficacy to alleviate non-alcoholic fatty liver disease (NAFLD). In this study, the lipidomic profiles of nonalcoholic steatosis in mice and HepG2 cells treated with PC isolated from eggs (EPC) and soybean (SPC) were evaluated. EPC and SPC could significantly ameliorate fatty liver disease by down-regulating triglyceride (TG) and diglyceride (DG) levels. Remarkably, EPC exhibited better performance in regulating the hepatic lipid profile leading to decreased PC and TG, ceramides, phosphatidylethanolamine and phosphatidylserine levels. A total of 117 and 20 lipid biomarkers in liver and HepG2 cells involved in glycerophospholipid metabolism were screened out, respectively. The regulatory mechanism of EPC may be attributed to a decrease in the expression of ACACA and SREBP-1c. EPC, via suppressing lipogenic gene expression, which was superior to that of SPC in alleviating nonalcoholic steatosis. Overall, EPC and SPC attenuated HFD-induced NAFLD by improving the hepatic lipid profile. The more significant effect observed with EPC may be attributed to its modulation of glycerophospholipid metabolism.

As a widely used food preservative, methyl paraben was experimentally evidenced with serious hormonelike adverse effects. Herein, a high performance thin-layer chromatography platformed bioluminescent bioautography and image analysis for the selective quantification and confirmation of methyl paraben was proposed and validated in vinegar and coconut juice. First, the detectability of the bioautography to the analyte on different layer materials was estimated, revealing that normal silica gel was the best choice. After that, the liquid of sample extract and working solution were separated to overcome the background noises due to co-extracted matrices. The separation result was then coupled to the optimized bioautography, enabling instant and straightforward screening of the targeted compound. For accurate quantification, bioluminescent inhibition pattern caused by the analyte was processed by image analysis, giving useful sensitivity (LOD > 16 mg/kg), precision (RSD < 10.1%) and accuracy (spike-recovery rate 76.9%–112.2%). Finally, the suspected result was confirmed by determining its MS fingerprint, further strengthening the reliability of screening.

In this study, the impacts of egg consumption on mice model of metabolic syndrome (MetS) were comparatively investigated. Mice were divided into five groups (n=8): normal diet group (ND), high-fat diet group (HFD), HFD with whole egg group (WE), HFD with free-yolk egg substitute group (YFES), and HFD with lovastatin group (Lov). Main biochemical indexes and a non-targeted lipidomic analysis were employed to insight the lipid profile changes in serum. It was revealed that WE could significantly improve serum biochemical indexes by reducing body weight, low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC), while increasing high-density lipoprotein cholesterol. YFES exhibited remarkably better performance in increasing phosphatidylglycerol and phosphatidic acids, while decreasing phosphatidylinositol than WE. A total of 50 differential lipids biomarkers tightly related to glycerophospholipids metabolism were screened out. Carnitine C18:2 and C12:1, SM (d18:0/12:0), and SM (d18:1/14:1) were significantly upregulated in YFES compared to WE. YFES reduced expression of SREBP-1c and Cpt1a, while did not affect the expression of PPAR-α. Sphingomyelin biomarkers were positively related to the TC (|r| > 0.6), while PPAR-α was negatively correlated with triglyceride and LDL-C levels. To sum up, YFES attenuated HFD-induced MetS by improving the serum phospholipids, which account for its modulation of glycerophospholipid metabolism.