A nondestructive optical method is described for the quality assessment of mini-Chinese cabbage with nanopackaging during its storage, using Fourier transform-near infrared (FT-NIR) spectroscopy. The sample quality attributes measured included weight loss rate, surface color index, vitamin C content, and firmness. The level of freshness of the mini-Chinese cabbage during storage was divided into three categories. Partial least squares regression (PLSR) and the least squares support vector machine were applied to spectral datasets in order to develop prediction models for each quality attribute. For a comparative analysis of performance, the five preprocessing methods applied were standard normal variable (SNV), first derivative (lst), second derivative (2nd), multiplicative scattering correction (MSC), and auto scale. The SNV-PLSR model exhibited the best prediction performance for weight loss rate (R_p² = 0.96, RMSEP = 1.432%). The 1st-PLSR model showed the best prediction performance for L* value (R_p² = 0.89, RMSEP = 3.25 mg/100 g), but also the lowest accuracy for firmness (R_p² = 0.60, RMSEP = 2.453). The best classification model was able to predict freshness levels with 88.8% accuracy in mini-Chinese cabbage by supported vector classification (SVC). This study illustrates that the spectral profile obtained by FT-NIR spectroscopy could potentially be implemented for integral assessments of the internal and external quality attributes of mini-Chinese cabbage with nanopacking during storage.

Antibacterials represent a pharmaceutical class that is extensively used and consumed worldwide. The presence of a large number of antibacterial agents in water could result in antibiotic resistance. Thus, the development of a fast, accurate, and high-throughput method to analyze these emerging contaminants in water is necessary. Herein, a method was developed to achieve the simultaneous determination of 43 antibacterials from nine pharmaceutical categories (i.e., sulfonamides, quinolones, fluoroquinolones, tetracyclines, lincosamides, macrolides, nitroimidazoles, diterpenes, and dihydrofolate reductase inhibitors) in water using automatic sample loading-solid phase extraction (SPE)-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Because the properties of these 43 antibacterials are quite different, the main objective of this work is to develop an extraction procedure that would enable the simultaneous analysis of a wide range of multiclass antibacterials. Given this context, the work presented in this paper optimized the SPE cartridge type, pH, and sample loading amount. Multiresidue extraction was performed as follows. The water samples were filtered through 0.45 μm filter membranes, added with Na₂EDTA and NaH₂PO₄, and pH-adjusted to 2.34 using H₃PO₄. The solutions were then mixed with the internal standards. An automatic sample loading device fabricated by the authors was used for sample loading, and Oasis HLB cartridges were used for enrichment and purification. The optimized UPLC conditions were as follows: chromatographic column, Waters Acquity UPLC BEH C₁₈ column (50 mm×2.1 mm, 1.7 μm); mobile phases, methanol-acetonitrile (2∶8, v/v) solution containing 0.1% formic acid and 0.1% formic acid aqueous solution; flow rate, 0.3 mL/min; injection volume, 10 μL. The compounds were step scanned using an electrospray ionization source in the positive and multiple-reaction monitoring (MRM) modes, and analyzed by internal and external standard methods. The results showed that the 43 compounds achieved high linearity in their respective linear ranges, with correlation coefficients (r²) greater than 0.996. The limits of detection (LODs) of the 43 antibacterial agents ranged from 0.004 ng/L to 1.000 ng/L, and their limits of quantification (LOQs) ranged from 0.012 ng/L to 3.000 ng/L. The average recoveries ranged from 53.7% to 130.4%, and the relative standard deviations (RSDs) were between 0.9% and 13.2%. The method was successfully applied to the determination of six tap water samples from different districts and six water samples obtained from the Jiangyin section of the Yangtze River and Xicheng Canal. No antibacterial compound was detected in any of the tap water samples, but a total of 20 antibacterial compounds were detected in the river and canal water samples. Among these compounds, sulfamethoxazole showed the highest mass concentrations, ranging from 8.92 to 11.03 ng/L. The types and contents of antibacterials detected in the Xicheng Canal were greater than those found in the Yangtze River, and two kinds of diterpenes, namely tiamulin and valnemulin, were found easily and commonly in water sample. The findings indicate that antibacterial agents are widespread in environmental waters. The developed method is accurate, sensitive, rapid, and suitable for the detection of the 43 antibacterial compounds in water samples.

Lipid hydrolysis catalyzed by endogenous lipases is a major contributor to quality deterioration in stored rice. This study aimed to elucidate how cold plasma (CP) treatment affects lipid stability by examining changes in lipase activity, structure, and endogenous ferulic acid (FA) during storage. After 60 days, CP-treated rice showed a 15.8% increase in FA content, accompanied by a 22.4% reduction in lipase activity and an approximately 25% decrease in free fatty acid value compared with the control. FT-IR spectroscopy revealed alterations in lipase secondary structure, including decreased α-helix (2.1%) and β-sheet (5.7%) and an increased random coil content (12.7%). Molecular docking confirmed FA binding within the active site via hydrophobic/hydrogen bonds, sterically hindering substrate access. Enzyme kinetic analysis showed that FA decreased V_max while increasing K_m, indicating mixed-type inhibition. Overall, CP treatment is associated with coordinated regulation of lipase structure and activity, contributing to improved lipid stability during storage.

Cadmium ion (Cd²⁺) detection technology plays a prominent role in food safety and human health. Herein, we designed and constructed an 2-aminoethyl dihydrogen phosphate (AEP)@upconversion nanoparticles (UCNPs) fluorescence sensor for quantitative detection of Cd²⁺ in paddy rice based on Inner filter effect (IFE) combined with enzyme inhibition mechanism. The AEP modification UCNPs can offer a stable fluorescence donor at 658 nm and be quenched by the oxidized tetramethylbenzidine (oxTMB) catalyzed by horseradish peroxidase (HRP) enzymes. Without addition of Cd²⁺, the fluorescence of AEP@UCNPs fluorescence sensor was weaken due to the IFE between AEP@UCNPs and oxTMB. With addition of Cd²⁺, HRP enzyme activity was inhibited by Cd²⁺, leading to the decreased oxTMB, resulting in the enhance upconversion fluorescence intensity. As a result, the fluorescence intensity signal at 658 nm of the IFE-based AEP@UCNPs fluorescence sensor increased linearly with the increase in Cd²⁺ in a wide range from 0.5 μmol/L to 6 μmol/L and the limit of detection (LOD) was 24.6 nmol/L. In addition, our proposed IFE-based AEP@UCNPs fluorescence sensor can achieve Cd²⁺ detection in paddy rice in 30 min.