Aflatoxin B₁ (AFB₁) with strong carcinogenic, teratogenic and mutagenic properties is mainly produced by Aspergillus flavus. Maize, due to its high moisture content, is prone to Aspergillus flavus growth and subsequent AFB₁. Both ultraviolet irradiation and cold plasma are non-thermal physical techniques with fungal inactivation and mycotoxin degradation capabilities. Ultraviolet combined with cold plasma technology can overcome the limitations of individual technologies, such as low penetration depth and inefficiency. However, there is little research on the effect of ultraviolet combined with cold plasma on degradation of AFB₁ in maize. Therefore, this article aims to explore the degradation efficacy, products and pathways of AFB₁, as well as effects on maize kernels quality treated by ultraviolet combined with cold plasma. AFB₁ standard was spiked onto glass dishes and maize kernels, respectively. The residual AFB₁ content was quantified after different ultraviolet combined with cold plasma treatment durations (5, 10, 15, 20, 25, 30 min). Liquid-chromatography mass spectrometry (LC-MS) was employed to analyze the potential structure of degradation products and degradation pathways. A comparison was mad on the moisture content, fatty acid value, color parameters (L^*, a^*, b^* and △E value), starch gelatinization properties, starch content, protein content, surface seed coat microstructure, and cross-sectional microstructure of endosperm starch granules of maize kernels before and after ultraviolet combined with cold plasma treatment. A systematic investigation was implemented to explore the effect on the quality of maize kernels. The results showed that ultraviolet combined with cold plasma treatment effectively degraded AFB₁, with degradation rates increasing progressively with prolonged treatment time. On glass substrates, the degradation rate of AFB₁ reached 98.96% after 30 min treatment. For maize kernels, which required turning to expose both sides, the degradation rate was 39.40% after a total treatment time of 60 min (30 min per side). A slower degradation process was observed in the complex food matrix. LC-MS analysis identified 11 major degradation products. The peak areas of most degradation products initially increased and then decreased, indicating their further degradation. This trend was more pronounced for products 1-6 compared to products 7-11. The primary reaction sites involved the furan ring, methoxy group, lactone ring, and carbonyl group of AFB₁. Structural modifications occurred at known toxicogenic sites of AFB₁, suggesting a potential reduction in toxicity. However, further toxicological assessment was required. Degradation pathways were proposed, suggesting initial formation of six products (products 1-6) via substitution, addition, or demethylation reactions. Product 6 underwent furan ring cleavage to form an intermediate (C₁₆H₁₄O₇), which subsequently yielded products 7-11 through oxidation, demethylation, demethoxylation, and ring-opening reactions. Regarding maize quality, ultraviolet combined with cold plasma treatment caused a significant decrease (P<0.05) in moisture content and fatty acid value, which was actually of benefit to the long-term storage stability of maize kernels. Starch gelatinization properties were slightly altered, with breakdown value, peak viscosity, trough viscosity, and final viscosity all showing a trend of initially decreasing followed by an increase. Meanwhile, the setback value, pasting time, and pasting temperature remained largely unaffected (P>0.05). These phenomena did not cause quality of maize deterioration. Moreover, color, starch content (including amylose and amylopectin), protein content, and the microstructure of surface seed coat and endosperm starch granules showed no significant changes (P>0.05). Overall, ultraviolet combined with cold plasma treatment did not adversely affect quality of maize kernels. In conclusion, ultraviolet combined with cold plasma technology can effectively degrade AFB₁ while ensuring maize kernels do not exhibit significant deterioration in quality. The finding can provide a theoretical reference for the application of ultraviolet combined with cold plasma in the control and detoxification of AFB₁ in maize.

This study processed Jingxi rice 7233 into reasonably well milled (RWM, bran degree 2.8%, 4.9%) and well milled (WM, bran degree 1.4%) grades, and compared the processing characteristics, physicochemical properties, fatty acid composition, volatile composition and taste quality between the two grades. The results showed that the average rice yield and head rice yield of RWM were 1.3% and 1.8% higher than those of WM, respectively. The contents of total phenolic acids, water-soluble protein, unsaturated fatty acids, especially polyunsaturated fatty acids, in RWM rice were more than 1.5 times as high as those in RWM rice. The color difference between RWM and WM rice was greater than 2.0, which could be perceived with the naked eye. Totally 62 characteristic peaks were marked by gas chromatography-ion mobility spectrometry (GC-IMS), and 38 compounds were accurately identified. The contents of 58% of volatile components were significantly higher in RWM rice than in WM rice. The cooking time of RWM rice was significantly longer than that of WM rice, and the breakdown viscosity of starch and stickiness were significantly lower than those of WM rice. RWM rice has great advantages in paddy utilization rate, nutrition and health, but further research and optimization are needed in terms of appearance, smell and taste quality.