Jie Yang

Apparent amylose content is a key determinant of rice flavor quality, yet traditional detection methods are often costly and time-consuming. To address this, we developed Ce-UiO66 nanozyme-based microfluidic paper-based analytical devices (μPADs) for the rapid quantification of apparent amylose. The sensing mechanism relies on the formation of a blue-purple apparent amylose-iodine complex via in situ catalytic oxidation, which is quantified through smartphone-based grayscale analysis. Mechanistic studies reveal that the catalytic activity of Ce-UiO66 is driven by O₂⁻ and H₂O₂ intermediates. The tri-zonal design of the μPADs (droplet, reaction, and detection zones) effectively minimizes in situ reaction interference. Under optimized conditions, the method achieved a linear range of 0–40% within 15 min, showing excellent agreement with flow injection analysis. This Ce-UiO66@μPAD platform demonstrates significant potential as a low-cost, portable tool for rapid monitoring of apparent amylose in rice. Graphical abstract

Lotus roots are widely consumed vegetables because of their great taste and abundant nutrients, but their quality varies with the environments and cultivar. This study systematically compared farinose (Elian No. 5) and crisp (Elian No. 6) lotus root cultivars from three geographical origins. Pasting and texture characteristics verified that Elian No. 5 possessed lower hardness and lower ability to withstand shear stress and heating during cooking compared with Elian No. 6. Untargeted metabolite profiling was first performed using ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) combined with a Zeno trap. In total, 188 metabolites were identified based on the matching chemistry database. Multivariate analysis demonstrated that lotus roots from different cultivars and origins could be adequately distinguished. Sixty-one differential metabolites were identified among three Elian No. 5 samples, and 28 were identified among three Elian No. 6 samples. Isoscopoletin, scopoletin, and paprazine were the most differential metabolites between Elian No. 5 and Elian No. 6. These results can inform future research on the discrimination and utilization of lotus roots.