Abstract: To promote the high-value utilization of lotus roots and their by-products, this study applied pulsed electric field (PEF) technology coupled with magnetic induction electric field (MIEF), high-speed dispersion homogenization (HDH), high-pressure homogenization (HPH), or enzymatic hydrolysis (Enz) to physically modify dietary fiber derived from lotus root nodes. The effects of excitation voltage, treatment time, frequency, and rotational speed on the soluble dietary fiber (SDF) content, SDF-to-insoluble dietary fiber (IDF) percentage, total phenolic content, in vitro antioxidant activity, and inhibitory activities against xanthine oxidase (XOD) and purine nucleoside phosphorylase (PNP) of the dietary fiber were systematically investigated. Both PEF + MIEF and PEF + HDH treatments effectively disrupted the dense fiber matrix, significantly increasing the SDF content and the SDF/IDF percentage while concurrently enhancing the antioxidant and uric acid-lowering activities. Correlation analysis revealed that the XOD and PNP inhibitory effects were positively correlated with the SDF/IDF percentage, whereas the antioxidant activity was positively correlated with the total phenolic content. Based on these findings, we proposed two targeted modification strategies: strategy 1 combined PEF with MIEF (excitation voltage 100 V, time 20 min, and frequency 50 kHz) or HDH (for 30 min at 12 000 r/min), which prioritized maximizing SDF content, total phenolic content, and antioxidant activity; strategy 2 combined PEF with either MIEF (excitation voltage 400 V, time 80 min, and frequency 65 kHz) or HDH (for 30 min at 18 000 r/min), aiming to maximize SDF conversion and uric acid-lowering efficacy. Collectively, PEF can synergize with MIEF or HDH to achieve targeted modulation of the composition and bioactivity of lotus root dietary fiber, providing a theoretical and technological basis for its precise application in functional foods.

Key words: lotus root; dietary fiber; physical field modification; antioxidant activity; uricase inhibitory activity; correlation analysis