Purine content of different soybean products and dynamic transfer in food processing techniques

The high purine characteristics of soybeans limit their industrial development through a multi-level transmission mechanism of health concerns, market contraction, research and development resource diversion, and increased policy costs. This research investigated purine dynamics during non-fermented soy product processing by high performance liquid chromatography (HPLC). Purine content was systematically quantified across processing stages to reveal the regulation mechanism of key processes on the dynamic change of purine. Results showed that processed products exhibited significantly reduced purine levels (15.11–84.42 mg/100 g, wet basis). Front-stages processing (soaking reduced purines by ~50 %, grinding / boiling reduced purines by~10 %) effectively lowered purines. However, back-stage processing (coagulation, squeezing, yuba formation) increased purine content by 3–50 % due to protein entrapment and moisture loss. This article first revealed a “decrease-then-increase” two-way regulation of purine, providing a theoretical basis for optimizing processes and developing low-purine soybean products. • Non-fermented soy products are low/mid-purine foods, lower than animal-derived foods; • Soaking is the key process for purine elimination; • The coagulation stage is the key for purine enrichment; • Two-way regulation of purine “decrease-then-increase” was revealed in soybean products.