Comparative analysis of the effect of processing techniques on purines in tofu products

Food processing techniques could have profound effect on the purine content and availability in different foods. Although tofu is generally regarded as a low purine food with very minimal impact on serum uric acid levels, different production techniques could significantly impact the purine content. The study examined the purine content in minimally processed and deep-processed tofu products, using High-Performance Liquid Chromatography (HPLC) and further determined differences in purine content per unit protein in different types of tofu. Results showed that minimally processed tofu was generally low purine content (9.73 ± 0.05 ~ 48.74 ± 2.79 mg/g), while deep-processed tofu could be classified as medium or high purine content (65.74 ± 5.25 ~ 121.18 ± 2.55 mg/g). Dried (121.18 ± 2.55 mg/g) and fried (106.03 ± 0.97 mg/g) tofu were highest in purine content suggesting increased consumption could pose risk for serum uric acid levels. Yuba (1.45 ± 0.12 mg/100g) showed the lowest purine content/protein unit and could be ideal as protein source for individuals at risk of hyperuricemia. This study provides empirical evidence which could be vital for planning healthy dietary choices with tofu for managing gout and hyperuricemia.