Revealing the distribution pattern of soybean purine content and its influencing factors based on an ultra-micro detection system

Abstract

In this study, an effective method for detecting purine in soybean seeds and products by ultra-micro spectrophotometry (UMS) was established. Addition of 35 % HClO₄ to 0.1 g of soybean flour and incubation in a water bath at 100 °C for 30 min and adjustment of the pH to 4 was optimal for purine hydrolysis and extraction of the total purine content of soybean seeds. No significant difference (P > 0.05) in total purine detection was observed between UMS and UPLC, and the relative standard deviation was less than 3 %, ensuring optimal precision and accuracy. Seed from 2083 soybean accessions grown in two years were analysed using UMS. Total purine content ranged from 65.49 to 379.84 mg/100 g, with 5.8-fold variation, and 11 elite accessions with under 100 mg/100 g of total purine were identified. The agronomic traits, environmental factors, and geographical significantly affected soybean total purine content. Furthermore, total purine content correlated positively with seed protein (r = 0.342∗∗∗) and negatively with oil (r = −0.330∗∗∗). The geographical distribution revealed that accessions from Southern and Northern China contain lower amounts of total purine content. This study provides a technical and material foundation for breeding low purine soybean.