Profiling and relationship of water-soluble sugar and protein compositions in soybean seeds

• Wide variations existed in both water-soluble sugar and protein compositions.
• The correlations between sugar and protein compositions in seeds were determined.
• Total water-soluble sugar and water-soluble protein showed a positive correlation.
• Total water-soluble protein showed negative correlations with fructose and glucose.
• 35 germplasms were clustered based on water-soluble sugar and protein contents.

Sugar and protein are important quality traits in soybean seeds for making soy-based food products. However, the investigations on both compositions and their relationship have rarely been reported. In this study, a total of 35 soybean germplasms collected from Zhejiang province of China, were evaluated for both water-soluble sugar and protein. The total water-soluble sugar (TWSS) content of the germplasms studied ranged from 84.70 to 140.91 mg/g and the water-soluble protein (WSP) content varied from 26.5% to 36.0%. The WSP content showed positive correlations with the TWSS and sucrose contents but negative correlations with the fructose and glucose contents. The clustering showed the 35 germplasms could be divided into four groups with specific contents of sugar and protein. The combination of water-soluble sugar and protein profiles provides useful information for future breeding and genetic research. This investigation will facilitate future work for seed quality improvement.