Integrated Proteomics and Metabolomics Analysis Highlights Correlative Metabolite-Protein Networks in Soybean Seeds Subjected to Warm-Water Soaking

Soaking of soybean seeds is a prerequisite
for the production of
soy foods, and it has been shown that the extent of water absorbed
during different imbibition conditions directly affects the quality
of the subsequent soybean seed products by yet unknown mechanisms.
In order to elucidate the molecular changes in soybean seeds during
different soaking temperatures, we performed an integrated proteomics
and metabolomics analysis of seeds soaked at 4, 25, and 55 °C.
Proteomics analysis revealed that various enzymes related to carbohydrate
and protein hydrolysis were activated in soybean seeds during water
soaking at 55 °C. Interestingly, results obtained from this integrated
proteomics and metabolomics study showed changes in various metabolites,
including isoflavones, amino acids, and sugars, that were positively
correlated with proteome changes occurring upon soaking at 55 °C.
Furthermore, soaking of soybean seeds at 55 °C resulted in degradation
of indigestible anti-nutrients such as raffinose oligosaccharides.
Taken together, our results suggest that the seed soaking at a high
temperature (55 °C) increases the nutritional value of soybean
seeds by decreasing the contents of some of the common anti-nutrients.