Natural Aging of Soybean Impacts Ingredient Functionality of Soy Protein Isolate

Soybean is an important source of functional protein ingredients. The seeds may be stored for different periods of time before protein isolation. However, little knowledge is available regarding how the aging of soybean seeds affects the functionality of the extracted protein as a food ingredient. To fill this knowledge gap, soybean seeds were harvested between 2019 and 2023. Then the samples were freeze-dried to obtain soy protein isolates (SPIs). SPI-2023 showed significantly higher water holding capacity and emulsion stability index than other SPIs. The obtained ingredient functionality results in the present work suggest that soybean seed aging period was a significant factor affecting some technofunctionalities; these significant impacts might relate to alterations of protein surface properties induced by aging. This study can guide the rational selection and storage of soybean seeds for SPI production, thereby improving the overall utilization of soybean resources and soy protein in the food industry.