Modulating soy protein isolate functionality through breeding approach

Authors: TENG, ZHOUTAI - North Carolina State University; SHEA, ZACHARY - Former ARS Employee; Taliercio, Earl; ZHENG, HAOTIAN - North Carolina State University

Submitted to: ACS Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2026
Publication Date: 8/21/2026
Citation: Teng, Z., Shea, Z., Taliercio, E.W., Zheng, H. 2026. Modulating soy protein isolate functionality through breeding approach. ACS Food Science and Technology. https://doi.org/10.1021/acsfoodscitech.6c00347.
DOI: https://doi.org/10.1021/acsfoodscitech.6c00347

Interpretive Summary: We evaluated the role of variety and growth location on soy protein traits important to the expanding alternative protein market. Functional properties, such as the composition of seed storage proteins, water holding capacity, oil holding capacity, foaming properties and emulsification properties were evaluated for NC-Raleigh and 4 of its progenies derived from crosses with wild soybean. Protein composition was influenced by location. Samples from Hugo, NC exhibited higher protein subunit ratios and were associated with improved solubility, water-holding capacity, and emulsifying capacity, compared with samples grown in Kinston, NC. However, the Hugo samples also displayed lower oil-holding capacity, reduced foam overrun and foam stability, and diminished emulsion stability. NC Raleigh and one of its progeny (NSPR-ET230) showed a complete profile of seed storage protein subunits. These were associated with significantly higher surface hydrophobicity compared to other genotypes, which lacked some subunits. These findings demonstrate that soybean breeding could improve soy protein’s utility in the alternative protein market, and that seed protein properties should be measured in protein functionality-focused breeding programs.

Technical Abstract: Soy protein, derived from the most widely produced oilseed crop globally, plays a crucial role in food applications due to its functional properties. However, limited research has explored the enhancement of soy protein techno-functionality through breeding. In this study, five soybean genotypes were evaluated, including a modern cultivar (NC Raleigh) and four progeny derived from crosses between NC Raleigh and wild soybean (Glycine soja) accessions: NSPR-ET230, N17-30812, N17-31806, and NT16-3364; these genotypes were cultivated in two locations, Caswell (CAS) and Hugo. Soy protein isolates (SPI) were extracted from the 5 genotypes using the isoelectric precipitation method and were used as ingredient samples for functionality study. The objective was to assess the impact of two variables, genotype and environment, on SPI functionality. NC Raleigh and NSPR-ET230 grown in Hugo exhibited a complete protein subunit profile regarding molecular weight distribution as characterized by gel electrophoresis. The identified subunits were a, a’, ß, acid polypeptides, and basic polypeptides. In contrast, other genotypes from Hugo and CAS showed a lack of a and a' subunits. Two-Way ANOVA analysis revealed that the environment was a significant factor impacting on water holding capacity (WHC) (p < 0.001), oil holding capacity (OHC) (p < 0.001), overrun (p < 0.001), foam stability (p < 0.01), emulsifying activity index (EAI) (p < 0.01), emulsion coalescence stability (p < 0.01), and SPI surface hydrophobicity (p < 0.001); whereas, the genotype was a meaningful factor affecting WHC (p < 0.001), overrun (p < 0.001), and SPI surface hydrophobicity (p < 0.001). CAS-grown samples showed superior foamability and foam stability, and coalescence stability, whereas Hugo-grown samples demonstrated enhanced EAI, and surface hydrophobicity. However, according to static multiple light scattering, emulsions made from Hugo exhibited poorer creaming stability after four weeks storage, particularly in NC Raleigh and NSPR-ET230. These findings provided practical evidence showing that breeding strategies, incorporating genotypes and environmental factors, can impact soy protein composition and techno-functionalities. This knowledge may be utilized in future works on tuning SPI functionality and/or rational selection of SPI towards different food applications.