Effect of environment and year on the relationships between tofu texture and chemical composition of soybean in Southern USA

Authors: CHANG, SAM - Mississippi State University; CHEN, RUIQI - Mississippi State University; Gillen, Anne; CHEN, PENGYIN - University Of Missouri; ZHANG, BO - Virginia Tech

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Genotype (line) and environmental factors such as location and planting year affect the food quality of soybeans. However, how the combination of location and year affects the quality performance of various genotypes has not been characterized. This study’s objective was to explore the combined impact of location and year on seed chemical components and to identify the correlations between seed chemical composition and the firmness of tofu. Seventeen soybean lines were grown in field trials in Mississippi, Virginia and Missouri in 2017 and 2018. Seed storage protein composition and structure, phytic acid content, and calcium and magnesium contents were determined. Results showed that an increase in the amount of a specific subunit (A3) contributing to protein composition or in the total number of a specific type of protein structure (beta-secondary structure) were associated with a corresponding increase in the firmness of both filled tofu and pressed tofu. This study confirmed the potential utility of using the amount of protein subunit A3 for selecting soybean genotypes with desirable tofu firmness within a given location. This information will benefit plant breeders by increasing the effectiveness of selection for tofu firmness to develop new varieties of soybean. This work showed that environmental factors, which vary over years and locations, have significant influence on tofu firmness. Food scientists will use this information to design studies to understand the complex chemical interactions that contribute to tofu characteristics.

Technical Abstract: Genotype and environmental factors such as location and planting year affect the food quality of soybeans. However, how the combination of location and year affects the quality performance of various genotypes has not been characterized. This study’s objective was to explore the combined impact of location and year on seed chemical components and to identify the correlations between seed chemical composition and the firmness of tofu. Seventeen soybean PI (Plant Introduction) were grown in replicated field trials in Mississippi, Virginia and Missouri in 2017 and 2018. The major storage proteins’ subunit composition, protein’s secondary structures, phytic acid content, Ca2+ and Mg2+ contents were determined. Results showed that the content of A3 polypeptide, which has the largest molecular size among all acidic (Ax) polypeptides of glycinin, positively correlated with filled tofu firmness in all six trials, and with pressed tofu firmness in five of six trials. In addition, the total beta-secondary structures (Beta-sheet+Beta-turn) had a positive correlation with the pressed and filled tofu firmness across all trials. This study confirmed the potential utility of using A3 polypeptide content for selecting soybean genotypes with desirable tofu firmness within a given location. Tofu of desirable firmness could be produced with a range of A3 polypeptide values, but within one trial, the genotype with highest A3 polypeptide generally had higher firmness. Environmental factors, which vary over years and locations and have significant influence on some chemical components should be considered carefully in selecting soybean for producing desirable tofu firmness.