Comparison of Physicochemical Properties of Seed Protein in Soybean Cultivars

Abstract

This study investigated and compared the protein properties of different cultivars of soybean. The cultivars of soybean examined were Daewonkong (DWK), Miso (MS), Seonpung (SP), Saedanbaek (SDB), and Cheongja5ho (CJ5). The yield of protein extraction was the lowest in DWK (32.56%), followed sequentially by MS (40.79%), SP (44.68%), SDB (45.03%), and CJ5 (45.48%). The in vitro digestibility of SDB was the highest (88.19%). Analysis of the protein molecular weight pattern of the soybean cultivars using SDS-PAGE revealed that SDB differed from other cultivars in the ranges 0∼75 kD, 25∼37 kD, and 15∼20 kD. The β-conglycinin content of CJ5 was the highest (126.64 mg/g), whereas maximum glycinin content was obtained in the SDB cultivars (130.75 mg/g). The ratio of 11S/7S was highest in CJ5 (1.11) and the lowest in MS (0.61). The overall amino acid composition also showed a proportional tendency with the crude protein results. Compared to other cultivars, both SDB and MS showed a significantly higher composition of all essential amino acids, except for methionine. A similar trend was observed for non-essential amino acid contents of SDB and MS, showing high composition of glutamic acid, aspartic acid, and arginine. Considering the functional characteristics of SDB and MS, we propose that these cultivars have great potential value as materials to be used in the protein product industry.