Evaluation of crude protein, crude oil, total flavonoid, total polyphenol content and DPPH activity in the sprouts from a high oleic acid soybean cultivar

James Mugisha¹³ Sovetgul Asekova² Krishnanand P. Kulkarni² Cheol Woo Park² Jeong-Dong Lee^2,*

¹Department of Government Services One Acre Fund-TUBURA/Rwanda
²School of Applied Biosciences, Kyungpook National University
³Department of Food Security and Agricultural Development, Kyungpook National University

Abstract

Soybeans [Glycine max (L.) Merill] are a rich source of antioxidants and other phytonutrients. Soybean sprouts contain many biologically active secondary metabolites and are rich in polyphenols, flavonoids, and phenolic compounds. In the present study, two soybean cultivars, Hosim, with high oleic acid (- 80% in total seed oil), and Pungsannamul, with normal oleic acid (- 23%) in seed, were examined for changes in the content of crude protein, crude oil, total flavonoids, total phenolics, and DPPH (1,1-diphenyl-2-picryl-hydrazyl) during the sprouting duration of 5 days. The protein content in both the varieties was found to increase by the days of sprouting. The crude oil content of Pungsannamul sprouts was found to be maximum on day 1 (16.9%, w/w) and decreased thereafter to reach to the level of 14.8% on day 5. No significant differences in the crude oil content of Hosim sprouts from day 1 to 5 were observed. Flavonoid content was found to increase up to day 4 and then dropped on day 5, in both the cultivars. Total polyphenol content showed a tendency to increase up to day 3 and started to decrease significantly from day 4. DPPH activity was found to increase up to day 5 in both the varieties. All the components studied in the high oleic acid soybean sprouts showed a change in content during the sprouting process similar to the change that would occur in normal oleic acid soybeans. The study showed that the contents of antioxidant, flavonoid, and polyphenol significantly increase during the sprouting.

Acknowledgements

This work was carried out with the support of the “Cooperative Research Program for Agriculture Science & Technology Development” (Project No. PJ01118303), Rural Development Administration, Republic of Korea.

Figures & Tables

Fig. 1. Variation in the crude protein, crude oil, total flavonoid, total polyphenol, and DPPH, in the two soybean cultivars Hosim and Pungsannamul, during 5 days of sprouting. The letters a, b, c, d, e are given on each figure to show the significant difference between and among the days of sprouting. Same letter above each bar indicate no significant difference between the days of sprouting (p < 0.05).