Profile analysis and correlation across phenolic compounds, isoflaves, and antioxidant capacity during germination of soybeans (Glycine max L.)

Authors: GUZMAN-ORTIZ, FABIOLA - National Polytechnic Institute; SAN MARTIN-MARTINEZ, EDUARDO - National Polytechnic Institute; RODRIGUEZ-AZA, YOLANDA - National Polytechnic Institute; VALVERDE, MARIA ELENA - National Polytechnic Institute; Berrios, Jose; MORA-ESCOBEDO, ROSALVA - National Polytechnic Institute

Submitted to: CyTA - Journal of Food
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2017
Publication Date: 6/5/2017
Citation: Guzman-Ortiz, F.A., San Martin-Martinez, E., Rodriguez-Aza, Y., Valverde, M., Berrios, J.D., Mora-Escobedo, R. 2017. Profile analysis and correlation across phenolic compounds, isoflaves, and antioxidant capacity during germination of soybeans (Glycine max L.). CyTA - Journal of Food. 15(4):516-524. https://doi.org/10.1080/19476337.2017.1302995.
DOI: https://doi.org/10.1080/19476337.2017.1302995

Interpretive Summary: The germination process mobilize the reserve proteins stored in the cotyledon protein bodies and cause changes in secondary metabolite distribution. In this research, the effect of germination for 2 and 6 days on the concentration of total and free phenolic, and other compounds with antioxidant activity of soybean extracts, was evaluated. After 6 days of germination, the concentration of most compounds with antioxidant activity increased compared to samples obtained from ungerminated soybean and soybean germinated for 2 days. Only the free phenolic compounds benzoic and vanillic acids decreased during the germination process. The results of the study demonstrated that the germination process for a period of 6 days at 26°C increased the bioactive compounds with antioxidant activity, which would render health-promoting soybean flours.

Technical Abstract: The germination process mobilize the reserve proteins stored in the cotyledon protein bodies and cause changes in secondary metabolite distribution. In this research, the effect of germination for 2 and 6 days on the concentration of total and free phenolic compounds, isoflavones, and the antioxidant activity of soybean extracts, was evaluated. After 6 days of germination, the concentration of most phenolics and isoflavones, significantly increased compared to samples obtained from ungerminated soybean and soybean germinated for 2 days. Only the free phenolic compounds benzoic and vanillic acids decreased during the germination process. The antioxidant activity of the seeds increased with germination time and a high correlation was observed among total phenolic compounds (TPC), trolox equivalent antioxidant activity (TEAC) and ferric reducing antioxidant power (FRAP) (r=0.995, r=1.000). Isoflavones also showed high correlations with TEAC and FRAP assays and only glicitin showed relatively low correlations (r=0.756, r=0.685). The germination process for a period of 6 days at 26°C increased bioactive phenolic compounds and isoflavone aglycon, which would render functional soybean flours.