Research Article

Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach

Volume: 2026 Number: 2 September 8, 2026

Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach

Abstract

Soybeans are recognized for their high-quality protein, antioxidant activity, and bioactive phytochemicals. This study evaluated five commercial soy products–soy milk, soy cheese, soy flour, soy ground meat, and soybean sprouts–using spectrophotometric assays (CUPRAC, ABTS, Folin-Ciocalteu, AlCl3/NaNO2) and HPLC, with protein quantified by Lowry and Cu(II)-neocuproine (Nc) methods. Marked variations were found across products. Total antioxidant capacities ranged from 11.54 ± 0.03 to 18.18 ± 0.16 mmol TE 100 g-1 (CUPRAC) and 14.95 ± 0.46 to 21.53 ± 0.10 mmol TE 100 g-1 (ABTS), with soy milk exhibiting the highest ABTS and CUPRAC activities. Phenolic contents varied between 10.51 ± 0.08 and 18.27 ± 0.03 mmol GA 100 g-1, while flavonoids ranged from 5.10 ± 0.11 to 8.85 ± 0.14 mmol CAT 100 g-1. Protein levels were greatest in soy flour (63.02 ± 0.95 g 100 g-1) and soy ground meat (59.40 ± 1.46 g 100 g-1). HPLC revealed product-specific isoflavone distributions: genistin dominated in soy milk and flour, genistein in soy cheese and sprouts, and daidzein in soy ground meat. The main phenolic compound was 4-hydroxybenzoic acid, while rutin predominated in sprouts. This integrated methodology offers a rigorous analytical framework for assessing phytochemical and nutritional diversity in plant-based foods.

Keywords

Supporting Institution

This study was supported by the Scientific Research Projects Coordination Unit of Istanbul University under project number 19146.

Project Number

19146

References

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Details

Primary Language

English

Subjects

Analytical Spectrometry, Instrumental Methods, Analytical Chemistry (Other)

Journal Section

Research Article

Publication Date

September 8, 2026

Submission Date

January 4, 2026

Acceptance Date

June 23, 2026

Published in Issue

Year 2026 Volume: 2026 Number: 2

APA
Karaman Ersoy, Ş., Tekgezer, D., & Sözgen Başkan, K. (2026). Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach. Journal of the Turkish Chemical Society Section A: Chemistry, 2026(2), 1-16. https://doi.org/10.18596/jotcsa.1855681
AMA
1.Karaman Ersoy Ş, Tekgezer D, Sözgen Başkan K. Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach. JOTCSA. 2026;2026(2):1-16. doi:10.18596/jotcsa.1855681
Chicago
Karaman Ersoy, Şeyda, Didem Tekgezer, and Kevser Sözgen Başkan. 2026. “Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach”. Journal of the Turkish Chemical Society Section A: Chemistry 2026 (2): 1-16. https://doi.org/10.18596/jotcsa.1855681.
EndNote
Karaman Ersoy Ş, Tekgezer D, Sözgen Başkan K (September 1, 2026) Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach. Journal of the Turkish Chemical Society Section A: Chemistry 2026 2 1–16.
IEEE
[1]Ş. Karaman Ersoy, D. Tekgezer, and K. Sözgen Başkan, “Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach”, JOTCSA, vol. 2026, no. 2, pp. 1–16, Sept. 2026, doi: 10.18596/jotcsa.1855681.
ISNAD
Karaman Ersoy, Şeyda - Tekgezer, Didem - Sözgen Başkan, Kevser. “Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach”. Journal of the Turkish Chemical Society Section A: Chemistry 2026/2 (September 1, 2026): 1-16. https://doi.org/10.18596/jotcsa.1855681.
JAMA
1.Karaman Ersoy Ş, Tekgezer D, Sözgen Başkan K. Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach. JOTCSA. 2026;2026:1–16.
MLA
Karaman Ersoy, Şeyda, et al. “Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach”. Journal of the Turkish Chemical Society Section A: Chemistry, vol. 2026, no. 2, Sept. 2026, pp. 1-16, doi:10.18596/jotcsa.1855681.
Vancouver
1.Şeyda Karaman Ersoy, Didem Tekgezer, Kevser Sözgen Başkan. Comparative Evaluation of Antioxidant, Phenolic, Flavonoid, Protein, And Isoflavone Profiles in Commercial Soy Products: A Multi-Methodological Approach. JOTCSA. 2026 Sep. 1;2026(2):1-16. doi:10.18596/jotcsa.1855681