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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #390076
Research Project: Gene Discovery and Designing Soybeans for Food, Feed, and Industrial Applications

Location: Plant Genetics Research

Title: Chapter seven - A fast and cost-effective procedure for reliable measurement of trypsin inhibitor activity in soy and soy products

Author
item KIM, SUNHYUNG - University Of Missouri
item Krishnan, Hari

Submitted to: Methods in Enzymology
Publication Type: Book / Chapter
Publication Acceptance Date: 8/8/2022
Publication Date: 1/27/2023
Citation: Kim, S., Krishnan, H.B. 2023. Chapter seven - A fast and cost-effective procedure for reliable measurement of trypsin inhibitor activity in soy and soy products. Methods in Enzymology. 680:195-213. https://doi.org/10.1016/bs.mie.2022.08.016.
DOI: https://doi.org/10.1016/bs.mie.2022.08.016

Interpretive Summary: Due to its superior nutritional quality, wide availability and relatively low cost, soybean meal is the most widely used protein source in animal diets. Despite these advantages, soybean meal cannot be used directly for animal feed mixtures due to the presence of trypsin inhibitors which reduce animal weight gain. Currently, trypsin inhibitor activity is measured utilizing the “standard method” that has been approved by American Oil Chemists Society (Method Ba 12-75) and American Association of Cereal Chemists International (Method 22-40.01). In this study, we have modified and improved this “standard method” resulting in the elimination of several time consuming and often unnecessary steps inherent in the earlier methods. The proposed 1 mL assay is rapid, accurate, cost-effective and amenable to high-throughput screening of soy products. Our improved assay procedure can be routinely employed by soy processors to measure trypsin inhibitor activity to assess the quality of soy meal used in the animal feed.

Technical Abstract: Rapid and accurate measurement of trypsin inhibitor is critical for soy processors to assess the quality of soy meal. Currently, trypsin inhibitor activity is measured using the American Oil Chemists’ Society (AOCS) and the American Association of Cereal Chemists International (AACCI) approved method. We have modified and improved the AACCI/AOCS approved method resulting in the elimination of several time-consuming steps and drastically reducing the assay volume. By employing our simplified procedure, we have measured trypsin inhibitor activity of several soy and soy products. A side-by side comparison of our simplified procedure with AOCS approved method revealed strikingly similar results indicating that several time-consuming and tedious steps associated with AACCI/AOCS approved methods can be eliminated without sacrificing the accuracy of the assay. Moreover, we demonstrate that our assay can also be carried out in 96-well microplates which will enable high-throughput screening of large number of soy meal samples.