Continuous method to determine the trypsin inhibitor activity in soybean flour

Area of Science:

• Food Science
• Analytical Chemistry
• Biochemistry

Background:

• Trypsin inhibitor (TI) activity is crucial for assessing soybean flour's nutritional value.
• Standard assays for TI activity are often time-consuming and complex.
• Developing efficient analytical methods is essential for food quality control.

Purpose of the Study:

• To introduce a novel, continuous spectrophotometric assay for determining trypsin inhibitor activity.
• To establish this method as a viable, cost-effective alternative to traditional discontinuous assays.
• To optimize the assay for increased sensitivity and a broader linear range.

Main Methods:

• A continuous spectrophotometric rate determination using N-benzoyl-DL-arginine p-nitroanilide as the substrate.
• Elimination of reaction stopping, acetic acid, and centrifugation/filtration steps.
• Comparison of TI activity in soybean flour samples using both the novel and standard assays.

Main Results:

• The novel method yielded statistically comparable TI activity results to the standard assay across various concentrations.
• The assay demonstrated coefficients of variation not exceeding 8%.
• Reducing incubation time to 2 minutes enhanced sensitivity and expanded the linear range.

Conclusions:

• A more economical, faster, and simpler assay for trypsin inhibitor activity has been developed.
• This method provides a reliable alternative for evaluating soybean flour nutritional value.
• The optimized assay offers improved performance characteristics for routine analysis.