Influence of Different Genotypes on Trypsin Inhibitor Levels and Activity in Soybeans

Mirjana Pesic,Sladjana Stanojevic,Miroljub Barac,Biljana Vucelic-Radovic,Viktor Nedovic

doi:10.3390/s7010067

Abstract

This study describes the relationship between the two major trypsin inhibitors (TI) in soybean, i.e., the Kunitz (KTI) and Bowman-Birk (BBI) trypsin inhibitors, as well as between them and the corresponding trypsin inhibitor activity (TIA). Twelve investigated soybean genotypes showed significant differences in TI levels and TIA. A very strong positive correlation was found between the levels of KTI and total BBI (r = 0.94, P < 0.05). No relationship was found between KTI, BBI or total TI and TIA. Based on this data, it appears that the levels of major TI in soybean are related. Understanding the relationship between trypsin inhibitors and their activities could be useful for further improvement of the health impacts of soy proteins.

Highlights

Soybeans present a good source of high quality protein and other nutrients
It has been suggested that the Kunitz (KTI) and Bowman-Birk (BBI) trypsin inhibitors suppress both initiation and promotion stages of carcinogenesis [8]In particular the Bowman-Birk inhibitor appears to be highly promising as a cancer chemopreventive agent
The Bowman-Birk type of trypsin inhibitors was detected in two zones, I and II, whereas the KTI was detected as one band

Summary

Introduction

Many phytochemicals in soybeans have been considered as antinutrients and irrelevant to nutrition, since they neither yield energy nor function as vitamins [1] To reduce their activity, different treatments on biologically active components, especially trypsin inhibitors, were extensively studied. The standard methods of measuring protease inhibitors in food by enzyme assays often gave inaccurate results with processed samples having low residual activity [3, 16]. These low activities must be assessed in the presence of other proteases [17] and compounds, which inactivate trypsin inhibitors. Understanding the relationship between the levels of trypsin inhibitors and corresponding TIA could be useful to facilitate the selection of genotypes for certain types of processing and specific applications

Experimental Section

Electrophoretic analysis

Correlation analysis

Findings

Trypsin inhibitor activity