The Estimation of Trypsin Inhibitor Activities in Soybean Meals Produced in Turkey

This study was conducted in order to determine the nutrient contents and some anti-nutritional factors of of soybean and soybean meal produced in the Adana province of Turkey and imported from various countries. Totally 8 samples, consisting of 5 soybean meals, 1 full-fat soybean meal, 2 raw soybeans, were used in this study as research materials. The trypsin inhibitor activities (TIA) and urease activities (UA) were determined as anti-nutritional factors. Additionally, the degrees of changes in these factors were analyzed in the soybeans which were exposed to heat, humidity and pressure. Besides, the cresol red (CR) test was used to estimate the toasting degree of the samples and to compare with other analysis results. The average TIA, UA and CR values in soybean meal of the soya produced in Turkey used in the experiment, were found to be 2.59 mg/g, 0.05 mg N/g/minute and 4.39 mg/g, respectively. TIA, UA and CR values are determined for the imported soybean meal are 1.62 mg/g, 0.082 N/g/minute and 4.45 mg/g respectively. These values are in the same order for for full-fat soybean, 9.60 mg/g, 0.071 mg N/g/minute and 4.43 mg/g. TIA values of raw soybean (1) which were autoclaved for 35 minutes at 100°C, 110°C, 120°C and 130°C were found as 23.20, 10.27, 2.91, 0.53 and 0.20 mg/g respectively. UA values for same raw soybeans were detected as 8.40, 2.36, 0.23, 0.00 and 0.00 mg N/g/min and CR values were found as 2.42, 2.42, 4.22, 4.46 and 4.95 mg/g respectively. TIA values were 30.00, 27.12, 26.74, 26.29 and 22.74 mg/g in the raw Soybean sample that was subjected to dry heat (heated at 100°C, 110°C, 120°C, 130°C). In the raw soybean sample, where dry heat was applied, the UA values were started with no heat applied, respectively, 8.87, 8.87, 8.80, 8.75 and 4.62 mg N/g/min; CR values were found as 3.03, 3.07, 3.07, 3.22 and 3.28 mg/g in the same order