Comparative evaluation of processes for production of soybean meal for poultry feed in Nigeria Evaluación comparativa de procesos para la producción de harina de soya para la alimentación de pollos en Nigeria

This work examined and compared three processes for production of low trypsin inhibitor soybean meal. Soybean flour was subjected to roasting, autoclaving and steaming to denature trypsin inhibitors. Roasting was done at 120, 130, 135 and 140 ºC for 5, 7, 8 and 9 minutes, respectively. Autoclaving was carried out at 121ºC, 15psig for 20, 30, 40 and 50 minutes. Steaming was carried out at 105 ºC for 10, 12, 15 and 18 minutes. Defatting of the samples was done and the activity of trypsin inhibitor was investigated. Proximate analysis and quality tests was carried out to ascertain quality of the heat treated soybean meals. Trypsin inhibitor in the soybean meals from the three heat treatment processes ranged from 1.20 to 3.54mg/g while that of raw sample was 6.01mg/g. Percentage crude protein in all the heat treated samples ranged from 39.38 to 40.58 % while that of raw sample was 44.60 %. Urease index ranged from 0.11 to 2.07 % for all heat treated samples while it was 2.11 % for the raw samples. % KOH protein solubility in Soybean meal from the three processes ranged from 45.2 to 73.1 % while that of the raw sample was 49.1%. The results were statistically significant at p>0.05. At significance level of p>0.05 it was established that local soybeans can be processed with adequate heat to obtain low activity soybean meal with good nutrient standard. The steaming process operated at 105 ºC for 18 minutes gave the best overall results with trypsin inhibitor activity of 1.20 mg/g