Quality control of full-fat soybean using urease activity: Critical assessment of the method

Abstract

A critical assessment of the method for determination of urease activity, as an indicator of the degree of full-fat soybean (FFSB) processing, has been undertaken. FFSB was processed by dry extrusion at five temperatures, ranging from 115ºC to 165ºC, and analyzed for urease activity by two laboratories and by two analysts at each laboratory, using the pH-difference procedure. The in vivo trial with chickens fed the processed FFSB has also been conducted. While the results of two analysts at each laboratory did not differ significantly (P>0.05), there was a significant difference (P<0.05) in urease activity results between the two laboratories. The overall conclusion of this study is that the urease activity determined by pH-difference method can not be recommended as a reliable indicator for FFSB quality control.

Keywords

• full-fat soybean
• dry extrusion
• degree of processing
• quality control
• urease activity