DETERMINATION OF TRYPSIN INHIBITOR ACTIVITY OF MICROWAVE-HEATED BEAN SEEDS USING BROMOCRESOLE PURPLE INDEX (BCPI
 
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Pol. J. Food Nutr. Sci. 2010;60(4):329–333
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ABSTRACT
The usefulness of a new analytical method called bromocresole purple index (BCPI) for determination of trypsin inhibitor activity (TIA) of microwave-heated bean seeds was tested. The study was conducted on bean seeds of “Jaś” cultivar which were microwave heated using one of ten variants of that process intensity. Each of the three radiation power levels (350, 500, or 650W) corresponded to three different processing times (60, 120, or 180 s), and one of the samples remained untreated (i.e. unheated). Each sample was analysed using the BCPI method and the TIA method (with a synthetic substrate BAPA – N-α-benzoyl-DL-arginine-p-nitroanilide). The comparison of those two analytical methods (BCPI and TIA) used to analyse the microwave-heated bean seeds samples indicates the superiority of bromocresole purple index method in terms of time consumption (τTIA=2.5 h,τBCPI=1.5 h), distinguishability (ρTIA=51.11%;ρBCPI=71.11%), accuracy of determination (lower coefficient of variation; πTIA=3.02–9.27; πBCPI=1.22–5.88) and detectability (detectable minimum μTIA=10.32 and μBCPI=5.01), whereas the TIA assayed proved superior in terms of method sensitivity (χTIA=0.40; χBCPI=0.16). The statistical analysis of experimental data indicates also that the results obtained for microwave-heated bean seeds using BCPI and TIA-BAPA methods are highly correlated (correlation coefficient r=95.28%), moreover both those traits may be related by mathematical functions TIA= f(BCPI). The usefulness of some of those traits in the analysis was confirmed statistically; based on high coefficients of determination of these equations to experimental data (e.g. R2=90.72% for linear equation and R2=91.11% for the IVo polynomial equation). Due to the specificity of quick, routine tests performed at an industrial laboratory, the application of the simplest linear regression equation: TIA=f(BAPA) seems to be the most justified, whereas its coefficient of determination R2 (in description of experimental data) should assure the reliability of calculations.
ISSN:1230-0322