Chickling vetch seeds (raw or autoclaved at 112°C for 10, 20 or 30 min. and at 121°C for 10, 20, 30, 60, 90 or 120 min) were applied as an object for comparison of three tests used for evaluation of seed thermal processing efficiency (i.e. trypsin inhibitor activity – TIA, cresole red index – CRI and protein dispersion index – PDI) with a method worked out by the authors and called bromocresole purple index (BCPI). Seed autoclaving caused a decrease in TIA (from 23.13 TUI/mgDM for a raw sample to 2.00 TUI/mgDM for a sample autoclaved at 121°C for 120 min) and in PDI (from 90.46% for a raw sample to 15.63% for a sample autoclaved at 121°C for 120 min), as well as an increase in CRI (from 1.48 mg/gDM for a raw sample up to 4.82 mg/gDM for a sample autoclaved at 121°C for 120 min) and in BCPI (from 15.10 mg/gDM for a raw sample up to 38.09 mg/gDM for a sample autoclaved at 121°C for 120 min). All compared estimation ways appeared to be useful at studied seed evaluation; however, due to great sensibility (c = 0.19), detectability (d = 327.6s), distinguishability (r = 94%) and low time-consumption (h = 1.5h), the application of BCPI tests was found the most proper. High correlation coefficients between BCPI and other evaluation methods (BCPI & TIA – r = -0.84; BCPI & CRI – r = 0.94; BCPI & PDI – r = -0.75) point out to the possibility of replacing the time- and cost-consuming determinations (e.g. antitrypsin activity – TUI or determination of protein dispersion index – PDI) with a simple, rapid and cheap bromocresole purple index – BCPI.