The DPPH free radical-scavenging activity of TRMHswas determined
by themethod of Kirby and Schmidt [23]. A volume of 500 μl of eachhydrolysate
at different concentrations (1–5 mg/ml) was added to 375 μl
of ethanol and 125 μl of DPPH solution (0.2 mMin ethanol) as free radical
source. The mixtures were incubated for 1 h in the dark at room
temperature. Scavenging capacitywasmeasured spectrophotometrically
(Labomed Inc., Los Angeles, CA, USA) by monitoring the decrease in
absorbance at 517 nm. In its radical form, DPPH has an absorption
band at 517 nm which disappears upon reduction by an antiradical
compound. Lower absorbance of the reaction mixture indicated higher
free radical-scavenging activity. The test was carried out in triplicate
and the results were mean values.