The 0.5 g fresh sample was extracted with 6 mLof 10% (w/v) trichloroacetic acid (TCA). The homogenate was centrifuged at 4000 ×g for 10 min. 1 mL supernatant and 1 mL TCA were added to 2 mL of 20% TBA solution containing 0.6% (w/v) thiobarbituric acid.