Fruit extracts for total phenolics and antioxidant activity
measured in methanol extract (AOAM) analysis were
prepared using the method of Swain and Hillis (1959),
with some modifications. Three grams of guava tissue were
mixed with 25 mL methanol and homogenized using the
Ultra-Turrax homogenizer. The homogenates were kept at
4 1C for 12 h and then centrifuged at 15,000 rpm for 20 min
using a vacuum micro centrifuge (Beckman, J2-21, Beck-
man Instruments Inc., USA). The supernatants were
recovered and stored at 20 1C until analysis. The pellet
was re-dissolved with 20 mL dichloromethane and homo-
genized for antioxidant activity measured in dichloro-
methane extract (AOAD) analysis.