Guava (Psidium guajava L.) is a tropical fruit, widely consumed fresh and also processed (beverages,
syrup, ice cream, and jams). Pulp and peel fractions were tested, and both showed high content of
dietary fiber (48.55-49.42%) and extractable polyphenols (2.62-7.79%). The antioxidant activity
of polyphenol compounds was studied, using three complementary methods: (i) free radical DPPH•
scavenging, (ii) ferric reducing antioxidant power assay (FRAP), and (iii) inhibition of coppercatalyzed
in vitro human low-density lipoprotein (LDL) oxidation. All fractions tested showed a
remarkable antioxidant capacity, and this activity was correlated with the corresponding total
phenolic content. A 1-g (dry matter) portion of peel contained DPPH• activity, FRAP activity, and
inhibition of copper-induced in vitro LDL oxidation, equivalent to 43 mg, 116 mg, and 176 mg of
Trolox, respectively. These results indicate that guava could be a suitable source of natural
antioxidants. Peel and pulp could also be used to obtain antioxidant dietary fiber (AODF), a new
item which combines in a single natural product the properties of dietary fiber and antioxidant
compounds.