Web Release Date: September 29,
Guava Fruit (Psidium guajava L.) as a New Source of Antioxidant Dietary Fiber
and
Departamento de Metabolismo y Nutrición, Instituto del Frío, Consejo Superior de Investigaciones Científicas, Ciudad Universitaria, E 28040 Madrid, Spain and Unidad de Investigación de Alimentos, Facultad de Farmacia, Universidad Central de Venezuela, Caracas, Venezuela
Received for review February 5, 2001. Revised manuscript received July 26, 2001. Accepted August 6, 2001. Author R.P. thanks the Comunidad de Madrid for the grant of a scholarship.
Abstract:
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 copper-catalyzed 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.
Keywords: Guava; Psidium; tropical fruits; dietary fiber; polyphenols; antioxidant dietary fiber; radical scavenging; reducing ability; low-density lipoprotein oxidation
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