Guava Fruit (<i>Psidium guajava </i>L.) as a New Source of Antioxidant Dietary Fiber

TLDR

Guava (Psidium guajava L.) is a tropical fruit widely consumed fresh and processed into beverages, syrups, ice cream, and jams. The study aims to develop antioxidant dietary fiber (AODF) by extracting antioxidant compounds from guava peel and pulp. Antioxidant activity of guava polyphenols was assessed using DPPH radical scavenging, ferric reducing antioxidant power (FRAP), and inhibition of copper‑catalyzed LDL oxidation. Pulp and peel fractions contain ~49 % dietary fiber and 2.6–7.8 % polyphenols, and all fractions show strong antioxidant capacity correlated with phenolic content, with a 1‑g dry peel portion equivalent to 43 mg DPPH, 116 mg FRAP, and 176 mg Trolox, confirming guava as a promising natural antioxidant source and candidate for AODF. Keywords: Guava; Psidium; tropical fruits; dietary fiber; polyphenols; antioxidant dietary fiber; radical scavenging; reducing ability; low‑density lipoprotein oxidation.

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