Polyphenol’s characterization and antioxidant activity of extracts from unripen and fruit fly-infested guava waste biomass

Abstract

A significant quantity of guava (Psidium guajava L.) fruit is annually wasted in Pakistan and other tropical regions due to the excessive cultivation of immature fruit and the infestation of pests such as the fruit fly (Bactrocera dorsalis). This wasted biomass is an underutilized source of bioactive chemicals, particularly polyphenols. This study aims to convert fruit waste into a valuable resource through an eco-friendly extraction, characterization and antioxidant activities of polyphenols. Using water-ethanol mixtures as a eco-friendly green solvents, polyphenols extracted from unripe wasted guava (UG) and fruit fly-infested guava (IG). The extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), and the profiles of individual polyphenol compounds using HPLC-DAD. We employed the DPPH, ABTS, and FRAP, assays to evaluate the efficacy of the antioxidants. The IG extract exhibited a significantly elevated TPC (91.28 ± 2.91 mg GAE/g dw) and TFC (48.52 ± 2.31 mg QE/g dw) compared to the UG extract (TPC: 76.37 ± 3.15 mg GAE/g dw; TFC: 32.23 ± 2.57 mg QE/g dw). HPLC studies indicated that IG extracts included higher concentrations of gallic acid, catechin, and quercetin compared to other extracts. Consequently, IG extracts shown superior antioxidant activity across all assessments as DPPH was 24.98 ± 1.36 mg AAE/g for IG compared to 19.03 ± 0.91 mg AAE/g for UG. Guava waste infested with fruit flies is frequently seen as a complete loss; nonetheless, it serves as a superior source of polyphenols with enhanced antioxidant capabilities compared to unripe guava. The efficient application of biomolecules extracts a sustainable and scalable method for converting guava waste into high-value nutraceutical components, thus promoting a circular economy in the agri-food sector.