# Centesimal Composition, Bioactive Compounds, and Antimicrobial Properties of White (Hylocereus undulatus) and Red (Hylocereus polyrhizus) Pitayas

## TL;DR

This study compares the nutritional and antimicrobial properties of red and white pitaya pulps, finding both rich in bioactive compounds with antioxidant and antimicrobial potential.

## Contribution

The study identifies specific bioactive compounds and evaluates antimicrobial and anti-quorum sensing properties in red and white pitaya pulps.

## Key findings

- Red pitaya pulp has higher total phenolic content and contains betalains like phyllocactin.
- Both pulps show antioxidant activity, with red pitaya performing better in ABTS and beta-carotene assays.
- Extracts from both pulps exhibit mild antimicrobial activity and anti-quorum sensing effects.

## Abstract

This study investigated the centesimal composition, physicochemical properties, bioactive compounds, antimicrobial activity, and anti‐quorum sensing (QS) potential of red pulp (RP; Hylocereus polyrhizus) and white pulp (WP; Hylocereus undulatus) pitayas. Both pulps exhibited high moisture content and low protein levels, with ash contents of 0.78% (RP) and 0.70% (WP), titratable acidity of 0.26% for both, and pH values of 5.75 (RP) and 5.12 (WP). RP pitaya presented a higher total phenolic content and contained 3.15 mg/100 g of betalains. Antioxidant capacity differed according to the assay employed: RP showed higher activity in the ABTS•+ and β‐carotene/linoleic acid methods, whereas WP exhibited greater radical scavenging capacity in the DPPH• assay. LC–MS/MS analysis revealed phyllocactin as the major betalain in RP pitaya, along with 4′‐O‐malonyl‐betanin and isophyllocactin. Four flavonoids were identified, with quercetin 3‐rutinoside as the predominant compound. Both extracts displayed mild antimicrobial activity against foodborne pathogens and inhibited violacein production by Chromobacterium violaceum, indicating anti‐QS activity. However, no inhibitory effects were observed on swarming motility or biofilm formation under subinhibitory concentration. Overall, the results highlight pitaya pulps as sources of bioactive compounds with antioxidant, antimicrobial, and anti‐QS properties, supporting their potential application in food systems and as natural ingredients for microbial control strategies.