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

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.