Valorization of Pitaya (Selenicereus monacanthus) Peels: Proof of Concept for Food Formulation

Cacti by-products are rich in bioactive compounds, yet they remain largely underexplored in foods. This study investigated the nutritional and functional potential of red pitaya (Selenicereus monacanthus) peel flour in an innovative chocolate truffle composition. The phenolic composition, antioxidant activity, in vitro bioaccessibility, and intestinal permeability of flour were evaluated. It showed a significant content of bioactive flavonoids, with isorhamnetin, rutin, myricetin, quercetin, and luteolin as major identified compounds. In vitro passive permeability of polyphenol from flour was moderate (P_app = 5.24 ± 0.85 × 10^- 6 cm/s). Chocolate truffles made with pitaya peel flour (BPF) showed an 86% increase in fiber, a 23% increase in ash content, a 27% reduction in lipids, and a 30% decrease in carbohydrates compared to those without addition. Adding peel flour increased the food's antioxidant activity (3.5-fold) and phenolic composition (2.6-fold) compared to the control. Under simulated digestion, polyphenols' bioaccessibility in BPF was higher in the ileum, and antioxidant activity was higher in the duodenal stage, compared to the gastric stage. Data indicates that pitaya peel flour is a promising input for developing foods.