Roriz, Custódio LoboHeleno, Sandrina A.Alves, Maria JoséOliveira, BeatrizPinela, JoséDias, Maria InêsCalhelha, Ricardo C.Morales, PatriciaFerreira, Isabel C.F.R.Barros, Lillian2021-11-022021-11-022022Roriz, Custódio Lobo; Heleno, Sandrina A.; Alves, Maria José; Oliveira, Beatriz; Pinela, José; Dias, Maria Inês; Calhelha, Ricardo C.; Morales, Patricia; Ferreira, Isabel C.F.R.; Barros, Lillian (2022). Red pitaya (Hylocereus costaricensis) peel as a source of valuable molecules: extraction optimization to recover natural colouring agents. Food Chemistry. ISSN 0308-8146. 372, p. 1-90308-8146http://hdl.handle.net/10198/24153Hylocereus costaricensis peel contains large amounts of betacyanins and can be exploited as a source of natural colorants. This work aimed the chemical characterization and evaluation of bioactive properties of this byproduct and the optimization of the ultrasound-assisted extraction (UAE) of betacyanins using the response surface methodology (RSM). Oxalic and malic acids and traces of fumaric acid were detected, as well as the four tocopherol isoforms, predominantly γ-tocopherol. Four betacyanins were identified and used as response criteria for UAE optimization, namely phyllocactin, isobetanin, isophyllocactin, and betanin. Sample processing at 487 W for 38 min result in the maximum betacyanin content (36 ± 1 mg/g dw). The peel extract inhibit the oxidative haemolysis, with IC50 values of 255 and 381 μg/mL for Δt of 60 and 120 min, respectively, and the growth of pathogenic bacteria, with minimum inhibitory concentrations ranging from 5 to 20 mg/mL. Furthermore, no toxicity was observed for normal cells.engHylocereus costaricensisBioactive compoundsBetacyaninsNatural colorantsUltrasound-assisted extractionProcess optimizationjournal article10.1016/j.foodchem.2021.1313441873-7072