Pitaya is a fruit belonging to the Cactaceae family and is a source of Phenolic Compounds and Betalains. However, these compounds tend to have low stability to oxidation and thermal degradation. The objective of this work was to microencapsulate pitaya extract (Hylocereus polyrhizus) obtained by ultrasound and carry out a stability study. The fruits were obtained at Santa Fé Farm (Garanhuns, PE). The pulp was lyophilized (Christ Alpha 1-4 LD Plus). 1 gram of lyophilized sample was diluted in 40 mL of ethanol (30%). For extraction, an ultrasonic probe (soniClean 2PS Sanders medical) was used for 20 minutes at 275 W, 30 kHz and 25 °C. The supernatant was centrifuged (2000 rpm/20 minutes) and
filtered. Microencapsulation was performed according to Bakar et al. (2012) with some modifications. The microencapsulated extract was packaged in laminated packages. During a period of 30 days at 25 °C, phenolic compounds (Wettasinghe; Shahidi, 1999), Betalains (Stintzing et al., 2005), moisture (infrared scale MARTE ID-50) and water activity (AQUALAB 4TE) were quantified. The content of Phenolic Compounds and Betalains significantly reduced between the initial time (38.70 μg EAG/mL) and (13.98 mg/L) and after 30 days of storage (32.56 μg EAG/mL) and (13, 02 mg/L), respectively. These findings are in agreement with the literature and are related to the degradation of the capsule wall due to increased moisture. There was a significant increase in moisture and water activity between the initial times (4.15%) and (0.15 aw) and after 30 days of storage (5.76%) and (0.46 aw), respectively. However, these values are considered safe against microbiological development. The microencapsulation was efficient in the protection of Phenolic Compounds and Betalains and guaranteed microbiological safety of the microencapsulated pitaya extract along 30 days of storage. Thus, the microencapsulated extract of pitaya has potential use in the food industry.