Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

The pitaya (Hylocereus polyrhizus) is an exotic fruit and its peel is a residue that presents nutritional potential. The aim of this study was to extract phenolic compounds from pitaya peel by ultrasound. The fruits were harvested in Santa Fé Farm (Garahuns, PE), washed, sanitized (hydrosteril 2.5%/15 minutes) and peeled manually. The peel was freeze-dried (Christ Alpha 1-4 LD Plus) for 48h under pressure of 20 millibar. Experimental planning 23, with three central point was carried out. The independent variables were ethanol concentration (30%, 50% and 70%), solvent/sample ratio (60 ml/g, 70 ml/g and 80 ml/g) and ultrasound immersion time (10, 15 and 20 minutes). The dependent variable was content of total phenolic compounds. Extraction was performed using an ultrasonic probe (Sonic Clean 2PS, Sanders medical) at 275 W and 25°C, using 1 gram of freeze-dried peel. The supernatants were centrifuged at (2,500 RPM/20 minutes), filtered and stored in amber glass at -22 °C. The content of phenolic compounds was quantified according to Folin-Ciocalteau method. The statistics were performed with Software Statistic 7.0 at 5% significance level. No variable was considered significant. The highest contents of phenolic compounds in the extract were obtained with assays 2 (550 ± 3.62 mg EAG/g), ethanol concentration 30%, solvent/sample ratio 60ml/g and immersion time in the ultrasound 10 minutes; and 1 (494.06 ± 0.78 mg EAG/g), ethanol concentration 70%, solvent/sample ratio 60ml/g and immersion time in the ultrasound 10 minutes. The extraction of phenolic compounds by ultrasound was considered efficient and showed that pitaya peel is a good source of this compound.