Ultrasound treatment for improving the bioactive compounds and quality properties of a Brazilian nopal (Opuntia ficus-indica) beverage during shelf-life

The use of ultrasound treatment for improving the bioactive compounds and quality properties of a Brazilian nopal beverage was studied. Physicochemical characterization and possible changes in nutritional, microbiological, and sensory parameters throughout the shelf-life were evaluated, and compared with heat treatment. Five products were prepared and analyzed during 28 days of shelf-life: control without treatment (C0), beverage submitted to heat treatment for 10 min (HP10), and beverages submitted to ultrasound treatment for 10 (US10), 20 (US20), and 40 (US40) min, with these times being defined based on a previously conducted pilot study. The US40 beverage presented the highest levels of oligosaccharides (31.99%), organic (48.93%) and ascorbic (26.09%) acids, and minerals (83.59%) compared to those found for HP10. The US40 also showed better antioxidant activity and 81.80% more phenolic compounds when compared with the HP10. The US40 presented greater stability for bioactive compounds and showed fewer changes in the color parameters, lower microorganism count, and greater acceptability regarding quality during shelf-life, while the HP10 sample presented the worst results. Therefore, the US40 beverage has higher functional potential, and ultrasound represents a promising technique to preserve or improve the quality of this product during its processing and shelf-life.