Sonoprocessing of freshly squeezed orange juice: Ascorbic acid content, pectin methylesterase activity, rheological properties and cloud stability

Ultrasound performance at low energy densities (9-86 J/mL) on the quality attributes of freshly squeezed orange juice was compared to heat treatment (90 degrees C/1 min). Mild sonoprocessing improved orange juice's kinetic stability preserving its ascorbic acid (vitamin C) content. The ultrasound energy densities could not promote the inactivation of pectin methylesterase (PME) in the orange juice samples. However, higher energy densities contributed to their cloud stability along cold storage. In contrast, the heat processing inactivated 96.3% of PME, but thermally treated samples lost their cloudiness and had their ascorbic acid content reduced by 7%. Cloud stabilization after sonoprocessing was mainly attributed to acoustic cavitation performance to modulate particle size distribution. Ultrasound processing is a promising technique to solve one of the main technological issues of the freshly squeezed orange juice. However, mild sonoprocessing must be combined with other innovative nonthermal technologies to provide a safe and high-quality orange juice.