Peach juice processed by the ultrasound technology: Changes in its microstructure improve its physical properties and stability

• The ultrasound technology improves peach juice stability and physical properties.
• The properties of both dispersed (pulp) and continuous (serum) phases were changed.
• Each processing stage has particular mechanisms and properties.
• Structure–process–properties relationships were described.

Ultrasound is a non-conventional processing technology, which can be used not only for food preservation, but also to improve its properties and quality. This study evaluated the physical properties and stability of peach juice processed by the ultrasound technology. The peach juice processed by the ultrasound technology showed changes in its structure, evidenced by the optical microscopy and particle size distribution, involved steps of cell damage and release of intracellular content, particle size reduction, disruption of the whole cells, polysaccharide size reduction and dispersion of constituents. These effects, depending of the processing time, can trigger different mechanisms with a complex behaviour. The interaction among them and the relative importance of each one change during processing, determining the final rheological properties, pulp sedimentation and serum cloudiness (turbidity). The results indicated that the ultrasound technology can be used to improve the physical properties of peach juice, increasing the stability to pulp sedimentation and serum cloudiness, maintaining or increasing the juice consistency, with insignificant colour changes during the storage.