Synergistic effect of ultrasound and pectin addition on enhancing yogurt structure

This study explored the individual and combined effects of ultrasonication (US) and pectin addition on milk to improve yogurt structure. The resulting yogurts were evaluated for their physicochemical characteristics, including water holding capacity (WHC), texture, chemical bonding, and microstructure. A significant enhancement in WHC was observed when ultrasonication and pectin were applied together. Firmness increased with each treatment individually and was highest with their combination. Adhesive force showed a notable increase only in the combined treatment group. While FTIR analysis revealed no changes in bond types, it indicated an increase in bond quantity, particularly under combined treatment. SEM imaging confirmed the synergistic effects of pectin's binding capacity and ultrasound-induced cavitation. The mechanism behind the synergistic effect involved ultrasonication promoting closer interaction between pectin and casein molecules through cavitation energy, followed by acidification to casein's isoelectric point, which strengthened the network through bonding. Overall, this study introduces a previously unreported synergy between ultrasound and pectin in enhancing yogurt structure.