Soymilk treated by ultra high-pressure homogenization: Acid coagulation properties and characteristics of a soy-yogurt product

The effects of ultra high-pressure homogenization (UHPH) on soymilk were investigated and its suitability for soy-yogurt manufacturing was compared with conventional heat treatments (UHT and autoclaved). UHPH soymilk at 40 and 50 °C inlet temperature was treated at 200 and 300 MPa. Coagulation parameters and acidification curves were determined for the fermentation process. Textural parameters, water-holding capacity and microstructure were performed on soy-yogurts obtained after cold storage during 24 h. Results indicated that conventionally heat-treated soymilks and UHPH-treated samples exhibited different behaviour to coagulation. Heat-treated soymilk had a shorter onset of gelation, and higher aggregation rate and gel network density than UHPH-treated soymilk. However, physical quality parameters, specially firmness, were much better in UHPH than in conventional heat-treated soy-yogurts.