Aliquots of the processed milks (200 ml) were equilibrated at 40 °C and inoculated with 1 g of commercial yoghurt starter culture (Yogotherm Yogurt Culture 77570, Abasia, St. Hyacinthe, Québec – Canada). The mixture was stirred for 2 min and then 16 ml of the mixture was transferred to a rheometer. The remaining 184 ml was heated separately in a water bath at 40 °C where pH change was monitored.