Rational design of a versatile lab-scale stirred milk gel using a reverse engineering logic based on microstructure and textural properties

The textural properties of stirred yogurts (i.e. stirred milk gels) are directly linked to their microstructure. In this study, a logic of reverse engineering was used to design a lab-scale process producing real-like stirred milk gels (1.5 kg batch). A reference of stirred fermented milk gel was produced at pilot scale (100 kg batch). The conditions of lab-scale homogenization (sonication), acidification (glucono-δ-lactone concentration) and stirring (filter, pumping rate, ultra-smoothing) were adjusted to obtain size distributions of fat droplets and of microgels and rheological properties similar to those of the pilot reference. The final lab-scale process was validated by comparing the properties of stirred milk gels produced at lab and pilot scales with two fat contents (6 and 10 wt%). Although the stirred milk gels obtained at the two scales differed slightly in microgel sizes and in rheological properties, they were similarly ranked according to their fat content.