2.2. Preparation of yogurt
Milk was sterilised at 110 C for 5 min and cooled to 42e45 C.
The starter (Chr.Hansen YF-L822) was added, according to the
manufacturer’s instructions [0.08% (m/v)]. The adjunct culture
L. casei AST18 was added to the milk at 0, 2, 4, 6 and 8% (v/v).
Fermentation was conducted at 42 C for 5 h. Both the control and
L. casei AST18-added yogurt samples were stored at 4 C, for 16 h
after ripening.
2.3. Analyses of the physical and chemical properties of yogurt
during storage at 4 C
The pH values of the yogurt samples were measured at 17e20 C
using a pH meter (HANNA, pH211, Italy) after calibrating with fresh
pH 4.0 and 7.0 standard buffers. Titratable acidity (TA) was