MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL, cilt.65, sa.2, ss.183-187, 2010 (SCI-Expanded)
The aim of this work was to study how glucono-delta-lactone (GDL) addition and the dry matter of skim milk affect the physicochemical and sensory properties of stirred yoghurt. Three different amounts (0.5, 1.0, and 3.0%, w/w) of GDL were added to the yoghurt milk with two levels of dry matter (13 and 15%). Stirred yoghurts prepared by adding GDL and produced using a starter culture were compared. Physicochemical and sensory properties of the stirred yoghurts were determined during storage at 4 degrees C over a period of 14 days. As the dry matter was increased, the number of grains, the perimeter of grains, the visual roughness and the syneresis decreased, however, the firmness and the viscosity of the yoghurt samples increased. In the yoghurts produced by adding GDL, less syneresis was observed but the number of grains, the perimeter of grains and the visual roughness increased. High concentrations of GDL (>0.5%) caused a significant decrease in the sensory characteristics of the stirred yoghurt samples, as well as in the firmness and the viscosity.