Akademik Veri Yönetim Sistemi
MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL, cilt.63, sa.3, ss.269-272, 2008 (SCI-Expanded)
Besides nutritional aspects, stirred yoghurt is also appreciated by consumers for its textural properties. The aim of this work was to study how heat treatment and dry matter of the skim milk affect texture properties, including graininess and roughness, of stirred yoghurt. Six different heat treatments (range 95-130 degrees C) were applied to the yoghurt milk with two levels of dry matter (11 and 13%). The milk was fermented with thermophilic starter cultures and after 14 days of storage at 4 degrees C textural properties were analysed and statistically evaluated. Roughness and grains were quantitatively determined by means of an image analysis and evaluated. Visual roughness, number of grains and perimeter of grains decreased, when heating temperature or dry matter increased. Storage modulus (G') and yield stress increased and syneresis decreased, when heating temperature decreased or dry matter increased. A combination of a 13% dry matter of the yoghurt with heating at 95 degrees C for 256s seems to be promising to reduce tendency of syneresis, graininess and visual roughness, and it causes an increase in the two rheological parameters (G' and yield stress) of stirred skim milk yoghurt.