Physico-chemical properties of yoghurt containing cress seed mucilage or guar gum

The changes in physico-chemical properties of yoghurt containing cress seed mucilage (CM) compared with yoghurt containing guar gum (GG) or plain yoghurt during storage at 5 ± 2 °C for 15 days were evaluated. CM was prepared and added to standardized buffalo’s milk (∼3.2% fat and ∼15.0% TS) at rate of 0.025%, 0.05% and 0.10% but GG was added at the rate of 0.025% and 0.05% to create 5 treatments. The latter batch had no CM or GG, serve as a control (C). No significant changes in pH values and proteolysis (SN/TN ratio) of all yoghurt samples throughout the storage period were observed. CM containing yoghurts showed adverse effect on the concentration of acetaldehyde and diacetyl until day 10 and day 15, respectively compared with C and that containing 0.025% GG. Yoghurt samples containing different levels from CM or 0.025% GG exhibited lower in wheying-off and whey syneresis compared with C. No significant changes in the firmness of the yoghurt containing 0.025% and 0.05% CM or 0.025% GG were found throughout the storage period, while yoghurt containing 0.05% GG exhibited lower firmness compared with other yoghurt samples. Apparent viscosity of yoghurt containing GG or CM was higher than that of C until day 10. However, yoghurt containing 0.025% and 0.05% CM or 0.05% GG showed continued increase in apparent viscosity until day 10 while for yoghurt containing 0.10% CM, the increase was observed until day 5 and decline thereafter.