Abstract
The aim of the present study was to assess the effect of chia flour at various levels of incorporation on the physicochemical, rheological, textural, mineral, microbiological and sensory properties of yoghurt during refrigerated storage. Five yoghurt formulations were evaluated: T0 (0% chia flour), T1 (2%), T2 (4%), T3 (6%), and T4 (8%). Samples were analyzed during refrigerated storage for pH, titratable acidity, moisture and protein composition, water-holding capacity (WHC), syneresis, viscosity, mineral composition, texture, microbial quality and sensory characteristics. The results show that acidity level increases and pH decrease with the increase of storage time. The maximum value of acidity was recorded as 1.1233% for T4 at 21st day and minimum values were 0.8733% for T2 at 0 day. Ash contents of chia yoghurt decreased with the storage time. The maximum value for ash was found to be 1.0167% for T2 at 0 day and minimum value was 0.7500% for T4 at 21st day. Protein contents decreased with the storage period. Moisture level of chia yoghurt decreases with the storage period. The maximum value of pH was found to be 4.50 for T3 at 0 day and minimum value was 4.2500 for T4 at 21st day. Fat contents decreased with the storage time. Syneresis also increases and water holding capacity decreases with the storage time. Total plate count also increases with storage time. Water holding capacity decreases due to the increase in acidity level. Sensory responses were not generally higher for one formulation, with T3 having the highest color score, T1 the highest flavor score, T2 the highest texture score, T0 and T3, and T0 and T1, having the highest overall acceptability score. Overall, chia flour demonstrated potential as a functional ingredient for modifying yoghurt quality and stability.