Effect of some hydrocolloids blend on viscosity and sensory properties of raspberry juice-milk.

Raspberry juice-milk is an acidic dairy drink (ADD) including two main phases, milk phase (pH: 6.6-6.7) and raspberry juice phase (pH: 3.2 ± 0.1). Due to the low pH in this beverage, milk protein sedimentation is usual problem and therefore hydrocolloid is added as a stabilizer. Thus, in current study the influences of pectin, CMC and Kappa-carrageenan on the stability of the milk-raspberry juice drink and their blend synergistic effect were investigated. For this purpose milk-raspberry juice drink samples were prepared using pure pectin, CMC and Kappa-carrageenan at concentrations of 0.2 %, 0.3 % and 0.35 % respectively. Blends of pectin and Carboxymethylcellulose (ratios of 25:75, 33.4:66.6 and 34.3:65.7) at concentrations of 0.2 %, 0.3 % and 0.35 %, were added during a certain process. Moreover, the stabilization mechanisms were studied using apparent viscosity and sedimentation percent measurements. Based on the findings of the present study, the best fitted samples were the ones containing the blends of pectin and Carboxymethylcellulose which were more stable and viscose than samples including pure Carboxymethylcellulose (P < 0.05). Kappa-carrageenan can not prevent casein agglomeration in raspberry juice-milk individually, but in the presence of CMC or CMC and pectin it produces a stable drink. In general, with utilizing synergistic effect of gum blend we can use lower gum concentration and decrease cost during manufacture.