Due to high nutritional value, dairy products especially milk are widely consumed by people which persuade manufacture to produce various products. Milk-juice beverage is a type of acidified milk drink which has been produced from milk, fruit juice, sugar and stabilizer mixtures. Red grape juice is considered as one of the most delicious drinks that Iranian people consume particulary in the summer time as a blood purgation and reduction hypertension. This juice contains organic acids (malic acid, tartaric acid and ascorbic acid); phenolic compounds and anthocyanins. Whey separation is a common problem in production and storage of acidified milk drinks (AMDs) which is due to the casein instability and sedimentation at low pH (4.6?.) To prevent or reduce protein aggregation, different stabilizers are used. In this study, pectin, tragacanth and their mixture (at 50:50 ratio) at concentrations such as 0.2, 0.3 and 0.4% w/w were used to improve stability of milk-red grape juice drink. The effect of red grape juice content was also evaluated at concentrations of 40, 50 and 60%. The parameters of sedimentation and whey separation of the treatments were determined after 12 days storage. The results showed that treatments containing 0.2, 0.3 and 0.4 pectin with 60% red grape juice, had the highest stability, respectively. After that, the optimal formulation was prepared and stored at refrigerator for 30 days and its physicochemical properties were investigated. The results showed that the effect of milk, red grape juice and pectin contents on sedimentation and whey separation were significant (p?0.05). The amount of anthocyanins, total phenolic compounds and antioxidant capacity of all the samples were increased over the storage. Those samples containing 60% red grape juice, 10% milk, 30% water and 0.2% pectin was selected as the best product wich showed the lowest sedimentation and whey separation. The results revealed that the production of milk-red grape juice drink with the lowest sedimentation and whey separation could be feasible by using pectin. Keywords: Red grape juice, Hydrocolloids, Milk-juice beverage, Milk-red grape juice
