The effect of using pomegranate and strawberry juices with red beet puree on the physicochemical, microbial and sensory properties of yoghurt

Abstract

There is currently a growing interest in creating dairy products fortified with natural fruits containing (phenolic and antioxidant compounds) and safe for human consumption. Therefore, this trend was applied in the current study, where a mixture of red beet puree with pomegranate and strawberry juices were used in the manufacture of yoghurt. The effect of supplementing yoghurt with the previous mixture on the physicochemical, microbiological properties, color, antioxidant activity, total phenolic content, reduced sugars, was studied. The use of fruit juices had slightly significant effect on the acidification rate of milk and the basic physical and chemical properties of the resultant yoghurt, but it increased slightly the red color. The total phenol content and the antioxidant activity were increased in yoghurt containing the mixture of fruit than in control one. Microbiological results revealed that the counts of lactic acid bacteria were increased in all treatments during storage and reached the maximum after 7 days of storage as slightly lower counts were recorded in the control treatment than in the other treatments, when fresh and during the storage period. All treatments were free from coliform and yeast and molds when fresh but it were noticed in all treatments at the 7 day. Organoleptic examination indicates that fruit treatments yoghurt gained the higher significant (p ≤ 0.05) scores as compared to control, when fresh and during storage period. Generally, results of this study show that the use of the mixture of the former fruits may be applied to produce a functional yoghurt rich in phenolic components, antioxidants activity and nutrients.