Evaluation of the Quality Characteristics of Probiotic Ice Cream Produced from a Mixture of Camel Milk and Cow Milk during Frozen Storage

  Background: Ice cream is one of the most important and popular frozen desserts based on cow milk that is popular in the world. Due to the valuable properties of camel milk and with the aim of diversifying the production of this product and improving its nutritional quality, Methods: In the present study, ratios of 0%, 20%, 30%, 40%, 50%, 60%, 70%, and 80% of camel milk were replaced. The probiotic ice cream formulation contained Lactobacillus acidophilus and the samples were stored in a freezer at -18 °C and on the days after (first) production, thirty and sixty days were subjected to physicochemical, microbial, and sensory tests. Results: The results showed that the trend of changes in pH, specific gravity and volume increase was irregular. In contrast, the trends of fat changes, melting resistance, and sensory properties were decreasing. In physicochemical tests, treatment based on 40% cow milk had the highest pH value and volume increased, while the highest viscosity and melting resistance were related to camel milk treatment. The highest fat content and specific gravity belonged to 80% camel milk treatment. Treatment based on 40% cow milk showed the highest L. acidophilus count, while the treatment based on 60% cow milk had the lowest count. In terms of sensory properties, this treatment received the highest flavor and overall acceptance scores in terms of evaluators, while the highest color and texture score belonged to the treatment based on 40% and 70% camel milk, respectively. Conclusion: The overall results showed that cow milk can be replaced by probiotic ice cream formulation with different proportions of camel milk and obtained a desirable product. Finally, treatments based on higher ratios of camel milk had better quality properties and 60% of camel milk was selected as optimum treatment.