Rheology and functionality of ayran-a yogurt drink

Milk is considered a miracle natural food in which fat exists as an emulsion. Yogurt is known for its health benefits, being a fermented milk product. It has a viscoelastic gel structure. Both are regarded as healthy foods and there have been many reports about their health functionality. These healthy foods have also received attention from consumers, researchers, and manufacturers. The concept of new product design starts from the consumer needs and demands, based on daily life requirements. This concept includes not only designing a new product but also making the product functional. These two characteristics of designing a new product can only be realized by understanding the structure-function relations of components in foods. It appears that this point is missing in the literature. Ayran, a yogurt drink, is a traditional fermented drink in Turkey and neighboring countries, with various reported benefits. Its rheological properties have continued to be studied to understand its stability and textural problems during manufacture, transportation, storage, and consumption. As functional foods have become a trend, its functional properties have also been studied with additions of "functional" ingredients such as probiotics or prebiotics. In this review, functional and rheological studies of ayran are discussed.