A study on rheological properties, sensory evaluation and shelf life of ayran-shalgam mixtures

Ayran, a dairy-based fermented beverage, and shalgam, a plant-based fermented beverage were mixed [25% ayran + 75% shalgam (v/v), 50% ayran + 50% shalgam (v/v) and 75% ayran + 25% shalgam (v/v)] and rheological data were obtained at different temperature levels (4-12 °C). Power law model was used to describe the data. Temperature had no effect on the flow behavior index, but it affected the consistency index of the mixtures. Ayran-shalgam mixtures had similar flow behavior index with that of shalgam irrespective of the levels of ayran or shalgam. However, consistency index increased as the amount of ayran increased in the mixtures at a constant temperature. Mixture with the higher amount of ayran [75% ayran + 25% shalgam] had the highest scores in sensory evaluation. Shelf life analyses up to 4 weeks at 4 °C indicated that serum separation increased till the second week and then stabilized for all mixtures. Slight increase (0.05-0.1 unit) in pH was observed during the first week then pH values were stabilized just like the serum separation. Microbiological analyses revealed that mixtures had a similar shelf life with that of ayran. Consequently, mixture of two different fermented beverages could be possible with similar flow behavior and shelf-life, and ayran-shalgam mixture has a huge potential for commercial production. This study may be a basis for designing new products to fulfill the healthy diet demands.