Production of soluble boza powder

Although boza is a traditional beverage originating from the Central Asian Turks, it has not received sufficient attention in Turkey due to its limited availability and being sold only during the winter months. While the lactic acid in boza has a refreshing effect that suggests it could be consumed in summer as well, high temperatures accelerate yeast and acetic acid fermentation, leading to a shorter shelf life. The aim of this study is to obtain a product by converting boza samples into powder form through the freeze-drying method, resulting in a microbiologically and chemically stable product with a long shelf life that is portable, easy to store, and can be conveniently reconstituted and consumed when desired. In this study, freeze-dried boza powder samples were stored at room temperature in doypack packaging for 90 days; physical, chemical, and microbiological analyses were conducted on days 0 and 90. On day 0, the dry matter content of the boza powder samples was determined to be 94.64 g/100 mL, water activity (aw) 0.21, Brix value 19.00 °Bx, pH value 3.78 and titratable acidity 0.38 g/100 mL. Bulk density was found to be 0.29 g/cm3, tapped density 0.36 g/cm3, and particle density 0.99 g/cm3. Porosity was measured at 63.48, flowability and stickiness values were found to be 20.33 and 1.26, respectively. Wettability time was 41.50 seconds, dispersibility 72.27%, and solubility 62.99%. Among the color values, L* was measured at 68.27, while a*, b*, and C* values were 1.07, 21.13, and 21.16, respectively. Additionally, αº was 87.14, and WI was 38.13. Microbiologically, on day 0, the lactobacillus count was found to be 5.51 log cfu/mL and the lactococcus count was 5.69 log cfu/mL. At the end of the 90-day storage period, a decrease was observed in dry matter and Brix value, while water activity, pH, and titratable acidity increased (p<0.05). Bulk and tapped densities increased, while particle density decreased (p<0.05). Porosity (p<0.05), flowability, and stickiness (p>0.05) values decreased. Wettability time increased (p>0.05), dispersibility increased (p<0.05), and solubility slightly decreased (p>0.05). In color analysis, L* value increased, while a*, b*, and C values decreased, indicating that the color of the product became lighter (p<0.05). Additionally, the hue angle increased, while the whiteness index decreased (p<0.05). Microbiologically, the number of lactic acid bacteria decreased, but the product largely retained its probiotic characteristics. Sensory analyses revealed that the reconstituted boza was preferred and rated more favorably than the traditional boza in terms of color, consistency, flavor, and aroma. In conclusion, this study revealed that the soluble boza powder, which is unprecedented in the literature, preserved most of boza's properties and offers a practical and long-lasting alternative for consumers.