Sensory evaluation of kefir samples prepared with various spices

In this study, the sensory and physicochemical properties of kefir, a traditional fermented dairy product, enriched with different spices were investigated. A total of 11 kefir samples were prepared, including 10 different spice-enriched variants (mastic gum, cardamom, clove, thyme, nutmeg, allspice, ginger, turmeric, vanilla, and star anise) and 1 control sample. The production process was carried out under professional kitchen conditions; the obtained products were subjected to sensory evaluation using a 9-point hedonic scale, and the most preferred samples were further analyzed for their physicochemical properties. The sensory evaluation results indicated that spice addition played a decisive role particularly in taste, aroma, and overall acceptability. Vanilla- and mastic gum-enriched kefirs received the highest preference scores, enhancing the sensory quality of the product, and along with the control sample, were among the most favored varieties. Thyme and turmeric kefirs achieved moderate acceptance, whereas star anise, nutmeg, clove, allspice, and ginger received lower scores, limiting consumer acceptance. In terms of color, spice addition did not produce a statistically significant difference. Regarding appearance and texture, vanilla and mastic gum contributed positively. According to the physicochemical analysis results, the pH values of the kefir samples ranged between 4.23 and 4.30, while the titratable acidity values varied between 3.15% and 3.54%. It was determined that spice addition did not cause a significant change in these fundamental properties. Thus, while spice enrichment did not alter the structural characteristics of kefir, it directly influenced its sensory properties. In conclusion, this study demonstrates that enriching kefir with different spices offers important opportunities for product development. Vanilla and mastic gum, in particular, emerged as the most suitable additives for enhancing consumer acceptance. Turmeric and thyme showed potential for evaluation in suitable combinations, whereas spices with lower preference scores could be reformulated at different concentrations or in combination with flavoring agents. Furthermore, future studies on spiced kefirs should not only focus on sensory aspects but also assess shelf life, microbiological stability, and functional properties (e.g., antioxidant capacity, preservation of bioactive compounds), thereby enhancing both their scientific and commercial value.