Fortification of fresh kombucha cheese with wild thyme (Thymus serpyllum L.) herbal dust and its influence on antioxidant activity

In addition to its beneficial effects on numerous acute and chronic health problems, kombucha drink (this term was used in the introduction to explain why kombucha was used as a starter culture) is characterized by the presence of a large number of acetic and lactic acid bacteria, which makes it a suitable alternative to starter culture in the production of fresh cheese. The valorization of the herbal dust, produced during the processing of tea, allows for obtaining various types of extracts rich in numerous bioactive compounds with significant antioxidant activity, why is the fortification of fresh cheese with wild thyme (Thymus serpyllum L.) highly desirable. Therefore, the aim of this study was to investigate the influence of wild thyme in the form of ground, supercritical fluid extract, and dry extract on the physicochemical properties, antioxidant activity, and sensory characteristics of functional fresh cheese after production and after ten days of storage. The greatest changes in physicochemical properties are associated with the increase in ash content and titratable acidity, but also with the decrease in pH of all samples during storage. The total phenols content increased in all samples during storage, especially in the one fortified with dry extract of wild thyme (from 1.86 ± 0.01 to 2.14 ± 0.01 mg GAE/g). The sample with wild thyme ground exhibited the highest antioxidant activity, especially ferric ion reducing antioxidant power (FRAP), which increased from 13.8 ± 0.00 to 15.10 ± 0.00 μM Fe2+/g after ten days. After ten days, the sensory characteristics remained as high as at the time of evaluation after preparation, which clarifies that the addition of wild thyme had a very good effect on consumer acceptance.