Article Highlights• Kinetics of saccharose fermentation by Kombucha was analysed • A saccharose concentration model was defined as a sigmoidal function • Reaction rates were calculated as first derivatives of Boltzmann's functions • Saccharose fermentation by Kombucha occurred according to complex kinetics Abstract The kinetics of saccharose fermentation by Kombucha is not yet well defined due to lack of knowledge of reaction mechanisms taking place during this process. In this study, the kinetics of saccharose fermentation by Kombucha was analysed using the suggested empirical model. The data were obtained on 1.5 g L -1 of black tea, with 66.47 g L -1 of saccharose and using 10 or 15% (V/V) of Kombucha. The total number of viable cells was as follows: approximately 5×10 5 of yeast cells per mL of the inoculum and approximately 2x10 6 of bacteria cells per mL of the inoculum. The samples were analysed after 0, 3, 4, 5, 6, 7 and 10 days. Their pH values and contents of saccharose, glucose, fructose, total acids and ethanol were determined. A saccharose concentration model was defined as a sigmoidal function at 22 and 30 °C, and with 10 and 15% (V/V) of inoculum quantity. The determination coefficients of the functions were very high (R 2 > 0.99). Reaction rates were calculated as first derivatives of Boltzmann's functions. No simple correlation between the rate of reaction and independent variables (temperature and inoculum concentration) was found. Analysis of the empirical model indicated that saccharose fermentation by Kombucha occurred according to very complex kinetics.The consortium of yeasts and acetic acid bacteria known as the Kombucha culture exhibits a metabolic activity on sweetened tea, under batch conditions, giving a pleasant sour beverage containing useful compounds such as some organic acids and certain vitamins. The activity of Kombucha on the traditional carbon source saccharose was investigated by several authors [1-6] and the main pathways of saccharose transformation were determined. It has been proven that the yeast cells are responsible for the extracellular enzymatic hydrolysis of saccharose into glucose and fructose, and transformation of glucose and fructose into ethanol and CO 2 , while acetic acid

Novel trends in fermented dairy technology are presented in this review paper. The application of new starter cultures (probiotics, kombucha), as well as quality improving ingredients like transglutaminase (TGase), milk protein fractions, and functional components of plant origin have been investigated by the authors worldwide. New processing techniques such as: high-pressure processing (HPP), high pressure homogenization (HPH), and ultrasonic processing (USP) are interesting because of their potential to achieve a specific and/or novel functionality or to improve the efficiency. Novel trends in fermented dairy technology contribute to the creation of various products with high nutritive value, possessing also specific functional properties. Basic health benefits of functional fermented dairy products are: biologically active peptides -ACE inhibitors and antioxidative activity. Due to the mentioned functional characteristics, these dairy products are considered to be among the most precious functional foods.

The aim of this study was the investigation of the possibilities of direct determination of calcium, sodium and potassium in the commercial and kombucha-based fermented milk products by flame photometry. Two procedures were used for sample preparation: simple dilution with water (direct method) and extraction with mineral acid. Calcium, sodium and potassium levels determined after mentioned sample preparation methods were compared. The results showed that the differences between the values obtained for the different sample treatment were within the experimental error at the 95% confidence level. Compared to the method based on extraction with mineral acid, the direct method is efficient, faster, simpler, cheaper, and operates according to the principles of Green Chemistry. Consequently, the proposed method for the direct determination of calcium, sodium and potassium could be applied for the rapid routine analysis of the mineral content in the fermented dairy products. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

The aim of this study was to examine the influence of different types and concentration of kombucha inoculum on content of sugar, organic acids and ethanol in the fermented beverages produced from milk of 0.9% fat content. Three different kombucha inoculums, cultivated on black tea with addition of sucrose: standard inoculum-10% (w/w) and 15% (w/w), concentrated by microfiltration-10% (w/w) and 15% (w/w), and concentrated by evaporation-1.5% (w/w) and 3.0% (w/w), were applied in the manufacture of fermented milk. Contents of lactose, galactose, glucose, fructose, organic acids, and ethanol in the kombuha fermented milk beverages were determined by the enzyme tests. It was found that the lactose content varied from 3.30 to 4.0 g/100g. All samples showed higher content glucose than fructose. The content of L-lactic acid in the samples ranged from 0.4 to 0.7 g/100g, while significantly lower level of D-lactic and acetic acid were determined in all samples of kombucha fermented milk (<0.06g/100g).

The quality of fresh cheese produced with the addition of traditional starter culture and kombucha inoculum have been investigated in this study. Fresh cheese was produced from milk with 3% fat content. The traditional starter culture FD-DVS XPL-1 (Chr. Hansen A/S, Denmark) and kombucha inoculum cultivated on black tea were applied for production two different fresh cheese samples. Physico-chemical and sensory characteristics of fresh cheese products were tested after production. The cheese yield of fresh cheese with traditional starter culture was higher compare to fresh cheese with kombucha inoculum. The obtained results showed significant differences in physicochemical properties and sensory characteristics between cheeses.