Evaluation of some physicochemical, nutritional, and microbiological properties and sensory profiles of green tea and almond milk kombucha beverages

Almond milk is one of the popular plant-based milks due to its nutritional properties and health benefits. Recently, using alternative raw materials instead of Camellia sinensis tea has attracted more attention in order to increase kombucha's health benefits and improve sensory properties. This study aimed to obtain a beverage with enhanced functional properties by fermenting almond milk with kombucha as a new substrate source, providing an alternative to kombucha derived from green tea. In this context, we prepared kombucha beverages using green tea (KT) and almond milk (AMK) and analyzed specific dynamic parameters at different fermentation times (up to 14 days) to evaluate the effects of substrate sources. According to the results, as fermentation progressed, the pH and total soluble solids decreased and titratable acidity increased in both kombucha beverages. On the 14th-day samples, AMK exhibited the highest values in terms of DPPH radical scavenging activity (96.90%), CUPRAC (1.28 mmol Trolox/g), and total phenolic content (611.66 mg GAE/L). In AMK, the highest counts were reached on the 14th day of fermentation for acetic acid bacteria (7.99 log CFU/mL) and yeast (7.23 log CFU/mL), while the highest lactic acid bacteria value was determined on the 7th day of fermentation in AMK (7.44 log CFU/mL). On the 7th and 14th days of fermentation, acetic, gluconic, glucuronic, lactic and citric acids were detected at the highest levels in the AMK sample. Kombucha beverages showed suitable ethanol levels (0.35-0.74 g/L). The findings show that almond milk can be used as an alternative raw material in the development of kombuchas with higher bioactive potential and contribute to optimizing the fermentation process.