Physical-chemical analyzes and sensorial evaluation of vinegar developed from kombucha (Medusomyces gisevii)

Abstract

Abstract Kombucha is a fermented drink made from tea, usually green (Camellia sinensis), sugar, or honey, with the addition of a symbiotic colony of yeast and bacteria. Because it is a drink with nutritional properties and a high concentration of organic acids, mainly acetic acid, kombucha is promising for developing vinegar through its fermentation for several weeks or months. In this study, the fermentative potential of kombucha culture was evaluated, proposing the production of three fermented acids: green tea kombucha vinegar (FAKCV), hibiscus kombucha vinegar (FAKH) and kombucha vinegar with pineapple (FAKA). The kombucha was prepared from an infusion of tea leaves and a culture of bacteria and yeast (Scoby), 10% fermented kombucha (starter), and sweetened with 70 g/L of Apis Melifera bee honey. By exploring the production of acetic acid and the sugar transformation process, physicochemical analyzes of pH, total acidity, ºBRIX, reducing sugars, sucrose, ash, and alcohol were carried out. The average value of acidity in acetic acid on the 28th and 63rd day for the fermented FAKCV was equal to 0.96 and 1.38% (m/V); FAKH 2.16 and 2.11% (m/V) and FAKA 1.88 and 2.05% (m/V), respectively. The pH values on day 28 and day 63 for FAKCV was 2.71 and 1.95; FAKH: 2.59 and 2.02, and FAKA: 2.94 and 2.15, respectively. For the soluble solids on the 63rd day of fermentation, ºBrix filtered were for FAKCV: 4.50% (m/V), FAKH: 3.75% (m/V), and FAKA: 2% (m/V). The reducing sugar content gradually decreased, and sucrose remained practically zero during fermentation. Ashes were identified close to zero on the 63rd day. The alcohol content found at the end of the fermentation process was between 0.27% (m/V) and 0.28% (m/V) for the three samples of fermented kombucha acids. A statistical study has shown an inverse relationship between the amount of residual reducing sugars and acetic acid produced. In the sensory analysis, it can be stated that green tea kombucha vinegar showed greater acceptance of aroma and flavor and greater preference among the three. It was observed that it is possible to use Apis Mellifera honey instead of sucrose in the kombucha drink or vinegar product. Given the acidity and pH obtained in the samples and the acceptability of assessors, the products have the potential to be consumed in food instead of commercial vinegar.