Extraction of polyphenols and antioxidant compounds from SCOBY, as a by-product of Kombucha, using different types of extraction

Abstract Kombucha is obtained through a symbiosis fermentation of bacteria and yeast, generating a floating film called SCOBY (Symbiotic Culture of Bacteria and Yeast). After a period of use, SCOBY becomes a production waste. Thus, alternative uses of SCOBY can add value to Kombucha production. In this way, this work aimed to produce and evaluate antioxidant activity and total phenolic contents of SCOBY ethanolic extracts, which were obtained by two different solid–liquid extraction with three different waste weight/extractor solvent volume ratios. The SCOBY evaluated had a high concentration of cellulose (9.42 ± 1.00%) and low concentrations of proteins (0.84 ± 0.04%) and lipids (0.29 ± 0.05%). All evaluated extracts showed a high concentration of total phenolics (40.7–64.3 mg GAE/100 g of SCOBY) and high antioxidant activity (ABTS •+ , FRAP and ORAC assays). The most efficient extraction of bioactive compounds was obtained by decoction using the highest solvent volume (ratio 1:20). The PCA showed clusters of the samples both by the type of extraction and by the different ratios of the weight of SCOBY to the solvent volume. Of our knowledge, our work is the first in the literature that describes such data. Therefore, the present work showed the possibility of using this industrial waste mainly to obtain active compounds and antioxidants.