The sea grapes algae, Ceulerpa racemosa, contains high levels of antioxidants and polyphenols, which, according to the Proceedings of the Nutrition Society (DOI: https://doi.org/10.1017/S002966512100272X), are found at optimum levels in the process making of kombucha and fermented tea.
In the study, 25g of drained sea grapes were exposed to different conditions when brewing kombucha, with varying quantities of the SCOBY—symbiotic culture of bacteria and yeast— starter solution as well and sugar conditions: 1 = 100 g of cane sugar, 2 = 100 g of Trigona sapiens honey, 3 = 100 g of brown sugar, 4 = 100 g of stevia powder, 5 = 100 grams rock sugar, and 6 = control with no addition. The SCOBY starter solutions concentrations v/v were V1 10%, V2 15% and V3 20%.
Each sugar condition was triplicated into each one of the SCOBY starter concentration solutions. All samples were fermented in 1 L bottles under anaerobic conditions at room temperatures ranging from 20oC to 25oC for the duration of twelve days. Researchers from Sam Ratulangi University analysed polyphenols amount via light spectrometry and antioxidant levels via 2.2-diphenyl-1-picrylhydrazyl (DPPH).
The results showed that in condition 1, V2 had the most antioxidant activity levels, and V3 had the highest quantity of polyphenols. Further, V3 showed the most antioxidants and polyphenols in conditions 2, 3, 5 and 6. Interestingly, within condition 4, the most antioxidant activity and polyphenol levels were in V1 and V2, respectively. Researchers noted that "The sample with the best pairs (high both antioxidant activity and polyphenol total) is 2 (sample with treatment 2 or with the addition of 100 g Trigona sapiens honey) and with 20% variation of SCOBY starter solution or V3.” Thus, concluding this to be the best formulation to enhance the functionality of the probiotic fermented drink, kombucha.