Study of the fermentation of pineaple water kefir with tibicos

Tibicos are macro-colonies of microbioglea useful for elaboration of kefir from pineapple water. In this work, the kinetics of the fermentation was studied and the biomass produced at 53 h of fermentation was 36.7g that correspond to a 74.6% of the initial value, with a pH of 4.67 ± 0.02. A reduction of 1.55 pH unit was achieved at the end of the fermentation, due to growth of tibicos and production of ethanol. During fermentation, lactic acid was produced reaching a value of 0.477g lactic acid/100mL and the kinetics was described with a first order model with R² = 0.989, k = 5.49 h^-1 y t_1/2 = 12.62 h. A linear relation between total rate of production of phenols and the rate of change of antioxidant activity was found indicating that phenols mainly provide the antioxidant activity since during fermentation they are liberated and becoming available. A higher number of colonies were found in the microbioglea than in the kefir.