Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Kefir grains are a symbiotic biomass (yeast and bacteria) commonly used to produce milk probiotic fermented beverages. The aim of this study was to produce a mixed beverage of whole milk and acai (Euterpe oleracea) berry pulp fermented by two different kefir cultures: one specific for milk and one specific for sugared water, adapted to milk. Based on the fermentation yield, pH and sensory analysis, the culture adapted to milk obtained the best results in a composition (g 100 g(-1)) of 70 of whole milk and 30 of acai berry pulp, at room temperature (similar to 25 degrees C), without agitation and fermented for 24 h. The results obtained by this formulation were an increase of 12% in the kefir biomass, 93% of fermentation yield, pH 5.10 and overall sensory acceptance of 7.05.464417424Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)