Functional beverages enhance the nutritional benefits of their ingredients by boosting their levels of vitamins, proteins, and other bioactive components like probiotics and prebiotics. For functional beverages to be popular, they must be both tasty and nutritious. This study analyses different mixtures of quinoa puree and cherimoya juice. Water-kefir grains were used to ferment these mixes at two specific temperatures, 25 and 32 °C. The measured quantities were the colony-forming units of lactic acid bacteria and yeasts in one millilitre (CFU/ml) and the overall likings (OL, -). The sensory attribute is a variable that includes the weights of four OL attributes: taste, smell, colour, and texture. Ten individuals, with partial training, assessed it on a 1–7-point hedonic scale. All three models exhibited R² values > 0.8, indicating their appropriateness. Optimising the collaboration of the three most crucial answers resulted in optimal conditions. At a temperature of 25 °C, the mass fractions of the mixes containing QP and CJ were 0.13 and 0.87, respectively. Under these optimal conditions, the levels of LAB and yeast increased by 4.2 and 4.4 log-bases, respectively, compared to the unfermented mixture of the raw materials from which they originated. In addition, we noted a 62 % rise in the total protein content. The kefir-granule consortium lowered the total sugar content by 52% and the levels of ascorbic acid by 82% for 48 hours of fermentation due to consumption by the kefir-grains consortium and Maillard's reaction between the reduced sugars and ascorbic acid.