FERMENTATION AND CARBOHYDRATE PROFILE PRESENT IN INFANT DAIRY COMPOUNDS

Children's dairy compounds contain carbohydrates such as lactose, glucose, and galactose, which can be fermented by oral bacteria, producing acids and favoring dental demineralization. This study aimed to evaluate the bacterial fermentation of these carbohydrates, simulating the composition of traditional and lactose-free dairy compounds, and to identify the acids formed by high-performance liquid chromatography (HPLC). For the fermentation test (n=3), cultures of Streptococcus mutans UA159 were grown in UTEYB medium supplemented (1:1) with: (i) water (negative control); (ii) lactose 1%; (iii) glucose 1.05%; (iv) galactose 1.05%; and (v) glucose + galactose 1.05%. The inoculum (OD₆₀₀=2.0) was added in a 1:10 ratio. Immediately after the addition of the inoculum and at the times of 2, 4, 6 h, samples were collected for determination of pH and identification of the acids, obtaining the fermentation curves and the area under the curve (AUC). After 3 h of incubation, glucose and glucose + galactose reached pH close to 4.5, while lactose and galactose maintained pH above 5.0, indicating lower acidogenicity. The mean AUC values (mol/L-min) confirmed higher acidogenicity for glucose (135.4 ± 7.2) and glucose+galactose (120.3 ± 1.8), followed by galactose (47.8 ± 2.7), lactose (34.9 ± 3.9) and control (2.6 ± 0.4). HPLC analysis after 6 h showed that glucose (4.1 ± 0.5 g/L) and glucose + galactose (3.5 ± 0.3 g/L) had the highest concentrations of lactic acid, the main fermentation product of S. mutans