Results of the chemical modeling obtained for the reference model parameters (listed in Table 4) compared with the observations. The curves shows the predicted abundances (relative to H-nuclei) of GA (blue) and ethanol (red) in the upper panel, and the GA/ethanol abundance ratios in the lower panel as a function of time. The symbols represent the values assuming T_ex equal to 15 (crosses), 30 (triangles) and 50 (squares) K, as measured at B0, B1 ans B2, respectively. The solid lines correspond to the reference model without GA injection from the dust grains, whereas the dashed lines correspond to the reference model with an injected GA abundance X(CH₂OHCHO) = 1.5 × 10⁻⁸.