In vitro digestion models that simulate human alimentary processes are indispensable for evaluating food processing effects and structural changes during digestion. While extensive research exists on whey proteins, studies specifically investigating the impact of glycation on whey protein isolate (WPI) digestion in vitro are scarce. This study aimed to assess the physicochemical properties and digestion behavior of WPI glycated with glucose via dry heating Maillard reaction using simulated infant gastric conditions. Non-glycated WPI and WPI-glucose conjugates were analyzed following incubation at 40 °C with Aw = 0.80 for 0, 1, and 2 days. Physicochemical analyses included colorimetric assessments (L*a*b* values and browning intensity at 294 and 420 nm) and OPA analysis indicating 53% conjugation on day 1, suggesting effective inhibition of advanced Maillard reaction product formation. Subsequently, both WPI forms underwent simulated in vitro gastric digestion at pH 3 as the optimum condition for pepsin activity. SDS-PAGE analysis of digesta revealed that neither non-glycated WPI nor WPI-glucose conjugates were efficiently hydrolyzed by pepsin. These findings provide the need for further research to elucidate how protein-disaccharide glycates influence in vitro infant gastric digestion, emphasizing the critical role of optimal pH control in simulation experiments.