Abstract: In order to mitigate protein bar aging during storage and enhance their sensory attributes, the effects of adding four different modified starches on protein bar aging were investigated in the present study through systematic measurements of hardness, colorimetric parameters, and amylose/amylopectin contents. The findings demonstrated that all four modified starches significantly inhibited protein bar hardening and browning (P<0.05). Pregelatinized acetylated distarch adipate (PADA), hydroxypropyl distarch phosphate (HDP), and distarch phosphate (DP) altered the ratio of straight-chain to branched-chain starch content while substantially increasing slowly digestible starch (SDS) levels (P<0.05). Acetylated distarch adipate (ADA) notably reduced hardness, browning intensity, and enthalpy of aging (P<0.05), thereby enhancing the sensory quality of protein bars. Therefore, ADA is the most suitable modified starch to be added to protein bars.