Objective To address key industrial challenges of leisure dried tofu subjected to mild sterilization, namely shortened shelf life (30~90 d) and susceptibility to photoenzyme-induced oxidative deterioration, this study aimed to elucidate the mechanisms by which tert-butylhydroquinone (TBHQ) inhibits quality deterioration in leisure dried tofu induced by photoenzyme initiators.Methods Leisure dried tofu was prepared using marinade treated with TBHQ and photoenzyme initiators (chlorophyll and azodiisobutyronitrile). During a 90 d storage period, dynamic changes in nutritional components, characteristic oxidation indices, textural properties, intermolecular forces, and microstructure of the dried tofu were systematically monitored.Results During the early storage stage (0~60 d), TBHQ significantly delayed the oxidative loss of protein (18.21 g/100 g) and fat (12.54 g/100 g), inhibited the increase in peroxide value (0.16 g/100 g), acid value (0.98 mg/g), and thiobarbituric acid reactive substances (TBARS, 1.58 mg/kg), and maintained L^* and b^* values close to those of the blank group. TBHQ stabilized disulfide bond interactions (1.96~2.48) and hydrogen bonding (0.16~0.25), while maintaining hardness and elasticity at 9.25~11.03 N and 0.85~0.91, respectively. During the late storage stage (75~90 d), TBHQ continued to inhibit the loss rates of protein and fat, resulting in fewer and smaller pores in the tofu gel network compared with the initiator group.Conclusion TBHQ exhibited a long-lasting and stable inhibitory effect on quality deterioration in dried tofu during 90 d of storage and can be considered a preferred antioxidant for dried tofu with extended storage periods.