Diabetes mellitus (DM) patients tend to be more susceptible to the COVID-19 virus. Evidence suggests that infection with the COVID-19 virus leads to increase reactive oxygen species (ROS) production. Moreover, hyperglycaemic conditions also produce excess ROS. Those can lead to oxidative stress in DM patients. This study aimed to prevent oxidative stress by using innovative functional food called tempe protein isolates, which were isolated from both non-germinated soybean (TPIN) and germinated soybeans (TPIG). TPIN, TPIG and commercial soy protein isolate (CSPI) were given 900 mg/kg BW to DM rats for 28 days. The DM rats were modelled by inducing an alloxan dose of 110 mg/kg BW intraperitoneally. Results showed there were no significant differences (p>0.05) in feed intake and blood profile. TPIN significantly prevented excessive weight loss and reduced blood glucose (p<0.05) better than TPIG and CSPI. TPIN and TPIG significantly (p<0.05) prevent the formation of MDA in the kidney, increase the activity of the SOD enzyme in both liver and kidney tissues and increase Cu,Zn-SOD antioxidant. This study concluded that the administration of TPIG and TPIN could prevent liver and kidney tissue damage by free radicals. Furthermore, TPIN has better potential than TPIG to prevent oxidative stress.