The global morbidity of metabolic disease continues to rise despite advances in modern treatment regimens, shifting attention towards diet-based strategies. Functional foods impart health benefits beyond basic nutrition, with the potential to mitigate metabolic pathways driven by oxidative stress and impaired glucose metabolism(1). Cereal-based proteins are recognised as containing peptide sequences with bioactive potential that are released upon hydrolysis. This study aims to investigate the antioxidant and antidiabetic properties of protein hydrolysates generated from major cultivated cereals, including sorghum, wheat, and rice. Proteins were extracted using alkaline extraction–isoelectric precipitation, and hydrolysates were generated by four-hour treatments with gastrointestinal enzymes (pepsin, trypsin, chymotrypsin) and a commercial protease (alcalase). Antioxidant activity was evaluated using radical-scavenging and redox-based assays, while antidiabetic properties were examined via the alpha-amylase inhibition assay. SDS-PAGE showed extensive hydrolysis with alcalase treatment, while other treatments revealed the breakdown of large-molecular-weight proteins. These results were confirmed by the degree of hydrolysis (DH) assay, which showed that alcalase treatments had significantly higher DH values than other digestive protease treatments (p < 0.05). In terms of antioxidant capacity, alcalase hydrolysates demonstrated the strongest ABTS radical scavenging, compared to trypsin, chymotrypsin and pepsin treatments (p < 0.005). Among them, rice hydrolysates had the highest ABTS scavenging value of 503.94 µM TE/g, followed by sorghum (394.98 µM TE/g) and wheat (375.25 µM TE/g). In the Ferric Reducing Antioxidant Capacity (FRAP) assay, sorghum and wheat hydrolysates had significantly higher FRAP values than their protein extracts, except for pepsin treatments. Among all samples, wheat alcalase hydrolysates exhibited the highest FRAP value, indicating a strong electron-transfer potential. Preliminary data from the alpha-amylase inhibition assay showed that wheat hydrolysates from trypsin, pepsin, and chymotrypsin have greater potency than the anti-diabetic agent acarbose. These results indicate that hydrolysis treatment improves the antioxidant capacity of cereal-grain proteins. Additionally, they support the potential of cereal-derived peptides as functional food ingredients or nutraceutical candidates targeting oxidative stress and glycaemic regulation, warranting further investigation in cell-based models.