Stability α-glucosidase inhibitory activity of fermented milk using <i>Lactoplantibacillus</i> strain L23 and SR17B during simulated gastrointestinal digestion and cold storage

Diabetes mellitus is a degenerative disease with increasing cases and mortality rates worldwide, including in Indonesia. One effective treatment for type 2 diabetes mellitus involves α-glucosidase inhibitors (AGI). Research has shown that hydrolyzed peptides in foods can have AGI properties. This study studied the resistance of AGI ability in fermented milk using bacterial isolates SR17B and L23 derived from AGI screening in BAL through human digestive tract simulation and during cold storage. Two strain Lactoplantibacillus L23 and SR17B which produced fermented milk with notable a-glucosidase inhibitory activity (35.15% and 35.94%, respectively) were used. The fermented milk underwent simulated gastrointestinal digestion with sequential exposure to pepsin for 3 hours, followed by bile salts and trypsin for 2 hours, and trypsin for 8 hours. Cold storage stability was tested at 4°C over 30 days. The bioactive peptides retained AGI activity after simulated digestion, although the inhibition levels declined. Similarly, AGI activity declined over the storage period but continued to exhibit significant inhibitory effects even after 30 days. Therefore, fermented milk could be a promising source of antihyperglycemic peptides and a dietary alternative for blood glucose management.