Incorporating salal berry (Gaultheria shallon) and blackcurrant (Ribes nigrum) pomace in yogurt for the development of a beverage with antidiabetic properties

In this study aqueous extracts from salal berry (SB) and blackcurrant pomace (BCP) were used to reformulate yogurt and the anti-diabetic properties of the beverage were investigated during 4 weeks of cold storage at 4 degrees C. Results indicated that alpha-amylase, alpha-glucosidase and DPP-IV inhibitory activities increased with storage time for all samples. At the end of storage period alpha-amylase, alpha-glucosidase and DPP-IV inhibition were >61%, 62% and 56% respectively for all yogurt types. This increase in bioactivity during cold storage is attributed to the viability of lactic acid bacteria (similar to 10 8 cfu/g), which is maintained for 4 weeks. Enzyme inhibition increased similarly for all yogurt types at 4 degrees C except for alpha-glucosidase. Yogurt with BCP showed the highest potency to inhibit alpha-glucosidase (>90%) with an IC50 value of 0.20 mg/ml (week 4). A peptidomic approach based on liquid chromatography coupled with mass spectrometry (LCMS) was used for the separation and identification of peptides generated in three types of yogurt. A total of 486 peptides mainly from caseins were identified, of which 15 have documented bioactivity, predominantly as antimicrobial agents or ACE-inhibitors.