Nutritional, rheological, and sensory effect of oat okara enrichment in plant-based ice cream

The use of agri-food by-products as novel ingredients has gained attention for developing functional foods. This study investigated the effect of non-dairy ice creams fortified with oat okara (OK) at different concentrations (6 %, 12 %, and 15 %), compared to a control (CTR), through proximate composition, rheological measurements (flow behavior and viscosity), in vitro glycemic index, simulated fecal microbiota, sensory analysis. OK6, OK12, and OK15 showed significantly higher dietary fiber (up to 6 g/100 g already in OK6) and protein content (up to 7.70 g/100 g in OK15), meeting the claims for “high fiber” and “source of protein”, respectively (Regulation (EC) No. 1924/2006). Rheological analysis revealed enhanced viscosity, consistency, and thixotropy in enriched OK samples, due to the water-holding capacity of fibers and the structuring effect of residual oat proteins. Specifically, OK12 reached a significant increase of viscosity (0.88) and thixotropy (30.46) compared to CTR (0.21 and 17.77, respectively). Furthermore, OK12 and OK15 displayed a significant reduction (67.36 % and 64.49 %, respectively) of predicted glycemic index (pGI) compared to CTR (76.43 %). Although no significant differences in prebiotic activity were shown between CTR and OK-enriched samples, all ice creams promoted the growth of beneficial bacteria compared to the baseline (T0), suggesting a prebiotic potential.