Physico-chemical properties, probiotic survivability, microstructure, and acceptability of a yogurt-like symbiotic oats-based product using pre-polymerized whey protein as a gelation agent.

Consumption of a food product containing prebiotics and probiotics has been recognized as an important factor in lowering risk of intestinal cancer and gastrointestinal diseases and risks associated with high cholesterol. An oats-based symbiotic yogurt-like food (Oagurt) was developed using oats and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium), with pre-polymerized whey protein (PWP) as a gelation agent. The product was also fortified with inulin to increase soluble fiber, minerals, and vitamins. Physico-chemical analyses and 9 wk shelf life for viability of probiotics and changes in pH and viscosity were carried out for formulations with (F) and without (C) fortification. Results of the shelf life study showed that both L. casei and Bifidobacterium remained at therapeutic levels: 4.8 x 10(6) CFU/g (F), 4.3 x 10(6) CFU/g (C) and 3.1 x 10(6) CFU/g (F), 3.17 x 10(6) CFU/g (C) after 9 wk. However L. acidophilus did not survive after 3 wk. Viscosity and pH decreased significantly during the study with the difference between formulations also significant for pH (P < 0.0001). Scanning electron microscopy of samples revealed that the pre-polymerized whey protein played a major role in the structure of the gel with an increased protein network structure visible at higher PWP levels. A consumer acceptability study showed that the product was "fair" for all organoleptic attributes.