Physiochemical Properties and Probiotic Survivability of Symbiotic Corn-Based Yogurt-Like Product

Corn is a major grain produced in northern China. Corn-based functional food products are very limited. In this study, a symbiotic corn-based yogurt-like product was developed. Corn milk was prepared through grinding, extrusion and milling, and hydration processes. Corn extrudate was prepared under the optimized conditions of corn flour particle size <180 μm, moisture content of 15% and extrusion temperature at 130 °C. The corn milk was prepared from 8% corn extrudate suspension and then milled twice with 0.1% glyceryl monostearate and 0.1% sucrose ester as emulsifiers. The corn milk was mixed with sugar (5%), glucose (2%), soy protein isolate (0.75%), inulin (1%), polymerized whey protein (0.3%) and xanthan gum (0.09%) as thickening agents. The mixture was fermented at 35 °C for 6 h using a probiotic starter culture containing L. plantarum. Chemical composition (%) of the symbiotic corn-based yogurt-like product was: total solids (17.13 ± 0.31), protein (1.12 ± 0.03), fat (0.30 ± 0.05), carbohydrates (15.14 ± 0.19), and ash (0.16 ± 0.02), respectively. pH value of this symbiotic product decreased from 4.50 ± 0.03 to 3.88 ± 0.13 and the population of L. plantarum declined from 7.8 ± 0.09 to 7.1 ± 0.14 log CFU/mL during storage at 4 °C. SDS-PAGE analysis showed that there were no changes in protein profile during storage. Texture and consistency were also stable during the period of this study. It can be concluded that a set-type corn-based symbiotic yogurt-like product with good texture and stability was successfully developed that would be a good alternative to the dairy yogurt.