Effect of steaming and defatting treatments of oats on the processing and eating quality of noodles with a high oat flour content

Oats are lipid-rich grains with high lipase activity. To extend the shelf life of noodles with a high oat flour content, oats were stabilized by steaming and subcritical butane defatting techniques. Subsequently, the physicochemical properties of oat flour and the processing, cooking and eating quality of noodles containing 70% oat flour were studied. Notably, steaming treatment completely inactivated lipase and peroxidase in oat flour, while subcritical butane defatting reduced the residual lipid content to <1%. After stabilization, the degree of oat flour gelatinization was 32.74%, and the water absorption and water solution indexes had increased significantly (p < 0.05). Moreover, the pasting temperature decreased significantly and the paste viscosity increased significantly (p < 0.05). The resistance to extension and adhesiveness of the dough sheet increased by 12.2% and 93.4%, respectively. A 16.2% decrease in cooking loss and 25.9% increase in water absorption of noodles were observed. The cooked noodles exhibited significant increases in hardness, springiness and adhesiveness (p < 0.05). These findings indicated that stabilization treatment not only effectively inactivated enzymes, but also helps to improve the processing, cooking and eating quality of oat noodles.