Oats have a high content of β-glucan soluble fiber. Its consumption lowers cholesterol and the glycemic response. One of the main components of many baked confectionery goods is sucrose. Reducing the amount of refined sugar in food has become urgently necessary as a result of the growing understanding of the link between excessive sugar consumption and the emergence of chronic diseases. Oat flour in the chiffon cake formulation was replaced at three levels, 50, 75 and 100% with wheat flour and we had replaced sucrose with erythritol. Raw materials and prepared chiffon cake were analyzed for their chemical composition. The final product was evaluated for baking quality (weight, volume, specific volume), glycemic index (GI) and organoleptic Properties of chiffon cake. The inhibitory effects of erythritol on Streptococcus strains were examined. The results suggest that it could be seen that a significant increase in fiber and fat contents (10.1 and 6.52 respectively) and a decrease in carbohydrate content 68.79, in oat flour compared to wheat flour. Our results indicated that in the presence of erythritol was decreased the growth of S. sanguinis by 73%. Chiffon cake produced with oat flours and erythritol it was characterized with their higher content of moisture, ash and fiber. The highest weight (360.0 g) was given by adding 100% oat flour to the chiffon cake sample compared to 342.6 g for control cake. The GI were decreased as the levels of oat flour were increased and substituted sucrose with erythritol. Chiffon cakes prepared with 50% oat flour and 100% erythritol was decreased in sweetness when compared with chiffon cake control but was still acceptable.