Quality Characteristics during Storage of Yackwa added with Ethanol Extract from Ulmus davidiana

Abstract

In conclusion, as the concentration of Ulmus davidiana in yackwa increased, decreases in L value, hardness, and off flavor, as well as an increase in water activity, expansion ratio, a value, b value and sensory characteristics were observed. Treatment with Ulmus davidiana caused yackwa to be darker, most likely because of the Maillard reaction. Furthermore, treatment with Ulmus davidiana caused the normal dehydration that occurs during frying to decrease and the consistency of the dough to increase; therefore, it could effectively reduce oil uptake in yackwa. In addition, the color, off flavor, and hardness of yackwa increased, while the water activity, expansion ratio, and sensory characteristics, decreased with storage time. The antioxidant activity of yackwa base that contained Ulmus davidiana extract was investigated using several assay methods. The results indicated that Ulmus davidiana could be a good antioxidant source. Generally, treatment with L-ascorbic acid, 0.2% Ulmus davidiana extract and BHT were highly effective at increasing the antioxidant properties assayed in this study. Although the antioxidant activity of yackwa that contained Ulmus davidiana extract was less than that of L-ascorbic acid and BHT, these compounds may be useful for retarding lipid oxidation under certain conditions. Therefore, Ulmus davidiana can be used to enhance the oxidative stability of oil-containing food. Furthermore, treatment with Ulmus davidiana did not affect the taste acceptability, and the sensory evaluations revealed that Ulmus davidiana could be used to substitute up to 0.1% of the wheat flour used to produce yackwa without decreasing acceptability. However, further studies to determine the mechanism and interaction between food and Ulmus davidiana, as well as studies to evaluate the biological activities of Ulmus davidiana should be conducted to certify that the extracts are safe.