Changes in physical properties of Yukwa (fried rice snack) by soybean extract concentration and incubation time.

This study assessed the effects of soybean extract concentration and incubation time on the physical properties of Yukwa, a traditional Korean oil-puffed snack. Notably, whiteness decreased, while redness and yellowness increased as the soybean extract concentration increased. The expansion rate of Yukwa increased as the soybean extract concentration increased. Moreover, that in the 0 and 7% soybean extract groups decreased, followed by slight increase as the incubation time increased, and the 14% soybean extract treatment group showed increased expansion with incubation time. The oil absorption rate of Yukwa increased with soybean extract concentration and incubation time, and the hardness of Yukwa was decreased as the soybean extract concentration and incubation time increased. Peak number increased with soybean extract concentration, but decreased with incubation time. Finally, response surface analysis showed that a soybean extract concentration of 7.69% and incubation time of 6.41 h were optimal for achieving the desired peak number.