The roasted food is generally referred to bread, biscuit, cake and other kinds of pastries. PGFE serves as emulsifier and foaming agent in the roasted food, which make oil and fat disperse more uniform, increase the volume dramatically, make the pasty softer, bigger, and more flexible, and make the inner structure appear like sponge. PGFE can retard the accumulation of starch granule and the release of cake ingredient, so the soft and crisp period of the cake crust prolongs. Meanwhile, PGFE is suitable to retard the consolidation of the crumb so there is the function of keeping fresh. The 4—5 days fresh period can be prolonged without hardening and loosing dregs. PGFE can increase the looseness and crispness of the biscuit, which make the biscuit demoud readily and make the flower pattern clear. Amount: 0.1—1% (calculating according to the flour amount).