EFFECT OF KERNEL SIZE, LOCATION, AND TYPE OF DAMAGE ON POPPING CHARACTERISTICS OF POPCORN

Popping characteristics, specifically expansion volume and popping tim e, were studied for damaged popcorn. A single variety of commercial un damaged yellow popcorn was separated into four size fractions (D < 4.3 6, 4.36 < D < 5.16, 5.16 < D < 5.95, and D > 5.95 mm) by screening wit h round-hole sieves. Kernels were damaged using a razor knife by eithe r slicing a 2-mm diameter piece of the endosperm or the germ or by cut ting through the pericarp and seed coat into the endosperm or the germ approximate to 2 mm. A total of five combinations of location and dam age were studied (tip cap removed, side cut, side sliced, germ cut, an d germ sliced) for each kernel size. A control sample with no damage w as also analyzed for each size fraction. All of the damaged kernels (r egardless of type of damage) popped, but they had expansion volumes 9. 1-47.5% smaller than those of undamaged kernels. The expansion volume of damaged kernels increased by 52.5-85.7%, depending on the damage, w hen the size of the kernel increased from <4.36 mm to >5.95 mm. Removi ng the tip cap and slicing through the germ caused less loss of expans ion volume than did other types of damage. Damaged popcorn kernels had faster popping times (12.2-24.0 sec) than did undamaged kernels (30.9 -34.6 sec). Popping times increased with increasing kernel size for al l types of damage.