KERNEL PROTEIN-CONCENTRATION IN SUGARY-1 AND SHRUNKEN-2 SWEET CORN

Changes in endosperm type used for commercial sweet corn (Zea mays L.) production may affect corn protein levels. The two most widely used e ndosperm types are sugary-1(su1) and shrunken-2 (sh2). To determine th e effects of endosperm type on protein concentration, we calculated ke rnel N concentrations of dry mature kernels of seven inbreds near-isog enic for su1 and sh2 and of four samples of commercially canned su1 an d sh2 sweet corn. Nitrogen values were converted to protein values usi ng a standard conversion factor for maize. For the dry kernels and the canned samples, significant differences were detected between endospe rm types for kernel protein concentration when measured on a weight ba sis. Averaged over all inbreds, the sh2 dry kernels had 30 % more prot ein than su1 kernels. On a weight basis, the sh2 canned samples averag ed 22 % more protein than the su1 samples. When compared on a kernel b asis, protein concentration of the two endosperm types did not differ. Thus, sh2 sweet corn marketed as a frozen or canned product may be id entified as a higher protein product when the serving size is based on weight or calories.