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.