Three varieties of sweet corn (Zea mays L.) , including
two supersweet (Crisp 'N Sweet 710 and Rogers 3376) and one
normal sweet (Jubilee), were harvested at six stages of
maturity (80-72% moisture for supersweet and 75-68% moisture
for normal sweet) at three days intervals. Changes in
physical and chemical properties over the 15 day harvest
period and effects of steam blanching on carbohydrate
composition of both genotypes of sweet corn were determined.
Moisture content of the kernels decreased with
maturity. A quick microwave oven moisture method for
determining moisture content of normal sweet and supersweet
corn was evaluated and found to be a good alternative method
for the time-consuming standard AOAC vacuum oven method.
Yield (as represented by average ear weight) increased
linearly with maturity. Percent soluble solids was determined to be a satisfactory maturity index for normal
sweet corn but not for supersweet corn. The pericarp
content in the normal sweet corn Jubilee increased 25% over
the 15-day harvest period compared to a mean of 5-6% in the
supersweet varieties. Values of the shear press tests were
not significantly correlated to % moisture, and only values
of compression work showed a positive trend to increase with
maturity.
Total sugars of supersweet corn averaged 2-3 times
higher and decreased more slowly than those of normal sweet
corn in the comparable maturity range for processing.
Sucrose was the major sugar in both corn genotypes and
represented about 80% of the total sugars (9-20% dry weight)
in normal sweet corn versus 90% of the total sugars (30-45%)
in supersweet corn. Polysaccharides consisted mainly of
starch in supersweet corn and of water soluble
polysaccharide (WSP) in normal sweet corn. Normal sweet
corn contained about twice as much polysaccharides as did
supersweet corn. Percent total polysaccharides increased
with maturity. Although higher in sugars, supersweet corn
had lower % total carbohydrates than normal sweet corn due
to its low polysaccharide content.
Blanching of corn-on-the-cob for 10 minutes in 99°C
steam resulted in a significant loss of sugars. Blanching
did not significantly reduce total polysaccharides of sweet
corn. / Graduation date: 1990
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27064 |
| Date | 04 October 1989 |
| Creators | Su, Shanghe |
| Contributors | Varseveld, George W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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