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Effect of physicochemical characteristics on extractable starch in maize. MUKTI BAJAJ (1), Marvin
R. Paulsen (1), Steven W. Mbuvi (2), and Robert K. Stewart (3). (1) Post-Doctoral Research Associate,
Professor, Agricultural Engineering dept., University of Illinois, Urbana, IL 61801; (2) Manager, Identity
Preserved Grain Lab, Champaign IL 61821; (3) Senior Consultant, Agricultural Education & Consulting,
Savoy, IL.
Starch is the major product from maize in the USA. Wet milling is used
to extract starch. The starch yields play an important role in the economics of the wet milling industry. This
study was designed to evaluate the relationships between the physicochemical characteristics of maize and
starch yield. Maize samples from 1998 and 1999 crop years of several types (waxy, white, low temperature
dried, commodity export and commodity elevator) were used in the study. Laboratory wet-milling
evaluations were performed using 100-g procedure and the product fractions of steepwater solids, germ,
fiber, coarse fiber, fine fiber, starch and gluten were measured. BCFM, damaged kernels, test weight, stress
cracks, percent thins, true density, kernel volume, and 1,000 kernel weights were also measured using
standard methods. Protein, oil, starch content, fiber and extractable starch were estimated measured using
Near Infrared Reflectance (NIR) calibrations. Correlations between the wet milling constituents and the
physicochemical characteristics as influenced by the crop year and type of maize were calculated.
Correlations varied by maize type. In general, as protein increased extractable starch decreased. As fine
fiber and total fiber increased, extractable starch decreased.
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