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A 10-g Laboratory Wet-Milling Procedure for Maize and Comparison With Larger Scale Laboratory Procedures

¹Center for Crops Utilization Research, 1041 Food Sciences Building, Iowa State University, Ames, IA 50011. ²Corresponding author. Phone: 515-294-4365. Fax: 515-294-6261. E-mail: ljohnson@iastate.edu

A very small scale laboratory procedure (≈10 g) is needed to test wet-milling characteristics of corn when amounts of corn available for testing are quite limited. The objective of this study was to downscale 100-g laboratory wet-milling methods already widely used to measure wet-milling properties of 10 g of corn. A Standard 100-g procedure, a Modified 100-g procedure, and an Experimental 10-g procedure were compared using three corn hybrids with known differences in wet-milling properties. All three procedures ranked most fraction yields (all except for germ) of the three hybrids the same. Germ separation was conducted differently for each procedure and probably accounts for these differences. Flotation and screening methods were likely affected by germ density and germ size, and hand-picking the germ was efficient in recovering a pure germ fraction. The two 100-g procedures were performed very similarly except for fiber recovery. The Modified 100-g procedure was more efficient in recovering fiber because of intensive washing. Hybrid effects on the starch/gluten separation were more pronounced when the Experimental 10-g procedure was used, which may allow for more discrimination among hybrids. Although most fraction yields are too small to run replicates for analytical tests, the Experimental 10-g procedure will be useful in measuring milling efficiency of early generations of corn hybrids where limited samples are available, such as when valuable recombinant proteins are expressed for therapeutics and industrial enzymes.