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Laboratory Wet Milling of Corn: Milling Fraction Correlations and Variations Among Crop Years

¹Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801. ²Corresponding author. Phone: 217-265-0697. Fax: 217-244-0323. E-mail address: krausch@uiuc.edu

Several coproducts result from fractionating corn in the wet-milling process. Because small changes in product composition and milling characteristics can have a major impact on coproduct yields and values, testing is done to anticipate final product yields. Using small sample size and controlled conditions, a laboratory wet-milling method proved to be a useful tool for wet milling and genetics industries. A wet-milling process (100-g batches) was used for data collection. Data collected during 11 years (1994–2004) were observed for samples used as benchmarks to verify process precision and accuracy and determine correlations among wet-milling yields. More than 400 milling tests were performed on benchmark samples. Data from benchmark samples also were pooled. Coefficients of variation were low (<6%) for mean yields; year-to-year standard deviations of benchmark sample yield means were homogenous and implied precision of the procedure. Some differences were detected in mean yields among years (P ≤ 0.05) for benchmark data due to combined effects of hybrid and environment. A negative correlation (r = –0.58) was observed between starch and gluten yield for pooled benchmark data. Four years (2002–2005) of milling data from commercially available hybrids were analyzed using the milling procedure. For pooled commercial data, the correlation between starch and fiber yield was (r = –0.80); correlation between starch and gluten was (r = –0.76).