Enzyme treatments on corn fiber from wet-milling process for increased starch and protein extraction

Complete starch extraction has been a problem in the corn wet-milling, and here enzymes affecting different structures were used to provide a thorough understanding of the contribution of those structures to starch and protein retention for a way to achieve higher extraction rates. The combination of Frontia Fiberwash (R) (mix of cellulases and xylanases) and Olexa (R) (protease) led to an increase in starch (4.5 %) and protein (3.0 %) extraction. Enzymes changed secondary structure composition of proteins due to change in concentration of protein sub-fractions. The protein matrix around starch granules, the key factor for starch retention, was weakened with reducing agents/acids or ultrasound, which better separated starch and protein bodies. Chemicals led to 3.3-5.4 % and 0.7-1.7 % increase in starch and protein extraction, respectively, whereas an ultrasound treatment resulted in 2.2 % and 0.6 % increase. Overall, the study showed starch granules and protein bodies can be freed from wet-milled fiber fraction leading to higher extraction rate when the protein matrix is loosened.

Automated summary

By using various enzymes and treatments, it was found that higher extraction rates of starch and protein can be achieved by altering the structure of the protein matrix, which leads to better separation of starch granules and protein bodies.