Enzyme Treatments to Enhance Oil Recovery from Condensed Corn Distillers Solubles

Abstract

AbstractThe objective of this study was to determine the effect of enzyme hydrolysis of various corn components on oil recovery from condensed corn distillers solubles (CCDS). Hydrolysis with a commercial protease significantly increased oil recovery as the enzyme concentration increased, with the greatest oil recovery being 70% at 10% v/w (dry weight basis) enzyme concentration. Increasing centrifugal force from 8,500 to 12,240×g was only slightly effective for the non‐enzyme treated samples. Reducing CCDS particle size by grinding with a mortar and pestle increased oil recovery to 83% when an enzyme combination of a commercial cellulase mixture and a protease was used. Particle size reduction of CCDS by high‐speed blending resulted in low oil recovery, but the oil recovery was significantly improved after enzyme treatment. Zein‐lipid interaction was very strong when tested in a model system, with only 10% of the oil being freed by centrifugation alone. Following enzyme hydrolysis of the zein‐oil complex with a protease, oil recovery was increased to 97%. Overall, enzyme hydrolysis and further particle size reduction showed a small, albeit statistically significant, effect in increasing oil recovery from CCDS. These small increases may not justify the use of enzymes or processing modifications to reduce particle size in the ethanol industry, nonetheless, these data may provide a reference or insight to design more effective treatments for oil recovery.