Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 4/2/2004
Publication Date: 4/4/2004
Citation: Moreau, R.A., Johnston, D., Hicks, K.B. 2004. Aqueous enzymatic extraction of corn oil from corn germ. Meeting Abstract. Conference proceedings, Corn Utilization and Technology Conference, June 7-9, 2004, Indianapolis, IN., Poster 2 Interpretive Summary:
Technical Abstract: Currently all commercial corn oil is obtained from corn germ by either hexane extraction or a process that combines pressing/hexane extraction. Because of the safety and environmental issues associated with the use of hexane, the construction and operational costs of hexane extraction facilities are high. Aqueous extraction methods have been proposed as an alternative to hexane extraction. Two previous papers described aqueous enzymatic extraction methods for corn oil that achieved yields of about 80%. This project was undertaken to attempt to develop an improved aqueous enzymatic extraction process to obtain higher yields of corn oil from corn germ. Using oven-dried corn germ from a commercial wet milling facility, we developed a modified aqueous enzymatic method for corn oil extraction with yields of about 90%. Three different commercial cellulases were equally effective. Ten other commercial enzymes were evaluated and resulted in significant, but lower oil yields. When no enzyme was added to the aqueous method, oil yields of 27 to 37% were achieved. No organic solvents are used in this process. The chemical compositions of hexane-extracted and aqueous enzyme-extracted corn oils were compared and were found to be nearly identical. Very low levels of free fatty acids were found, indicating that lipase activity was minimal. The levels of phytosterols (free and esterified) were slightly lower in the aqueous enzyme-extracted oil, but the levels of gamma-tocopherol were significantly higher. Unlike the previous corn germ methods which included a 'hydrothermal pretreatment' step, heating of the germ was not required. In conclusion, our new aqueous enzymatic extraction process results in oil yields of about 90%. Since several commercial cellulases resulted in high yields, we anticipate that some of the new generation of cellulases (that are being developed for biomass conversions) may result in even higher oil yields and will likely be more economical than the current generation of cellulases.