Corn oil typically is recovered from the corn germ through a solvent-based process using hexane. Due to capital equipment requirements and special handling and disposal considerations, the use of hexane is considered a rather expensive process. Unfortunately, water-based methods for oil recovery have not been successful because the yields of corn oil are much less than those obtained using hexane extraction.
A thermal analysis of the unprocessed germ was performed to identify whether ambient or cryogenic grinding would be recommended. The transition temperatures were measured on a differential scanning calorimeter (DSC). The DSC output shown in figure 1 identified a glass transition temperature (TG) for the starch component at around -72°F (-58°C) and a melting temperature (TM) for the oil component at around -4°F (-20°C). These results were consistent with literature values for similar materials. Therefore, based on the rather low T G, the material was considered appropriate for using cryogenic conditions in grinding to expose sufficient surface area to maximize the oil extractability.