Recovery from wheat germ

Supercritical CO2 has been used to extract oil and tocopherols from wheat germ in several research studies (Ge et al., 2002 Panfili et al., 2003 Eisenmenger et al., 2006 Shao et al., 2008 Piras et al., 2009 Gelmez et al., 2009). These have focused on the effects of extraction parameters (i.e., temperature, pressure, CO2 flow rate, cosolvent flow rate, extraction time) on oil and tocopherol yield and sterol and phospholipid content of the extracted oil. A recent study optimized the SC-CO2 extraction for antioxidant concentration and antioxidant activity of the SC-CO2 extracts rather than simply the oil yield (Gelmez et al., 2009). The effects of pressure (148-602 bar), temperature (40-60°C) and extraction time were modelled. The optimum extraction conditions were 336 bar, 58°C and 10 min, resulting in 5.3% tocopherol yield, 6 mg gallic acid equivalent (GAE) phenolics/g extract, 6.7 mg tocopherol/g extract and 57.3 mg scavenged DPPH/g extract. The tocopherol yield under these conditions corresponded to almost complete recovery. 

Saito and Yamauchi [19] attempted to collect tocopherols from wheat germ by preparative SFC and reported 30 to 50% recoveries which is unsatisfactory. They concluded that the compounds were probably removed by the mist of ethanol, used as modifier solvent, in the vent line and suggested that use of a cold trap might help. The system used by these Japanese workers incorporated the Jasco electronic back pressure regulator described by Saito et al. [9] which allows for collection at atmospheric pressure but does not solve the problem of non-quantitative recovery. 

Naphthas are used for extraction on a fairly wide scale. They are applied in extracting residual oil from castor beans, soybeans, cottonseed, and wheat germ and in the recovery of grease from mixed garbage and refuse. The solvent employed in these cases is a hexane cut, boiling from about 65 to 120°C (150 to 250°F). When the oils recovered are of edible grade or... 

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