Quality Characteristics of Wheat Germ Oil Obtained by Innovative Subcritical Butane Experimental Equipment

Subcritical butane extraction (SBE) was used to extract oil from wheat germ and was compared with conventional n‐hexane extraction (CHE) and supercritical CO₂ extraction (SC‐CO₂E) methods. By analyzing the extraction yield, composition of fatty acids and characteristic functional contents such as VE, phytosterols and phospholipids in wheat germ oil (WGO), the selective extraction characteristics of subcritical butane were evaluated. The results indicated that compared with SC‐CO₂E and CHE, SBE had no significant difference in oil yield, fatty acid compositions, acid value and peroxide value of WGO. However, the content of phytosterols in the oil extracted by SBE (2,326 mg/100 g) was higher than that extracted by CHE (921 mg/100 g) or SC‐CO₂E (1,381 mg/100 g). The VE content of WGO extracted by SBE (359 mg/100 g) was equivalent to that extracted by CHE (357 mg/100 g) and slightly less than that extracted by SC‐CO₂E (374 mg/100 g). And the content of phospholipids in WGO extracted by SBE (12.41 mg/g) was lower than that extracted by CHE (17.78 mg/g). In conclusion, SBE was able to retain the bioactive compounds in WGO when compared with CHE. PRACTICAL APPLICATIONS: Wheat germ oil is a type of functional oil enriched with bioactive compounds that have great latent capacity for further exploitation. However, conventional extraction methods of edible oil lead to oil oxidation and degradation or loss of bioactive components after desolvation and refinement (Pradhan et al. 2010). In addition, due to the shortcomings of supercritical CO₂ extraction technology such as costly equipment investment, low productivity and high cost of production, subcritical fluid extraction technology can be applied to industrial production owing to its use of low pressure and room temperature for extraction. The present study demonstrates that subcritical butane has better extracting power for bioactive compounds in wheat germ oil than conventional n‐hexane. Choosing subcritical butane extraction technology can help the fats and oils industry to improve the quality of high value‐added oil while lowering production costs.