Abstract: In this experiment, gas chromatography-mass spectrometry (GC-MS) was used to study the effects of traditional degumming and deacidification on the volatile compositions of cold- and hot-pressed rapeseed oils. It was found that both volatile compositions and flavors of cold- and hot-pressed oils varied greatly and the volatile composition of hot-pressed oil was more complicated than that of cold-pressed oil. Degumming and deacidification could reduce the complexity of volatile composition in rapeseed oil. Principal component analysis (PCA) indicated that deacidification had a great influence on the volatile compositions of both oils, while degumming had a lesser influence. The degumming process had no significant effect on the acid value of rapeseed oil. Degumming and deacidification had significant effects on the peroxide value of coldpressed oil but not on hot-pressed oil.

Key words: cold pressing, hot pressing, refining, flavor, principal component analysis (PCA)