Application of electronic nose and GC-MS to differentiate volatiles of soybean oils prepared with different temperature conditions

In order to establish rapid detection technology and ensure the safety of edible oil, investigations were carried out to explore the relationship between soybean oil volatiles and temperature conditions. Chemical sensor technology and headspace-solid phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS)were used to analyze the volatiles of soybean oil with different temperature conditions. The results showed that chemical sensor can be sensitive to detect the odor changes of soybean oil in the heating process. Fresh, 150°C, 180°C and 220°C soybean oil volatiles were significantly different by PCA and LDA methods. There were 27, 60, 100 and 115 kinds of volatile compounds detected from fresh, 150°C, 180°C and 220°C soybean oil, respectively. Among these compounds, most of them were hydrocarbons, aldehydes, ketones, ethers, esters, acids, heterocyclic compounds, and hydro-peroxides. The content of hydroperoxides in fresh soybean oil was higher than other samples. Ketones and alcohols with oil incense were the main volatiles of soybean oil at 150°C. Aldehydes and heterocyclic compounds were the main volatiles of 180°C and 220°C soybean oil, and they produce coke flavor, roasted flavor also endanger human health.