Abstract: The relationship between volatile compounds produced during thermal degradation of carotenoids in sweet corn juice and its flavor was studied. By using C30-high-performance liquid chromatography with diode array detection-atmospheric pressure chemical ionization-mass spectrometry (C30-HPLC-DAD-APCI-MS) and solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), the main carotenoids were separated and identified in fresh sweet corn juice. The volatile compounds generated in the heat-treated corn juice were analyzed. Then the correlation between the thermal degradation of carotenoids and the volatiles was examined. Results showed that 12 carotenoids were identified in fresh sweet corn juice. With increasing the heat temperature, the contents of all-trans carotenoids were reduced gradually, and the content of cis-carotenoids was firstly increased and then decreased. A total of 35 volatile compounds were determined in the fresh and heat-treated sweet corn juices. The contents of dimethyl sulfide, 1-octene-3-ol, methyl heptanone, β-ionone, and P-umbrella were increased during heating. The correlation analysis showed a significant and negative relationship between the aroma-active compounds β-ionone, methyl heptanone, limonene, benzaldehyde, 2-octanone, P-umbrella, toluene and 1,2,3-trimethylbenzene and thermal degradation of carotenoids. Among these aroma compounds, the contribution rates of lutein and β-carotene were the highest. Therefore, the major volatile compounds produced during the thermal degradation of carotenoids may play a non-negligible role in the flavor of sweet corn juice.

Key words: sweet corn juice, carotenoids, thermal degradation, volatile compounds