Abstract:

In order to improve the quality of lac products and avoid odor, volatile components from 5 different lac raw materials and final products were trapped by a dynamic head-space closed cycle adsorption method and analyzed by thermal cryotrapping- gas chromatography/mass spectrometry (TCT-GC/MS). Results showed that benzene homologues were predominant, which were over 90% in volatile components from lac raw materials, over 90% from seed lac, over 60% from bleached shellac dried at room temperature, over 30% from lyophilized bleached shellac and over 80% from heating-crushed bleached shellac. Volatile chemical components in different raw materials and final products were also different due to various purification and drying styles. No significant change in volatile components was observed during bleaching of lac. Therefore, proper techniques will be benefited for avoiding odor during lac processing and utilization.

Key words: lac, volatile component, thermal cryo-trapping-gas chromatography/mass spectrometry (TCT-GC/MS)