Non-thermal electrohydrodynamic (EHD) drying improved the volatile organic compounds of lotus bee pollen via HS-GC-IMS and HS-SPME-GC-MS

Abstract

The effect of non-thermal processing on food flavor and aroma components is still unclear. Non-thermal electrohydrodynamic (EHD) drying was applied as a novel technology for the drying of lotus bee pollen. The effect of different output voltage (10, 20, 30, 40, and 50 kV) of EHD on volatile organic compounds (VOCs) was studied, samples of hot air drying (HAD) and natural sun drying (NSD) was also evaluated. Results showed that 147 volatile organic compounds were identified from lotus pollen, and most of them were aldehydes and terpenes. Due to lipid oxidation and protein modification, most aldehydes and terpenes increased with increase of voltage, while alcohol and acid concentrations first increased and then decreased with voltage. The concentration of alcohols accumulated was the highest in natural sun drying, which caused by fermentation when exposed to natural environment for a long time drying. Four VOCs, ethnol M, ethnol D, acetic M, and acetic D, were selected by variable importance in projection variable selection method of partial least squares discriminant analysis as potential markers to distinguish different drying lotus bee pollen. These findings in current work revealed the flavor formation and related mechanism of bee pollen during non-thermal drying.