Identification of Major Bitter Compounds in Zanthoxylum bungeanum Under Different Thermal Processing Techniques

Zanthoxylum bungeanum, as a vital spice, the presence of its bitter components has a notable impact on the overall flavor of the food. To deeply explore the formation mechanism of the bitter components in Z. bungeanum and correlated influencing factors, this study used bitterness intensity as an indicator and employed sensory evaluation to optimize the processing conditions of Z. bungeanum during boiling and frying through single-factor optimization. Furthermore, organic solvent extraction, solid-phase extraction, and preparative high-performance liquid chromatography were used to isolate and concentrate the bitter fractions from Z. bungeanum water and oil. Subsequently, taste dilution analysis was employed to evaluate the contribution of these bitter fractions to the sensory characteristics of food. Additionally, high-performance liquid chromatography-mass spectrometry was adopted to identify the bitter components in Z. bungeanum water and oil. The results indicated that during the boiling process, increasing the amount of Z. bungeanum and extending the boiling time intensified the bitterness, while the bitterness of Z. bungeanum during frying process increased with raised temperature, extended frying time, and increased amount of Z. bungeanum. The recommended conditions for consumption and processing of Z. bungeanum water and Z. bungeanum oil were as follows: Z. bungeanum water was recommended to be boiled at 100 ℃ for 5 min, and the dosage of Z. bungeanum could be controlled at less than 2 g to reduce the bitter flavor. Z. bungeanum oil was recommended to be fried at 105~120 ℃ for 10~30 min, and the amount of Z. bungeanum could be added moderately to keep the bitter flavor low. The main bitter substances in Z. bungeanum water might be quercetin-3-rhamnose gentiobioside, quercetin-3,7-di-O-β-D-glucopyranoside, quercetin-3-O-robinobioside, and nuciferine, while the primary bitter compounds in Z. bungeanum oil were hydroxy-α-sanshool and hydroxy-β-sanshool. This study provides data reference and theoretical basis for the processing, quality control, and bitterness reduction of Z. bungeanum.