Steam Explosion Pretreatment Alters The Composition Of Phenolic Compounds And Antioxidant Capacities In Chrysanthemum Morifolium Ramat Cv. "Hangbaiju"

Steam explosion has gained much attention in the food industry. This study aimed to investigate if steam explosion could change the composition of phenolic compounds and antioxidant feature of a Chinese indigenous herb "Hangbaiju" (HBJ). Results showed that the color attributes, microstructure, and composition of phenolic compounds of HBJ were altered after the pretreatment. With the increasing pressure and duration, the contents of 3- and 4-O-caffeoylquinic acid increased. Meanwhile, some flavone aglycones, such as apigenin, luteolin, and acacetin, showed content increases, whereas apigenin-7-O-glucoside, luteolin-7-O-glucoside, and diosmetin-7-O-glucoside showed content increases and then decreases. Furthermore, 3,5-O-caffeoylquinic acid and 5-O-caffeoylquinic acid exhibited content reduction. Some caffeoylquinic acids exhibited the structural rearrangement and degradation during the steam explosion, which also hydrolyze flavone glycosides to flavone aglycones. Hence, steam explosion pretreatment is suitable for the extraction of 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, and some flavone aglycones, as well as the modification of HBJ samples.Novelty impact statement Steam explosion altered the appearance of "Hangbaiju" and disrupted its microstructure. Different pressure and duration of steam explosion showed different effect on phenolic compounds composition and antioxidant capacities of "Hangbaiju." Furthermore, steam explosion pretreatment increased flavone aglycones content in "Hangbaiju."