Identification and quantitative analysis of anthocyanins composition and their stability from different strains of Hibiscus syriacus L. flowers

Hibiscus syriacus flower has high ornamental, edible and medicinal value. The pigments in the H. syriacus flower always tend to fade during food processing. To clarify composition and stability of the pigments, qualitative and quantitative analyses of anthocyanins in H. syriacus flower were performed by LC-ESI-QTOF-MS, and the total anthocyanins with variations in presence of some factors were determined by UV-Vis and HPLC. The results showed that the anthocyanins contained in the four strains of H. syriacus were HSR>HSPU>HSP>HSW. Among the 40 color-related components identified in H. syriacus flowers, the anthocyanin aglycone structures involved included cyanidin, delphinidin, procyanidin, peonidin, pelargonidin, petunidin, malvidin, and dihydroflavonoids, but the depth of the flower color was mainly related to the number of functional groups on B-ring of skeleton. In the temperature range of 4–65 ℃, higher temperatures had a significant color-enhancing effect on the anthocyanins. Light significantly promoted the degradation of anthocyanins, while acidic conditions were conducive to the stability of the anthocyanins in H. syriacus flowers. Metal-ions of Cu2+, Mg2+ and Al3+, ascorbic acid, oxidant and reducing agent can reduce the stability of anthocyanins. The research data provides scientific guidance and foundation for the breeding, resource utilization and edible development of H. syriacus flower.