Analysis of Changes of Sophorae Flos before and after Processing Based on UPLC Fingerprint and Chromatic Value

  OBJECTIVE  To analyze the difference and dynamic change rules of UPLC fingerprint and chromatic value of Sophorae Flos before and after processing, and to provide reference for the identification and processing technology of Sophorae Flos, fried Sophorae Flos, and Sophorae Flos carbonisatus.

  METHODS  The UPLC fingerprint of Sophorae Flos before and after processing was established, and chromatic value was determined by spectrophotometer.The differences of Sophorae Flos, fried Sophorae Flos, and Sophorae Flos carbonisatus were analyzed according to the similarity evaluation, one-way ANOVA, cluster analysis, principal component analysis, orthogonal partial least squares discriminant analysis (OPLS-DA), et al.The dynamic change rule of the fingerprint and chromatic value of Sophorae Flos at different processing time points were also analyzed.

  RESULTS  There were obvious differences in fingerprints and chromatic value before and after processing.15 common peaks were calibrated for Sophorae Flos, 16 for fried Sophorae Flos, and 14 for Sophorae Flos carbonisatus.Peak 2, 3, 8, 9, 10, 11, 14, and 15 were identified as 5-HMF, protocatechuic acid, rutin, isoquercetin, kaempferol-3-O-rutinoside, narcissin, quercetin, and kaempferol, respectively.Peak 1 and peak 2(5-HMF) were the chemical components produced after processing and peak 17 was the component disappeared after processing.There was a significant change in the chromaticity value before and after the processing of Sophorae Flos.The chromaticity values L^*, b^*, E^* of Sophorae Flos carbonisatus were much lower than those of Sophorae Flos and fried Sophorae Flos.The chromaticity value a^* of fried Sophorae Flos was slightly higher than that of Sophorae Flos and Sophorae Flos carbonisatus.It was possible to distinguish samples of Sophorae Flos, fried Sophorae Flos, and Sophorae Flos carbonisatus by the chromaticity value.Cluster analysis and principal component analysis could distinguish Sophorae Flos, fried Sophorae Flos, and Sophorae Flos carbonisatus.The results of orthogonal partial least squares discriminant analysis show that rutin and quercetin were the important components causing the difference between Sophorae Flos and its processed products (VIP>1).Within 46 min of processing of Sophorae Flos, the ratio of peak area/scale sample size/1 000 of peak 1 to peak 16 increased first and then decreased, while peak 17 decreased continuously.Using the color of the slices as an evaluation indicator when the frying temperature was 160℃, the appropriate frying time for fried Sophorae Flos, Sophorae Flos carbonisatus should be 4-6 min and 14-18 min, respectively.

  CONCLUSION  The established UPLC fingerprint and chromatic value determination method can provide reference for the identification and processing technology of Sophorae Flos, fried Sophorae Flos, and Sophorae Flos carbonisatus.