| As a kind of health product with high nutritional value, honey is very popular for consumers. The phenolic compounds is a kind of biological and pharmacological activity compound in honey, which shows wide pharmacological effects upon anti-oxidant, anti-inflammatory, anti-microbial activities. Moreover, the findings from recent studies have also revealed that phenolic compounds can be use as indicators of botanical origins and the quality of honey. In this study, the new method of HPLC-ECD to detect phenolic compounds in black locust honey, fingerprint of antioxidant components in honey was constructed by HPLC-ECD to provide a new idea for identification of variety and adulteration of honey, and the method of HPLC-ECD was performed by monitoring the variations of phenolic levels in honey during processing and storage. The author’s main works are as follows five points:1. A new method for simultaneous separation and determination of ten phenolic compounds, including gallic acid, protocatechuic acid,4-hydroxybenzoic acid,4-hydroxyphenylacetic acid, caffeic acid, p-coumaric acid, ferulic acid, sinapic acid, isochlorogenic acid, and vanillic acid in black locust honey by high performance liquid chromatography using electrochemical detection (HPLC-ECD) has been established. All the test sample and phenolic compounds can be separated well, and all calibration curves of the ten phenolic compounds showed good linearity (r≥0.9997) within the test ranges, this method was sensitive and accurate, whereby paying the way for the establishment of a better quality control of black locust honey.2. The fingerprints of black locust honey from different regions were constructed by HPLC-ECD. Both correlation coefficient of similarity in chromatograms and relative peak areas of characteristic compounds are calculated for quantitative expression of the HPLC fingerprints. In the black locust honey fingerprints, the22common peaks and3phenolic compounds index peaks, including ferulic acids, sinapic acid, vanillic acid were found. Our results revealed that all the common peaks in black locust honey are the exactly same, but the content of them are different, and the similarity indexs of all samples compared to the reference chromatogram reflect that most of sample are similar.3. The effects of various operations in black locust honey production on the content of phenolic compounds are investigated. Phenolic compounds were quantified by HPLC-ECD after each stage including preheating, filtration, vacuum concentration, and pasteurization. The results showed the four processing steps chould reduce the content of phenolic compounds, and the total loss of rates of p-coumaric is38.2%, ferulic acid is32.5%, and quercitin is21.6%. Among the four stages, preheating step had some effects on the content of phenolic compounds. The loss rates of gallic acid, ferulic acid, quercetin in honey are about11.3%,17.1%, and14.96%, respectively, pasteurization step also had the significant effects, The loss rates of p-coumaric, ferulic acid, caffeic acid in honey are about31.37%,17.74%, and13.3%respectively.4. The effects of storage temperature and storage time on phenolic levels were evaluated. The results showed all the phenolic compounds declined slightly at4℃, after6month, the retention rating of the phenolic compounds close to50%, but retention rating of the phenolic compounds less than30%at25℃and37℃after6month. Therefor, in order to preserve the activity components, honey should storage at low temperature.5. A simple, sensitive, and accurate liquid chromatographic method with electrochemical detection (ECD) has been developed for analysis of caffeic acid and caffeic acid phenyl ester in propolis. ECD is more sensitive than diode-array detection for analysis of the two phenolic compounds. The calibration plots show linearity is good (r≥0.9995) in the ranges tested. Recovery was from93.5%to97.4%. |
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