Studies On Main Ingredients And Antioxidant Activities Of Four Kinds Of Honey In Yunnan

The main active ingredient in honey including carbohydrates and phenolic compounds have great significance on the functional activity and quality of honey. In this study,24 experimental samples from four kinds of characteristic honey (megranate honey, Vicia honey, coffee honey and rubber honey) were collected in Yunnan and the content of glucose, fructose and oligosaccharides were studied by using ion chromatography. Besides, the types and contents of phenolic compounds in these honey were also analyzed by using high-performance-liquid-chromatography (HPLC). At last, the reducing power, scavenging ability to DPPH free radical and oxygen radical absorbance capacity (ORAC) were compared between different floral species and origins, the results were as follows:1. Glucose, fructose, isomaltose and kestose were found in the four kinds of honey. The content of carbohydrates in honey was determinated by ion chromatography. The results showed that:in all honey samples there contained glucose, fructose, isomaltose and kestose, while the content of sucrose, maltose and other carbohydrates were less than 0.01%. The average content of total carbohydrates in the four kinds of honey were degressive in an order of coffee honey, megranate honey, Vicia honey and rubber honey.2. The total polyphenols content (TPC) of honey was related to the antioxidant capacity of honey. Among them, the highest TPC was found in megranate honey, while the lowest one was in rubber honey. There existed a significant difference between the TPCs in different honey samples after a comparative analysis by Duncan’s multiple range test in SPSS.3. The content of flavones in honey was related with the color of honey. The total flavones content (TFC) of honey samples were determined by ultraviolet-visible spectrophotometry. Among them, the lowest levels of TFC was found in the lightest color of rubber honey, while the highest levels of one was in the darkest color of coffee honey. The TFC in coffee honey was twice more than that in rubber honey. There existed a significant difference between the TFCs in different honey samples. The darker the honey was, the higher TFC it would contain. And vice versa.4. A new experimental method by a reversed-phase (RP) HPLC to determine phenolic compounds in honey were settled. At 280nm of wavelength, the types and contents of phenolic compounds in honey were determined. The results showed that different honey had different types and contents of phenolic compounds, as well as different gradient elution. Four different optimized methods could be as an effective method for measuring contents and types of phenolic compounds in honey.5. There was a significant difference in the type and content of phenolic compounds between different types of honey. The polyphenols extract of four kinds of honey was analyzed by an optimized HPLC-DAD analysis method. There were 20 compounds including abscisic acid, caffeine,18 phenolic acids and their esters flavones have been identified. Among them, three main components were in megranate honey, twelve main ingredients in Vicia honey and eight major components in coffee honey. The most important compound in rubber honey was caffeine. The total content of polyphenols in all the identified honey was degressive in an order of rubber honey, megranate honey, Vicia honey and coffee honey.6. The difference of antioxidant capacity in honey varied with floral species and origin. The antioxidant capacity of honey samples from different regions were compared and the differences were found. Since the types and contents of trace chemical constituents (such as oligosaccharides and phenolic compounds) in honey were different, the anti-oxidation performance of honey would vary with different nectar plants and their origins, geographical environment and other factors. There was a degressive order in antioxidant capacity among megranate honey, coffee honey, rubber honey and Vicia honey.It is rich in phenolic compounds in four kinds of honey and they have strong antioxidant capacity. It is worthy of developing this kind of resource. The related study can be used as its theoretical basis.