A Comparative Study On The Composition And Biological Activity Between Naturally Mature Honey And Immature Honey From Rape Flower

The phenomenon of honey adulteration that has a huge negative impact on the beekeeping industry and restricting the healthy development of the honey market.For a long time,people did not harvest honey until the bees were capped with beeswax,and it was also known as mature honey.Nevertheless,recent years more and more beekeepers didn't wait for bees to capped with beeswax and harvest the immature honeys to increase the honey yield.Obtained immature honey will subsequently concentrated and dehydrated,and those processed honeys still fall within the standard.Although the basic physical and chemical indicators of the concentrated honey had no differences from natural mature honey,the trace substances and biological activity of honey may be influenced greatly.So,to explore the difference between immature honey and naturally mature honey,we compared the capped mature rape honey?Mature honey,MH?and uncapped immature rape honey?Immature honey,IMH?from the same rape?Brassica napus L.?flower seasons in the western honeybees?Apis Mellifera L.?colonies.The main results of the study are as follows:I.The water,sugar,acidity,HMF value,amylase value and other basic physical and chemical indexes in two kinds of rape honey were tested following the methods provided by the national standard.The results showed that all the physical and chemical indexes of MH were in accordance with the standard,while the indexes of IMH were not up to the standard except the HMF value.?.The information of the small-molecule substances in the honey was collected and analyzed by ultra-high performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry-based untargeted metabolomic.MH and IMH can be effectively distinguished by principal component discriminant analysis,and the difference analysis results showed that composition were significant differences between MH and IMH.The contents of organic acids,glycosides,plant bases and other substances in IMH were richer than MH,while the contents of phenolic substances in MH were higher than IMH.?.The polyphenols in rape honey were studied by targeted metabolomics analysis.The results showed that a total of 20 polyphenols were detected,among which Kaempferol,Apigenin,Pinocembrin,3-?3,4-Dimethoxyphenyl?-2-propenoic acid,Chrysin and Phenethyl caffeate is lower in IMH than the detection limit.Vanillic acid and Syringic acid content in IMH is higher than the MH,but the rest of common phenolics is lower.IV.The results of determination of DPPH and ABTS^+·free radical scavenging ability and iron reduction ability showed that MH had stronger in vitro antioxidant ability than IMH.The results of bacteriostatic experiments showed that both kinds of honey showed inhibitory effects against Staphylococcus aureus and Escherichia coli,and MH had a larger bacteriostatic sphere and a stronger bacteriostatic effect,but both two kinds of honey had no inhibitory effect on Bacillus subtilis.?.The oxidative stress model of mouse fibroblasts L929 was induced by hydrogen peroxide and the protective effect of two kinds of honey against oxidative stress damage were evaluated.Results showed that the honey extract from MH at a concentration of 300?g/mL significantly increase the cell viability of H₂O₂-induced damaged cells,while the honey extracts from IMH at a concentration of 600?g/mL showed the above effect.Two kinds of honey extract increased the expressions of antioxidant genes.Importantly,the mature rape honey extract has more potent inductive effects on the antioxidant genes in the cells damaged by oxidative stress.Our study showed that the mature rape honey had more abundant polyphenols and a better biological activity,which also laid a theoretical foundation for the quality standard and evaluation basis of the mature honey in the future.