Analysis Of Volatile Components And Identification Of Main Aroma Components In Four Kinds Of Bee Products

As four main bee products,honey,royal jelly,bee pollen and propolis possess special natural fragrance with high edible,marketable and commercial value.However,the volatile substances and main characteristic aroma components of bee products are different among various nectar sources.In this study,a method for volatile components analysis of four main bee products was established.Then,the volatile substances and main characteristic aroma components were identified by GC-MS and GC-MS-O,which provided theoretical basis for the quality identification of bee products.The contents and results of study are as follows:1.A comparative study on three extraction methods including headspace solid phase microextraction(HS-SPME),freezing solvent extraction and direct headspace injection has been carried out.The results showed that HS-SPME was the best extraction method.By optimizing extraction conditions,the best extraction parameters were obtained as follows:extraction head of 65 μm PDMS/DVB,extraction temperature of 60℃,extraction time of60 min,the sample mass of honey and royal jelly of 8 g,and the sample amount of bee pollen and propolis of 4g.2.By analyzing the GC-MS results of four bee products(honey,royal jelly,bee pollen and propolis),a total of 326 volatile compounds were identified,including alcohols,aldehydes,ketones,esters,phenolic acids,thioethers and other compounds.The thioether compounds were detected only in litchi and schisandra fruit honey.The content of esters in rape nectar was up to 42%,which was more than other honey sources.Phenylacetaldehyde was detected in all honey samples with the highest relative content of 20.10%,but not detected in other bee products.The volatile components of 12 different kinds of honey sources such as rape nectar,schisandra honey and acacia honey were different.The highest relative content of phenolic acid compounds in Vetch honey was 81.97%;the highest relative content of alcohol compounds in litchi honey was 77.68%;the highest relative content of aldehyde compounds in Schisandra honey was 52.24%;the relative content of ester compounds in rape nectar was 42.30%.Phenylethyl alcohol and capric acid were detected in royal jelly,bee pollen and rape nectar from rape nectar.3.By analyzing the GC-MS-O results of four bee products(honey,royal jelly,bee pollen and propolis),,there were 64 kinds of characteristic aroma components,including13 kinds of alcohols,11 kinds of aldehydes,19 kinds of esters,and 10 kinds of ketones,7kinds of phenolic acids,4 others kinds of compounds.The characteristic aroma components of the four bee products could be classified into four categories,namely aromatic,cream,sweet and refreshing and stimulating.By comparing the radar charts of the four bee products,the characteristic aromas of the bee products are quite different.The creamy and aromatic taste of royal jelly occupies the main flavor,and the aroma intensity of other odors is relatively small.Bee pollen has a strong aroma and creamy taste.Propolis has the refreshing flavor of Chinese herbal medicine,and the aroma characteristics of propolis are consistent with its botanical sources of acacia,rape,and citrus.litchi honey and gall honey have an aroma of aging and creamy taste.The aroma of Chinese gallic honey presents a thick and slightly sweet aroma.