Study On The Determination Of Carbohydrates In Rape Honey And High Fructose Syrup

Honey is a natural nourishment and health products,however it is constantly subjected to adulteration with inexpensive sweeteners,predominately high fructose syrup,which is difficult to detect.Therefore,resolving the honey quality and monitoring the safety of honey products requires an accurate detection methodical system designed to detect the adulteration of high fructose syrup.This thesis is based on the study of rape honey and high fructose syrup,by detecting of carbohydrate constituents in both experiment objectives.The main results were listed as followed:(1)Established the HPLC-RI method by referring to Chinese national standards to detect the main carbohydrates in honey and high fructose syrup.Using this method,the LOD of fructose and glucose of honey major carbohydrate were 0.263 g/100 mL,0.061 g/100 mL,respectively,and the LOD of sucrose and maltose of micro-carbohydrate were 0.124 g/100 mL and 0.147 g/100 mL.(2)There were 36 types of rape honey and one kind of high fructose syrup detected by using the above method.The results showed that the contents of fructose,glucose,sucrose and maltose were 26.00~38.16 g/100 g,23.65~39.68 g/100 g,0.14~0.62 g/100 g and 1.09~3.10 g/100 g,respectively.The contents of fructose,glucose and maltose in high fructose syrup were 36.62 g/100 g,31.75 g/100 g and 0.23 g/100 g,respectively,and no sucrose was detected.(3)Research compared the homology of 26 S rDNA sequence and structured the phylogenetic tree,four yeasts were identified: Zygosaccharomyces microellipsoides,Schizosaccharomyces malidevoans,Saccharomycodes ludwigii and Wickerhamia fluorescens.By studying of the fermentation curve,the fermentation conditions of rape honey and high fructose syrup by these 4 types of yeast were determined.Wickerhamia fluorescens has the highest fermentation efficiency in fermenting the major carbohydrates in rape honey and high fructose syrup.Rape honey and high fructose syrup were enriched into twentieth of national standards method after fermentation and freeze-drying,and the concentration of micro-carbohydrates in rape honey and high fructose syrup were improved significantly.(4)The method for detecting micro-carbohydrates in honey and high fructose syrup was established.Chromatographic column was Waters carbohydrate high performance column.Mobile phase was acetonitrile and ultrapure water,the proportion of acetonitrile was 90%.Flow velocity was 1.2 mL/min.The temperature of column and detector were 25°C and 35°C.The sample size was 10 ?L.Maltose was used as a benchmark to study the reliability of detecting the contents of micro-carbohydrates in honey and high fructose syrup by optimized HPLC-RI method.The results showed that the recovery rate of maltose was between 98% ~ 102% after fermentation and concentration,the RSD was less than 1.02%,and the LOD was 0.080 g/100 mL.(5)Using maltose as a benchmark,both the traditional national standards method and the developed analytical method(combined fermentation with HPLC-RI)were used to detect micro-carbohydrates in honey and high fructose syrup.And the results showed that the concentration range of maltose of rape honey increased from 0.055~0.155 g/100 mL to 1.24~3.27 g/100 mL;the concentration of maltose in high fructose syrup increased from 0.011 g/100 mL to 0.28 g/100 mL.There was a significant difference in maltose concentration between rape honey and high fructose syrup.Simulated the actual adulteration by adding the high fructose syrup into rape honey,under the traditional method,the maximum deliberate adulteration portion of high fructose syrup without being detected was 10%,and the developed analytical method allowed detection sensitivity of adulteration at a 5% level.In conclusion,this thesis established an efficient fermentation method for concentrating micro-carbohydrates of honey and high fructose syrup.Meanwhile,the HPLC-RI conditions were also been optimized.It improved the detection sensitivity of micro-carbohydrates in honey and high fructose syrup,and provided an alternative thinking and new approach for detection of the adulteration of high fructose syrup.