Rapid Determination Of Fumaric Acid In Apple Juice Concentrated With Near-Infrared Spectroscopy

The process conditions of extracting fumaric acid from apple juice concentrated with macro porous resin and ion change cartridge is studied; then we establish a mathematical prediction model of fumaric acid extracted with FT - NIR spectrometry for rapid determination. The main contributions of this thesis are as follows:The properties of static and dynamic adsorption and desorption of macro porous resin for fumaric acid were investigated. The D-296R resin was selected to purify fumaric acid. The effects of concentration, pH and work speed of the infusion on the adsorption of the D-296R resin were studied with static experiment. An orthogonal design was used for adsorption technology: the temperature is 30℃,the pH is 3.0,the concentration is 1 mg/ml,the flow velocity is 1 BV/h。;Desorption technology of studied with : The distilled water with 8 volumes of macro porous resin is used for washing impurity, 80% alcohol with the flow velocity of 1BV/h for washing fumaric acid out.The different parameters which affected the extraction procedure were studied and optimized to establish the optimal conditions for maximum recovery of fumaric acid and minimum extraction of interferences. The optimized procedure used a cartridge which was activated with 4 ml of 0.1 M sodium hydroxide solution. A 25 ml volume of apple juice solution (pH=7.0) was passed at a flow-rate. The cartridge was washed with 4 ml of water and fumaric acid was eluted with 1.5 ml of 0.1 M sulfuric acid. This solution was injected directly into the chromatograph. The recovery of juice sample was satisfactory and ranged from 60.8 to 79.4%.Near infrared reflectance spectroscopy has advantages of rapid determination, non-destruction, non-polluting and low cost. In the work, a mathematical prediction model of fumaric acid in apple juice concentrated with FT - NIR spectrometry was established. The determination coefficient ( R~2) of the model was97.53 and its root mean square error(RMSE) was 0.00416 in cross validation , and the average relative standard deviation between predicted value and measured value is 8.65%. This method was simple, rapid and accurate , it could be used to determine fumaric acid in apple juice concentrated.