Study On Preparation Of Food Additive Pectin And Functional Food Materials Edible Fiber And Hemicellulose Using Apple Pomace

Process condition for preparation of both food additive pectin by salting out method and functional hemicellulose and edible fiber by alkali reaction were studied systematically using apple pomace as the raw material. In addition the elementary toxicological experiments of hemicellulose were also tested in this dissertation. This work has provided "the foundation for application of apple pomace synthetically to achieve transformations of commercial waste solid apple pomace into valuable and reduce the pollution.The optimal hydrolytic process conditions of pectin were determined firstly. Then, influence of process parameters, such as variety and dosage of salts, the pH, salting out time and temperature, dosage of hydrochloric acid and de-salting solution, de-salting time and temperature, concentration of ethanol, temperature and pH of de-colorization on the yield of pectin were carried out. The process parameters of preparation for functional hemicellulose including solid-liquid ratio, concentration of sodium hydroxide, reaction time and temperature were also discussed. Moreover, effects of concentration of alkali solution, de-colouring pH, concentration of hydro peroxide, de-colouring time and temperature on both the yield of edible fiber and dosage of hemicellulose were investigated. The elementary toxicological experiments, which provided the foundation for further scale-up and application of apple pomace synthetically, were confirmed using some part of products.The optimal process conditions for preparation of pectin, which observed from experimental results, are as follows: hydrolysis at 85℃,pH 2.0 for 2.0 hours, solid-liquid ratio is 1:10g/ml; as aluminum sulfate used as the salt, the salting out pH is in range of 5 to 7 and dosage of it is 5 ml at 60℃ for 60-75mins; the dosage of de-salting solution is 300 ml, dosage of hydrochloric acid is 3% and de-salting time is about 30-45 mins; thede-colouring temperature for pectin is at room temperature, pH is between 7 and 8, and concentration of ethanol is above 50%.The optimal process conditions for preparation of hemicellulose are: concentration of alkali solution is 1.5mol/L, reacting temperature is 75C, reacting time is 3.0 hours, solid-liquid ratio is 1 : 10g/ml.The optimal process conditions for preparation of edible fiber from apple pomace are:react at room temperature, concentration of alkali solution is 0.5-1.0mol/L for 2-4 hours; and optimal de-colouring conditions are:pH is at 10.0, concentration of hydro peroxide is 5%, reaction temperature is 40C for 2.0 hours. The urgent toxicological experiments of hemicellulose show that the product is nontoxic and safety with LD50 above 15,000mg/kg.DENG HONG(Chemical Engineering) Supervised by Professor SONG JI rong...