Studies On Extracting Naringin, Pectin And Limonoids From Pomelo Peel And Pomelo Seed

Many bioactive constituents abound in pomelo peel and pomelo seed, such as naringin and pectin and limonoids, could promote health and prevent disease to human's body, which led to high economic values of pomelo. This dissertation based on the extraction of pectin and naringin and limonoids from pomelo peel and pomelo seed, could be divided into the three parts:Firstly, tartaric acid aqueous extraction system was used, pectin yield as the main evaluation indicators, and the best technical conditions were obtained through orthogonal design L₁₆ (4⁵). The weight ratio of tartaric acid aqueous solution and pomelo peel was 15:1, extraction solution of tartaric acid was controlled at pH 1.5, extraction temperature was 90℃, and extraction time was 60min. Under the best conditions, the average yield of pectin was up to 18.73%, the quality of pectin was better, which showed higher technical advantages than the reported.Secondly, a new technology of extraction of naringin from pomelo peel was explored with the application of ultrasonic reactor. The chemical investigation on pomelo peel has led to the isolation of naringin in higher yield rate from 1.44 percent to 2.32 percent and shorter reaction time from 3h to 30min, which was confirmed by IR and ¹H NMR, The optimum extraction conditions are determined by orthogonal design method as follows: extraction temperature was 25℃, extraction time was 30 min, the weight ratio of saturated Ca(OH)₂ solution and orange peel was 4:1, and the frequency of ultrasonic reactor is 25 KHz. The average yield of naringin are 1.82% in triple experiments (1.58 times more than normal extraction method).Thirdly, the technology of the extraction, isolation and purification of limonoids in pemelo seeds was explored in this part. After defatted sufficiently, pemelo seeds were extracted continuously with acetone. The extracted mixture was isolated by double-solvent recrystallization to yield two lemonoids, limonin and nomilin. The chemical structures of limonin was verified by IR, NMR and MS. The method is simple and applicable, low-cost and high-yield, and practical.