Study On Extraction Of Pectin From Lemon Peel

As a complicated carbohydrate of high molecular weight, pectin is contained in cell walls of many plants. Now pectin shows a great effect in food , medication, fine chemicals and papermaking. With the development of medication and light industry, pectin must get more and more applications. But the research level of pectin extraction and its commercial production in china is still in the beginning stage, the quality and quantity of pectin is very low, it can't content the need of many industry in china, so pectin relies on import from abroad. There are a number of lemons in china,because lemon peel has a great of pectin, we can extract pectin from it.The important research of task is extraction on pectin, for improve the ratio of extraction, the extraction can have two steps: (1) break the cell -wall of lemon peel; (2) extraction of pectin from lemon peel.Ultrasonic was applied for cell-wall-breaking.In the course of extraction, two method was adopted to extract pectin—extraction by acid and extraction by acid with colophony.During the cell-wall-breaking process, three factors including the power of ultrasonic, the time of ultrasonic and the ratio of liquid to solid were studied by single factor analysis method. At last, through orthogonal experimentation, the optimal conditions of cell-wall-breaking were obtained as follows: the power of ultrasonic is 500 W, the time of ultrasonic is 9min, the ratio of liquid to solid is 25:1.During extraction by acid process, four factors including the sort of solvent, pH, temperature of extraction, time of extraction were studied by single factor analysis method. At last, through orthogonal experimentation, the optimal conditions of extraction were obtained as follows: the solvent is oxalic acid, pH is 2.0, temperature of extraction is 80℃, time of extraction is 80min. We knew that the sort of solvent hadn't much effect to extraction by orthogonal experimentation, and consided the result of single factor experimentation, so we decided that during extraction process by acid with colophony, the oxalic acid was used as solvent and four factors including the concent of colophony, pH, temperature of extraction, time of extraction were studied by single factor analysis method. At last, through orthogonal experimentation, the optimal conditions of extraction were obtained as follows: the solvent is oxalic acid, the concent of colophoony is 10%, pH is 1.5, temperature of extraction is 90℃, time of extraction is 80min.Through contrast the pectin concent in liquid of extraction with two ways, the best way is extraction by acid with colophony. It can improve the effect of extraction,so applied in industry, it will have great economical and social benefits.