Study On Countercurrent Extraction And Extraction Kinetics Of Pectin From Orange Peel

Pectin, as polysaccharides with a high-molecular weight, is widely contained in tissues of many plants. It has better gelatification, stabilization and emulsification, is widely used in foodstuff industry and is an indispensably adjuvant in pharmacy and chemical industry. The marketing requirement of pectin is large both home and abroad. Though research on pectin and commercial production abroad has developed greatly, pectin production in China is still in the beginning stage, and the neediness of industrial pectin relies on import from abroad. Because Traditional technology which uses more ethanol costs higher and the equipments are behindhand, the production of pectin is restrained. At present, our orange manufactures mostly use its pulp, orange peel is discarded as rubbish. Obviously, this situation leads to serious environmental pollution and makes a great waste of social resource. Therefore, adopting advanced technology to extract pectin from orange peel will has great marketing competence.The main tasks of this paper are as follows:(1) Using orange peel as material, batch extraction method, step extraction method and simulated countercurrent extraction method are adopted to extract pectin, and makes some ameliorates due to problems come from simulated countercurrent extraction. The result shows: step extraction method is best, improved simulated countercurrent extraction method takes second place, batch extraction method is worst.(2)Countercurrent extraction method is adopted to study the effect of pH, liquor-solid ratio, extraction time and extraction temperature on extraction content of pectin By means of orthogonal experiments, the optimal conditions of countercurrent extraction method are obtained as follows: pH is 2.0, liquor-solid ratio is 20, extraction time is 50min, and extraction temperature is 80℃.(3)According to the kinetics models which were established on the basis of Fick' first law, the extraction kinetics models for pectin of orange peel are established. The relationships between concentration of pectin and extraction time, size of particle, liquor-solid ratio and extraction temperature are obtained. And the models are validated by means of extraction experiment. The result shows: The relationships between lnC and lnt, lnC and lnσ, lnC and lnM, lnC and 1/T are linear. The result is in accordance with kinetics models. The kinetics models can preferably describe the relationships between concentration of pectin and extraction time, size of particle, liquor-solid ratio and extraction temperature.Using orange peel as material to extract pectin not only provide application foundation but also resolve the lack problem of pectin, it give birth to profound economic, social and ecological significances.