In the food industry, pectin is an important raw material for the production of jams, jellies, and confectionery. It is widely used as an emulsifier and stabilizer in other light industries. It is used as a base for ointments in medicine and has a wide range of uses. The content of pectin in citrus peel accounts for about 1.5% to 3.0% of fresh skin. General extraction methods include peel treatment and pectin extraction. The extraction of essential oil residue is a good raw material for pectin. The following describes the extraction method of pectin. Peel processing. The orange peel residue after the extraction of essence will be soaked in water and rinsed continuously until the water does not contain sugar and glycogen, and the water is squeezed for use. The rinsing peel cannot be carried out in time, and a heat treatment is first performed during the leaching process, ie, the peel slag is heated to 95-97° C. for about 10 minutes to passivate the pectinase. After the heat treatment, the water was impregnated twice, squeezed to remove water, dried, stored, and kept dry until pectin was extracted. Rubber. The orange peel treated above was poured into the extraction pot, about 5 times of water was added, and the pH was adjusted to 1.8-2.7 by adding sulfite. After steaming, the mixture was heated to 87-90°C with stirring and held for about 2 hours to extract most of the pectin. Separated. The extracted material was filtered through a filter press while hot. Add 1.5% to 2% of activated carbon to the filtrate, keep the temperature at 80°C, filter press after 20 minutes, and achieve the purpose of decolorization. If the filtrate has a high viscosity and is difficult to be filtered, 1% to 4% of diatomaceous earth can be added to stir and repress. concentrate. The filtered pectin was sent to a scraped film evaporator for concentration. The pectin solution has a short heating time and a low temperature, allowing continuous operation. The degree of concentration should not be too high, so as to prevent the pectin from being precipitated to produce "bulk" lumps that are not easy to wash and are difficult to crush after drying. Therefore, the concentration of the concentrate should be controlled at about 4%. dry. In order to facilitate the preservation of the transportation, the water in the pectin must be removed to make a powder. Drying methods include spray drying, solvent precipitation, and aluminum salt precipitation. Spray drying method. The above-mentioned concentrated liquid was sprayed into the drying chamber through a high pressure spray head, and the room temperature was maintained at 120-150°C. After the pectin mist contacts the hot air, it instantly dries into fine powder and falls to the bottom of the drying chamber. And by the screw conveyor to the packaging workshop. Solvent precipitation method. The concentrate is added to the alcohol, while stirring, and the alcohol concentration of the mixture may be 45% to 50%. At this point the pectin is essentially completely precipitated. The precipitated pectin was washed with 80% alcohol to remove alcohol-soluble impurities. Then use 95% alcohol to dehydrate, lay a thin layer at 65-75°C and dry it to a moisture content of less than 8%, and then pectin. Aluminum salt precipitation method. The concentrated solution was slowly added with stirring to a dilute solution of aluminum sulfate, followed by adjusting the pH to 3.8-4.2 with sodium hydroxide and precipitated together with pectin to form a yellow-green, solid gel. Then remove the water and wash off excess mother liquor with cold water. After pressure filtration, aluminum hydroxide, a pectin precipitate, is washed with 10% hydrochloric acid and 70% alcohol to convert aluminum hydroxide to alumina and dissolve in alcohol, followed by 75% alkaline alcohol. Wash away hydrochloric acid. Then dehydrate with absolute alcohol. The pressure-filtered wet pectin is dried to a moisture content of 7% to 10% and the pectin can be crushed. package. The pectin was sieved through a 60-mesh sieve, packed in an airtight container, sealed and stored in a cool, dry place.