Sorbitol is an edible sugar alcohol obtained by hydrogenation of glutinous rice by double enzyme saccharification into glucose. The saccharification conversion rate of sorbitol produced by the glutinous rice double enzymatic method is up to 97%, and 3% is not converted into glucose, such as maltose, oligosaccharide, maltodextrin, etc., and these sugars also react when the hydrogenation of glucose, therefore, Sorbitol produced by the double-enzymatic method of glutinous rice is not suitable for the production of vitamin C, but it is very suitable for food, toothpaste, cigarette and other industries.

First, glutinous rice starch process: glutinous rice → weighing purification → water immersion → rice rotten wet grinding → filtration → starch slurry.

Second, starch pulp sorbitol process: starch slurry → milking → liquefaction → enzyme digestion → saccharification → enzyme digestion → filtration → bleaching → filtration → ion exchange → evaporation → pH adjustment → hydrogenation → sedimentation → filtration → ion exchange → concentration → Finished product.

Third, the production operation process: weighed glutinous rice or broken rice, divided into hanging shovel, soaked in water, washed, ventilated with air compressor, rinsed for 20 to 30 minutes, after washing, dip rice for 2 hours, feel It is soft, brittle, and basically removes suspended matter and water-soluble impurities to start refining.

The rice is wet and ground. The key to refining is to master the fineness and concentration. According to the production experience, it is better to filter 60 mesh, and the milled pulp should be free of granular. Add 0.15% to 0.25% calcium chloride, adjust the pH to 6.5-6.7 with soda ash, and add 0.5-0.6 liters of high-temperature α-amylase per ton of dry matter. In the liquefaction, the liquefaction is carried out, and the liquefaction temperature is 102 to 105 ° C. The slurry is liquefied by heating and liquefying for 30 to 60 minutes to fully liquefy. The appearance of the liquefied liquid requires separation of the slag, that is, the sample is dripped, clear, and has a small viscosity. The temperature was raised to 120 ° C to kill the enzyme. The key to liquefaction is to initially hydrolyze rice starch to dextrin, reduce the viscosity, promote protein flocculation, produce no insoluble particles, and not aging. The liquefied pulp was cooled to about 60 ° C, 120 units/g of saccharifying enzyme was added, stirred, and kept for 32 to 40 hours. The saccharification was completed, and the temperature was raised to 80 ° C to inactivate the enzyme, and the temperature was kept for 20 minutes.

The saccharification solution is cooled to below 70 ° C, and filtration is started with a polypropylene plate frame filter press. The filtration pressure is 2 kgf/cm 2 , the filtrate is turbid and must be refluxed, and the protein is an amphoteric substance at a pH value near its isocratic point. It has the least solubility and can remove the protein from the rice and the added enzyme solution.

The filtered saccharified solution was heated to 60 ° C, activated carbon having a weight of 1% by weight, stirred and heated to 80 ° C, kept for half an hour, and allowed to stand for 15 to 20 minutes to carry out decolorization treatment. After decolorization, the sugar liquid should be colorless and transparent; the filtered liquid is pumped into the ion exchange column for separation and purification, the purpose is to remove inorganic salts, amino acids and ionic pigments in the sugar liquid, and the pH value is measured by a pH meter to control the leaving point.

Hydrogenation: The decolored and dissociated glucose is pumped into the high tank for storage, and then placed in a metering tank. The pH value is adjusted to 8 in the metering tank, the concentration is about 0.06%, and the concentration of the sugar solution is 20%. The amount of glucose added is about 2/3 of the volume of the reactor, and 10% to 15% of the catalyst active nickel is added. The air in the reactor is replaced with nitrogen, and the nitrogen in the reactor is replaced with hydrogen to ensure the space in the reactor. In a 99% pure hydrogen medium, the temperature was then raised to 140 °C. After warming up, it can be boosted to the required pressure. After the reaction temperature and pressure were reached, stirring and reaction were started, and hydrogen was continuously charged to stabilize the pressure at 4.5 MPa. After the reaction for 1 to 2 hours, the hydrogen gas is no longer absorbed. When the residual sugar of the reaction solution is below 0.5%, the reaction is finished, and the reaction is stopped for a while. When the temperature drops below 100 ° C, the sorbitol is used under the residual pressure in the kettle. The mixture was hydraulically discharged, filtered after 2 hours, and the precipitated and filtered catalyst was recycled. Sorbitol is precipitated by filtration and is in a clear, clear state, but also contains a small amount of nickel ions, which must be removed by ion exchange.

Ion exchange is carried out in an exchange column containing a cation exchange resin. Since the amount of cation exchange is large, the exchange of clarified sorbitol can be carried out multiple times. Check that the sorbitol solution flowing out of the exchange column does not contain nickel ions, and the iron ions are not more than 20 mg/kg. After clarifying that sorbitol is obtained from qualified sorbitol after leaving, it contains 500 g/L of alcohol and is concentrated to 700 g/L, which can be packaged and shipped.

Fourth, the main equipment and manufacturers of sorbitol production: the main equipment for the production of sorbitol are: 1 sand plate starch mill. Model MS60D, power 15 kW, produced by Ningbo Grain Machinery Factory, Zhejiang Province. 2BAS16/630-U reinforced polypropylene plate and frame filter. The filtration area is 16 m 2 and the manufacturer is Zhejiang Yongjia Anti-corrosion Filter Press Factory. 3 mashing pot. Self-made, lined with stainless steel sleeve, equipped with a stirring shaft and a serpentine heating coil, with a volume of 10 m3. 4 hydrogen reactor. Model 5—500TF, 5 of the model is designed pressure 5MPa, 500 is 500 liters, and produced by Guangzhou Heavy Machinery Factory, Guangzhou Autoclave Development Company.