The invention relates to a process for removing the sour taste of sucralose
Sucralose, a kind of sucrose, is a new type of sweetener.Its sweetness is 600 times that of sucrose, and it has the advantages of pure sweetness, no heat, safety and non-toxicity [1-2].Its chemical name is 4,1 ‘, 6 ‘-trichloro-4, 1’, 6 ‘-trideoxygalactose, its chemical structure is shown in figure 1.The synthesis method of sucralose is provided in many literatures and patents. In all synthesis methods, the last step of synthesis is deacylation reaction, and then the crystallization of sucralose is purified.In all the literature and patents, we can know, sucralose crystallization method is commonly after take off the acetoxylation, to remove the methanol solution of sucralose are sucralose crude products, and then water as solvent, active carbon decoloring, again make sucralose recrystallization, mother liquor circulation into the next batch of products need decoloring [3, 4],It is mentioned in zilibuli CN101210034A and CN101260126A that two different organic solvents are used as recrystallization solvents, and the crystallization of sucralose is made in the process of decompression recovery of one of the solvents [5,6].Figure 1 Chemical structure of sucralose The above methods inevitably have some disadvantages: single water as solvent, long crystallization time, low yield;High water content reduces the shelf life of the product;Using two organic solvents as solvents, solvent recovery and separation is difficult, the cost is high, and the mother liquor will become acidic with the increase of the number of cycles, ultimately leading to the quality of the product decline, in the above method, did not consider the recovery of crystal mother liquor, resulting in the waste of products in the mother liquor.Therefore, this paper focuses on improving the recrystallization method of sucralose, so that the obtained sucralose has better stability and will not produce acidic odor in the process of preservation.1 test part 1. 1 Reagents and instrument reagents are chemically or analytically pure;Sucralose crude: homemade.Phb-3 pH meter, 85-1B stirrer, DL-120J ultrasonic vibrator, DHG-9030A oven, dryer.1.2 Test Method 1.2.1 Influence of concentration of mixed Solvent on product stability Without adding any buffer, the crude product of sucralose was recrystallized by adding different concentrations of ethanol/water mixed solvent, and the prepared product was to be tested.1.2.2 Influence of concentration of Buffering agent in crystallization mother liquor on product stability Adding different amounts of buffering agent in crystallization mother liquor of sucralose, after stirring crystallization to prepare multiple batches of sucralose products to be tested.1.2.3 Influence of water content of sucralose products on its stability Through the test under the condition of different water content, multiple batches of sucralose products were prepared to test the influence of its stability.The water content of the product was determined by drying and weight loss method.1.2.4 pH stability test take about 100mL of deionizing water, adjust pH to 5.8 ~ 6.0 with 0.1 n salt acid or 0.1 n sodium hydroxide, and record the pH reading.Accurately weigh 10 ± 0.001g of the sample to be tested, and use pH adjusted deionized water to a constant volume of 100mL. After ultrasonic shock solution, measure pH and record.The pH of water is adjusted to subtract the pH of sample solution. If the result is ≤ -1. 0, the sample is regarded as unqualified .1. 2. 5 stability test of the sample under test to test the stability of each batch of products, aluminum foil bags and sealing treatment, then put the samples in the dryer, record the sample time is put in the dryer, every 24 h, drawn from the aluminum foil bag samples for pH stability test, until they are testing a batch of qualified samples inspection department,Record the time of nonconformity.1.2.6 Moisture determination The water content was measured by karl-Fischer method.Take a certain amount of methanol on the reactor volume, Karl fischer reagent titration amount methanol water trace water volume, titration to the pointer with the calibration fairly and keep at constant 1 min, open the inlet, adding said good sample immediately, epithelial plug plug stirring, Karl fischer reagent titration end to keep unchanged for 1 min, record consumption volume.Water content = FV/W Where: F is the water equivalent of Karl Fischer’s reagent, mg/ml;V is the Karl Fischer reagent consumed by titration, m L;W is the sample mass, g.Results and Discussion 2.1 Influence of mixed solvent concentration on product stability Under different concentrations of ethanol/water, the product stability results are shown in Figure 2.It can be seen from Figure 2 that the stability of the product increases with the increase of the concentration of ethanol/aqueous solvent. When the concentration of ethanol/aqueous solution reaches 50%, the stability of the product shows little trend of increase. In addition, as the concentration of ethanol/aqueous solution increases, the yield of recrystallization of the product decreases.At the same time, the concentration of ethanol/aqueous solution is shown in FIG. 2. The influence of different concentrations of alcohol/aqueous solvent on the stability of the product increases, leading to the increase in the amount of ethanol and cost. Therefore, 40% ~ 50% ethanol/aqueous solution is the best choice.2. 2 the crystallization of the buffer in the mother liquor concentration effect on the stability of the product due to the constant to paraphrase of the crystallization mother liquor, can make the products slowly produces acid smell, so at the time of crystallization mother liquor applied, using a buffer can avoid repeated crystallization mother liquor to paraphrase, make the products produced by acid smell, and in order to not introduce new material in the product,We chose sodium acetate as the buffer.The influence of buffer concentration on product stability is shown in Figure 3.It can be seen from Figure 3 that the stability of the product increases with the increase of the concentration of the buffer, but when the concentration of the buffer is greater than 50mg /kg, the stability of the product decreases. Therefore, when the dosage of sodium acetate of the buffer is 50mg /kg, the stability of the product is the best.And none of the tests produced any acidic gases.2.3 Influence of water content on the stability of sucralose The influence of water content on the stability of sucralose is shown in Figure 4.As can be seen from Figure 4, the stability of sucralose products is directly proportional to water content. When the water content of the product is about 0.8%, the stability of the product is the best; when the water content is more than 0.8%, the stability of the product has a downward trend.3 Conclusion It can be seen from the above results that in the crystallization process of sucralose, when 40% ~ 50% ethanol/aqueous solution is used, and then in each batch of crystallization mother liquor, adding the buffer sodium acetate content of 50mg/kg, the stability of sucralose is very good, and under this condition,The product will not produce acidic odor in the preservation process, and control the water content of the product at about 0. 8%, which can better improve the stability of the product when it is preserved.