Preparation And Properties Of Compound Emulsifier Based On Transesterification Of Sucrose And Hydrogenated Vegetable Oil

Sucrose fatty acid ester（Sucrose ester）,is a non-ionic surfactant that can be used as an emulsifier,a foaming agent,an antibacterial agent,a fresh-keeping water-holding agent,and the like.Sucrose esters are low-toxic,odorless,low-irritant,and easily biodegradable,so they are widely used in the food industry.In industry,N,N-dimethylformamide（DMF）or dimethyl sulfoxide（DMSO）is most often used as a solvent to produce sucrose ester.This method has a fast synthesis rate and a high degree of esterification.But the solvent has high toxicity and boiling point,and can be hardly removed which will bring safety hazards to food applications.Glycerides are also non-toxic,non-ionic surfactants used in the food industry as emulsifiers or thickeners.Due to the great difference in polarity between sucrose esters and glycerides,there is a lack of rapid and accurate qualitative and quantitative analysis methods for sucrose esters and glycerides in substances.In addition,the typical commercial surfactants on the market are all single substances.However the effect of compound use of different surfactants is often better than that of a single surfactant.This research uses cheap and readily available sucrose and hydrogenated palm oil as a reaction raw materials to solve these problems.The solvent-free method which conforms to the direction of non-toxic and low-cost green chemical synthesis,was used to synthesize compound emulsifiers containing both sucrose esters and glycerides.The main research results are as follows:（1）Developed a simultaneous,accurate and quickly quantitatively detection method to analyze sucrose esters and glycerides:Ultra Performance Convergence Chromatography-Mass Spectrometry（UPC²-MS）.We compared commercially available sucrose esters and glycerides with the contens given by the merchants by UPC²-MS.The results showed the accuracy and effectiveness of this method.The advantages of this method are as follows:（1）UPC²-MS provides a standard multifunctional ionization source,which facilitates the screening of target ions,effectively improves the efficiency of method development,and improves the accuracy of test results;（2）The method can simultaneously detect sucrose esters and glycerides,and is one of the fastest and most accurate method for simultaneous measuring sucrose esters and glycerides on the market.It not only improves the efficiency of the experiment but also provides a method for detecting substances with large differences in polarity;（3）UPC²-MS uses CO₂with low toxicity and good economy as a solvent,which is more in line with the development concept of green chemistry.（2）The compound emulsifier was synthesized using sucrose and hydrogenated palm oil as the reaction raw materials.The solvent-free method was used as the reaction method,and the monoester content was increased through a series of purification operations.The optimal reaction conditions were determined by single factor experiments:the catalyst was selected as a basic catalyst K₂CO₃/KOH（1:2,mol/mol）,and the dosage was 10 wt%of the total mass of the reaction raw materials.,the surfactant selects potassium stearate,and the consumption is 10 wt%of the total mass of the reaction raw materials,and the reaction is carried out at 135°C for 3.5 h.The maximum content of sucrose monoester in the compound emulsifier obtained under this condition is 23.42%,comparable to that of S-570 produced by Mitsubishi,Japan.The content of sucrose esters is similar;the highest content of monoglycerides is 35.69%.（3）Comparing the surface properties,foaming properties and emulsifying properties of the prepared emulsions of the compound emulsifier obtained by the solvent-free method using cheap raw materials sucrose and hydrogenated palm oil and the commercially available sucrose ester products.There is no obvious difference surface tension,and the CMC of the sample performs better than the selected product.In addition,the foaming performance and foaming stability of the compound emulsifier is much higher than that of the chosen commercial product.Compared with the commercial products,the emulsion made by the compound emulsifier has a smaller particle size and a longer shelf life.At the same time,it has better stability under different temperatures,p H and ionic strength.These research results show that the use of cheap sucrose and hydrogenated palm oil as raw materials for the reaction.The use of a solvent-free method is expected to replace the traditional commercially available sucrose esters with the same monoester content.Our study could provide a valuable guidance for the development of non-ionic surfactants in food industry.