Research On Physicochemical Properties Of Coconut Oil-based Diacylglycerol And Its Application In Non-dairy Creamer

Coconut oil-based diacylglycerol(CO-DAG)prepared from coconut oil(CO)can significantly reduce serum triacylglycerol content and the level of fat synthesis-related enzymes,thereby inhibiting the accumulation of fat and improving lipid metabolism.However,researches on the physicochemical properties of CO-DAG and its application in food were limited.In this study,the acylglycerol composition,fatty acid composition,melting point,solid fat content,crystallization and melting curve,rheological properties and crystal form of CODAG were investigated systematically.Results showed the content of DAG had a significant effect on the physicochemical properties of CO-DAG.CO-DAG with more than 50% DAG has similar solid characteristics like hydrogenated vegetable oil.Using CO-DAG to replace hydrogenated vegetable oil in non-dairy creamers,could avoid the problem of high trans-fatty acid and saturated fatty acid content.Based on that,this study explored the preparation technology of CO-DAG non-dairy creamer,and investigated the characterization of CO-DAG non-dairy creamer and its application in black coffee,providing scientific reference for industrial application of CO-DAG.The results are as follows:1.Study on physicochemical properties of coconut oil-based diacylglycerolThe substance basis and physicochemical properties of CO-DAG were investigated systematically.The results showed lauric acid(46～49%)was the main fatty acid of the four CO-DAG samples,and the DAG content was 31.05%,51.40%,70.49%,and 90.18%,respectively.The melting point,solid fat content,crystallization and melting curve,rheological properties and crystal form between CO-DAG and CO were significantly different(p<0.05).With the increase of DAG content,the melting point of CO-DAG increased from 24.8°C to38.8°C,and the solid fat content at the same temperature also increased significantly(p<0.05).The melting peak of the DSC curve moved to higher temperature(peak temperature increased from 23.55°C to 38.08°C).Investigating the rheological properties found that higher the DAG content,the more significant the solid characteristics of CO-DAG.In addition,the main crystal form of CO-DAG was β-type,and it also contained some β’-type crystals,and the diffraction peak intensity of β’ crystal form was enhanced,with the increase of DAG content.2.Study on the preparation technology of non-dairy creamer using CO-DAGWith CO-DAG as the core material,the screening of wall material and the preparation of non-dairy creamer were investigated.Compared with the oil used in commercial non-dairy creamers,the melting point of CO-DAG contained 50%DAG was the most suitable for preparing non-dairy creamer.According to the results of emulsion stability,entrapment rate and scanning electron microscope,isomalto-oligosaccharides and sodium caseinate were chose as wall materials.Based on the single-factor experimental results,a response surface experimental design was carried out,the addition of sodium caseinate,wall-to-core ratio,and solid content were selected as independent variables,and the embedding rate was the response value.Results indicated that the wall-to-core ratio had the greatest effect on the entrapment rate of CO-DAG non-dairy creamer.The optimal preparation parameters of CO-DAG non-dairy creamer were:the addition of sodium caseinate was 4.20%,the wall-to-core ratio was 2.2:1,and the solid content was 32%.The entrapment rate of CO-DAG non-dairy creamer prepared under optimal conditions was 92.74%.3.Characterization of CO-DAG non-dairy creamer and its application in black coffeeTaking commercial non-dairy creamer as comparison,the properties of CO-DAG nondairy creamer were characterized,and its practical application effect in black coffee was evaluated.The water content of CO-DAG non-dairy creamer was less than 2%,the solubility and wettability were good,and the particles were complete and regular spherical without obvious cracks or breakage.Thermogravimetric analysis showed that the mass loss of CO-DAG non-dairy creamer before 280°C was lower(21.12%)than that of commercial non-dairy creamer 2(25.60%),indicating that it had better thermal stability.After 12 weeks of storage at25°C,the embedding rate of CO-DAG non-dairy creamer remained above 90%.The average particle size of CO-DAG non-dairy creamer reconstituted milk was 0.42 μm,and the particle size span was significantly smaller than that of commercial non-dairy creamer(p<0.05),which meant a better stability.Furthermore,when the CO-DAG non-dairy creamer was applied to black coffee,the whiteness index of the coffee increased from 33.07 to 54.20,which was higher than that of the coffee with commercial non-dairy creamer 2(50.22),demonstrating that CODAG non-dairy creamer had a good whitening effect.