The Formation Of Diglyceride Oleogels With Ethyl Cellulose As Gelator And Its Effect On Cake Quality

Traditional plastic fats can produce the saturated and trans fatty acids during hydrogenation processing,excessive intake of which adverse to human health.Oleogels are ideal substitutes for traditional plastic fats due to their low trans and saturated fatty acids.Currently,a large number of oleogel studies have mainly focused on the effects of factors such as the category of vegetable oil,the type and level of gelator,heating and cooling conditions on the physical properties of oleogels,and their potential applicability on various food products.However,there are relatively few reports on the impact of oil structure differences and interactions between components on the physicochemical properties of oleogels.Compared with triglyceride-based vegetable oils,diacylglycerol(DAG)lacks one fatty acid chain and is often used as a gelator to construct oleogels.However,there are few reports on the preparation of oleogels from soybean DAG cooking oil(SDO)with a purity of 80%(continuous phase).Therefore,the present study aimed to investigate the effect mechanism of oil type(soybean oil and SDO)on the physical properties of oleogels,while examining the viscosity and concentration of commonly used gelator ethyl cellulose(EC),the mass ratio of EC and antioxidantγ-oryzanol(GO)on the physical and chemical properties of SDO oleogels,and exploring its oxidation stability.Finally,the application potential of SDO oleogels in baked products was explored.The specific research contents and main conclusions are as follows:(1)SDO and soybean oil(SO)were used to prepare oleogels,the effect of oil type on the physical properties of oleogels and interactions between its components was investigated using a combined experimental and theoretical calculation method.The results of glyceride and fatty acid composition analysis of SO and SDO showed that triglyceride and DAG were the main components of SO and SDO,and their contents were94.36%and 81.84%,respectively.The contents of unsaturated fatty acids in SO and SDO were as high as 82.78%and 82.92%,respectively.They were similar in total fatty acid composition,but showed significant differences in glyceride composition.When 8%(mass fraction)EC was added to prepare SDO oleogel,the surface flow phenomenon occurred after the oleogel was inverted,indicating that the oleogel was not formed and was a sol.However,its oil binding capacity is strong,which is 96.60%.Adding the same quality of EC can form SO oleogels,and its oil binding capacity is low,which is 63.60%.SDO oleogel was successfully prepared,and the oil binding capacity(99.84%)and hardness(152.81 g)of SDO oleogel were significantly higher than those of soybean oleogel(70.44%)and hardness(15.10 g)when EC was 10%.In addition,interactions between the gel components were analyzed using density functional theory.Results showed that the binding energy of the triacylglycerol-EC complex(-61.70 k J/mol)was significantly lower than that of the DAG-EC complex(-55.32 k J/mol).The results of energy decomposition analysis based on the force field showed that the van der Waals interaction was the main contribution to the total interaction.In summary,relatively strong interactions between triacylglycerol and EC may decrease the interactions between gelators,leading to the relatively low strength of triacylglycerol oleogel.The results of the study are expected to provide a theoretical basis for the development of healthy oleogels products.(2)The effects of EC viscosity and concentration,EC/GO mass ratio on the physicochemical properties of SDO oleogels were studied,and the interaction and formation mechanism between gel components were further explored.The results showed that compared with the high viscosity EC45(45～55 m Pa·s),the SDO oleogels prepared by low viscosity EC18(18～22 m Pa·s)has higher binding capacity,hardness and gel strength.Moreover,the hardness and rheological properties of oleogels were negatively correlated to GO addition.When GO level increased to 4%,the hardness of SDO oleogel made with EC18 and EC45 was 48.91%and 76.91%of that of oleogels without GO,respectively.Therefore,molecular dynamic simulation was used to understand this effect of GO addition,showing that EC-GO complex had lower binding energy(-107.14 k J/mol)than the complexes of GO-DAG(-105.64 k J/mol)and EC-DAG(-101.96 k J/mol),leading to the disruption of the capacity of EC to structure SDO,resulting in the decrease of hardness and gel strength of SDO oleogels.In addition,the Fourier transform infrared spectroscopy and molecular dynamics simulation showed that intermolecular hydrogen bonding interactions gave little contribution to the formation of SDO oleogels made with EC.Interactions between the components were mainly governed by van der Waals interactions.The ester bond of DAG and the pyran ring of EC are involved in the formation of intermolecular hydrogen bonds,which is beneficial to improve the stability of GO-DAG,DAG-EC and GO-EC complexes.Compared with liquid oil,the peroxide value of the oleogels was lower and decreased with the increase of EC concentration,indicating that the oleogels with higher hardness had better oxidation stability.As the EC18/GO and EC45/GO mass ratio changed from 12:0 to 12:4,the peroxide value of the oleogels decreased by 1.89 mmol/kg and 2.53 mmol/kg,respectively,indicating good antioxidant activity of GO.Overall,the characteristics of SDO oleogels could be modulated by the addition of GO.The study may provide considerable potential to develop healthy and stable oleogels with high DAG,low saturated and trans-fatty acids for food industry.(3)SO and SDO were gelatinized by EC and as substitutes for traditional plastic fats in heavy oil cake.The physical properties and sensory characteristics of batter and heavy oil cake prepared with plant butter,animal butter,SO and SDO oleogels were compared.The results of the microstructure of the batter indicated that the SO and SDO oleogels batters have a higher quantity of dispersed bubbles,while the vegetable butter and animal butter batters have almost no bubbles.Moreover,the three oleogels cake exhibit low levels of baking loss,moisture content,and fat migration,staying below 5.50%,16.00%,and 14.00%,respectively.Among them,the SDO oleogel batter prepared with 12%EC shows the lowest baking loss rate,remaining below 13%during the storage period.Compared with plant and animal butter cakes,the specific volume of SDO oleogels cakes increased by 0.81 and 0.35 m L/g,and the volume increased by 75.98 and 66.43 cm~3respectively.The texture analysis reveals that the SDO oil-gelled batter prepared with 12%EC exhibits resistance to external forces and the ability to maintain the integrity of the cake’s interior.The sensory evaluation results showed that the overall acceptability of SDO oleogel cakes was little difference from that of animal butter cakes,but the score in flavor was only 84%of that of animal butter cakes.In conclusion,the SDO oil-gelled batter prepared with 12%EC holds promise as a potential substitute for fats.